DATE: 5/13/98 STATUS: GO (12:30 PM departure) EQUIPMENT STATUS: Mobile Mesonets: Finished. FC vehicle has a faulty "Low Oil Level" indicator which will be repaired during the next down period. DOWS: Ready. Josh arrives at OKC during noon hour. UMASS Radar: down indefinitely Rockets: NOT READY Turtles: operational RALPH: operational NOAA P-3: Arrives this weekend SYNOPSIS: Strong upper trof over W US moving eastward. The Plains are presently under an upper ridge with weak flow aloft. Low-level Gulf moisture is increasing. DAY 1 FORECAST: As the upper systems progress eastward, mid-tropospheric flow increases to levels supportive of supercells in the High Plains. Upper-tropopsheric storm-relative flow will be quite weak. Therefore, supercells are expected to be HP if they form. Strong pressure falls in eastern CO will lead to increasing SSE-SE surface winds in the High Plains from SW KS to the TX South Plains, and the advection of higher dewpoints westward. CAPE will be high (> 2500 J/kg) and CIN will be reduced to small values by evening. We expect 50-65% probability of convection in the target area (NE TX Panhandle to DDC). We expect a 40% conditional probability of supercells given convection (HP type). Owing to the weak upper flow but decent low-level shear, we expect brief low-level mesocyclone formation, but any tornadoes should be short-lived followed by big gushes of rainy downdraft. Poetic. We estimate the conditional probability of tornadoes given supercells at 10-20%. Our tentative target: the escarpment in the NE TX Panhandle where terrain uplift will be best. Erik's pick: Spearman Paul's pick: Booker DAY 2 FORECAST: We have not yet seen numerical guidance valid for tomorrow evening. However, it appears that strong, difluent upper flow will spread across the plains tomorrow, with a sharp dryline from W KS to W OK to SW TX. CAPE will be large. We expect targetable dryline supercells. The best turning in the wind profile should be to our southwest. Operations are expected. DAY n FORECAST: (Friday) The first shortwave will be lifting NE toward the Great Lakes with a new shortwave dropping into the W US trof. A stalling front may be in the southern/central Plains with continuing adequate flow aloft for supercells. Operations are possible. MISCELLANEOUS: 1. TRAVEL ORDERS: If you gave your address and SSN to Kelly Lynn, I have your travel orders and will give them to you. If you haven't given this info to Kelly (and hence I have no travel orders), you must do so IMMEDIATELY. If you don't have travel orders by departure time, you cannot go. 2. CAM team members: See David Blanchard for video documentation forms. Erik, Paul, Jerry, with David Dowell DATE: 5/14/98 STATUS: go...arrive at 1130, departure at 1145. EQUIPMENT STATUS: Mobile Mesonets: CAM1 in Sayre with a blown transmission. A replacement vehicle is being sought. DOWS: In Woodward. Status unknown. UMASS Radar: down indefinitely Rockets: Under development Turtles: operational RALPH: operational NOAA P-3: Arrives Saturday SYNOPSIS: Strong shortwave trof in the Rockies moving eastward across the Central Plains tonight. Good moisture and smoke in place. DAY 1 FORECAST: First the easy part... a squall line will form late this evening in the High Plains and move eastward across N TX, OK and KS during the night. This will happen as southerly flow through the depth of the tropopshere, combined with strong lifting, causes a line of convection to form. The harder part is to find a way for supercells to form in advance of this system. We think it can occur this way: convergence will persist along the dryline near the eastern edge of the Caprock in W TX. During the afternoon, southeasterly flow will increase in the eastern part of W TX, increasing the convergence and advecting high potential buoyancy air onto the Caprock as the dryline slowly retreats. Inhibition will be weak (convection temperatures of 78-86 F with ~14 g/kg). Supercells may form along the dryline between roughly 3-6 PM, with the area northwest of CDS to LBB being favored (most westerly component in the upper trop giving the most favorable deep shear). Toward sunset, upper flow will back and strengthen significantly, causing seeding effects to send the storms toward HP and eventually toward a solid line of convection. Probabilities: convection in W TX before 7 PM: 55-65%, conditional prob of supercell given convection 65-75%; conditional probability of >F1 tornado given supercell: 12-20%. DAY 2 FORECAST: Operations are possible. As tonight's shortwave lifts northward with the attendant surface low, upper flow becomes westerly over the southern Plains and the surface front stalls. So shear and CAPE may be more favorable tomorrow than today. DAY n FORECAST: Good pattern for MCS's in the S. Plains, supercells in the High Plains of CO and the northern Plains. We will weigh options for operations in that latter area in a few days. MISCELLANEOUS: 1. I badly need an assistant FC who can commit to all the remaining missions this year. Any volunteers???? DATE: 5/15/98 STATUS: no-go EQUIPMENT STATUS: Mobile Mesonets: CAM2 being repaired in OKC. Completion date unknown. DOWS: Unknown. UMASS Radar: down indefinitely Rockets: In Jerry's mind. Turtles: operational RALPH: operational NOAA P-3: SYNOPSIS: Weakening cold front in central OK to SW TX will stall near a line from E OK to about 58 mi E of DAL to near ACT/AUS by evening. Return flow will commence by Saturday morning. DAY 1 FORECAST: No supercells expected ahead of the front in our region because of poor wind profiles. DAY 2 FORECAST: There is a slight chance of operations in the TX Panhandle. Moisture return is expected to be marginal. The wind profile will contain good turning but may be marginal in strength. If moisture return is stronger than forecast, and upper tropospheric flow is stronger than forecast, supercells will become more likely in the target area. DAY n FORECAST: Long-range progs indicate near zero probability of supercells in the southern Plains. The nearest band of flow supportive of supercells will extend from the Colorado High Plains into the northern Plains during the 3-10 day period according to the MRF. If the upper high develops further SE, it is possible that adequate flow will exist in the TX Panhandle into W KS and Nebraska. The experiment PI's are considering an extended road trip to the central High Plains and/or Northern Plains during the period beginning Sunday. MISCELLANEOUS: 1. I am still seeking a Deputy FC who can be available on most/all missions until the end of the experiment. 2. Please notify ER by email if you are willing/unwilling to participate in an extended "road trip" during the coming week. SUBVORTEX STATUS MESSAGE DATE: 5/16/98 STATUS: NO-GO (*** SEE MISC AT BOTTOM REGARDING TOMORROW ***) EQUIPMENT STATUS: Mobile Mesonets: CAM1 will be replaced on Monday. All other systems OK. DOWS: Ready. UMASS Radar: down indefinitely Rockets: Virtual Turtles: operational RALPH: operational NOAA P-3: Arrives today SYNOPSIS: Strong ridge over southern Plains. Lee troughing underway, with low-level moisture returning via the Great Western Circuit. DAY 1 FORECAST: Low-level moisture and deep shear is inadequate for supercells in targetable regions. DAY 2 FORECAST: Shear will be adequate in KS as a jet max moves out of the central Rockies and low-level flow strengthens in response. Low-level moisture may increase to adequate levels. Operations are possible, and an early departure _may_ be required. DAY n FORECAST: We have two quite different model solutions to work off of. The MRF and Euro models show a high-amplitude upper ridge leading to subsidence and very weak upper flow over the southern and central Plains. The NOGAPS model persists (past four runs) in forecasting a split in the subtropical jet which is very strong across the Pacific. One branch heads SE toward the Caribbean with another into the central Plains by midweek. It also forecasts persistent high pressure in the midwest and an associated stationary front across KS in the middle of the week, with intense cyclogenesis in the central High Plains midweek. If true, we would have several days of supercells in the central Plains beginning roughly Mon or Tue, spreading southward into W TX later in the week. However, the MRF shows no significant split and the STJ turns SE toward the Caribbean. Last year, we found the NOGAPS upper flow prog to be a better prog. MISCELLANEOUS: 1. CHECK FOR THE STATUS MESSAGE AT *** 9 AM *** on SUNDAY MORNING. We would expect a 10 AM departure IF we operate. We will CONSIDER a multi-day road trip beginning tomorrow (SUNDAY). Rasmussen/Markowski/Askelson SUBVORTEX STATUS MESSAGE DATE: 5/17/98 STATUS: LIKELY GO...ANOTHER STATUS MESSAGE WILL BE ISSUED BY 945 AM SYNOPSIS: Morning surface data and soundings indicate that a plume of moisture has advected northward in W TX, TX Panhandle, WRN OK, and SW KS. Morning soundings at DDC and AMA show moisture already sufficient to produce significant CAPE and attainable convective temperatures during late afternoon. 12Z profiler and rawinsonde data also reveal 80-90 kt jet streak entering SW KS from NE NM. DAY 1 FORECAST: Vertical shear should support supercells in the TX Panhandle and SW KS. At this time, we are on standby for another hour to better assess the jet position and evaluate the possibility of overnight stay, depending on today's target to be chosen and the future outlook. Today will be a likely go to either the TX Panhandle or SW KS. DAY 2 FORECAST: We are currently assessing Day 2. DAY n FORECAST: Latest MRF is considerably different from past runs and appears to be converging toward NOGAPS solution, which would yield several very favorable days for the southern half of the Plains this week. MISCELLANEOUS: Status will be reissued at 945 AM. Markowski/Rasmussen --------------------------------------------------------- ----------------------- UPDATE -------------------------- --------------------------------------------------------- SUBVORTEX STATUS MESSAGE DATE: 5/17/98 STATUS: STANDBY UNTIL 12 PM CDT FOR POSSIBLE 1245 DEPARTURE SYNOPSIS: Morning surface data and soundings indicate that a plume of moisture has advected northward in W TX, TX Panhandle, WRN OK, and SW KS. Morning soundings at DDC and AMA show moisture already sufficient to produce significant CAPE and attainable convective temperatures during late afternoon. 12Z profiler and rawinsonde data also reveal 80-90 kt jet streak entering SW KS from NE NM. DAY 1 FORECAST: Vertical shear should support supercells in the TX Panhandle and SW KS. Big question is initiation. Eta forecasts warming aloft at 700 mb during the day...this is in question because upstream temps are colder (thus advection cannot accomplish the warming) and lapse rates are neutral from around 550 mb to 780 mb on AMA 12Z sounding (thus, subsudence could not warm temps unless parcels descend to 700 mb from above 550 mb...quite a vertical displacement). Initiation on low terrain will be difficult to impossible...but if moisture remains on high terrain, convective temperatures will be approached or attained. Any storm that is initiated will have a high probability of becoming a supercell. CAPE will be high (on the order of 3-4 kJ/kg). Forecast problem is western edge of moisture. Model data have been scarce this morning...SAMEX data and 12Z RUC are still unavailable. Therefore we will remain on standby until 12 pm. If the dryline is on low terrain at that time, we will not depart. If the dryline is on the elevated terrain, departure will be at 1245 pm. DAY 2 FORECAST: We suspect that adequate flow for supercells may continue to be ejected from massive jet offshore SW US, despite progs' display of weaker flow. Flow aloft will have to be monitored daily. DAY n FORECAST: Latest MRF is considerably different from past runs and appears to be converging toward NOGAPS solution, which would yield several very favorable days for the southern half of the Plains this week. MISCELLANEOUS: Overnight stay is still being considered. Markowski/Rasmussen --------------------------------------------------------- ----------------------- UPDATE -------------------------- --------------------------------------------------------- SUBVORTEX STATUS MESSAGE DATE: 5/17/98 STATUS: GO...1245 PM DEPARTURE EQUIPMENT STATUS: Mobile Mesonets: operational DOWS: unavailable UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Dryline is expected to move little throughout the afternoon. Cap strength trend is uncertain. Dryline is presently located from near CVS to just west of AMA, although confluence zone currently is about 40 miles farther east. Initiation is probably only likely on terrain above 2800 feet. 12 pm update: AMA is now 83 F...6-7 F from convective temp. Cu abound along and north of I-40 in western OK and eastern TX Panhandle. Winds have also backed at AMA to 170 deg. DAY 1 FORECAST: Convective initiation question remains unanswered. We put the probability of initiation around 30%...but CAPE is high and shear north of about I-40 is expected to support classic supercells. Conditional probability of a supercell given initiation is from 60-75%. DAY 2 FORECAST: Similar scenario to today. DAY n FORECAST: MRF shows more promise, appears to be converging toward favorable NOGAPS solution. MISCELLANEOUS: No overnight stay tonight. Rasmussen/Markowski SUBVORTEX STATUS MESSAGE DATE: 5/18/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: CAM1 being repaired today DOWS: Hard down for repairs UMASS Radar: down indefinitely Rockets: Strobe kits being ordered today Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Strong upper ridge over the Southern Plains. Adequate upper flow exists at the periphery of the ridge over the High Plains from the TX Panhandle through Nebraska. However, lower-tropospheric flow has weakened and become more southerly, and lower-tropospheric shear no longer will support supercells. DAY 1 FORECAST: No targetable supercells expected. Non-supercell convection may develop in the High Plains. DAY 2 FORECAST: An E-W front with a surface low in Nebraska may provide favorable low-level shear and convergence for supercell formation in central Nebraska. This area is being evaluated for possible operations. DAY n FORECAST: The front should stall somewhere in N KS allowing moisture to pool and advect westward. If this occurs, large CAPE will develop in the high terrain of W Nebraska and NE CO and SE WY, with very favorable shear profiles for supercells Wed-Thur (at least). NOGAPS shows the subtropical jet moving NE into the Southern Plains toward next weekend which, if correct, would result in conditions supportive of supercells closer to home. The MRF does not show this evolution, but instead weakens upper flow all across the US. MISCELLANEOUS: 1. *** IMPORTANT *** Tomorrow's status message will be issued at 8:30 AM for a possible departure at 9:15 AM. This would be an overnight (likely 2-night trip). YOU MUST FIND A CAPABLE SUBSTITUTE IF YOU ARE NOT WILLING TO GO ON THIS MULTI-DAY TRIP! 2. We had marvelous data collection on the dryline yesterday. Thanks to all who helped out. 3. Drivers... we depart with full tanks of gas. 4. Please move your mobile mesonet data into subdirectories at the end of each mission. Talk to David Blanchard about this. 5. The week of 24 May is "pre-TIMEX" week, and you can expect that we may go to the field to do boundary studies even if no supercells are forecast. Please help us with this important work. SUBVORTEX STATUS MESSAGE DATE: 5/19/98 STATUS: GO...915 DEPARTURE (MULTI-OVERNIGHT) EQUIPMENT STATUS: Mobile Mesonets: CAM2 is ready at the barn and should be picked up by one of the team members. All other vehicles are ready. DOWS: in Salina UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Front near I-70 is forecast by models to retreat slowly northward today. Moisture pooling and modest westward moisture advection should allow dewpts to rise into at least the low 60s in central NE by afternoon. Front should initiate convection between 21 and 00Z. CAPE and shear should be adequate for supercells in NE. DAY 1 FORECAST: Best combination of CAPE, shear, and least inhibition expected near GRI late this afternoon. More likely initiation will be in the High Plains, but lack of CAPE and relatively dry low levels may reduce tornado probability. Our target is a 100 mi diameter circle centered just SW of GRI, where we have a probability of thunder of 40-65%, conditional of supercell given thunder 60-90%, and conditional of tornado given supercell 20-30%. DAY 2 FORECAST: Moisture will pool along the front today, and advection will bring adequate low-level moisture westward toward higher terrain. The front and advection may be stronger tomorrow owing to overnight convection. The target area will be SW NE, far NW KS, NE CO, or SE WY. DAY n FORECAST: NOGAPS jet prog is very bullish for the High Plains on Thur. Expect a dryline with supercell convection to become the focus toward Thur/Fri, with the southern Plains of OK/TX coming under supercell threat this weekend. We may be operating for a number of days. Bring quarters for the coin laundries. We must point out that the MRF and the NOGAPS are worlds apart on the upper trop prog for the next 7 days. The NOGAPS apparently allows the western US upper trof to "pick up" part of the flow of the subtrop jet, while the MRF maintains almost all of this jet across Mexico. If the MRF is correct, the long-range will be considerably less interesting. If you blend the progs, we will probably have _adequate_ upper flow for supercells. MISCELLANEOUS: 1. Team members should give thought to what may be required for multi-day work, such as batteries, rechargers, etc. 2. No parking of experiment vehicles in the main NSSL parking lot... use the gravel lot to the south of the lab. 3. YOU MUST HAVE TRAVEL ORDERS TO GO ON THIS MISSION!!! SEE KELLY LYNN IMMEDIATELY IF YOU DO NOT!!! SUBVORTEX STATUS MESSAGE DATE: 5/20/98 STATUS: GO (depart from Sidney NE midday... overnight at least once more) EQUIPMENT STATUS: Mobile Mesonets: All operating normally. DOWS: In Sidney UMASS Radar: down indefinitely Rockets: Not available Turtles: operational RALPH: operational NOAA P-3: unknown SYNOPSIS: Upper ridge continues in the Plains. Upslope flow will continue in the High Plains of NE CO, SW NE, and E WY today and tomorrow. DAY 1 FORECAST: We expect SE upslope flow to initiate storms in the High Plains of NE CO, SW NE, E WY, and the NE Panhandle today. The best combination of shear and CAPE is progged for the AKO CO area this afternoon. This is our initial target. SE surface winds (E component of 10-15 kt) with SW mid-level flow of 30-40 kt, and SW upper trop flow of 60-70 kt will support supercells. Surface humidities may be too low for significant tornadoes (owing to outflow strength, lack of low-level stretching, or combinations of these [and other?] problems. DAY 2 FORECAST: We expect increased tornadic supercell potential along the warm front from a surface low east of DEN to N KS/ S NE. DAY n FORECAST: Friday: strong SW jet and cyclogenesis will support supercells in W KS. MISCELLANEOUS: 1. Excellent intercept in the Sidney area yesterday evening. The supercell produced hail to 3" diameter, a great RFD with an anticyclone extending to the surface, but no strong low-level cyclone. Excellent MM and photography data were colected. Dual-DOW data were not collected on this storm. SUBVORTEX STATUS MESSAGE DATE: 5/21/98 STATUS: GO (departing Ft. Morgan 11 AM CDT) EQUIPMENT STATUS: Mobile Mesonets: All operational DOWS: In Julesburg CO UMASS Radar: down indefinitely Rockets: Nope Turtles: operational RALPH: operational NOAA P-3: Status unknown SYNOPSIS: W. US upper trof now moving eastward, with strong upper-tropospheric jet moving N through E CO today. DAY 1 FORECAST: Surface boundary from KS/NE boarder westward to near SNY and into E WY will persist today. Cyclongenesis will occur near the left front nose of the approaching jet max (in far NE CO). Wind profiles will favor supercells near the surface boundary (N side). Initiation is expected owing to a combination of upslope and large-scale lift in the southern part of the NE Panhandle by mid-afternoon, with storms quickly becoming supercellular. One or two supercells may produce strong tornadoes near the boundary. ETA progged winds suggest CL type storms that move ENE 20-25 kt as mature supercells. Target area: SNY-LBF-MCK-IML-SNY. Probabilities: convection-75-90%, conditional supercells given convection: 80-100%, conditional probability tornado given supercell: 15-60% (Straka 15, Rasmussen 50, Markowski 60). DAY 2 FORECAST: Same setup, 250 miles further east. DAY n FORECAST: A jet that has no end. We will abandon the nose of the jet as it heads into Wisconsin on Sat, and start focusing on dryline/front intersection below the jet for the remainder of May. Donations will be accepted. MISCELLANEOUS: 1. Excellent mobile mesonet and photography data collected once again on Wed 5/20. A supercell occurred as forecast near AKO CO. Data were collected for 2-3 hours in all parts of the RFD. This storm produced 2.5" hail and 3-m wind gusts to 53 kt accompanied by a 6 C temperature rise under the RFD. A second supercell's RFD was sampled after sunset. DOW data were not obtained on these supercells. Erik, Jerry SUBVORTEX STATUS MESSAGE DATE: 5/22/98 STATUS: GO... Hutchinson to South Haven EQUIPMENT STATUS: Mobile Mesonets: All systems OK DOWS: Ready UMASS Radar: down indefinitely Rockets: No Turtles: operational RALPH: operational NOAA P-3: Unknown SYNOPSIS: Deep trof moving eastward toward the Plains. Strong jet advancing out of NM into N OK this evening. DAY 1 FORECAST: No time.... Target: McPherson/Hesston/Wichita/Wellington etc. Probability of convection 35-60%. Conditional Prob of supercell 90-98%. Conditional prob of tornado 50-60%. CAPE will be huge; shear will be huge; today we don't have cirrus or cold pool problems. DAY 2 FORECAST: Unknown. DAY n FORECAST: Stay tuned. MISCELLANEOUS: Another good data collection mission from McCook to Holdredge NE yesterday with MM's, photography, and DOWs. SUBVORTEX STATUS MESSAGE DATE: 5/23/98 STATUS: STRANGE GO (11:45 AM departure) (see below) EQUIPMENT STATUS: Mobile Mesonets: operational DOWS: in NE KS UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Weak low in SC KS will move ENE and fill today. Warm advection and convergence along the warm front _may_ lead to severe storms in N MO and perhaps S IA, and possible SE KS and W MO if convergence is strong enough. It's hard to see how this scenario will play out given the way things happened yesterday. Moist low-level air has been pooling behind the front for two days, and is now moving southward into the TX Panhandle and OK. The SAMEX MM5 10 km run from last night is the only model to adequately depict this morning's surface pattern. It shows winds in the TX Panhandle becoming E'ly by evening, with a tongue of higher dewpoints and CAPE and some precip by evening in the NW TX Panhandle. We believe an isolated supercell may occur in that region. The third region of concern is NW TX. Cold advection at 700, SAMEX MM5 10 km precip forecast, strong shear, and convergence along the dryline suggest the possibility of isolated supercells from CDS/SPS SSWward. DAY 1 FORECAST: NW TX Panhandle. Prob of convection: 30-35%. Cond prob supercell: 40-60%. Cond prob tornado: 20-25%. NW TX: Prob of convection: 25-30%. Cond prob supercell: 35-60%. Cond prob tornado: 10-20%. DAY 2 FORECAST: ETA sux. But Jet prog from NOGAPS shows good surge of flow aloft over our area tomorrow through Mon. Chances are good somewhere in OK/ N TX for supercells tomorrow. DAY n FORECAST: Gradually diminishing flow aloft will end intercept chances until the end of the month. MISCELLANEOUS: 1. Label all diskettes clearly and turn them in to DOB ASAP. 2. Label all videocassettes clearly with date/time/location and turn them in to DOB ASAP. Unlabelled tapes are not ACCEPTABLE. 3. Put all of your receipts (all but food) in a large envelope (one per person), with your name, address, and SSN clearly labeled on the outside. Turn them in to Jerry Straka ASAP. 4. TODAY:::: ALL VOLUNTEER MISSION. IF YOU ARE TIRED OR DON'T LIKE THE CHANCES, YOU SHOULD FEEL FREE TO STAY HOME TODAY. WE WILL ASSEMBLE TEAMS OUT OF THE GROUP OF VOLUNTEER PARTICIPANTS WHO ARRIVE AT NSSL. THANK YOU. 5. TOMORROW. REGULAR MISSION. SUBVORTEX STATUS MESSAGE DATE: 5/24/98 STATUS: GO...11:15 DEPARTURE EQUIPMENT STATUS: Mobile Mesonets: All OK DOWS: In EMP KS; departing toward the west at 11 AM. UMASS Radar: down indefinitely Rockets: no Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Low pressure is developing in the TX Panhandle, with pressures forecast to fall more to the west and/or north of that area. This is causing low-level easterly flow over OK, with advection of higher dewpoints westward. Mid-levels have cooled significantly over the last 36 h across the central and southern Plains. DAY 1 FORECAST: We have viewed the SAMEX 10 km MM5, the NSSL MM5 ensembles, and the RUC. All have the same general idea... pressures falling in the High Plains of NE NM and/or SE CO, with an increasing easterly component at the surface. Mid- and upper-tropospheric flow is weakening with time, so we must find the strongest low-level easterly winds to provide the best 0-6 km layer shear magnitude. The range of forecast scenarios is initiation near higher terrain from NE of AMA to S of DDC KS, with the most likely area of enhanced low-level easterly flow being in the Woodward OK area. CAPE will be in the 2500-3200 J/kg range in the target area. Supercell type should be CL if surface winds are 15-20 kt easterly, or HP if surface winds are weaker. (Note that this is based on the assumption that the anvil is spreading at 9-10 km; with the high trop and much stronger flow at 10-12 km, it is possible that the storms will be a bit "drier" than forecast.) Motion will be eastward at 10-15 kt for mature supercells. Probabilility of convection in target region: 80-85%. Conditional probability of supercells: 55-72%. Conditional probability of tornadoes given supercells: 15-23%. DAY 2 FORECAST: Indications are that upslope flow will continue in the High Plains, while upper-tropospheric flow weakens more. At this time, it is not clear whether upper flow will continue to support supercells tomorrow, but most likely HP supercells will continue to be possible. IF WE NEED TO BE IN THE HIGH PLAINS TOMORROW, WE MAY DECIDE TO STAY OUT OVERNIGHT TONIGHT. THIS WOULD BE A ONE-NIGHT TRIP. DAY n FORECAST: We anticipate several days with upper-trop flow too weak to support supercells in reachable areas. By late in the week, strong jet flow should resume over the southern and central Plains, with the possibility of an active dryline pattern setting up. MISCELLANEOUS: 1. Receipts (preferably photocopies!) in large envelopes marked with SSN, name, and address to Jerry ASAP please. 2. POSSIBLE OVERNIGHT SUBVORTEX STATUS MESSAGE DATE: 5/25/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: P1 MM system needs repairs; FC RH sensor malfunctioning. DOWS: Both systems broken; hard down. UMASS Radar: down indefinitely Rockets: No. Turtles: operational RALPH: operational NOAA P-3: Unknown SYNOPSIS: Upper flow too weak to support supercells; mid-tropospheric warming has ruined the good deep lapse rates of the last week. DAY 1 FORECAST: Any supercells in the central/southern Plains will be short-lived low-level spinups which quickly become HP in character and then lose supercell character entirely. These storms will be most likely in N TX near the old outflow boundary. We do not consider these to be targetable storms. Probability of convection in N TX / S OK this afternoon/evening: 50-70%. Cond prob of targetable supercells: 5-20%. Conditional probability of tornadoes given supercells: 3-5%. DAY 2 FORECAST: Upper flow is likely to remain too weak for targetable supercells. However, a lee trof/dryline should form through the High Plains. The ETA progs a weak shortwave in W TX toward evening with 500 mb flow increasing to over 40 kt. Operations are possible though unlikely due to the progged weakness in upper tropospheric flow and the overall unreliability of the ETA this spring. DAY n FORECAST: NOGAPS continues the more-or-less zonal pattern (flow from ~250 in the upper half of troposphere) through the period. It progs a major jet (> 130 kt at 200 mb) entering the Plains on Friday. It progs a strong shortwave into the Central Plains on Saturday. Thus we expect operations to resume late this week. The MRF once again builds the upper ridge over the Plains. This forecast has failed to verify for the past two weeks. MISCELLANEOUS: 1. Please download your laptops to diskettes during the upcoming quiet period. See David for more diskettes (David see Mac). 2. Thank you everyone for the hard work over the last week. We did a good job sampling four non-tornadic supercells. In addition, we raised Marko's no-tornado mileage to 11,800 miles!!! 3. Yesterday, subVORTEX intercepted a non-tornadic supercell (3" hail) between Medicine Lodge and Anthony KS. The storm was well sampled by the mobile mesonets. DOW radars caught a similar storm in SW KS. 4. Receipts to Jerry Straka in envelopes labeled with your name, address, and SSN. It would be wise to turn in photocopies instead of originals. SUBVORTEX STATUS MESSAGE DATE: 5/26/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: P1, FC needing equipment repairs DOWS: Unknown UMASS Radar: down indefinitely Rockets: No Turtles: operational RALPH: operational NOAA P-3: Down SYNOPSIS: Upper flow continues to weaken today. Deep lapse rates are much poorer than previous days. We do note that the EML has reappeared at MAF and DRT, and that strong upper trop flow may be occurring in Mexico and just now increasing along the Rio Grande. So we suspect that supercells may occur today in SW TX, roughly from MAF-ABI-SJT-DRT-P07-MAF. This area will not be targeted because we need to spend today working on equipment and data quality checks. DAY 1 FORECAST: No supercells targetable. For the region outlined above, the probability of convection is 65%, conditional probability of supercells 60%, conditional probability of tornadoes 10%. DAY 2 FORECAST: Operations very unlikely owing to lack of shear. DAY n FORECAST: NOGAPS indicates strong flow entering the High Plains on Friday; MRF timing is closer to Saturday. The two solutions have flip-flopped, with the MRF now showing ongoing low heights and strong flow across the southern Plains during the 1 June- 4 June period, with the NOGAPS showing the strong flow retreating north to the northern Plains after 2 June, and indications of a blocking pattern at our latitude with a cutoff west of California and a wicked ridge across the southern Plains. At this time, we anticipate the next operations day to be Friday, with a period of 2-4 days of supercell potential. This may be the last period of operations this spring. MISCELLANEOUS: 1. All teams MUST turn in labeled diskettes and videotapes today. This will enable us to do quality assurance tests prior to the next operations period. 2. Alnado is forbidden to chase. SUBVORTEX STATUS MESSAGE DATE: 5/27/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: repaired and operational DOWS: need some repairs UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Dying MCS in central and eastern TX. Upper flow and vertical shear are weaker than yesterday. Supercells anywhere on the southern High Plains are not anticipated today as upper level geopotential gradient continues to weaken. DAY 1 FORECAST: See above. Supercells are not expected in the Southern Plains. DAY 2 FORECAST: Eta forecasts a dryline to be in western OK during afternoon/evening. Deep-layer shear is expected to be too weak to support supercells for any convection that may be initiated along the dryline. DAY n FORECAST: MRF and NOGAPS are almost identical with the MRF being slightly slower than the NOGAPS by about 12 hours. NOGAPS brings 50-70 kt 200 mb flow back to the High Plains of New Mexico and W TX by Friday evening. MRF brings 50 kt flow into the High Plains by Friday evening, with 50-70 kt brought in by Saturday morning. By Saturday evening, both models bring a strong jet into the central Plains, and several days of fast upper tropospheric flow may persist beyond Saturday. Operations are anticipated for Friday and Saturday, and possibly into early next week. A multi-day road trip may be necessary. MISCELLANEOUS: 1. There is a slight chance we may need to depart tomorrow (Thursday) afternoon or early Fri morning depending on how far north we need to be on the High Plains. 2. Travel reimbursement: Please make photocopies of receipts. Also on a seperate page include 1) name, 2) SS#, 3) address, 4)DATE/TIME of departure and DATE/TIME of return for timely repayment (JS). 3. There will be a brief team leader's meeting Thursday morning at 11 AM in the NSSL Main Conference Room. SUBVORTEX STATUS MESSAGE DATE: 5/28/98 STATUS: GO (Travel day; 3:30 PM NSSL all-participants discussion/meeting; 4 PM departure) EQUIPMENT STATUS: Mobile Mesonets: All ready DOWS: Unknown UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH and BOB: operational NOAA P-3: unknown SYNOPSIS: Upper ridge over Plains will drift eastward as a new jet propagates into the central Plains toward this weekend. A weak surface front will stall across N KS this evening. DAY 1 FORECAST: Slight chance of supercells in the High Plains of E WY, MT, and NE CO. Not targetable. DAY 2 FORECAST: Flow will increase rapidly toward the end of the day across a large part of the High Plains. Shear in W NE is progged to be about 50 kt 0-6 km, with CAPE in excess of 3000 J/kg. We expect supercells, possibly tornadic, in western NE. DAY n FORECAST: Strong jet moves into Plains on Saturday. Tornadic supercells are possible near the left-front nose of this jet (E NE, IA region; perhaps into S Minnesota and/or W IL). After Satuday, the evolution is uncertain but the long-range progs agree on a strong anticyclonically-curved jet across the central Plains for a period of at least four days. MISCELLANEOUS: 1. Ravenna 2. TODAY WE WILL TRAVEL TO SALINA KS. THIS WILL GIVE US OPTIONS TO THE DRYLINE IN W KS TOMORROW IF THE FLOW COMES OUT SOONER THAN EXPECTED AND THE CAP IS WEAKER THAN FORECAST. MORE LIKELY, WE WILL TRAVEL TO WESTERN NEBRASKA ON FRIDAY. THIS IS LIKELY TO BE A MULTIPLE-OVERNIGHT TRIP. 3. Jerry needs your receipts from the last trip ASAP. (Required on the envelope: name, SSN, address, and time/date of departure and return.) SUBVORTEX STATUS MESSAGE DATE: 5/29/98 STATUS: GO...TARGET: SW NEBRASKA EQUIPMENT STATUS: Mobile Mesonets: C1 being repaired (hygrometer down) DOWS: unknown UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: not operational SYNOPSIS: Upper anticyclone with very warm temperatures being established over the southern Plains. Overnight MCS has removed high theta-e airmass from the central Plains, but it is beginning to recover, with strong moisture advection in central KS. Rapidly strengthening upper flow will commence this evening. DAY 1 FORECAST: The situation is very unclear this morning. High theta-e air is in Oklahoma and south-central KS. Strong SE winds should advect this toward NW KS and SW NE. We are concerned that the leading edge will mix out as it advances, and if the high theta-e air does not move northward into NE, where mid-level temperatures are much cooler, initiation may not occur. Initiation will likely occur in the very high terrain of E WY and NE CO, but CAPE will not be very large there. An additional constraint is that deep shear favoring supercells is confined to latitudes north of 40 N. Our target area is AKO-GLD-HLC-MCK-LBF-SNY-AKO. In this target area, we estimate these probabilities: initiation 20-40%; conditional probability of a supercell 80%; conditional probability of a tornado given supercell 5-10%. DAY 2 FORECAST: Now it really gets toughh. NOGAPS phases falling heights in the Midwest with the jet coming through the western states, causing the favorable left front dynamics to shift from E CO to IA/MN in 12 hours. MRF does not phase, and has the upper jet turning anticyclonically around the upper high, with the favorable left-front dynamics over NE KS. So we are guessing that supercells may occur between roughly EMP KS and S MN. We will probably return to central NE tonight to play whatever region becomes targetable, including IA. DAY n FORECAST: Very unclear. The best/only plays will be in the High Plains where moisture returns on the north side of any quasi-stationary front that sets up under the strong upper flow. MISCELLANEOUS: 1. Ravenna SUBVORTEX STATUS MESSAGE DATE: 5/31/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: FC needs new RH sensor DOWS: Unknown UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH and BOB: operational NOAA P-3: unknown SYNOPSIS: Upper ridge has strengthened to climatologically extreme strength, with 500 mB temperatures near -1 over TX. The surface cold front will lead to convergence across OK, S KS, and N TX today, but hot temperatures aloft will preclude thunderstorm development. DAY 1 FORECAST: No convection. DAY 2 FORECAST: Moisture will be absent after the passage of the Day 1 cold front; temperatures aloft will remain scorching. No convection. DAY n FORECAST: Long range progs indicate that a shortwave will be moving into the High Plains toward Wed or Thur, and then into the Plains and Midwest. The ridge will weaken slightly as this passes. It is possible that upslope and deep shear may support supercells later this week in the High Plains from W TX to CO/WY. We will be watching this pattern evolve. MISCELLANEOUS: subVORTEX was badly battered, bruised, and burned yesterday as we chased a tornadic supercell across IA. When we closed in for the intercept, the storm dissipated. SUBVORTEX STATUS MESSAGE DATE: 6/1/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: FC needs new RH sensor DOWS: unknown UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Upper ridge persists over Plains with fast flow aloft in Central Plains. Front has become stationary near the Red River. DAY 1 FORECAST: East winds over OK may advect mid 60s dew points westward onto the higher terrain of the TX Panhandle. Vertical shear supports supercells; however, middle and upper tropospheric temperatures are near climatologically extreme warmth (+13 to +15 C at 700 mb, -4 to -6 C at 500 mb, 0 C at 500 mb at DRT, -33 C at 300 mb); thus, CAPE will be scarce and initiation probably not possible. Operations will not be conducted. DAY 2 FORECAST: Height falls at 500 mb on the order of 30 m are progged to occur on the Texas High Plains by tomorrow evening as central US upper ridge amplitude decreases slightly. Eta places surface low in SE CO by tomorrow evening beneath vertical shear supportive of supercells, however CAPE may still be scarce and upslope flow appears to be weak at best. Thus, operations tomorrow are probably not likely, however a hard down has not been declared. DAY n FORECAST: By Wednesday, a strong stationary front will be in KS, with low pressure in W KS. Gradual height falls will reduce CIN along and north of the stationary front. A dryline will extend from the low southward into W TX or E NM, but warm temperatures aloft should prevent convection on the dryline. It is also likely that upslope in the High Plains of E CO will lead to supercells there (Alnado says Kit Carson and Baca counties). Expect operations (SLIGHT chance of a Tue PM departure for an overnight stay in SW KS; more likely an early Wed AM departure). On Thursday, cooling aloft may allow limited coverage of convection along the dryline near the low, and more extensive convection along or north of the stationary front. This cooling is associated with a fairly strong shortwave in the southern stream, and significant severe weather may occur in W TX / KS/ NW OK. Expect operations. On Friday, the front is progged to move into TX, and may be too far away for operations. Beyond.... MRF develops a DEEP trof over the E US, keeping the Plains in near-winter chill (OK.. an exaggeration). NOGAPS develops a strong zonal current across our latitudes, so more storms may occur toward Sunday. MISCELLANEOUS: SUBVORTEX STATUS MESSAGE DATE: 6/2/98 (Third anniversary of Dimmitt/Friona) STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: FC needs new RH sensor DOWS: Ready UMASS Radar: down indefinitely Rockets: uh-uh Turtles: operational RALPH: operational NOAA P-3: unknown SYNOPSIS: Climatologically extreme ridge persists over the Southern Plains. Temperatures will exceed 100 over a large area today, with temperatures over 110 expected across SW OK and NW TX. A very strong surface cold front is in the central Plains, with snow being reported in N. Dakota. You explain it. DAY 1 FORECAST: CIN is much too strong for convection today in the southern or central Plains. No storms expected. DAY 2 FORECAST: Heights begin to fall on Wednesday as the West Coast short wave begins to eject eastward. We see one scenario for possible convection. If the cold front slows/stalls across N OK, low-level moisture may pool and advect NW toward the high terrain of SE CO. This scenario is more common with shallow, stalled fronts than advancing strong fronts such as the one now in the Plains. It is very doubtful if we can get the necessary low-level theta-e advected to a location where CIN is minimal (cooler conditions aloft). ON THE OUTSIDE CHANCE THAT THIS CAN HAPPEN, WE REQUEST YOU TO CHECK THE STATUS MESSAGE BY 8:15 AM WED MORNING FOR A POSSIBLE 9 AM DEPARTURE. DAY n FORECAST: The West Coast shortwave trof will be ejecting into the Plains on Thursday. NOGAPS suggests there will be an associated jetlet, and in response the surface low deepens near DDC. MRF does not have the jetlet, and right-rear jet dynamics cause the low to deepen near CSM. The latter is more likely in any case because it seems that the front will likely be into at least central or southern OK by Thursday. If heights fall at low enough latitudes, surface winds may remain backed in OK and we MAY be able to retain large enough theta-e to overcome the cap. If the shortwave ejects more to the north, low-level winds will likely veer, and no moisture will be available for convection with this system. Stay tuned. This weekend, long-range progs are in agreement that a new wave will be advancing toward the Plains, with vigorous low-level moisture return and possible dryline storms by Sunday in West Texas. MISCELLANEOUS: 1. Lazbuddie SUBVORTEX STATUS MESSAGE DATE: 6/3/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: FC needs humidity sensor DOWS: Ready UMASS Radar: down indefinitely Rockets: No Turtles: operational RALPH: operational NOAA P-3: Hard down SYNOPSIS: Upper ridge continues. More record heat expected today in the southern Plains. The strong cold front is moving southward through the High Plains this morning, but should stall somewhere across OK into West Texas this afternoon. DAY 1 FORECAST: No targetable supercells. Elevated supercells may form north of the front late this afternoon or evening over far SW MO, SE KS, and points east. These will be untargetable due to terrain and should not produce tornadoes. DAY 2 FORECAST: A shortwave moving out of the southwest US will be approaching the southern and central Plains. At this time, the associated evolution of surface features is not clear. However, with good cooling aloft near 700 mb, it seems that convection will be possible, perhaps even in the warm sector. CAPE and shear may support targetable severe storms. Status message at 10:30 AM. DAY n FORECAST: Cool air mass expected to reach to near the Gulf Coast on Friday. Return flow should commence on Saturday as heights fall again across the W. US. By Sunday, the mid-trop short wave ridge passes, and dryline storms become possible in the High Plains of W TX. MISCELLANEOUS: 1. Erik Rasmussen will return to Boulder today, and will assume the role of nowcaster for the duration of the experiment. 2. Paul Markowski will continue to issue the morning status messages at 10:30 AM unless otherwise posted. 3. The field teams will be reconstituted as follows: PROBE1: Markowski (driver), Davies-Jones (leader), Jason Lynn PROBE2: Straka (leader), Herndon (driver), assistant PROBE3: Blanchard (leader), Miller (driver), assistant CAM1: Smith/Stumpf (driver), Biddle (photographer), assistant Assistants: Scharfenburg, Burke, volunteers 4. In the field, Blanchard will be the final arbiter of disagreements regarding strategy, targets, etc. 5. David Blanchard will be the NSSL spokesperson for media contacts and interviews. SUBVORTEX STATUS MESSAGE DATE: 6/4/98 STATUS: GO...12:30 DEPARTURE EQUIPMENT STATUS: Mobile Mesonets: FC will not be used today...P1-3 and C1 or 2 will be used DOWS: hard down today UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational...6 pm take-off SYNOPSIS: Front has stalled between OUN and ADM. 12Z RUC forecasts surface low, near MAF at 14Z, to move NEward toward ABI and SE of SPS by evening in right rear quad of departing jet. DAY 1 FORECAST: We will depart at 1230 for north or northwest TX, depending on surface evolution during next few hours. Models suggest CAPE will be large (~3500-4000 J/kg) just south of front, with deep-layer shear supportive of supercells. We suspect convection may be initiated along most of front toward evening as midlevel (~700 mb) cooling occurs due to advection/upward motion. Best option will probably be to play westernmost storm due to possible seeding effects. Winds at the sfc will likely back to around 160 degrees ahead of surface low. Negative for today will be high LFC and high LCL (large T-Td spreads). Otherwise, wind profiles support classic supercells for non-seeded updrafts. An MCS is likely tonight along or north of the front. Probability of initiation: 65% Conditional probability of supercells: 70-80% Conditional probability of tornadoes: 5-12% DAY 2 FORECAST: Operations are not expected, but a hard down has not been declared. DAY n FORECAST: If there's a germ of truth in the NOGAPS, there will be many excellent dryline days next week, possibly beginning as early as Sunday. Moisture return will be about as strong as it can be (probably 30-40 kt LLJ day after day and 20-25 kt sfc current), beneath westerly upper flow of about 100 kts for days. Friday and Sat will probably be down, but rest up for a likely extended trip next week. MISCELLANEOUS: 1. Erik Rasmussen is shoveling snow in Boulder today, and will assume the role of nowcaster for the duration of the experiment (Blanchard and Markowski are betting Rasmussen won't be able to avoid temptation of returning if NOGAPS verifies next week). 2. Paul Markowski will continue to issue the morning status messages at 10:30 AM unless otherwise posted. 3. The field teams will be reconstituted as follows: PROBE1: Markowski (driver), Davies-Jones (leader), Jason Lynn PROBE2: Straka (leader), Herndon (driver), assistant PROBE3: Blanchard (leader), Miller (driver), assistant CAM1: Smith/Stumpf (driver), Biddle (photographer), assistant CAM2: Depending on staffing today Assistants: Scharfenburg, Burke, Askelson, Schneider, Witt, others 4. In the field, Blanchard will be the final arbiter of disagreements regarding strategy, targets, etc. SUBVORTEX STATUS MESSAGE DATE: 6/5/98 STATUS: NO-GO EQUIPMENT STATUS: Mobile Mesonets: 5 vehicles operational DOWS: operational UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Strong cold front has pushed to INK-JCT-LFK "line" by 13Z. Large height falls have occurred in the southern Plains in response. Broad middle and upper tropospheric trough is now present over the western 2/3 of the continental U.S. DAY 1 FORECAST: CAPE has been removed over the Plains except for extreme southern TX south of the front. Moisture remains high on the Gulf Coast, with mixing ratios around 21-22 g/kg. Sufficient shear may be present south of the front for a few HP supercells later today. Another MCS or two may also be triggered this evening north of the front in eastern TX, LA, or southern AR. SubVORTEX OPERATIONS WILL NOT BE CONDUCTED TODAY. DAY 2 FORECAST: Eta believes front will stall near Gulf Coast, with relatively strong high pressure over the Plains (surface ridge axis from Minot to Grand Island to Dalhart). CAPE may be present in extreme southern TX from the Davis Mountains to DRT to the Gulf Coast, but dewpoints supporting desirable CAPE for operations are not expected to return to any targetable region (e.g., the High Plains of TX). THUS, OPERATIONS ON SATURDAY ARE NOT ANTICIPATED...SATURDAY IS A HARD-DOWN DAY...NO 1030 AM STATUS WILL BE ISSUED...HOWEVER, A SATURDAY AFTERNOON STATUS WILL BE ISSUED DISCUSSING POSSIBLE EARLY DEPARTURE (I.E., BEFORE 10 AM) ON SUNDAY (See below for forecast). IF YOU CANNOT CHECK YOUR EMAIL SATURDAY AFTERNOON, PLEASE BE SURE TO CHECK BY 8 AM SUNDAY. DAY n FORECAST: Moisture return to the High Plains may be sufficient as early as Sunday for operations. Early departure may be warranted on Sunday depending on the location of the moist axis. Sufficient shear for supercells is just about a guarantee beneath stout 80-100 kt zonal current and progged strong SElies at the sfc. Beyond Sunday, MRF and NOGAPS are in relatively good agreement that there will be several days in a row of High Plains dryline operations (with slight northward shifts each day possible if cap strength increases from south to north). Unseasonably fast upper flow will persist, lee troughing will be strong, shear will be great, and CAPE should be large (q > 21 g/kg along Gulf available to be advected NWward). This looks to be the main show for the season, so be prepared for several consecutive intercept days and possible overnights (depending on how far west dryline is). MISCELLANEOUS: 1. NEXT STATUS WILL BE ISSUED SATURDAY AROUND 5 PM. SATURDAY IS A HARD-DOWN FOR SUBVORTEX. 2. SUNDAY'S DEPARTURE MAY BE FOR A MULTI-DAY MISSION. ADDITIONAL DETAILS WILL BE PROVIDED IN THE SATURDAY AFTERNOON STATUS MESSAGE. 3. ALL TEAM MEMBERS ARE REQUIRED TO BE AT NSSL 30 MIN. PRIOR TO DEPARTURE SO THAT ALL VEHICLES MAY BE ADEQUATELY STAFFED (I.E., WE NEED TO KNOW HOW MANY SUBS WE NEED TO FIND BEFORE 5 MIN. PRIOR TO DEPARTING)...IF AN 1115 AM DEPARTURE IS REQUIRED FOLLOWING A 1030 AM STATUS, THEN ARRIVE AS SOON AS YOU CAN. Markowski/Blanchard SUBVORTEX STATUS MESSAGE DATE: 6/6/98 STATUS: EARLY DEPARTURE LIKELY SUNDAY...STATUS WILL BE ISSUED BY 845 AM SUNDAY EQUIPMENT STATUS: Mobile Mesonets: 5 vehicles operational DOWS: operational UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Front is presently just offshore of TX Gulf Coast. Deep moisture remains at Brownsville and is expected to beginning returning northward tonight. Upper flow remains strong over the Plains. DAY 2 FORECAST: Moisture return is expected to commence by 03Z and to be strong overnight and Sunday. Degree of moisture return is biggest uncertainty at this time. I feel that low 60s dewpoints may be possible tomorrow in the TX Panhandle, which would give rise to CAPE on the order of 2000 J/kg on the higher terrain. Eta progs strong (996 mb) lee cyclogenesis in eastern CO Sunday afternoon. A dryline should extend from somewhere near the low southward through the TX Panhandle. Deep-layer shear will be very favorable for supercells from the High Plains of W NE through W TX. Warm 700 mb temperature are forecasted to spread NEward during Sunday over the High Plains; thus, I expect a southern limit to the chances of dryline initiation Sunday afternoon. Initiation should be possible along the dryline in western KS, OK Panhandle, and most of the TX Panhandle, but the cap will probably preclude initiation south of Plainview or LBB. The most desirable target on Sunday will probably be the area farthest north that good moisture (say, the 60 F isodrosotherm on the high terrain?) returns to. At this time it is suspected that this region will be the northern half of the TX Panhandle, the OK Panhandle, or possibly extreme SW KS (vertical shear is also expected to be greatest in this region). THEREFORE, EARLY DEPARTURE ON SUNDAY IS PROBABLE, ESPECIALLY IF WE NEED TO BE WEST OF AN AMA-GCK LINE. A STATUS MESSAGE WILL BE ISSUED BY 845 AM SUNDAY. DEPARTURE MAY BE AS EARLY AS 945 AM SUNDAY. DAY n FORECAST: NOGAPS still suggests an active High Plains period next week. A trough is expected to amplify over time in the West, but stout upper flow will persist over the High Plains each day. We may need to shift operations north or south each day on the High Plains depending on the location of jet maxima embedded in the flow and cap strength, but overall, supercells may occur somewhere on the High Plains just about everyday next week. Thus, a multi-day mission may be required, depending on the longitude of the dryline. Sunday's status will address overnight and/or multi-night prospects. MISCELLANEOUS: 1. CHECK FOR THE STATUS MESSAGE THAT WILL BE ISSUED AT 845 AM SUNDAY. 2. Sunday's mission may be an overnight mission. This is still being assessed. 3. D. Blanchard: Map discussion will be from 735 to 845 am Sunday. Please meet me outside the Plaza Level of the Energy Center at 730 am. Markowski SUBVORTEX STATUS MESSAGE DATE: 6/7/98 STATUS: GO...11 AM DEPARTURE EQUIPMENT STATUS: Mobile Mesonets: 5 vehicles operational DOWS: semi-operational UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Sluggish mmoisture return is forecast to increase during the day...big question remains as to just how much can return to the region with weaker cap and colder temps aloft. Shear will be extremely favorable for supercells. DAY 1 FORECAST: Low-level flow continues to increase on the High Plains per profiler data. Latest RUC guidance suggests initiation along the dryline as early as 21Z. CAPE will probably only be on the order of 1200-2000 J/kg, but low-level shear (SRH>500 anticipated, possibly as high as 800) will produce very significant dynamical contributions to low-level vertical motion (if you're an EHI believer, EHI for 600 SRH and 1200 CAPE is 4.5). DAY 2 FORECAST: Eta places surface low in SE CO with probable dryline continuing over High Plains. Eta also shows 700 mb warming spreading over the southern half of the TX Panhandle and W TX, but the cap isn't expected to be as strong farther north. Operations may be conducted anywhere from northern TX Panhandle to SW KS along the dryline. Moisture should not be as big an issue. DAY n FORECAST: NOGAPS and MRF both show strong flow aloft for remainder of week (remainder of experiment)...both also amplify trough in West and ridge in eastern Plains, leading to warming aloft and the need to possibly venture north over time. MISCELLANEOUS: 1. THIS WILL BE A MULTI-NIGHT TRIP 2. PLEASE ARRIVE AT THE LAB AS SOON AS YOU CAN...DEPARTURE WILL BE _PROMPTLY_ AT 11 AM FOR THE WESTERN TX PANHANDLE 3. DRIVERS...PLEASE REFUEL BEFORE WE DEPART 4. CURRENT STAFFING WILL SUPPORT PROBES 1-3 AND CAM1...CAM2's OPERATIONS WILL BE CONTINGENT UPON THE APPEARANCE OF ADDITIONAL INDIVIDUALS Markowski/Blanchard/Straka SUBVORTEX STATUS MESSAGE DATE: 6/8/98 STATUS: GO...Departing AMA at about 12:30 PM CDT EQUIPMENT STATUS: Mobile Mesonets: 5 vehicles marginally operational (Two broken windshields and broken pressure ports; intermittent GPS on PROBE1) DOWS: semi-operational Turtles: operational RALPH: operational NOAA P-3: operational SYNOPSIS: Shortwave lifting through NE will support a surface cyclone tracking across S NE through the day. The dryline will trail southwestward to about Midland TX by evening. Very deep, extremely humid and relatively cool boundary layer exists in the southern and central Plains. Poor low-level lapse rates and weak inhibition should mean that supercells in E KS and E NE will be relatively weak and convection should grow upscale quickly into an MCS-type system. Better inhibition, best 0-6 km shear, and best CAPE will be in a band along the dryline from Woodward to Altus to Jayton TX by 00Z. DAY 1 FORECAST: Widespread convection in KS, MO, and E NE. Briefly supercellular, then trending toward more mesoscale type convection. Probability of convection: 99%. Cond prob of supercells given convection: 70%. Cond probability of tornadoes given supercells: 10% (owing to weak low-level accelerations). Isolated-broken band of convection along the dryline from Spur TX to Childress to Woodward. Probability of convection from 30% south end to 70% north end. Conditional probability of supercells given convection 60% south end; 80% CDS-Erick; 70% north end. Conditional prob of tornadoes given supercells generally 15%; 20-25% in a narrow zone where wetted soil from last night's storm may give us a region of enhanced SRH (basically near and north of CDS-LTS line. > > DAY 2 FORECAST: > Dryline may retreat in response to surface low forming in E CO (in response to next shortwave ejecting from SW US). Operations expected. DAY n FORECAST: MISCELLANEOUS: WE WILL ATTEMPT A DRYLINE BOUNDARY STUDY TODAY IN THE E TX PANHANDLE WITH KEVIN KNUPP AND THE MOBILE PROFILER FROM UAH. THIS WILL BE DONE UP UNTIL THE TIME OF INITIATION OF DEEP CONVECTIVE CLOUDS. Erik Rasmussen SUBVORTEX STATUS MESSAGE DATE: 6/9/98 STATUS: GO...11 AM DEPARTURE EQUIPMENT STATUS: Mobile Mesonets: DOWS: operational UMASS Radar: down indefinitely Rockets: not operational Turtles: operational RALPH: operational NOAA P-3: 3 pm departure SYNOPSIS: Front is stalled from MAF to SPS to PNC. Latest RUC guidance suggests winds behind front will veer to easterly or southeasterly this afternoon. Moisture may be advected westward onto higher terrain producing CAPE anywhere from 500 J/kg to 4000 J/kg. Upper flow is very strong (perhaps too strong) at speeds at or above 100 kt at 10 km. 850 mb winds are progged to become SE over all of the High Plains by evening. DAY 1 FORECAST: See above. DAY 2 FORECAST: Upper flow is expected to become more meridional as heights rise on the Plains in association with digging trough in west. Deep-layer shear will probably not be sufficient for classic supercells along the dryline, however, the warm front may provide the better shear needed...although this may be too far north for us to target at this stage. DAY n FORECAST: Heights on the Plains are progged to fall slightly, with upper flow becoming less meridional once again. Operations are possible Thursday and/or Friday. MISCELLANEOUS: 1. Drivers are reminded that they should be watching the road and not the storm. 2. Some laptop disk drives are quickly running out of space. This is easy to correct by deleting unneeded application software. Team leaders should check disk space regularly on the laptop and let either J. Straka or D. Blanchard know if space is low. Sub-VORTEX has concluded its study of the 1998 Plains Tornado Drought. A few good intercept days are possible in the next week, but due to numerous vehicle and equipment problems (and the fact that the experiment was scheduled to conclude on Friday anyway), the program was terminated last evening. We are grateful to all volunteers for their tireless efforts, dedication, patience, and flexibility. Despite the lack of tornadoes, we do have some valuable data on RFDs associated with non-tornadic supercells. We will keep you posted on what we learn from these data. Everyone did a great job. A few miscellany... 1. Please provide all receipts (COPIES--KEEP ORIGINALS) in sealable envelope. Jerry needs name / address / ss# .. and time of departure and return (date/time are essential). They can be given to Jerry in person and I will give them a receipt...or they can put them in his mail box at OU --- Energy Center room 1310. Or they can be mailed to Jerry Straka School of Meteorology Energy Center, Room 1310 University of Oklahoma Norman, OK 73019 2. Markowski is now up to 16,310 tornadoless miles on 31 chases...others probably have done worse, but these are impressive numbers considering the fact that 90% of the miles were driven with continuous nowcast support. Thanks again everyone! Paul Markowski Jerry Straka Erik Rasmussen David Blanchard Bob Davies-Jones