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