VORTEX STATUS MESSAGE AND FORECAST DISCUSSION
NATIONAL SEVERE STORMS LABORATORY
1130 AM CDT APRIL 28 1995


OPERATIONAL STATUS AT 1100 CDT:
TARGET AREA:  n/a  
SUPPLEMENTAL SOUNDING/ARCHIVE II REQUESTS:  
LBB, AMA, MAF

DAILY FORECAST DISCUSSION:
Moderately strong (and increasing) mid- and upper-level 
westerlies across northwest Texas have resulted in about
90 degs. of shear from the sfc to 700 mb today.  Dew points 
are on the low side, but increasing rapidly into the mid
and upper 50s as a 30-40 kt southerly low-level jet 
continues.  With 20+ deg. mid-lvl lapse rates, it appears
that 2500 joules of CAPE is not unreasonable.  Fairly large
cap is a problem, but very warm air on and west of the dry 
line is progged by RUC and ETA models, so cap should break
near the dry line.  The strong temp gradient near the dry 
line should help in establishing aftn vertical circulations.
Expectations are for shear to be too strong for instbility
of most updraft candidates, but 1 or 2 should make 
it to t-storm stage - and probably become supercells.
All of this should occur on the higher terrain.

More widespread convection is expected later tonight and 
Saturday as next cool front overtakes dry line and pushes 
surface low se into central Texas by Saturday afternoon.    
Weakening shears and mid-level winds indicate decreasing
supercell potential Saturday.


PROBABILITIES OF OCCURRENCE IN VORTEX OPS AREA THRU 04Z (DAY1) 
AND 12-04Z (DAY2)...
                           DAY1    DAY2
LIGHTNING                   60      99
SEVERE                      50      50
TORNADOES                   20      10
TARGETABLE STORM            40      20 

FCST STORM MOTION - TARGETABLE STORMS ONLY
PRE-SUPERCELL             260/35  280/30  
SUPERCELL                 290/25  300/20 

FCST INITIATION TIMES (LT) - TARGETABLE STORMS ONLY 
LIGHTNING                 1700    on-going 
1ST SEVERE RPT            1800    1500 
1ST TORNADO               1830    1630 (low-chances) 


Moller