VORTEX STATUS MESSAGE AND FORECAST DISCUSSION
NATIONAL SEVERE STORMS LABORATORY
1145 AM CDT APRIL 21 1995


OPERATIONAL STATUS AT 1100 CDT: standby til 1 pm
TARGET AREA:  southeast ok and northeast tx
SUPPLEMENTAL SOUNDING/ARCHIVE II REQUESTS: maf, fwd, shv,
crp at 18z  

DAILY FORECAST DISCUSSION:

perplexing situation today...one which both the models and 
the human fcstrs are having difficulty with.  once again 
very strong winds aloft exist acrs ok and n tx...with a 
chance of very high helicities where easterly or sely winds
hold in the vicinity of bndries.  one such bndry is the 
stnry fnt acrs se and s cntrl ok.  

low-lvl mstr is incrsg rpdly alg the lwr tx coastal plains 
nwd into the aus/sat area.  dew pts were incrsg alg the upr
tx coast...but they started to mix out at 16z.  thus...nwd
trajectories into n cntrl tx/se ok offer deeper mstr.
this mstr should race north under a stg cap in s tx, where
chcs for thunder appear to be extremely low next 6-10 hrs.
there may be enough mstr conv and lift for a few tstms nr
the fnt by 00z...but little help is expected from main short
wave which wl continue to intensify and dig a bit tdy.  

thus...main show should be late in coming...prbly after
04z.  however should 1 or 2 storms go up by 00z they 
should quickly bcm svr...spcly should advancing mstr bcm 
juxtaposed with low-lvl forcing and blo an area of
20+ mid-lvl lapse rates (which have been slowly 
expanding nwd from s tx since 00z last ngt).         

PROBABILITIES OF OCCURRENCE IN VORTEX OPS AREA THRU 04Z (DAY1) 
AND 12-04Z (DAY2)...
                           DAY1    DAY2
LIGHTNING                   40      70
SEVERE                      20      50
TORNADOES                   10      10
TARGETABLE STORM            20      20 

FCST STORM MOTION - TARGETABLE STORMS ONLY
PRE-SUPERCELL             2340    2240 
SUPERCELL                 2735    2535 

FCST INITIATION TIMES (LT) - TARGETABLE STORMS ONLY 
LIGHTNING                 1600    0630   
1ST SEVERE RPT            1800    0630
1ST TORNADO               1900    0630