ZCZC SPCSWOMCD ALL
ACUS11 KWNS 302010 
SPC MCD 302010 
OKZ000-TXZ000-302245-

Mesoscale Discussion 0296
NWS Storm Prediction Center Norman OK
0310 PM CDT Mon Apr 30 2018

Areas affected...Parts of west TX into the eastern TX/OK Panhandles

Concerning...Severe potential...Watch possible 

Valid 302010Z - 302245Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms are expected to develop between 22-23Z in
vicinity of the dryline from west TX into the central and eastern
portions of the TX and OK Panhandles.  Severe hail, some very large,
and damaging wind gusts will be the greatest threats.

DISCUSSION...Trends in early afternoon surface analyses showed a
dryline continuing to mix eastward into central parts of the OK/TX
Panhandles and part of west TX, and analyzed at 19-20Z extending
from in vicinity of KGUY, KPPA, KLBB, then southwest to near 25 NNW
MAF.  The southern portion of the dryline has been slower to mix
eastward into more of the TX portion of the Permian Basin, given a
greater westward influx of moisture return into the lower Trans
Pecos region.  12Z AMA sounding modified for surface data east of
the dry line indicated the removal of much of the inhibition. 
However, at the present time, weaker surface convergence along the
dryline appears to be precluding surface-based cumulus formation. 
Farther south, visible satellite imagery indicated sustained cumulus
development from 50 ENE KHOB to 30 WNW KLBB, where stronger
southeasterly winds are supporting upslope flow.  This increase in
the cumulus field may be suggesting the leading extent of height
falls attendant to the southern Rockies shortwave trough are
beginning to spread across the southern High Plains.

An increase in low-level convergence is expected by 22-23Z along the
dryline.  The presence of steep lapse rates, moderate instability
and strengthening of vertically veering winds will support
thunderstorms into the evening becoming severe.  The CAPE/shear
parameter space, given mainly high-based storms, should tend to
favor hail and damaging wind gusts as the primary severe threats.

..Peters/Grams.. 04/30/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...OUN...LUB...AMA...MAF...

LAT...LON   32720253 35290150 36910136 36949996 36319988 34600014
            33220087 32330136 32260224 32720253 

NNNN