Tuesday, April 24, 2007

MESO: Mesoscale Discussion 0557

ACUS11 KWNS 241230
SWOMCD
SPC MCD 241229
TXZ000-241400-

MESOSCALE DISCUSSION 0557
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT TUE APR 24 2007

AREAS AFFECTED...ERN PERMIAN BASIN INTO CONCHO VALLEY OF TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 241229Z - 241400Z

SEVERE THREAT IS EXPECTED TO INCREASE THIS MORNING AS ONGOING STORMS
INTENSIFY. CONVECTIVE TRENDS ARE BEING MONITORED FOR A POSSIBLE WW
ISSUANCE.

TSTMS HAVE RECENTLY DEVELOPED ALONG A PRE-FRONTAL TROUGH OR WIND
SHIFT LINE OVER GLASSCOCK...REAGAN AND UPTON COUNTIES IN THE ERN
PERMIAN BASIN. AMBIENT AIR MASS IS QUITE MOIST AND POTENTIALLY
UNSTABLE ALREADY THIS MORNING BASED ON 12Z DRT SOUNDING WITH AN
MLCAPE OF 2000-2500 J/KG. A WELL DEFINED CAP WAS OBSERVED ABOVE
MOIST BOUNDARY LAYER AROUND 800 MB...AND THIS MAY TEND TO SLOW
CONVECTIVE DEVELOPMENT INITIALLY.

HOWEVER...AS PACIFIC COLD FRONT /EXTENDING FROM CNTRL BORDEN TO NEAR
MAF TO WARD COUNTY AS OF 1215Z/ OVERTAKES PRE-FRONTAL
TROUGH...LOW-LEVEL CONVERGENCE IS EXPECTED TO INCREASE. THIS
COUPLED WITH DAYTIME HEATING SHOULD RESULT IN CAP REMOVAL...
SUPPORTING AN INCREASE IN STORM COVERAGE/INTENSITY. THIS IS
REFLECTED IN 09Z RUC AND 06Z GFS GUIDANCE. LINEAR FORCING ALONG
FRONTAL BOUNDARY SUGGESTS THAT MODE SHOULD TEND TOWARD
LINEAR...THOUGH ALREADY SUFFICIENT DEEP LAYER VERTICAL SHEAR DOES
INDICATE POTENTIAL FOR EMBEDDED SUPERCELLS CAPABLE OF MAINLY LARGE
HAIL AND LOCALLY DAMAGING WINDS.

.MEAD.. 04/24/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...SJT...MAF...

30600249 30860254 31200236 31570195 31920157 32040116
32000087 31680054 31060073 30600096 30360154

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