Wednesday, February 6, 2013

MESO: Mesoscale Discussion 0116

ACUS11 KWNS 061925
SWOMCD
SPC MCD 061925
TXZ000-062100-

MESOSCALE DISCUSSION 0116
NWS STORM PREDICTION CENTER NORMAN OK
0125 PM CST WED FEB 06 2013

AREAS AFFECTED...PORTIONS OF DEEP S TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 061925Z - 062100Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...AN ISOLATED SVR THREAT MAY EXIST ACROSS PORTIONS OF DEEP
SOUTH TX THIS AFTERNOON...AND THE ISSUANCE OF A WW IS UNLIKELY.

DISCUSSION...VISIBLE SATELLITE IMAGERY AND SFC OBS INDICATE AN
OUTFLOW BOUNDARY STRETCHING FROM THE LOWER TX COAST 30 SSE CRP TO
THE RIO GRANDE RIVER 20 S LRD. MESOSCALE ASCENT IS LOCALLY ENHANCED
WHERE THE BOUNDARY INTERSECTS A N/S-ORIENTED CUMULUS-MANIFESTED
CONVERGENCE BAND OVER SRN DUVAL/NRN JIM HOGG/NWRN BROOKS COUNTIES.
THAT PORTION OF THE BOUNDARY OVER THE COASTAL PLAIN IS PROGRESSING
SWD OWING TO STRONGER COLD POOL GENERATION ACCOMPANYING CONVECTION
TO ITS N. THAT PORTION OF THE BOUNDARY FARTHER TO THE W HAS BECOME
MORE QUASI-STATIONARY...AS CONVECTION ON THE COOL SIDE OF THE
BOUNDARY REMAINS MORE SPARSE. MODIFIED 12Z CRP RAOB TO ACCOUNT FOR
STRONG SFC HEATING S OF THE BOUNDARY -- I.E. SFC TEMPERATURES IN THE
UPPER 70S TO AROUND 80 -- AMIDST MIDDLE/UPPER-60S DEWPOINTS...
SUGGESTS 1500-2000 J/KG OF MLCAPE. STORMS INVOF THE BOUNDARY MAY
BRIEFLY BECOME SEVERE. WITH 40-45 KT OF DEEP SHEAR PER CRP VWP
DATA...SUPERCELL STRUCTURES CANNOT BE RULED OUT...WITH ISOLATED SVR
HAIL/WIND POSSIBLE. A BRIEF TORNADO CANNOT BE RULED OUT GIVEN AROUND
100 M2/S2 OF 0-1-KM SRH AND AMBIENT VERTICAL VORTICITY ALONG THE
BOUNDARY.

THE LACK OF STRONGER MID-LEVEL FORCING FOR ASCENT...AND THE INFLUX
OF MID-LEVEL DRY AIR PER WATER VAPOR IMAGERY...SHOULD INHIBIT STORM
COVERAGE. FURTHERMORE...AS CONVECTION GRADUALLY ADVANCES TOWARD THE
TX COAST...IT MAY HAVE A TENDENCY TO BE UNDERCUT BY THE PROGRESSIVE
SEGMENT OF THE BOUNDARY...THUS MITIGATING THE SVR THREAT. AS
SUCH...ANY SVR THREAT SHOULD REMAIN ISOLATED THROUGH THE AFTERNOON.

..COHEN/HART.. 02/06/2013

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

ATTN...WFO...CRP...BRO...

LAT...LON 26689730 26589799 26789851 27199885 27589888 27579833
27489758 27229740 26689730

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