SWODY2
SPC AC 011729
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CST SAT MAR 01 2008
VALID 021200Z - 031200Z
..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN PLAINS...
..SYNOPSIS...
PRIMARY FEATURES OF INTEREST DURING THE DAY TWO PERIOD WILL BE
PROGRESSIVE SHORT WAVE TROUGH CURRENTLY OVER THE PACIFIC NW AND
OPENING WAVE OVER NRN BAJA. THE LATTER WILL PRECEDE THE MAIN TROUGH
WITH SOME MODEL VARIANCE IN INTENSITY OF THIS SYSTEM AS IT
TRANSLATES ENEWD INTO THE SRN PLAINS SUNDAY. MEANWHILE...MAIN SHORT
WAVE TROUGH WILL INTENSIFY THROUGH THE PERIOD AS IT PROGRESSES SEWD
THROUGH THE FOUR CORNERS REGION IN RESPONSE TO HEIGHT FALLS
ASSOCIATED WITH DIGGING UPPER JET STREAK FROM THE GREAT BASIN INTO
SRN ROCKIES.
IN THE LOW LEVELS...ATTENDANT COLD FRONT INITIALLY FROM THE ERN
DAKOTAS SWWD INTO CNTRL HIGH PLAINS WILL PUSH SEWD THROUGH THE
PERIOD...LIKELY EXTENDING FROM THE UPPER GREAT LAKES SWWD INTO CNTRL
TX BY MONDAY MORNING. THIS FRONT WILL BE THE PRIMARY FOCUS FOR
STRONG TO POTENTIALLY SEVERE TSTM DEVELOPMENT SUNDAY AFTERNOON AND
NIGHT.
..SRN PLAINS...
12Z OBSERVED SOUNDINGS OVER S TX INDICATED THAT A MOIST BOUNDARY
LAYER IS ALREADY IN PLACE WITH 100MB MEAN MIXING RATIOS OF 11-12
G/KG. STRENGTHENING SLY/SWLY FLOW IN THE LOW LEVELS WILL SUPPORT
THE NWD ADVECTION OF AN INCREASINGLY MOIST BOUNDARY LAYER WITH
DEWPOINTS INCREASING INTO THE 50S AHEAD OF FRONT AS FAR NE AS THE
MID MS VALLEY. RICHER BOUNDARY LAYER AIR /DEWPOINTS IN THE 60S/
WILL LIKELY REMAIN CONFINED TO PORTIONS OF CNTRL/SERN TX. THIS
MOISTURE RETURN WILL OCCUR BENEATH A PLUME OF RATHER STEEP MIDLEVEL
LAPSE RATES /7-8 C PER KM/...SUPPORTING SBCAPES OF 500-1000 J/KG
OVER OK AND N TX...INCREASING TO 1000-1500 J/KG OVER CNTRL TX.
ALL MODEL GUIDANCE IS RELATIVELY CONSISTENT IN SUGGESTING THE
DEVELOPMENT OF TSTMS ALONG COLD FRONT BY MID AFTERNOON FROM CNTRL KS
SWWD INTO NWRN OK AND THE FAR ERN TX PNHDL. SEWD FRONTAL SURGE
COUPLED WITH A GROWING SYSTEM COLD POOL SHOULD SUPPORT THE GROWTH
AND MAINTENANCE OF A QLCS SEWD THROUGH OK AND NRN/CNTRL TX FROM LATE
SUNDAY AFTERNOON THROUGH SUNDAY NIGHT. THE PRESENCE OF THE STEEP
MIDLEVEL LAPSE RATES AND STRENGTHENING VERTICAL SHEAR WITH TIME
INDICATE THE POTENTIAL FOR EMBEDDED BOWING AND/OR SUPERCELL
STRUCTURES CAPABLE OF MAINLY DAMAGING WINDS AND LARGE HAIL.
THERE IS CONSIDERABLY MORE UNCERTAINTY AS TO WHETHER ANY ADDITIONAL
TSTMS WILL DEVELOP AHEAD OF THE PRIMARY LINEAR SYSTEM. FORECAST
SOUNDINGS INDICATE THAT THE CAP WILL REMAIN PROBLEMATIC...THOUGH
FORCING FOR ASCENT ATTENDANT TO LEAD SHORT WAVE TROUGH MAY BE
SUFFICIENT TO OVERCOME THE CONVECTIVE INHIBITION. THIS NOTION IS
SUPPORTED BY THE OPERATIONAL NAM-WRF...ETAKF AND GFS WHICH DEVELOP
ADDITIONAL STORMS LATE SUNDAY AFTERNOON OR EVENING ALONG OR E OF THE
I-35 CORRIDOR OVER N-CNTRL/NERN TX INTO S-CNTRL/SERN OK.
THIS ADDITIONAL DEVELOPMENT WOULD BE COINCIDENT WITH A NOTABLE
STRENGTHENING OF LLJ ACROSS THE SAME GENERAL REGION...RESULTING IN
INCREASINGLY STRONG LOW-LEVEL SHEAR PROFILES. THUS...IT APPEARS THE
GREATEST SUPERCELL AND TORNADO POTENTIAL WILL EXIST WITH ANY MORE
DISCRETE STORMS THAT CAN FORM IN THIS REGIME OVER SERN OK INTO NERN
TX SUNDAY NIGHT.
.MEAD.. 03/01/2008
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