SPC AC 310734
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0234 AM CDT THU MAY 31 2007
VALID 021200Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE SRN
PLAINS...
...SYNOPSIS...
SIMILAR UPPER PATTERN WILL PERSIST INTO DAY 3...BUT UPPER TROUGH
OVER THE NRN U.S. WILL LIKELY SHIFT A LITTLE FARTHER EAST INTO THE
UPPER MS VALLEY WITH HIGH AMPLITUDE RIDGING OVER THE WRN STATES.
TIMING DIFFERENCES EXIST AMONG THE MODEL REGARDING EWD PROGRESS OF
NRN GULF UPPER LOW WITH THE GFS BEING FASTER THAN THE NAM AND ECMWF.
SURFACE FRONT WILL LIKELY PERSIST FROM A SURFACE LOW OVER THE UPPER
MS VALLEY SWWD INTO THE SRN HIGH PLAINS OF TX.
...SRN PLAINS AND HIGH PLAINS AREAS...
MODEST 20 TO 30 KT NWLY FLOW ALOFT WILL PERSIST BENEATH SELY LOW
LEVEL FLOW EAST OF LEE LOW OVER THE SRN HIGH PLAINS OF WRN TX. THIS
WILL CONTRIBUTE TO VERTICAL SHEAR SUFFICIENT FOR ORGANIZED STORMS.
SOME HEIGHT RISES MAY OCCUR IN WAKE OF SHORTWAVE TROUGH THAT WILL
ROTATE TROUGH UPPER LOW AND INTO THE MID MS...AND TIMING OF ANY
UPSTREAM IMPULSES IS UNCERTAIN AT THIS TIME. POTENTIAL WILL ONCE
AGAIN EXIST FOR STORMS TO DEVELOP OVER THE HIGHER TERRAIN OF NM OR
HIGH PLAINS OF WRN TX AND SPREAD ESEWD INTO THE INSTABILITY AXIS.
OTHER STORMS MAY DEVELOP ALONG FRONT FROM PARTS OF WRN TX NEWD INTO
OK. DESPITE POTENTIAL FOR WEAK UPPER FORCING WHICH COULD LIMIT STORM
COVERAGE...ESPECIALLY OVER THE HIGH PLAINS WHERE THE CAP COULD BE
STRONGER...POTENTIAL WILL ONCE AGAIN EXIST FOR STORMS TO DEVELOP
OVER THE HIGHER TERRAIN OF NM AND SPREAD EWD INTO THE INSTABILITY
AXIS. OTHER STORMS MAY DEVELOP ALONG FRONT FROM PARTS OF WRN TX NEWD
INTO OK. VERTICAL SHEAR MAY BECOME SUPPORTIVE OF SUPERCELLS OVER THE
SRN HIGH PLAINS....BUT WEAKER SHEAR FARTHER NE IN VICINITY OF THE
FRONT ACROSS OK SUGGEST MULTICELLS WILL BE MORE LIKELY. ISOLATED
LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREATS.
...MIDDLE AND UPPER MS VALLEY THROUGH GREAT LAKES...
STORMS WILL LIKELY REDEVELOP AND MAY INTENSIFY ALONG AND IN ADVANCE
OF THE FRONT AS THE ATMOSPHERE DESTABILIZES. STRONGEST VERTICAL
SHEAR WILL LIKELY REMAIN IN POST FRONTAL REGION. THIS ALONG WITH
MODEST LAPSE RATES MAY LIMIT POTENTIAL FOR A MORE ROBUST SEVERE
THREAT. HOWEVER...AS THE BOUNDARY LAYER WARMS DURING THE
AFTERNOON...MULTICELL STORMS MAY BECOME CAPABLE OF PRODUCING
ISOLATED STRONG WIND GUSTS AND HAIL THROUGH EARLY EVENING.
...FL...
MODEL TIMING DIFFERENCES EXIST IN BRINGING UPPER LOW INTO THE FL
PENINSULA. HOWEVER...AS THIS SYSTEM ARRIVES...MODELS BRING STRONG
LOW LEVEL WIND FIELDS WITH LARGE LOW LEVEL HODOGRAPHS IN THIS REGION
WHICH WOULD SUPPORT A THREAT FOR SUPERCELLS AND ISOLATED TORNADOES.
UNCERTAINTY EXIST REGARDING DEGREE OF INSTABILITY GIVEN EXPECTED
WEAK LAPSE RATES AND WIDESPREAD CLOUDS. THIS ALONG WITH UNCERTAINTY
IN TIMING OF UPPER LOW PRECLUDES MORE THAN 5% SEVERE PROBABILITIES
AT THIS TIME. HOWEVER...AN UPGRADE TO A CATEGORICAL OUTLOOK MAY BE
NEEDED IN LATER OUTLOOKS.
..DIAL.. 05/31/2007
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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