SPC AC 220726
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0226 AM CDT SAT SEP 22 2007
VALID 241200Z - 251200Z
...NO SVR TSTM AREAS FORECAST...
...PART OF UPPER MS/LOWER MO VALLEYS SWWD TO KS AND OK/TX PNHDLS...
ALTHOUGH MODELS TEND TO AGREE WITH THE DEVELOPMENT OF A LESS
AMPLIFIED AND MORE ZONAL UPPER FLOW PATTERN ACROSS THE CONUS ON
MONDAY...THEIR OUTPUT DIFFERS WITH THE EWD PROGRESSION OF A SHORT
WAVE TROUGH ORIGINATING FROM THE GREAT BASIN/CENTRAL ROCKIES. THE
NAM IS THE FASTEST WITH THIS FEATURE...SINCE IT SUGGESTS PHASING OF
THIS SYSTEM WITH A SHORT WAVE TROUGH TRACKING EWD ACROSS SRN CANADA.
IN THE LOW LEVELS...A COLD FRONT IS EXPECTED TO SPREAD EWD THROUGH
THE UPPER MS/LOWER MO VALLEYS TO THE GREAT LAKES/MIDWEST REGION AND
ALSO SWD THROUGH THE CENTRAL INTO SRN PLAINS.
DESPITE THE MODEL UNCERTAINTIES...A STRONG BAND OF SWLY MID LEVEL
FLOW SHOULD EXTEND FROM THE CENTRAL ROCKIES NEWD THROUGH THE MID MO
VALLEY TO THE UPPER GREAT LAKES...BUT GENERALLY WITHIN THE
POST-FRONTAL ENVIRONMENT. MODELS SUGGEST WEAK TO MODERATE
INSTABILITY WILL BE POSSIBLE ALONG AND JUST AHEAD OF THE COLD FRONT
FROM WI/SERN MN SWWD THROUGH IA/NRN MO TO THE OK/TX PNHDLS MONDAY
AFTERNOON. ALTHOUGH STRONGER DEEP LAYER SHEAR IS EXPECTED TO LAG
THE COLD FRONT...THERE WILL BE A POTENTIAL FOR AT LEAST LOW SEVERE
WEATHER PROBABILITIES WITH TSTMS ALONG MUCH OF THE COLD FRONT MONDAY
AFTERNOON AND EARLY EVENING. MODELS DO AGREE THAT THE NRN EXTENT OF
THIS LOW RISK AREA INTO SERN MN/WI WILL HAVE THE BEST POTENTIAL FOR
INSTABILITY/STRONGER SHEAR TO BE JUXTAPOSED...BUT THERE ARE
DIFFERENCES IN THE DEGREE OF INSTABILITY.
..PETERS.. 09/22/2007
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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