SPC AC 200727
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0227 AM CDT SUN AUG 20 2006
VALID 221200Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE NERN
U.S....
...THERE IS A SLGT RISK OF SVR TSTMS MUCH OF THE NRN HIGH PLAINS...
...SYNOPSIS...
STRONGER FLOW WILL GRADUALLY SAG SWD ACROSS THE NRN THIRD OF THE
U.S. EARLY NEXT WEEK. THIS GRADUAL COOLING AND STRENGTHENING OF MID
LEVELS WILL ENHANCE THE PROSPECTS FOR DEEP ORGANIZED CONVECTION NEAR
THE CANADIAN BORDER.
...NEW ENGLAND...
MUCH OF NEW ENGLAND WILL EXPERIENCE SIGNIFICANT HEIGHT FALLS DURING
THE DAY3 PERIOD AS UPPER TROUGH DEEPENS OVER SERN CANADA INTO THE
NERN U.S. LARGE SCALE PATTERN FAVORS DEEP WLY FLOW AHEAD OF FRONTAL
PASSAGE WHICH SHOULD ALLOW BOUNDARY LAYER TO WARM AND DESTABILIZE
SUFFICIENTLY FOR CONVECTIVE DEVELOPMENT. LATEST THINKING IS
THUNDERSTORMS SHOULD DEVELOP BY MID DAY ALONG ADVANCING COLD FRONT
WHERE VERTICAL SHEAR PROFILES WILL MORE THAN SUPPORT ORGANIZED LINE
SEGMENTS CAPABLE OF GENERATING STRONG WINDS. FORECAST STORM MOTIONS
OF ROUGHLY 35KT WILL ENHANCE CONVECTIVE DOWNBURST POTENTIAL WITH
STORMS AS THEY MOVE QUICKLY TOWARD COASTAL ME.
...NRN PLAINS...
MUCH OF THE NRN PLAINS WILL BE DOMINATED BY UPPER RIDGING DURING THE
EARLY PART OF THE DAY3 PERIOD. HOWEVER...INCREASING FLOW AHEAD OF
WELL DEFINED UPPER TROUGH WILL FLATTEN RIDGE OVER MT DURING THE
OVERNIGHT HOURS. IT APPEARS SFC CYCLOGENESIS WILL EVOLVE OVER
SCNTRL MT AS LLJ RESPONDS TO THIS FEATURE OVER THE HIGH PLAINS OF
THE WRN DAKOTAS. STEEP LAPSE RATES OFF THE HIGHER TERRAIN AND
STRENGTHENING LOW LEVEL WARM ADVECTION REGIME WILL BECOME
INCREASINGLY CONDUCIVE FOR LATE AFTERNOON/EARLY EVENING SUPERCELL
DEVELOPMENT. STRENGTH OF UPPER SYSTEM SUGGESTS MULTIPLE
THUNDERSTORM CLUSTERS MAY EMERGE DURING THE OVERNIGHT HOURS
DOWNSTREAM OVER WRN ND.
..DARROW.. 08/20/2006
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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