SPC AC 210735
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0235 AM CDT THU SEP 21 2006
VALID 231200Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER GREAT LAKES TO
CNTRL TX...
...SYNOPSIS...
A VERY ACTIVE CONVECTIVE DAY APPEARS TO BE EVOLVING FOR THE UPCOMING
DAY3 PERIOD. ALTHOUGH LATEST MODEL GUIDANCE IS QUITE DIVERGENT IN
SOLUTIONS BEYOND THE DAY1...IT APPEARS THE GFS IS A MUCH BETTER
SOLUTION THAN THE NAM AND IT WILL BE FOLLOWED FOR THIS FORECAST
CYCLE.
MID-HIGH LEVEL SPEED MAX WILL EJECT NEWD ACROSS THE CNTRL PLAINS
EARLY IN THE PERIOD WITH INTENSIFICATION EXPECTED ACROSS THE MID
MS/OH VALLEY REGION WHERE H5 FLOW SHOULD BE ON THE ORDER OF 100KT.
LOW LEVEL CYCLONE ASSOCIATED WITH THIS FEATURE SHOULD LIFT NEWD
ALONG RETREATING WARM FRONT ACROSS MO INTO LOWER MI WHERE DEEPENING
IS EXPECTED. OF PARTICULAR CONCERN IS THE EXPECTED RAPID WARM
SECTOR RECOVERY AND THE PROSPECT FOR LEGITIMATE MARITIME TROPICAL
BOUNDARY LAYER MOISTURE TO BE INGESTED INTO SUPERCELL STRUCTURES.
GFS IS CONSISTENT BRINGING UPPER 60S/LOWER 70S SFC DEW POINTS NWD
ACROSS THE OH VALLEY AHEAD OF SFC LOW. THUNDERSTORMS WILL LIKELY BE
ONGOING AT THE BEGINNING OF THE PERIOD AHEAD OF SHORTWAVE FROM
MO...SWWD INTO ERN OK. UPWARD GROWTH IN BOTH AREAL
COVERAGE/INTENSITY MAY OCCUR DURING THE DAY AS FRONTAL BOUNDARY
SWEEPS EWD. WIDESPREAD SEVERE THUNDERSTORM EVENT MAY EVOLVE ACROSS
A LARGE PART OF THE U.S. FROM PORTIONS OF NERN TX INTO THE LOWER
GREAT LAKES REGION...INCLUDING THE POSSIBILITY OF TORNADOES. GIVEN
THE UNCERTAINTIES THAT CURRENTLY EXIST IN SHORT RANGE GUIDANCE WILL
MAINTAIN A SLIGHT RISK...HOWEVER...AN UPGRADE MAY VERY WELL BE
NEEDED AS PREDICTABILITY INCREASES.
..DARROW.. 09/21/2006
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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