ACUS01 KWNS 210530
SWODY1
SPC AC 210528
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 AM CDT THU AUG 21 2008
VALID 211200Z - 221200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER CNTRL ND...
...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF NRN FL AND SE
GA...
...ND...
UPPER TROUGH CURRENTLY MOVING INTO THE PACIFIC NW WILL ADVANCE
THROUGH THE NRN ROCKIES AND NRN HIGH PLAINS THURSDAY. A SERIES OF
VORTICITY MAXIMA WILL ROTATE THROUGH THIS FEATURE AND PROVIDE
IMPETUS FOR A COLD FRONT TO CONTINUE EWD. BY THURSDAY EVENING THE
FRONT WILL EXTEND FROM N CNTRL ND SWWD THROUGH SERN MT AND NE WY. A
DRYLINE WILL EXTEND SWD FROM W CNTRL SD THROUGH WRN NEB AND WRN KS.
BOUNDARY LAYER MOISTURE WITH DEWPOINTS GENERALLY IN THE UPPER 50S
WILL PERSIST IN PRE-FRONTAL WARM SECTOR OVER THE NRN PLAINS.
INCREASING SWLY MID LEVEL FLOW WILL ADVECT WARMER TEMPERATURES AND
STEEPER LAPSE RATES OVER THE MOIST AXIS. THIS WILL CONTRIBUTE TO
DESTABILIZATION...MLCAPE AROUND 1500 J/KG...AS WELL AS A STRONG CAP.
THE WARM SECTOR WILL REMAIN CAPPED TO SURFACE BASED STORMS MUCH OF
THE DAY. CONVECTIVE INHIBITION WILL GRADUALLY WEAKEN AS TEMPERATURES
WARM TO NEAR 90. MODELS SUGGEST INITIAL STORMS MAY DEVELOP NEAR THE
ND/MANITOBA BORDER DURING THE AFTERNOON WHERE THE CAP WILL BE
WEAKER. STRONGER STORMS WILL LIKELY DEVELOP FARTHER SWWD OVER ND BY
EVENING WITHIN ZONE OF INCREASING FRONTAL FORCING AUGMENTED BY
APPROACHING UPPER TROUGH. STRONGER WIND PROFILES WILL REMAIN POST
FRONTAL. HOWEVER...BULK SHEAR MAY INCREASE TO 35-40 KT ALONG
INSTABILITY AXIS AS UPPER TROUGH APPROACHES. STORMS MAY ORGANIZE
ALONG THE FRONT WITH A THREAT OF ISOLATED DAMAGING WIND AND LARGE
HAIL THROUGH MID EVENING BEFORE WEAKENING OVERNIGHT.
...NRN FL THROUGH SERN GA...
TROPICAL STORM FAY IS FORECAST BY THE NHC TO MOVE VERY SLOWLY WNWWD
THURSDAY. THIS SHOULD EVENTUALLY PLACE PARTS OF NRN FL AND SE GA IN
THE MORE FAVORABLE NE QUADRANT FOR A THREAT OF ISOLATED TORNADOES OR
WATERSPOUTS TO MOVE INLAND. ANY BREAKS IN OVERCAST AWAY FROM CENTER
SHOULD RESULT IN POTENTIAL FOR CONVECTIVE CELLS WITHIN OUTER BANDS
TO INTENSIFY OVER THE GULF STREAM AND MOVE ONSHORE...WITH HODOGRAPHS
SUPPORTIVE OF LOW TOPPED SUPERCELLS.
..DIAL/GRAMS.. 08/21/2008
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