SWODY2
SPC AC 120447
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1147 PM CDT SUN APR 11 2010
VALID 131200Z - 141200Z
...NO SVR TSTM AREAS FORECAST...
...PLAINS...
GFS AND NAM ARE IN MUCH BETTER AGREEMENT TONIGHT REGARDING THE LEAD
UPPER TROUGH EJECTING NEWD ACROSS THE GREAT BASIN/CNTRL ROCKIES INTO
THE NRN HIGH PLAINS BEFORE SETTLING INTO SRN SK LATE. THIS FEATURE
WILL INDUCE STRONG SFC CYCLOGENESIS IN THE LEE OF THE NRN ROCKIES
OVER NERN WY/SERN MT EARLY WITH A FAIRLY SHARP LEE TROUGH/FRONTAL
WIND SHIFT TRAILING SWD ACROSS ERN CO/NM. THIS ZONE OF LOW LEVEL
CONVERGENCE WILL ONLY SHIFT SLIGHTLY EAST DURING THE DAY AS PRIMARY
FORCING OVERSPREADS THE NRN PLAINS INTO SRN CANADA. OF NOTE IS THE
PERSISTENT ANTICYCLONIC SUBSIDENT REGION THAT IS WEDGED EAST OF THE
APPALACHIANS INTO THE CNTRL/WRN GULF STATES. THIS HAS PREVENTED
MEANINGFUL BOUNDARY LAYER MOISTURE FROM RETURNING TO THE
PLAINS...ALTHOUGH DEW POINTS AOA 50F SHOULD ACCOMPANY THE RECOVERING
WARM SECTOR IMMEDIATELY SOUTH OF THE RETREATING WARM FRONT.
GIVEN THE STRENGTH OF THE APPROACHING UPPER TROUGH IT SEEMS VERY
LIKELY THAT A STRONG LLJ WILL BE IN PLACE ACROSS THE PLAINS EARLY IN
THE PERIOD...WITH ONLY SLIGHT VEERING EXPECTED TOWARD 14/12Z INTO
PORTIONS OF THE UPPER MS VALLEY. ELEVATED THUNDERSTORMS ARE
EXPECTED TO BE ONGOING AT THE BEGINNING OF THE PERIOD DUE PRIMARILY
TO WARM ADVECTION NORTH OF WARM FRONT. AN ARCING BAND OF CONVECTION
SHOULD EVOLVE AND SPREAD NWD TOWARD THE CANADIAN BORDER BY MID
AFTERNOON BEFORE STRONG DIURNAL HEATING AND APPROACHING SPEED MAX
LIKELY INDUCE SFC-BASED CONVECTION FARTHER WEST FROM SWRN ND...SWD
ALONG THE DRYLINE. ALTHOUGH VERTICAL SHEAR PROFILES ARE IMPRESSIVE
ACROSS THIS REGION WITH SFC-6KM VALUES ON THE ORDER OF
40-60KT...MEAGER MOISTURE/INSTABILITY WILL CERTAINLY BE A CHALLENGE
FOR SUSTAINING ORGANIZED SEVERE THUNDERSTORMS. WILL MAINTAIN 5%
PROBABILITIES FOR ISOLATED SUPERCELLS ALONG A LENGTHY SPAN OF THE
DRYLINE FROM THE DAKOTAS...SWD INTO ERN NM. IF SFC DEW POINTS
MANAGE TO INCREASE JUST A BIT MORE THAN MODELS/SFC DATA WOULD
OTHERWISE SUGGEST...A SLIGHT RISK WILL BE MORE THAN WARRANTED FOR
MUCH OF THE HIGH PLAINS.
..DARROW.. 04/12/2010
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