[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 230609
SWODY1
SPC AC 230607

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0107 AM CDT SUN APR 23 2006

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...CNTRL PLAINS AND OZARK PLATEAU...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF PA AND NJ...

...CNTRL AND SRN PLAINS...
AN UPPER-LEVEL TROUGH OVER THE WEST COAST IS FORECAST TO SLOWLY
DRIFT ENEWD WITH HEIGHTS GRADUALLY FALLING ACROSS THE HIGH PLAINS.
THIS WILL AID THE DEVELOPMENT OF A LEE SFC LOW OVER WRN KS WITH A
SFC TROUGH/DRYLINE EXTENDING SWD INTO THE TX PANHANDLE. 

IN RESPONSE TO THE HEIGHT FALLS...A 50 KT LOW-LEVEL JET EARLY IN THE
PERIOD WILL CONTINUE MOISTURE ADVECTION ACROSS WEST TX AND WRN KS
THIS MORNING WITH SFC DEWPOINTS LIKELY INCREASING INTO THE 55 TO 60
F RANGE ACROSS MUCH OF THE REGION. AS SFC TEMPS WARM BY MIDDAY
SUNDAY...MODERATE INSTABILITY SHOULD EXIST ALONG AND EAST OF A WEST
TX/SWRN KS DRYLINE AND SOUTH OF A STATIONARY FRONT EXTENDING EWD
ACROSS CNTRL KS. EARLY AFTERNOON FORECAST SOUNDINGS ACROSS THE WARM
SECTOR SHOW A CAPPING INVERSION IN PLACE. THIS COMBINED WITH THE
INFLUENCE OF THE UPPER-RIDGE SHOULD HOLD CONVECTIVE INITIATION OFF
UNTIL THE MID-AFTERNO0N. THE MOST LIKELY AREAS FOR INITIAL
CONVECTIVE DEVELOPMENT WOULD BE ALONG AND JUST EAST OF THE DRYLINE
AND POSSIBLY ALONG THE BOUNDARY IN CNTRL AND ERN KS. 

FORECAST SOUNDINGS ACROSS THE REGION SHOW MODERATE DEEP LAYER SHEAR
WHICH WITH THE INSTABILITY SHOULD BE ADEQUATE FOR SUPERCELL
DEVELOPMENT IN THE LATE AFTERNOON AND EARLY EVENING. IN
ADDITION...MODEL FORECASTS SHOW A PLUME OF VERY STEEP LAPSE RATES
EXTENDING NEWD FROM THE SRN ROCKIES INTO THE CNTRL PLAINS. THIS
SUGGESTS LARGE HAIL WILL BE LIKELY WITH THE STRONGER STORMS. IN
ADDITION...AN ISOLATED TORNADO THREAT MAY ALSO DEVELOP IN SW KS AND
ACROSS THE ERN TX AND OK PANHANDLES BY EARLY EVENING AS THE STORMS
MOVE EWD INTO THE MOIST AXIS AND THE LOW-LEVEL JET STRENGTHENS AND
EXPANDS ACROSS THE REGION. ISOLATED WIND DAMAGE WILL ALSO BE
POSSIBLE WITH THE STRONGER SUPERCELL STORMS. AS STORMS INCREASE IN
COVERAGE AND MOVE EWD INTO THE GREATER LOW-LEVEL MOISTURE...MCS
DEVELOPMENT APPEARS LIKELY DURING THE EVENING. THE SEVERE THREAT
COULD CONTINUE INTO WCNTRL OK AND ACROSS SCNTRL KS OVERNIGHT BUT THE
THREAT SHOULD BECOME INCREASINGLY MARGINAL AFTER MIDNIGHT DUE TO
DECREASING INSTABILITY.

...OZARK PLATEAU...
AN UPPER-LEVEL RIDGE WILL REMAIN IN PLACE ACROSS THE PLAINS TODAY
WITH NWLY FLOW ALOFT IN PLACE ACROSS THE OZARKS. AS SFC TEMPS
WARM...MODERATE INSTABILITY SHOULD DEVELOP ALONG AND SOUTH OF A
STATIONARY FRONTAL BOUNDARY EXTENDING EWD ACROSS SCNTRL MO.
LOW-LEVEL CONVERGENCE IN THE AFTERNOON SHOULD BE STRONG ENOUGH TO
OVERCOME A WEAK CAPPING INVERSION ALLOWING ISOLATED TO SCATTERED
THUNDERSTORMS TO INITIATE. FORECAST SOUNDINGS ALONG THE BOUNDARY IN
SCNTRL MO THIS AFTERNOON SHOW MODERATE VERTICAL SHEAR AND STEEP
MID-LEVEL LAPSE RATES. THIS COMBINED WITH THE INSTABILITY SHOULD BE
SUFFICIENT FOR ISOLATED SUPERCELL DEVELOPMENT DURING THE LATE
AFTERNOON AND EARLY EVENING. LARGE HAIL AND WIND DAMAGE WILL BE
POSSIBLE WITH THE STRONGEST STORMS. HOWEVER...THE SEVERE THREAT
SHOULD GRADUALLY DIMINISH DURING THE EVENING AS THE UPPER-RIDGE
DRIFTS SLOWLY EWD AND INSTABILITY DECREASES ACROSS THE REGION. 

...PA/NJ...
AN UPPER-LEVEL LOW OVER THE GREAT LAKES REGION WILL SHIFT ESEWD
TODAY. IN RESPONSE...MID-LEVEL TEMPS WILL DROP FROM WEST TO EAST
ACROSS THE CNTRL APPALACHIAN MTNS DURING THE AFTERNOON. THIS
COMBINED WITH STRONG LARGE-SCALE ASCENT WILL MAKE THUNDERSTORM
DEVELOPMENT LIKELY IN THE AFTERNOON. FORECAST SOUNDINGS SHOW STEEP
MID-LEVEL LAPSE RATES AND MODERATE VERTICAL SHEAR WHICH SHOULD BE
FAVORABLE FOR LARGE HAIL WITH STORMS THAT MOVE EWD ACROSS PA AND
POSSIBLY AS FAR EAST AS WRN NJ DURING THE LATE AFTERNOON.
HOWEVER...AS SFC TEMPS COOL IN THE EARLY EVENING...THE SEVERE THREAT
SHOULD GRADUALLY DIMINISH.

..BROYLES.. 04/23/2006