[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 220103
SWODY1
SPC AC 220101

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0801 PM CDT SUN MAY 21 2006

VALID 220100Z - 221200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE OZARK REGION ESE
INTO TN VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS WRN PARTS OF THE
NRN/CENTRAL PLAINS...

...OZARK REGION ESE TO TN VALLEY/SRN APPALACHIANS...
QUASI-STATIONARY BOUNDARY REMAINED LOCATED FROM THE SRN APPALACHIANS
WNWWD THROUGH SRN-WRN TN INTO NRN AR TO NORTH CENTRAL OK BEFORE
BECOMING A LITTLE MORE DIFFUSE INTO THE SRN HIGH PLAINS.  WATER
VAPOR IMAGERY INDICATED SEVERAL WEAK SHORT WAVE TROUGHS/MCVS ALONG
THE EXTENT OF THIS BOUNDARY WITH ONE LOCATED OVER THE TN VALLEY AND
TWO UPSTREAM OVER WRN AR AND NERN OK/SERN KS.  ASCENT ASSOCIATED
WITH THESE FEATURES AS THEY TRACK ESE COMBINED WITH LOW-LEVEL WAA
AND AIR MASS REMAINING MODERATELY UNSTABLE THROUGH 06-09Z ALONG THE
SURFACE BOUNDARY WILL SUPPORT ADDITIONAL TSTMS. GREATEST
THUNDERSTORM COVERAGE AND SEVERE POTENTIAL IS EXPECTED TO EXTEND
FROM SRN MO/NRN AR INTO MIDDLE TN/FAR NRN AL...AND POSSIBLY NWRN GA
THROUGH 12Z.  EFFECTIVE SHEAR/INSTABILITY WILL FAVOR HAIL/ STRONG
WIND GUSTS WITH ADDITIONAL STORMS.

...WRN PART OF THE NRN/CENTRAL PLAINS...
THUNDERSTORMS OVER CENTRAL/ERN MT AND SWD FROM FAR ERN WY INTO WRN
NEB/NWRN KS ARE BEING AIDED BY LARGE SCALE ASCENT ASSOCIATED WITH A
COUPLE OF SHORT WAVE TROUGHS OVER MT AND WY.  THIS ASCENT COMBINED
WITH INCREASING WAA PER A STRENGTHENING SLY LLJ OVER WRN KS AND
SSELY LLJ ALONG NRN HIGH PLAINS EXPECTED TO MAINTAIN POTENTIAL FOR
ADDITIONAL THUNDERSTORMS THROUGH 06-09Z.  GREATEST LIKELIHOOD FOR
UPSCALE GROWTH INTO AN MCS IS EXPECTED WITH SRN CLUSTER OF STORMS
OVER SWRN NEB/FAR NWRN KS WITH ACTIVITY SPREADING ESE OVERNIGHT
ALONG INSTABILITY AXIS.  STRONG WIND GUSTS AND HAIL ARE EXPECTED TO
BE THE PRIMARY SEVERE THREATS.

...OK/TX PANHANDLES SWD THROUGH W TX...
ISOLATED SEVERE STORMS WILL REMAIN POSSIBLE FOR THE NEXT FEW HOURS
ACROSS WEST TX INCLUDING THE PANHANDLE...WHERE 00Z SOUNDINGS
INDICATED A DEEPLY MIXED SUB-CLOUD LAYER SUPPORTIVE OF STRONG
DOWNDRAFTS. DIABATIC COOLING SHOULD WEAKEN AVAILABLE INSTABILITY AND
REDUCE THE LIKELIHOOD FOR SEVERE STORMS LATER THIS EVENING.

...INTERIOR PACIFIC NORTHWEST...
INCREASING SLY MID LEVEL FLOW ACROSS ERN ORE/WA/ID/FAR WRN MT AND
ASSOCIATED LARGE SCALE ASCENT WITHIN EXIT REGION OF THIS JET
EXPECTED TO SUPPORT ADDITIONAL POTENTIAL FOR THUNDERSTORMS THROUGH
THE EVENING.  STRONG DEEP LAYER SHEAR WILL SUPPORT SOME STORM
ORGANIZATION...BUT WEAK INSTABILITY SHOULD LIMIT SEVERE COVERAGE.

...ERN NEW ENGLAND...
THE PORTION OF THE STRONGLY FORCED LINE OF LOW-TOPPED CONVECTION
THAT HAD PRODUCED SOME SEVERE STORMS ACROSS NEW ENGLAND DURING THE
LATE AFTERNOON HAS MOVED EWD OFFSHORE THE MA COAST...THUS LIMITING
THE POTENTIAL FOR ADDITIONAL SEVERE STORMS.  OVERALL PROBABILITY FOR
THUNDERSTORMS WILL ALSO DECREASE OVERNIGHT AS THE ATTENDANT STRONG
MID LEVEL IMPULSE...NOW CENTERED OVER NEW ENGLAND...TRACKS EWD
TOWARD NOVA SCOTIA.

..PETERS.. 05/22/2006