[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 110054
SWODY1
SPC AC 110053

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0753 PM CDT SUN SEP 10 2006

VALID 110100Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NW TX/ERN TX PANHANDLE
INTO WRN OK...

...SYNOPSIS...
A BROAD MID/UPPER LEVEL TROUGH WILL MOVE SLOWLY EWD ACROSS THE
CENTRAL U.S. THIS FORECAST PERIOD.  WATER VAPOR IMAGERY INDICATED
SEVERAL SMALLER SCALE SHORT WAVE TROUGHS EMBEDDED WITHIN THE BROADER
TROUGH...WITH TWO OF THE MORE WELL-DEFINED FEATURES MOVING ACROSS IA
AND THE LOWER MO RIVER VALLEY AT THIS TIME.  MEANWHILE...SEVERAL
WEAKER IMPULSES WERE LOCATED WITHIN THE WLY MID/UPPER LEVEL FLOW
REGIME FROM THE CENTRAL/SRN ROCKIES EWD INTO THE CENTRAL/SRN PLAINS.
PRIMARY SURFACE LOW WAS LOCATED OVER NERN KS EARLY THIS EVENING AND
WILL TRACK ENEWD OVERNIGHT INTO NRN MO.  TRAILING COLD FRONT WILL
SPREAD ESE ACROSS KS/OK AND SHOULD EXTEND FROM NWRN MO SWWD THROUGH
ERN KS AND CENTRAL OK TO THE TX S PLAINS BY 12Z MONDAY.  A WARM
FRONT EXTENDED ESEWD FROM THE SURFACE LOW ACROSS CENTRAL MO INTO THE
LOWER OH VALLEY.

...PARTS OF NW TX/ERN TX PANHANDLE INTO WRN OK...
ASCENT AHEAD OF WEAK MID LEVEL IMPULSES TRACKING EWD INTO THE SRN
PLAINS THIS FORECAST PERIOD WILL SUPPORT ONGOING CLUSTER OF STORMS
EXTENDING FROM WRN OK INTO PARTS OF NW TX.  WSR-88D VWP AND AREA
WIND PROFILERS INDICATED A BAND OF WLY MID LEVEL FLOW AT 25-30 KT
EXTENDING FROM ERN NM INTO OK...WHICH IS RESULTING IN EFFECTIVE BULK
SHEAR OF 25-35 KT.  AIR MASS ACROSS THE ERN TX PANHANDLE/NW TX INTO
WRN OK IN ADVANCE OF THE COLD FRONT SHOULD REMAIN MODERATELY
UNSTABLE THROUGH 03Z...PRIOR TO MORE PRONOUNCED BOUNDARY LAYER
STABILIZATION. THUS...THE CAPE/SHEAR VALUES SHOULD REMAIN
SUPPORTIVE OF ORGANIZED STRONG TO SEVERE STORMS FOR THE NEXT FEW
HOURS...WITH HAIL AND STRONG WINDS BEING THE PRIMARY THREATS.

AFTER 03Z...DECREASING INSTABILITY SHOULD LIMIT THE EWD EXTENT OF
THE SEVERE THREAT...BUT CONTINUED ASCENT ACROSS THE SRN PLAINS
SHOULD SUPPORT A CONTINUED CONVECTIVE POTENTIAL ALONG/AHEAD OF THE
COLD FRONT.

...EAST CENTRAL PLAINS INTO LOWER MO RIVER VALLEY...
AN AREA OF MODERATE INSTABILITY EXTENDING NEWD ALONG AND EAST OF THE
COLD FRONT AND SURFACE LOW SHOULD SUPPORT A FEW MORE HOURS /UNTIL
03Z/ OF SURFACE BASED THUNDERSTORM DEVELOPMENT.  STRONGER EFFECTIVE
BULK SHEAR VALUES WERE LOCATED PRIMARILY NORTH OF THE SURFACE
LOW/WARM FRONT...AND THUS DISPLACE NWD OF THE AXIS OF GREATER
INSTABILITY.  EFFECTIVE BULK SHEAR AROUND 30 KT DID EXTEND INTO NERN
KS AND MAY SUPPORT A FEW ADDITIONAL STRONG TO SEVERE STORMS ACROSS
ERN KS...PRIOR TO THE ONSET OF BOUNDARY LAYER COOLING. 
OTHERWISE...ASCENT AHEAD OF THE SHORT WAVE TROUGH MOVING ACROSS MO
SHOULD MAINTAIN A POTENTIAL FOR THUNDERSTORMS OVERNIGHT FROM IA/MO
SWWD INTO ERN OK.

...CENTRAL/SRN HIGH PLAINS...
ASCENT AHEAD OF A COUPLE OF MID LEVEL IMPULSES TRACKING EWD ACROSS
THE CENTRAL/SRN ROCKIES COMBINED WITH UPSLOPE FLOW REGIME INTO THE
HIGHER TERRAIN OF ERN CO TO NERN NM SHOULD SUPPORT A FEW ADDITIONAL
STORMS DURING THE EARLY EVENING.  MODEST WLY MID LEVEL FLOW AT 20-25
KT ATOP ENELY WINDS IN THE LOWEST 1 KM WILL MAINTAIN SUFFICIENT DEEP
LAYER SHEAR FOR ROTATING STORMS.  AXIS OF WEAK INSTABILITY EXTENDING
FROM AROUND DEN SEWD INTO THE SRN HIGH PLAINS WILL SUPPORT A FEW
STRONG TO SEVERE STORMS THROUGH ABOUT 03Z...PRIOR TO BOUNDARY LAYER
STABILIZATION WITH LOSS OF DAYTIME HEATING.  ISOLATED HAIL AND
STRONG WIND GUSTS ARE EXPECTED TO BE THE PRIMARY THREATS.

..PETERS.. 09/11/2006