DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 300036
SWODY1
SPC AC 300034

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0734 PM CDT MON AUG 29 2011

VALID 300100Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SE MT AND NE
WY...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN NC AND ERN
SC...

...NRN AND CNTRL HIGH PLAINS...
A LINE OF STRONG THUNDERSTORMS IS CURRENTLY ONGOING IN SE MT AND NE
WY LOCATED ON THE ERN EDGE OF A POCKET OF MODERATE INSTABILITY. THE
ACTIVITY IS BEING SUPPORTED BY STRONG LARGE-SCALE ASCENT ASSOCIATED
WITH A SHORTWAVE TROUGH OVER THE NRN HIGH PLAINS EVIDENT ON WATER
VAPOR IMAGERY. IN ADDITION...MESOANALYSIS SHOWS A LOW-LEVEL JET
FEEDING INTO THE CONVECTION FROM THE SOUTHEAST. THESE FACTORS ALONG
WITH 40 KT OF DEEP LAYER SHEAR AND STRONG DIRECTIONAL SHEAR EVIDENT
ON THE RAPID CITY WSR-88D VWP SHOULD SUPPORT A SEVERE THREAT AS THE
STORMS MOVE SEWD ACROSS SE MT AND NE WY THIS EVENING. HAIL AND
STRONG GUSTY WINDS WILL BE POSSIBLE FOR ANOTHER HOUR OR TWO BEFORE
THE CONVECTION LOSES INTENSITY DUE TO WEAKENING INSTABILITY.

FURTHER TO THE SOUTH...MESOANALYSIS CURRENTLY ANALYZES A NARROW AXIS
OF MODERATE INSTABILITY FROM WRN NEB SWD INTO ERN CO. SEVERAL SMALL
CLUSTERS OF STRONG THUNDERSTORMS ARE ONGOING ON THE ERN EDGE OF THE
INSTABILITY AXIS. REGIONAL WSR-88D VWPS SUGGEST 0-6 KM SHEAR VALUES
ARE IN THE 40 TO 50 KT RANGE AND SOUNDINGS SHOW STEEP MID-LEVEL
LAPSE RATES IN PLACE. THIS ENVIRONMENT SHOULD SUPPORT A MARGINAL
SEVERE THREAT EARLY THIS EVENING. HOWEVER...THE THREAT SHOULD BECOME
INCREASINGLY ISOLATED AS THE STORMS MOVE EWD INTO A MORE STABLE
AIRMASS ACROSS WCNTRL NEB AND NW KS.

...ERN CAROLINAS...
A BROKEN LINE OF STRONG THUNDERSTORMS IS ONGOING FROM ECNTRL NC
SSWWD INTO ERN SC ALONG THE WRN EDGE OF MODERATE TO STRONG
INSTABILITY. THE STRONGEST DEEP LAYER SHEAR IS CURRENTLY LOCATED
ACROSS NC WHERE 0-6 KM SHEAR VALUES ARE ESTIMATED IN THE 35 TO 45 KT
RANGE. IN ADDITION...LOW-LEVEL LAPSE RATES ARE STILL STEEP ALONG AN
AXIS FROM COLUMBIA SC NNEWD TO AROUND RALEIGH NC. THE STEEP LAPSE
RATES ALONG WITH THE SHEAR AND INSTABILITY SHOULD SUPPORT AN
ISOLATED WIND DAMAGE THREAT EARLY THIS EVENING. THE SEVERE THREAT
MAY PERSIST FOR ANOTHER HOUR OR TWO BEFORE THE CELLS DIMINISH IN
INTENSITY.

..BROYLES.. 08/30/2011

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