SPC AC 012028
DAY 1 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0328 PM CDT SUN JUN 01 2008
VALID 012000Z - 021200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS AR...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS...MID MS VALLEY AND ERN SEABOARD...
CORRECTED FOR HEADLINE AREAS
...GREAT PLAINS...
WATER VAPOR CURRENTLY SHOWS AN UPPER-LEVEL RIDGE IN PLACE ACROSS THE
HIGH PLAINS WITH A MID-LEVEL JET AXIS LOCATED UT AND CO EXTENDING
ESEWD INTO SRN KS. A SHORTWAVE TROUGH IS LOCATED ACROSS THE NRN AND
CNTRL ROCKIES AND THIS FEATURE SHOULD RIDE ENEWD OVER THE TOP OF THE
RIDGE. LARGE-SCALE ASCENT AHEAD OF THE TROUGH ALONG WITH SFC HEATING
WILL SUPPORT SCATTERED THUNDERSTORM DEVELOPMENT IN THE HIGHER
TERRAIN OF ERN WY AND ECNTRL CO THIS AFTERNOON. STORMS SHOULD
INCREASE IN COVERAGE WITH AN MCS ORGANIZING ACROSS WRN NEB AND NE
CO. MODEL FORECASTS MOVE THIS MCS SEWD ALONG A GRADIENT OF STRONG
INSTABILITY INTO WRN KS THIS EVENING.
CONCERNING THE SEVERE THREAT...REGIONAL PROFILERS SHOW STRONG
VERTICAL SHEAR PROFILES ACROSS MOST OF THE REGION ASSOCIATED WITH
THE MID-LEVEL JET. IN ADDITION...RUC OBJECTIVE GUIDANCE HAS AN
ELEVATED MIXED LAYER WITH STEEP MID-LEVEL LAPSE RATES /850 TO 500 MB
LAPSE RATES OF 7.5 TO 8.5 C/KM/ EXTENDING EWD FROM THE CNTRL AND NRN
ROCKIES ACROSS MUCH OF THE WRN PART OF THE SLIGHT RISK AREA. THIS
ALONG WITH THE STRONG VERTICAL SHEAR SHOULD BE FAVORABLE FOR
SUPERCELLS WITH VERY LARGE HAIL. STORMS SHOULD GRADUALLY INCREASE IN
COVERAGE AND A BROAD ZONE WITH LARGE HAIL POTENTIAL SHOULD EXIST
EARLY THIS EVENING. AN ISOLATED TORNADO/WIND DAMAGE THREAT WILL ALSO
BE POSSIBLE WITH THE MORE PERSISTENT SUPERCELLS OR BOW ECHOES.
...MID MS VALLEY...
A BOWING MCS IS CURRENTLY MOVING SEWD ACROSS CNTRL AR. THE
ENVIRONMENT AHEAD OF THE DERECHO IS CHARACTERIZED BY STRONG
INSTABILITY /MLCAPE VALUES IN THE 2000 TO 3000 J/KG RANGE/...SFC
DEWPOINTS NEAR 70 F AND MODERATE VERTICAL SHEAR AS SHOWN BY REGIONAL
WSR-88D VWPS. THIS SHOULD SUPPORT THE MCS AS IT TRACKS SEWD INTO
NWRN MS LATE THIS AFTERNOON. HOWEVER...THE RELATIVELY WEAK LOW-LEVEL
FLOW SHOULD RESULT IN A SLIGHTLY LESS WIDESPREAD WIND DAMAGE THREAT
ESEWD ACROSS NCNTRL MS.
...ERN SEABOARD...
A BROAD UPPER-LEVEL TROUGH IS CURRENTLY LOCATED ACROSS THE NRN
APPALACHIAN MTNS AND MID-ATLANTIC REGION. LARGE-SCALE ASCENT
ASSOCIATED WITH THE TROUGH AND SFC HEATING IS RESULTING IN SCATTERED
THUNDERSTORM DEVELOPMENT FROM THE VIRGINIAS SWD ACROSS TN AND THE
CAROLINAS. THE ACTIVITY IN WV AND ERN KY IS LOCATED ALONG A COLD
FRONT AND RUC GUIDANCE SUGGESTS INSTABILITY IS WEAK SOUTH OF THE
BOUNDARY. EVEN SO...COLD TEMPS ALOFT WITH THE TROUGH AND STRONG
VERTICAL SHEAR ASSOCIATED WITH A 55 TO 65 KT MID-LEVEL JET MAX WILL
SUPPORT AN ISOLATED LARGE HAIL THREAT LATE THIS AFTERNOON. FURTHER
SOUTHWEST ACROSS THE CAROLINAS AND TN VALLEY...VERTICAL SHEAR IS
MUCH WEAKER. HOWEVER...THE WARM SECTOR IS MODERATELY UNSTABLE
ACCORDING TO RUC GUIDANCE AND THIS ALONG WITH STEEPENING LOW-LEVEL
LAPSE RATES SHOULD SUPPORT AN ISOLATED WIND DAMAGE THREAT.
...ERN MAINE...
A SMALL CONVECTIVE CLUSTER IS ONGOING IN ERN MAINE AND IS LIKELY
ASSOCIATED WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST
SOUTHWEST. THE LATEST WSR-88D VWP FROM NRN MAINE SHOWS
UNIDIRECTIONAL FLOW WITH ABOUT 50 KT AT 6 KM. THIS ALONG WITH STEEP
LOW-LEVEL LAPSE RATES EXCEEDING 8.0 C/KM SHOULD SUPPORT A MARGINAL
WIND DAMAGE THREAT WITH THE STRONGER CELLS.
..BROYLES.. 06/01/2008
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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