Thursday, August 9, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 100040
SWODY1
SPC AC 100037

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0737 PM CDT THU AUG 09 2007

VALID 100100Z - 101200Z

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH VALLEY INTO THE
MIDDLE ATLANTIC...

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS NRN NEB...

..THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF ND...

..OH VALLEY/MIDDLE ATLANTIC...

REPETITIVE THUNDERSTORM CLUSTERS HAVE GRADUALLY OVERTURNED
INSTABILITY FROM SERN OH...ACROSS SRN PA INTO THE DELMARVA REGION.
EVEN SO...STRONG THUNDERSTORMS ARE NOTED ESPECIALLY ALONG SRN
PERIPHERY OF CONVECTION WHERE AIR MASS REMAINS QUITE WARM. 00Z
SOUNDING FROM IAD INDICATES SUFFICIENT MID LEVEL
INSTABILITY...ROUGHLY 1800 J/KG WITH PARCEL LIFTED FROM 850 MB...FOR
THE MAINTENANCE OF STRONG/ORGANIZED UPDRAFTS. SEVERAL NE-SW LINE
SEGMENTS WILL PROGRESS SEWD ACROSS THE REMAINDER OF THE SLIGHT RISK
REGION...SUPPORTED LARGELY BY UPPER SHORTWAVE TROUGH AND
WARM...MOIST AND BUOYANT AIRMASS IN THE LEE OF THE APPALACHIANS.
DAMAGING WINDS ARE THE GREATEST SEVERE THREAT.

..NRN/CNTRL PLAINS...

00Z SOUNDING FROM LBF IS QUITE UNSTABLE THIS EVENING WITH STEEP
LOW-MID LEVEL LAPSE RATES...ROUGHLY 9 C/KM...AND NICE VEERING
PROFILES THROUGH A DEEP LAYER. WEAK WARM ADVECTION INTO NCNTRL NEB
MAY ALLOW ONGOING THUNDERSTORM CLUSTERS TO GRADUALLY EXPAND AS THEY
PROPAGATE ESEWD THIS EVENING.

FARTHER NORTH...LLJ IS EXPECTED TO STRENGTHEN MARKEDLY OVERNIGHT
ACROSS NWRN NEB INTO THE DAKOTAS. THIS MAY ASSIST HIGH BASED...WEAK
INSTABILITY CONVECTION ACROSS WRN ND. NAM GUIDANCE SUGGEST THIS
WEAK CONVECTION WILL GRADUALLY EVOLVE INTO A MORE SIGNIFICANT
THUNDERSTORM CLUSTER AFTER DARK. HAIL AND GUSTY WINDS WOULD BE THE
PRIMARY THREATS IF THIS ACTIVITY DOES INDEED EVOLVE AS MENTIONED.

..SOUTH HIGH PLAINS/SRN ROCKIES...

NUMEROUS THUNDERSTORMS HAVE DEVELOPED ACROSS THE HIGHER TERRAIN OF
NM INTO THE TX PANHANDLE...AND NOW NWRN OK. SHEAR PROFILES ARE NOT
PARTICULARLY NOTEWORTHY ACROSS THIS REGION WITH SFC-6KM BULK SHEAR
ON THE ORDER OF 10-20KT. DESPITE MODEST INSTABILITY IT APPEARS
GUSTY WINDS OR PERHAPS MARGINALLY SEVERE HAIL ARE THE MAIN THREATS.

.DARROW.. 08/10/2007

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