Saturday, August 11, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 120039
SWODY1
SPC AC 120037

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0737 PM CDT SAT AUG 11 2007

VALID 120100Z - 121200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MS VALLEY AND
UPPER GREAT LAKES...

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS SRN GA AND NRN FL...

..UPPER MS VALLEY/UPPER GREAT LAKES...

THUNDERSTORMS HAVE STRUGGLED TO ORGANIZED ALONG ZONE OF LOW LEVEL
CONFLUENCE FROM THE ARROWHEAD OF MN INTO THE MSP REGION. WEAK
BOUNDARY LAYER FLOW AND THE ABSENCE OF MEANINGFUL LARGE SCALE
SUPPORT ALONG SRN PERIPHERY OF SHORTWAVE TROUGH APPEAR MOSTLY TO
BLAME FOR STRUGGLING ACTIVITY. 00Z SOUNDING FROM MPX SUPPORTS
DEEPENING WLY FLOW...ALTHOUGH INSTABILITY IS QUITE HEALTHY WITH
MLCAPE VALUES ON THE ORDER OF 3000-4000 J/KG ACROSS SRN HALF OF WW.
AS BOUNDARY LAYER DECOUPLES THIS EVENING ELEVATED THUNDERSTORMS MAY
DEVELOP DUE TO WEAK ISENTROPIC LIFT FARTHER DOWNSTREAM ACROSS
PORTIONS OF WI AND NRN LOWER MI...AS WELL AS THE U.P OF MI. IT/S
NOT ENTIRELY CLEAR HOW MUCH ADDITIONAL SFC-BASED ACTIVITY WILL
EVOLVE SWWD ALONG BOUNDARY INTO SRN MN OR NRN IA. SUPERCELLS IN THE
MSP METRO AREA WILL CONTINUE TO PRODUCE LARGE HAIL AND STRONG WINDS
AS THEY MOVE SEWD AT 20-30KT. LARGE HAIL IS THE MOST LIKELY THREAT
WITH OVERNIGHT ACTIVITY DOWNSTREAM.

..SRN GA/NRN FL...

00Z SOUNDING FROM JAX DEPICTS A VERY UNSTABLE AIR MASS WITH MLCAPE
VALUES IN EXCESS OF 3500 J/KG. THIS EXTREME BUOYANCY WILL PROVE
MORE THAN ADEQUATE FOR MAINTAINING COMPLEX OF THUNDERSTORMS AS THEY
SAG SWD ACROSS SRN GA INTO NRN PORTIONS OF FL. WEAK DEEP LAYER
SHEAR SUGGESTS STRONG WINDS ARE THE GREATEST THREAT ALONG LEADING
EDGE OF LOOSELY ORGANIZED MCS.

.DARROW.. 08/12/2007

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