DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 280100
SWODY1
SPC AC 280058

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 PM CDT SAT MAR 27 2010

VALID 280100Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OZARKS AND
MID-MS VALLEY...

...OZARKS/MID-MS VALLEY...
THE LATEST WATER VAPOR IMAGERY ACROSS THE SRN U.S. SHOWS A
WELL-DEVELOPED UPPER-LEVEL TROUGH OVER THE SRN PLAINS WITH A DRY
SLOT EXTENDING FROM NORTH TX NEWD INTO SW AR. A BROKEN LINE OF
DISCRETE STORMS IS PRESENT JUST AHEAD OF THE DRY SLOT IN CNTRL AR
ALONG AN AXIS OF WEAK INSTABILITY WHERE SFC OBS SHOW SFC DEWPOINTS
ONLY IN THE UPPER 40S AND LOWER 50S F. A BAND OF STRONG LARGE-SCALE
ASCENT ALONG WITH A STRENGTHENING LOW-LEVEL JET WILL HELP MAINTAIN
THE LINE EWD TO THE MS RIVER LATE THIS EVENING IN SPITE OF THE WEAK
THERMODYNAMIC ENVIRONMENT...SEE MCD 217.

THE LINE OF STORMS IS CURRENTLY IN THE LITTLE ROCK AREA AND THE LZK
WSR-88D VWP AT 0030Z SHOWS ABOUT 60 KT OF DEEP LAYER SHEAR WITH 0-3
KM STORM RELATIVE HELICITY AROUND 330 M2/S2. THIS WIND SHEAR
ENVIRONMENT SHOULD SUPPORT A CONTINUED THREAT FOR SUPERCELLS AND
POSSIBLY A TORNADO OR TWO. THE TORNADO THREAT SHOULD REMAIN ISOLATED
MAINLY DUE TO LIMITED LOW-LEVEL MOISTURE WITH THE THREAT REMAINING
SOUTH OF HIGHWAY 64 IN ERN AR WHERE SFC WINDS ARE LOCALLY BACKED AND
LCL HEIGHTS APPEAR A BIT MORE FAVORABLE. IN ADDITION...OBJECTIVE
ANALYSIS SHOWS A POCKET OF STEEP MID-LEVEL LAPSE RATES OVER CNTRL AR
WITH 850 TO 500 MB LAPSE RATES OF 7.5 TO 8.0 C/KM. THIS ALONG WITH
THE STRONG DEEP LAYER SHEAR SHOULD SUPPORT A LARGE HAIL THREAT WITH
SUPERCELLS AND THE MORE INTENSE MULTICELL STORMS. THE THREAT FOR
HAIL SHOULD CONTINUE FOR A FEW MORE HOURS AS THE CELLS APPROACH THE
MS RIVER LATE THIS EVENING. A WIND DAMAGE THREAT MAY ALSO EXIST
ESPECIALLY IF SOME OF THE DISCRETE STORMS CAN CONGEAL INTO A
LINE-SEGMENT. FORECAST SOUNDINGS LATE THIS EVENING INCREASE FLOW
JUST ABOVE THE SFC INTO THE 45 TO 55 KT RANGE WHICH SHOULD HELP THE
STORMS BECOME MORE EFFICIENT AT PRODUCING DAMAGING WIND GUSTS. THE
POSSIBILITY FOR DAMAGING WIND GUSTS MAY CONTINUE EWD AS FAR AS WRN
TN AND NW MS LATER TONIGHT.

..BROYLES.. 03/28/2010

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