DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 021619
SWODY1
SPC AC 021616

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1116 AM CDT WED MAY 02 2007

VALID 021630Z - 031200Z

..THERE IS A SLGT RISK OF SVR TSTMS A LARGE PART OF TEXAS EXCLUDING
THE PANHANDLE...

..SYNOPSIS...
A STRONG LATE SPRING TROUGH MOVING INLAND WRN U.S. DRIVING THE
WEAKER SRN BRANCH S/WV EWD ACROSS SRN PLAINS. DOWNSTREAM ANOTHER
STRONG TROUGH SHIFTS EWD ACROSS NERN U.S.

SURFACE FRONTAL ZONE TRAILING WSWWD FROM DELMARVA TO VICINITY OH
RIVER TO WEAK SURFACE LOW VICINITY CENTRAL OK.

..TEXAS...
ONGOING SEVERE STORMS SWRN TX IN RESPONSE TO INTERACTION OF SHEAR
AND VERTICAL MOTION FIELDS OF APPROACHING S/WV TROUGH OVER NM AND
THE VERY MOIST AND MODERATELY UNSTABLE AIRMASS REMAINING ACROSS MUCH
OF SRN AND SWRN TX.

MORNING INHIBITION NOTED ACROSS MUCH OF CENTRAL AND SOUTHERN TX WILL
WEAKEN WITH DAYTIME HEATING AS MLCAPES CLIMB TO 2000 J/KG CENTRAL
AND UP TO 3000 J/KG SRN TX. RESULT WILL BE THAT BY MID
AFTERNOON...SEVERE THUNDERSTORMS WILL INCREASE IN BOTH NUMBER AND
INTENSITY ACROSS CENTRAL TO SWRN TX. GREATEST POTENTIAL FOR
SUPERCELLS WILL BE VICINITY BOTH THE OUTFLOW BOUNDARIES ACROSS
CENTRAL TX FROM TUE ACTIVITY AND BOUNDARIES GENERATED BY CURRENT
ACTIVITY MOVING E/SE FROM SWRN TX,

IN ADDITION TO VERY LARGE HAIL...THE 50-60KT OF DEEP LAYER SHEAR
COUPLED WITH VEERING LOW LEVEL HODOGRAPHS SUPPORT TORNADO POTENTIAL
BY MID AFTERNOON WITH ANY SUPERCELL.

BY EARLY TONIGHT INCREASING POTENTIAL FOR GENERATION OF A COLD POOL
WITH CONVECTIVE MODE EVOLVING INTO MORE OF A SQUALL LINE. THIS WILL
THEN INCREASE RISK OF A MORE ORGANIZED WIND DAMAGE EVENT AS THE
SHEAR/CAPE REMAINS SUPPORTIVE FOR SEVERE ALL THE WAY TO THE TX COAST
BY 12Z THU.

CONSIDERED AN UPGRADE TO A MDT GIVEN THE POTENTIAL INSTABILITY AND
APPROACHING UPPER TROUGH...HOWEVER WITH THE CURRENT UNCERTAINTY OF
THE MODE AND TIMING OF A POSSIBLE SQUALL LINE DEVELOPMENT ATTM WILL
MAINTAIN A STRONG SLIGHT RISK.

..WY/MT...
MOISTURE IS SPREADING NWD FROM CENTRAL ROCKIES INTO WY AND MT IN
ADVANCE OF BOTH COLD FRONT ALONG ID/OR BORDER AND THE MAJOR COLD
TROUGH. HEATING AND AVAILABLE STEEP LAPSE RATES WILL RESULT IN
MLCAPES INCREASING TO 500 J/KG DURING AFTERNOON WRY WY INTO MT.
THUNDERSTORMS SHOULD BECOME FAIRLY WIDESPREAD THIS SAME AREA BY MID
AFTERNOON. IN ADDITION TO GUSTY WINDS...ISOLATED LARGE HAIL IS
LIKELY IN STRONG STORMS GIVEN 40-50KT OF DEEP LAYER SHEAR ACROSS
AREA.

..SERN VA/NERN NC...

REF MCD 645

FRONT SAGGING SWD THRU VA THIS AFTERNOON. STRONG HEATING COUPLED
WITH 25-35KT OF DEEP LAYER SHEAR WILL PROVIDE KINEMATIC ENVIRONMENT
FOR A FEW SEVERE STORMS. BY MID AFTERNOON MLCAPES WILL BE NEAR 1000
J/KG...SUFFICIENT FOR THUNDERSTORMS...A COUPLE LIKELY SEVERE. AREAL
COVERAGE OF THE SEVERE EXPECTED TO BE INSUFFICIENT FOR A SLIGHT
RISK.

.HALES/LEVIT.. 05/02/2007

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