SPC AC 031743
DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1243 PM CDT TUE APR 03 2007
VALID 041200Z - 051200Z
...THERE IS A SLGT RISK OF SVR TSTMS TIDEWATER REGION -- ERN NC TO
SRN DELMARVA PENINSULA...
CORRECTED FOR MISSING 15% LINE
...SYNOPSIS...
IN MID/UPPER LEVELS...PROGRESSIVE WAVE TRAIN IS FCST TO SLOW AND
AMPLIFY DURING DAY-2 PERIOD ACROSS NRN CONUS. SHORTWAVE TROUGH WITH
SMALL EMBEDDED LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER
EXTREME ERN DAKOTAS/WRN MN -- WILL DEEPEN INTO LARGER CLOSED LOW AS
IT MOVES EWD ACROSS UPPER GREAT LAKES...REACHING MIN 500 MB HEIGHT
VALUE AROUND END OF PERIOD OVER ERN LH OR ADJACENT PORTIONS ONT.
ASSOCIATED SFC CYCLONE -- NOW ANALYZED OVER ERN IA/NWRN IL AND
SOMEWHAT DIFFUSED BY CONVECTIVE PROCESSES -- SHOULD REGAIN BETTER
DEFINITION AND DEEPEN CONSIDERABLY THROUGH REMAINDER DAY-1. BY
4/12Z...LOW SHOULD BE OCCLUDING OVER LH...BECOMING MORE CLOSELY
STACKED IN VERTICAL WITH MID-UPPER LEVEL PERTURBATION THEREAFTER.
SFC COLD FRONT -- NOW ANALYZED FROM LOW SWWD ACROSS SERN KS...SWRN
OK...TO SERN NM -- SHOULD MOVE RAPIDLY FROM CENTRAL/SRN APPALACHIANS
AT 4/12Z OFFSHORE MOST OF ATLANTIC COAST BY 5/12Z. SECONDARY
CYCLOGENESIS REASONABLY IS PROGGED ACROSS DELMARVA REGION WEDNESDAY
MORNING THROUGH AFTERNOON -- PERHAPS BEGINNING BEFORE 4/18Z INLAND
OVER VA. RESULTING SFC LOW SHOULD LIFT NEWD TOWARD CAPE COD BY END
OF PERIOD. TRAILING PORTION OF COLD FRONT SHOULD SWEEP SWD OVER
N-CENTRAL/NERN GULF...BUT WILL MOVE MORE SLOWLY SWD ACROSS S TX.
...DELMARVA...VA/NC TIDEWATER REGION...
SFC HEATING BEFORE COLD FROPA SHOULD WEAKEN CAP AND PERMIT TSTM
DEVELOPMENT. NRN BOUND OF SVR POTENTIAL SHOULD BE SHARPLY
DELINEATED BY POSITION OF WARM FRONT -- E OF DEVELOPING SFC
CYCLONE...LIKELY ACROSS SOME PART OF CHESAPEAKE BAY AND DELMARVA
PENINSULA. WARM SECTOR SFC DEW POINTS LOW-MID 60S AND INSOLATION
MAY RAISE MLCAPES INTO 1000-1500 J/KG RANGE. 35-45 KT DEEP-LAYER
SHEAR AND PROBABILITY OF LINEAR FORCING ALONG FRONT SUGGEST MAIN
THREAT WILL BE DAMAGING WIND. HOWEVER...RELATIVELY BACKED FLOW
ALONG ATLANTIC COAST WOULD ENLARGE LOW LEVEL HODOGRAPHS...ENHANCING
SUPERCELL POTENTIAL AND DIVERSIFYING SVR THREAT.
FRONTAL BAND OF CONVECTION MAY EXTEND MUCH FARTHER N OVER PORTIONS
PA/NJ AND POSSIBLY NY. HOWEVER...ASSOCIATED POTENTIAL FOR STG-SVR
GUSTS TO REACH SFC WILL BE GREATLY LIMITED BY STABLE BOUNDARY LAYER
THAT WILL BE PROGRESSIVELY DEEPER WITH NWD EXTENT.
...SC TO FL PANHANDLE...
SCATTERED TSTMS SHOULD DEVELOP FROM LATE MORNING THROUGH
AFTERNOON...INVOF SFC COLD FRONT. MOIST ADVECTION AND SFC HEATING
WILL RAISE BOUNDARY LAYER THETAE AND REMOVE CINH...WITH MLCAPES
1000-2000 J/KG RANGE POSSIBLE. LOW LEVEL SHEAR WILL BE
SIGNIFICANTLY LIMITED BY NEARLY UNIDIRECTIONAL COMPONENT OF FLOW
FROM SFC-700 MB...AND DEEP-LAYER BULK SHEAR SHOULD WEAKEN WITH SWWD
EXTENT...SW OF CATEGORICAL SLGT RISK AREA. THIS WILL LIMIT
ORGANIZATION OF SVR POTENTIAL...HOWEVER A FEW MULTICELLS OR SHORT
BANDS OF CONVECTION MAY PRODUCE GUSTS/HAIL NEAR SVR LEVELS.
ACTIVITY SHOULD DIMINISH CONSIDERABLY WITH LOSS OF DIURNAL HEATING.
...S TX...
PLUME OF VERY MOIST SFC AIR -- ALREADY IN PLACE ACROSS THIS REGION
-- WILL PERSIST THROUGH DIURNAL HEATING CYCLE DAY-2...AHEAD OF SFC
FRONT. ASSOCIATED BOUNDARY LAYER WILL BE CAPPED THROUGH MOST OF DAY
BY PRONOUNCED ELEVATED MIXED LAYER EMANATING FROM MEX HIGHLANDS.
HOWEVER...TSTMS MAY DEVELOP IN STRONGLY HEATED AND VERY UNSTABLE
AFTERNOON ENVIRONMENT...WITH AID FROM NEAR-FRONTAL CONVERGENCE.
MLCAPES 3000-4000 J/KG APPEAR LIKELY...SUPPORTING POTENTIAL FOR
STG-SVR GUSTS AND HAIL WITH ANY ACTIVITY THAT CAN DEVELOP OVER S TX.
FLOW IS FCST TO BE RELATIVELY WEAK THROUGH LOW-MIDDLE LEVELS...ONLY
5-15 KT. STRONG DIRECTIONAL SHEAR SHOULD EXIST IN ASSOCIATION WITH
BOUNDARY LAYER ELY COMPONENT NEAR FRONT...WHICH ALSO WOULD AID IN
STORM-RELATIVE INFLOW. DEVELOPMENT IS MORE PROBABLE OVER NEARBY
PORTIONS MEX WHERE OROGRAPHIC ASCENT ALSO WILL CONTRIBUTE. IN THIS
KINEMATIC PROFILE...STRONG ELEMENT OF DISCRETE PROPAGATION SHOULD BE
MAJOR INFLUENCE ON STORM MOTION -- KEEPING MOST STORMS THAT FORM ON
MEX SIDE OF RIO GRANDE AWAY FROM TX.
..EDWARDS.. 04/03/2007
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0800Z
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