SWODY2
SPC AC 280544
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1244 AM CDT SUN MAR 28 2010
VALID 291200Z - 301200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
PROGRESSIVE UPPER AIR PATTERN FCST THROUGH PERIOD...LED BY STG
SHORTWAVE TROUGH WITH EMBEDDED UPPER LOW NOW OVER OZARKS. THIS
TROUGH IS FCST TO MAINTAIN POSITIVE TILT WHILE MOVING EWD ACROSS
LOWER GREAT LAKES...OH...SRN APPALACHIANS AND CENTRAL GULF OF MEXICO
EARLY IN PERIOD. VERY STG NUMERICAL PROG CONSENSUS -- I.E.
OPERATIONAL WRF/SPECTRAL PLUS 18/21 SREF MEMBERS -- REDEVELOP 500 MB
LOW ALONG TROUGH BY 30/00Z...CENTERED OVER WRN NC/WRN VA REGION.
THIS LOW SHOULD MOVE NEWD TOWARD DELMARVA REGION BY END OF PERIOD.
AT SFC...CYCLONE NOW OVER SRN IL IS EXPECTED TO MOVE ENEWD GENERALLY
UP OH VALLEY AND WEAKEN DAY-1...WITH NEW/TRIPLE-POINT LOW FORMING BY
EARLY DAY-2 PERIOD INVOF COASTAL SC OR SERN NC..AND FRONTAL ZONE
CONNECTING EACH LOW. TRAILING COLD FRONT AT THAT TIME SHOULD EXTEND
SWWD OFFSHORE GA COAST AND ACROSS PORTIONS ERN/SRN FL
PENINSULA...MOVING OFFSHORE FL BY ABOUT 29/18Z.
...CAROLINAS/VA/MD...
CARRYING OVER FROM DAY-1 PERIOD...BAND OF TSTMS SHOULD BE ONGOING
ALONG OR JUST AHEAD OF FRONTAL ZONE AND N OF DEVELOPING COASTAL
LOW...FROM CAROLINAS TO COASTAL MID-ATLANTIC. MAIN CONCERN ATTM IS
ISOLATED STG/DAMAGING GUSTS WHERE NEAR-SFC STABLE LAYER IS NOT TOO
STG OR DEEP. INFLOW SECTOR FOR THIS CONVECTION MAY BE SFC-BASED
OVER NC AND PARTS OF VA...BECOMING PROGRESSIVELY MORE ELEVATED WITH
NWD EXTENT FROM ERN VA. ALSO...ELY COMPONENT OF SFC WINDS WILL
ADVECT RELATIVELY STABLE MARINE-LAYER AIR FROM ADJOINING PARTS OF
ATLANTIC ACROSS DELMARVA/NJ.
INITIAL BAND OF MORNING TSTMS MAY DEPART QUICKLY ENOUGH TO PERMIT A
FEW HOURS OF CLEARING WITH ADDITIONAL/DIABATIC SFC DESTABILIZATION
OF RESIDUAL MOIST BOUNDARY LAYER...BEFORE TOO MUCH CAA/DRY ADVECTION
OCCURS TO SUPPORT CONVECTION. MOST PROBABLE AREA FOR THIS PROCESS
APPEARS TO BE INTERIOR CAROLINAS...WHERE FCST SOUNDINGS SUGGEST
SUFFICIENT COOLING ALOFT TO SUPPORT UP TO ABOUT 1000 J/KG MLCAPE.
WEAK LOW-MIDLEVEL WINDS WILL PREVAIL...HOWEVER...SO ANY SVR CONCERN
WOULD BE DISORGANIZED AND MRGL FOR HAIL OR PULSE GUSTS.
...SRN FL PENINSULA...
BAND OF TSTMS IS EXPECTED TO CONTINUE FROM DAY-1 PERIOD AND MOVE EWD
ACROSS REMAINDER PENINSULA PRIOR TO FROPA. THIS WILL OCCUR PRIOR TO
STRONGEST SFC DIABATIC HEATING...ALTHOUGH ENOUGH PRE-STORM
INSOLATION MAY OCCUR NEAR SERN COAST TO BOOST MLCAPE TO AROUND 1000
J/KG. PREFRONTAL SFC WINDS WILL BE UNDERGOING VEERING
TREND...SUPPORTING LINEAR CHARACTER AND SOMEWHAT REDUCING SFC
CONVERGENCE AND LOW-LEVEL SHEAR WITH TIME. STILL...ETA-KF FCST
SOUNDINGS REASONABLY SUGGEST 35-45 KT OF EFFECTIVE SHEAR...WITH A
FEW EMBEDDED LEWP/BOW FORMATIONS POSSIBLE IN SUPPORT OF STG AND
PERHAPS DAMAGING CONVECTIVE GUSTS.
...NWRN CONUS...
HEIGHT FALLS FCST TO BEGIN EARLY IN PERIOD...OR EVEN LATE
DAY-1...AND CONTINUE THROUGHOUT DAY-2 AS SERIES OF MINOR SHORTWAVES
PASSES OVERHEAD...AMIDST BROADLY CYCLONIC/SWLY FLOW. STEEP
LOW-MIDLEVEL LAPSE RATES AND AT LEAST POCKETS OF MRGL LOW-LEVEL
MOISTURE WILL CONTRIBUTE TO POTENTIAL FOR WIDELY SCATTERED TSTMS.
COOLING ALOFT MAY OCCUR TO SUPPORT 100-300 J/KG MLCAPE...EVEN WITH
SFC TEMPS ONLY IN MID 40S TO MID 50S F IN LOWER ELEVATIONS INLAND.
FAST DEEP-LAYER FLOW WILL CONTRIBUTE TO RAPID STORM MOTIONS --
POTENTIALLY 50-60 KT...BUT WEAKNESS OF BUOYANCY ALSO MAY IMPERIL
CONTINUITY OF CONVECTIVE COLUMNS IN WHAT SHOULD BE STG DEEP-LAYER
SHEAR. SOME POTENTIAL MAY DEVELOP FOR STG-SVR GUSTS...BUT APPEARS
TOO CONDITIONAL...ISOLATED AND DISPERSED ATTM TO INTRODUCE SVR
PROBABILITIES. ISOLATED TSTMS ALSO ARE POSSIBLE THROUGHOUT MOST OF
PERIOD NEAR COAST...IN MRGLLY UNSTABLE MARINE AIR MASS WITH UP TO
ABOUT 200 J/KG MUCAPE.
..EDWARDS.. 03/28/2010
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