Severe Thunderstorms Possible on Saturday in VA/NC/MD

[VAWXWatcher6]

...CAROLINAS THROUGH THE MID ATLANTIC AREA...

A STRONG VORT MAX AND 80 KT MID LEVEL JET IS CURRENTLY MOVING SEWD
INTO THE UPPER MS VALLEY AREA. THIS FEATURE WILL AMPLIFY SEWD INTO
THE MEAN TROUGH POSITION OVER THE ERN U.S. SATURDAY ACCOMPANIED BY
A COLD FRONT AND SURFACE LOW. BY LATE TOMORROW AFTERNOON THE FRONT
SHOULD EXTEND FROM A SURFACE LOW OVER PA SWWD THROUGH THE CAROLINAS
THEN WWD INTO THE SERN U.S..

STORMS SHOULD BE ONGOING SATURDAY MORNING IN ZONE OF WARM ADVECTION
FROM PA SWD THROUGH THE CAROLINAS. LINES AND EMBEDDED SUPERCELLS
SHOULD BE THE PRIMARY MODES WITH THREAT FOR MAINLY DAMAGING WIND
AND HAIL AS STORMS CONTINUE EWD DURING THE MORNING. UNCERTAINTIES
REGARDING EVOLUTION OF ONGOING STORMS WILL BE PRIMARY COMPLICATING
FACTOR. ONE SCENARIO IS THAT THESE STORMS MAY INTENSIFY AS THE
ATMOSPHERE DESTABILIZES DOWNSTREAM. ANOTHER SCENARIO IS ADDITIONAL
STORMS MAY DEVELOP UPSTREAM ALONG FRONT OR LEE TROUGH AS ATMOSPHERE
DESTABILIZES IN WAKE OF EARLY STORMS. COLDER MID LEVEL TEMPERATURES
N OF THE JET AXIS IN MID ATLANTIC SUGGEST UPPER 50S BOUNDARY LAYER
DEWPOINTS MAY PROVE SUFFICIENT FOR MODERATE INSTABILITY WHERE
SURFACE HEATING CAN OCCUR. FARTHER S INTO THE CAROLINAS...DEWPOINTS
IN THE 60S WILL LIKELY BE NEEDED TO DEVELOP MODERATE INSTABILITY
DUE TO WARMER AIR ALOFT. DEWPOINTS ARE NOW IN THE 50S OVER THE
CAROLINAS AND VALUES INCREASING TO THE 60S DOES NOT SEEM
UNREASONABLE GIVEN EXPECTED STRONG SWLY LOW LEVEL JET WHICH SHOULD
ADVECT HIGHER MOISTURE NOW RESIDING OVER THE LOWER MS VALLEY.

VERY STRONG SHEAR WILL ACCOMPANY THE UPPER TROUGH AND ITS
ASSOCIATED JETS WITH DEEP SHEAR IN EXCESS OF 50 KT AND LOW LEVEL
HELICITY FROM 300 TO 400 M2/S2 ALONG LOW LEVEL JET AXIS FROM THE
CAROLINAS INTO THE MID ATLANTIC AREA. THUS...WHERE SUFFICIENT
DESTABILIZATION OCCURS...ORGANIZED STORMS WILL BE LIKELY INCLUDING
LINES/BOWS AND SUPERCELLS. DAMAGING WIND...LARGE HAIL AND ISOLATED
TORNADOES WILL BE POSSIBLE. GIVEN POTENTIAL FOR SIGNIFICANT WIND
DAMAGE AND TORNADOES...PORTIONS OF THE CAROLINAS INTO THE MID
ATLANTIC MAY BE UPGRADED TO MODERATE RISK IN DAY 1 OUTLOOKS


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This is from (SPC Day 2) (1730 Update)

[Stephanie]

I think that there's a possibility for strong to severe thunderstorms in the Philadelphia area as well tomorrow (which is also a part of the Midatlantic).

[VAWXWatcher6]

...MID-ATLANTIC...
DYNAMIC SHORT WAVE TROUGH EXPECTED TO BE OVER THE CENTRAL GREAT
LAKES/LOWER OH VALLEY AT 12Z...WITH AN 80 KT 500 MB JET IN THE BASE
OF THE TROUGH WILL TRACK SEWD INTO THE MID-ATLANTIC STATES TODAY.
THIS FEATURE WILL DEEPEN LATE TONIGHT AS A CLOSED LOW DEVELOPS OFF
THE NJ COAST BY 12Z SUNDAY. SURFACE LOW AND TRAILING COLD FRONT
ACCOMPANYING THE UPPER TROUGH WILL MOVE SEWD INTO THE MID-ATLANTIC
STATES. THE SURFACE LOW IS EXPECTED TO BE OVER FAR SWRN PA BY LATE
AFTERNOON...AS A SECONDARY LOW DEVELOPS IN LEE OF THE APPALACHIANS
OVER SWRN VA. COLD FRONT WILL EXTEND FROM WRN VA SWWD THROUGH THE
WRN CAROLINAS AND THEN WSWWD INTO THE CENTRAL GULF COAST STATES.

AS THE UPPER TROUGH MOVES ACROSS THE CENTRAL APPALACHIANS THIS
MORNING INTO THE EARLY AFTERNOON...STRONG SWLY LLJ WILL ADVECT
MOISTURE NEWD INTO THE CAROLINAS AND SRN/SERN VA AIDING IN
DESTABILIZATION...WITH LOWER TO MIDDLE 60S SURFACE DEWPOINTS
EXPECTED INTO THIS REGION BY 18Z.

CONVECTION EXPECTED TO BE ONGOING AT THE BEGINNING OF THE PERIOD
FROM OH SWD INTO ERN TN WILL CONTINUE EWD AND INCREASE IN INTENSITY
EAST OF THE APPALACHIANS BY EARLY AFTERNOON WITHIN AN INITIALLY
MARGINALLY UNSTABLE AIR MASS. STRONG DEEP AND LOW-LEVEL SHEAR WILL
FAVOR LINE SEGMENTS AND SUPERCELLS FROM VA SWD INTO SC WITH THIS
LEADING AREA OF CONVECTION. GIVEN THE STRONG WIND FIELDS...
DAMAGING WINDS...HAIL AND ISOLATED TORNADOES WILL BE LIKELY.

SWLY LOW-LEVEL WINDS WILL CONTINUE TO ADVECT MOISTURE NEWD WITH
MODERATE INSTABILITY EXPECTED TO EXTEND NWD INTO SRN/SERN VA.
ADDITIONAL STORMS WILL DEVELOP ALONG THE COLD FRONT BY MID
AFTERNOON FROM WRN VA SWD INTO CENTRAL NC...WITH A CONTINUED THREAT
FOR DAMAGING WINDS...ISOLATED TORNADOES AND HAIL. THIS LINE OF
STORMS ALONG THE COLD FRONT WILL MOVE EWD INTO SRN MD/SERN VA/ERN
NC BY 00Z. AS THIS OCCURS...DAMAGING WIND THREAT IS EXPECTED TO
INCREASE AS THE LLJ VEERS TO WLY...WITH THIS SQUALL LINE MOVING OFF
THE DELMARVA AND NC COAST BY 03Z.

[VAWXWatcher6]

...MID ATLANTIC REGION...
A BAND OF PRE-FRONTAL/WARM CONVEYOR-BELT TSTM ACTIVITY SHOULD
CONTINUE EAST ACROSS VA AND ERN NC THIS MORNING WITHIN WEAKLY
UNSTABLE AIRMASS. INCREASINGLY STRONG WLY FLOW ACROSS THE MOUNTAINS
WILL RESULT IN STRONG LEE-TROUGHING AND STEEPENING BOUNDARY LAYER
LAPSE RATES BY AFTERNOON WITH AN AXIS 500-1500 J/KG MLCAPE
DEVELOPING FROM NRN VA SWWD INTO SC BY 18 UTC. RAPID ADVANCE OF
UPPER FORCING /90-120M MID LEVEL HEIGHT FALLS SPREADING ACROSS THE
MOUNTAINS/ SUGGESTS COLD FRONT WILL QUICKLY REDEVELOP INTO THE LEE
TROUGH POSITION WITH LARGE SCALE ASCENT AND DESTABILIZATION DRIVING
RAPID INTENSIFICATION OF CONVECTION ALONG/AHEAD OF THE SURFACE
FRONT BETWEEN 18-20 UTC/2-4PM EDT. DEEP LAYER SHEAR VECTORS RANGING
FROM 40-60KT ORIENTED NORMAL TO THE LOW LEVEL LINEAR FORCING WILL
FAVOR THE DEVELOPMENT OF FAST MOVING LINE SEGMENTS AND SUPERCELLS.
PRIMARY SEVERE WEATHER THREAT IS EXPECTED TO BE WIDESPREAD
POTENTIAL FOR DAMAGING WINDS WITH EVOLVING BOW ECHO/SQUALL LINE AS
MID LEVEL JET CORE AND MID/UPPER LEVEL DRY AIR INTRUSION SPREAD
ACROSS ERN VA/NC. HOWEVER...BREAKS WITHIN THE LINE...AND POTENTIAL
FOR STRONG TO INTENSE LOW LEVEL SHEAR INDICATE TORNADOES COULD
OCCUR ALONG/WITHIN THE CONVECTIVE LINE...AND ALSO NEAR THE SURFACE
LOW AS IT MOVES ACROSS THE DELMARVA DURING THE EVENING. BULK OF
CONVECTION SHOULD BE OFFSHORE OF THE NC CAPES BEFORE MIDNIGHT AS
COASTAL LOW WRAPS UP OFF THE NJ COAST.