National Weather Service Raw Text Product

276 
ACUS1 KMKC 021942
SWODY1
MKC AC 021942

CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O.

VALID 021930Z - 031200Z

REF WW NUMBER 0491...VALID TIL 0010Z

THERE IS A MDT RISK OF SVR TSTMS THROUGH THIS EVENING FOR EASTERN
OHIO...MUCH OF WEST VIRGINIA...PENNSYLVANIA...SOUTHERN NEW YORK...
NEW JERSEY...MARYLAND...DELAWARE...AND CENTRAL AND NORTHERN
VIRGINIA.  THE AREA IS TO THE RIGHT OF A LINE FROM 30 NE ORF 30 S
RIC 25 NE DAN BLF HTS 10 SE CLE 15 S BUF 15 N ITH 45 WSW ALB 20 E
NEL.

SURROUNDING THE MODERATE RISK...THERE IS A SLGT RISK OF SVR TSTMS
TO THE RIGHT OF A LINE FROM 15 ESE SAV 25 WNW AND 40 NW CSV 15 ESE
SDF DAY 45 SE DTW ...CONT... 15 WNW ART 25 NE PSF 15 SW EWB.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 NNE SSI 20 W CHA
HOP EVV IND 35 SW JXN 45 SE OSC ...CONT... 45 NNE BML 20 SW BHB.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 WNW OFK 30 S EAR
CYS 30 NNE RKS ENV TPH 30 NE FAT 45 NW SAC 35 E 4BK 20 ESE SEA
40 ENE GEG 3DU 40 N COD GCC 45 ENE CDR 40 WNW OFK.

...SEVERE THUNDERSTORM FORECAST DISCUSSION...

...CENTRAL APPALACHIANS TO THE MIDDLE ATLANTIC STATES...

APPROACHING SHORT WAVE TROUGH IS EXPECTED TO ENHANCE RAPID INCREASE
IN THUNDERSTORM COVERAGE AND INTENSITY DURING THE AFTERNOON HOURS
ALONG ADVANCING COLD FRONT.  

POTENT VORTICITY MAXIMUM OVER THE EASTERN GREAT LAKES IS FORECAST
TO SWEEP EAST ACROSS THE NORTHEAST AND NEW ENGLAND TONIGHT.  ETA
MODEL FORECASTS ENORMOUS UVV MAXIMUM WITH THIS FEATURE...ESPECIALLY
THIS EVENING OVER NEW YORK AND PENNSYLVANIA.  

ANOTHER FEATURE OF NOTE IS DRYING ON WATER VAPOR IMAGERY MOVING
ACROSS OHIO AT THIS TIME.  THIS APPEARS TO BE EXIT REGION OF STRONG
UPPER LEVEL JET.  SIGNIFICANT SUPERCELL IS ALREADY OCCURRING WITH
THIS FEATURE OVER CENTRAL WEST VIRGINIA.  DUE TO DEGREE OF
DYNAMICS...THIS ACTIVITY MAY BE ABLE TO SPREAD ACROSS THE
APPALACHIANS LATE THIS AFTERNOON AND THIS EVENING. 

LOW LEVEL CONVERGENCE AND SURFACE PRESSURE FALLS HAVE BEEN
INCREASING FROM CENTRAL NEW YORK INTO CENTRAL VIRGINIA.  STRONG
WESTERLY MID LEVEL FLOW IS ENHANCING LEE TROUGHING IMMEDIATELY EAST
OF HIGHER TERRAIN FROM CENTRAL PENNSYLVANIA TO CENTRAL VIRGINIA. 
IN RELATION TO THIS FEATURE...A NARROW TONGUE OF HIGHER LOW LEVEL
MOISTURE WITH DEWPOINTS IN THE 60S EXTENDS AS FAR NORTH AS SOUTH
CENTRAL PENNSYLVANIA.  THUS...COMBINATION OF NEW DEVELOPMENT AND
ACTIVITY MOVING OVER THE MOUNTAINS FROM THE WEST SHOULD INCREASE
RAPIDLY BY EARLY THIS EVENING.  

THROUGHOUT THIS AREA AND ESPECIALLY IN MODERATE RISK AREA...DEGREE
OF DEEP LAYER VERTICAL WIND SHEAR STRONGLY SUGGESTS POTENTIAL FOR
SUPERCELLS.  ETA FORECAST OF 300-600 M2/S2 0-3 KM STORM RELATIVE
HELICITY IMPLIES ISOLATED SIGNIFICANT TORNADOES ARE POSSIBLE AS
WELL.  

..CRAVEN.. 06/02/98