Severe Thunderstorm Warning 162, NWS State College, PA

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
850 PM EDT MON JUL 20 1998

...ZONES WL BE AVBL TO PIT/PHL VIA ADMCTP AROUND 920 PM...

...DISCUSSION...

FAIRLY CLEAR AND QUIET EARLY EVENING ACROSS CENTRAL AND WESTERN PA
IS NO INDICATION OF WHAT WILL ARRIVE IN JUST AN HOUR ACROSS THE
NORTHWEST COUNTIES...AND PROBABLY THROUGH THE REMAINDER OF THE
NORTHWEST OF ROUTE 220 (I.E. KAOO TO KIPT LINE) BY 04-05Z. SPC JUST
SENT PRELIM MESSAGE FOR SVR TSRA WATCH TIL 07Z.

DCURRENT LARGE SCALE BOW ECHO MOVING INTO NW PA WILL MAINTAIN ITS
BEST STRENGTH ON THE SRN FLANK AS IT MOVES/DEVELOPS SE ALONG THE
BEST MESOSCALE INSTABILITY/MOIST CONVERGENCE AXIS. NEW DEVELOPMENT
EXPECTED WITH A WEAK SHORT WAVE/AREA OF H250 DIVERGENCE LATER
TONIGHT MAY SHOW PREFERENCE FOR FORMING ACROSS SWRN PA AND THE
LAUREL HIGHLANDS ALONG THE OUTFLOW BOUNDARY FROM THE CURRENT SQUALL
LINE.

DIFFICULT QPF FORECAST WITH EXTREME RANGE IN PRECIP BETWEEN
GRIDPOINTS ONLY 100 MI APART. STRONG BELT OF WESTERLIES ALOFT WILL
GRADUALLY SETTLE SOUTH OVER THE GREAT LAKES AND U.S/QUEBEC BORDER
DURING THE NEXT 48 HOURS IN CONJUNCTION WITH SLOWLY FALLING HEIGHTS.

BAND OF STRONG LLVL CONVERGENCE/VVEL WILL SET UP ALONG A QUASI STNRY
FRONT...WHICH WILL EVENTUALLY BECOME STRUNG OUT ON A KORD TO KCLE
AND KROC LINE BY EARLY WED AFTERNOON.

QPF AMOUNTS OVER 2.0 PROJECTED BY THE ETA ACROSS THE NW COUNTIES
OF PA WITH GENERALLY .25 TO .50 SE OF KAOO AND KIPT.

THUS...I DONT HAVE A HIGH DEGREE OF CONFIDENCE IN ETA QPF...WHICH
MAY ACTUALLY BE THE HIGHEST OVER THE SW AND SCENT COUNTIES DURING
THE NEXT 18 TO 24 HOURS.

WILL RE-ISSUE AN SPS FOR POTENTIAL HEAVY RAINS AND KEEP A CLOSE EYE
ON MVMT/REDEVELOPMENT OF TSRA OVER OHIO FOR A POSSIBLE FLASH FLOOD
WATCH.

MBE (MESO BETA ELEMENT) VECTORS VIA ETA HOURLY PROFILE DATA ARE WEAK
FROM THE SSE SUGGESTING A STRONG TENDENCY FOR TRAINING ECHOES
OVERNIGHT.

WILL ADJUST WORDING OF PRECIP OVERNIGHT AND UP POPS IN ALL AREAS OF
THE CENT AND WEST.

.CTP...SEVERE THUNDERSTORM WATCH TIL 07Z FOR
       PAZ004>006-010-011-017>019-024>026-033-034

LAMBERT

PAZ004>006-010>012-017-018-024-211505-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
411 AM EDT TUE JUL 21 1998

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER NORTHWESTERN PENNSYLVANIA...

A VERY WARM...MOIST AND UNSTABLE AIR AND A WEAK NORTH TO SOUTH
FRONTAL BOUNDARY WILL BRING THE POTENTIAL FOR SEVERE THUNDERSTORMS
OVER NORTHWESTERN PENNSYLVANIA THIS AFTERNOON AND EVENING.

THUNDERSTORMS LATER THIS AFTERNOON COULD PRODUCE STRONG
STRAIGHT LINE WINDS AND LOCALLY HEAVY DOWN RAIN.

IT IS ANTICIPATED THAT THUNDERSTORMS WILL DEVELOP IN THE
LATER AFTERNOON OR EARLY EVENING HOURS.

SKYWARN ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON OR
EVENING.

STAY TUNED TO NOAA WEATHER RADIO...RADIO OR TELEVISION FOR THE
LATEST UPDATES CONCERNING THIS DEVELOPING WEATHER SITUATION.
GRUMM/FITZGERALD

PAZ004>006-010>012-017-018-024-211505-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
411 AM EDT TUE JUL 21 1998

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER NORTHWESTERN PENNSYLVANIA...

A VERY WARM...MOIST AND UNSTABLE AIR AND A WEAK NORTH TO SOUTH
FRONTAL BOUNDARY WILL BRING THE POTENTIAL FOR SEVERE THUNDERSTORMS
OVER NORTHWESTERN PENNSYLVANIA THIS AFTERNOON AND EVENING.

THUNDERSTORMS LATER THIS AFTERNOON COULD PRODUCE STRONG
STRAIGHT LINE WINDS AND LOCALLY HEAVY DOWN RAIN.

IT IS ANTICIPATED THAT THUNDERSTORMS WILL DEVELOP IN THE
LATER AFTERNOON OR EARLY EVENING HOURS.

SKYWARN ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON OR
EVENING.

STAY TUNED TO NOAA WEATHER RADIO...RADIO OR TELEVISION FOR THE
LATEST UPDATES CONCERNING THIS DEVELOPING WEATHER SITUATION.
GRUMM/FITZGERALD