Flash Flood Warning 28, NWS State College, PA

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
205 AM EDT THU SEP 11 1997

...SUGGESTIONS...
FFA CAN BE DROPPED FOR SC PA SINCE HEAVIER PRECIP WILL HV MOVED N
AND E W/ PASSAGE OF SHRT WAVE BY ZONE TIME.
TODAY... BEST SHOT FOR ANTHR BATCH OF HEAVIER RAIN LATER TODAY WILL
BE SUS VLLY AND POINTS E WUD HV CAT POPS FOR RAIN... PSBL THUNDER.
SHUD BE A BREAK IN THE ACTION THIS AM IN PA. CNTRL/SC MTNS TO NRN
MTNS WILL SEE SHOWERS AND MAYBE A FEW THUNDERSTORMS ESP TWD AFTRN
AND EVE.
TONIGHT...PRECIP SHUD BE WINDING DOWN WITH MAINLY SCTRD ACVTY LEFT
OVER AFTR MIDNIGHT. SUS WILL SEE RAIN TAPERING TO SCTRD ACVTY
LATEST BY 0600 UTC FRI.
FRIDAY...PA UNDER COLD POOL WITH WRLY LL MOIST FLO. THINK SCTRD
SHRA WITH EMPHASIS ON MTN AREAS.

...DISCUSSION...
IR SATL IMAGERY SHOWG COLD TOPS BLOSSOMING OVR PA IN ASSCTN WITH A
SHRT WAVE RIPPLING NORTHWARD ON THE EAST-SIDE OF THE UPR TROF ACRS
THE ERN U.S. AN INTENSE MESOSCALE RAINBAND SET-UP ACRS SC AND C PA
LAST EVE AND ERLY THIS AM JUST W OF THE SUS RIVER AND HAS BEEN
DUMPED VERY HEAVY RAINS IN THESE AREAS. REPORTS OF NUMEROUS ROAD
CLOSINGS... SMALL STREAMS AT BANKFUL AND 2 WATER RESCUES HV BEEN
RECEIVED SO FAR AND EXPECT WE WILL BE RECEIVING MORE REPORTS AS THE
NIGHT WEARS ON. THIS MESOSCALE RAINBAND DVLPED IN ASSCTN W/ LL CONV
AS A MOIST LL ERLY FLO RUNS INTO A MORE NE FLO IN CNTRL PA. KCCX
AND KLWX VWP/S SHOWING ALMOST DUE SOUTH FLO FROM JUST ABV THE SFC
THROUGH 20 KFT. THE RAINBAND WAS ALIGNED PARRALLEL TO THE MEAN WIND
THROUGH THE TROPOSPHERE THUS WE HV BEEN SEEING SIGNIFICANT
TRAINING. W/ THE FREEZING LVL NR 13 KFT AND MUCH OF THE HIGHEST
REFLECTIVITY CORES BLO 10 KFT... THINK EFFIFICENT WARM RAIN
PROCESSES ARE TAKING PLACE AND PRECIP ESTIMATES LIKELY ARE
UNDERDONE. WE HV HAD SOME EVIDENCE OF THIS SO FAR.

THE SHRT WAVE THAT WAS MOVG NORTHWARD ACRS PA WAS DISRUPTING THE
MESOSCALE BAND AND PRODUCING ENUF ASCENT TO SPREAD THE PRECIP OUT
OVR A WIDER AREA IN C/SC PA. THIS WAVE WILL BE N OF CWA BY 1200 UTC
AND CERTAINLY WILL CLR AREAS IN THE FFA BY ZONE TIME... THUS MOST
OF THE HVY RAINS WILL BE GONE BY MORNING AND CUD DROP FLOOD
WATCHES. WE PROBABLY WILL HV FLOOD WARNINGS UP THRU SUNRISE TO CVR
HARD HIT AREAS.

AFTER THIS FIRST WAVE PASSES N... ANTHR ONE APPRCHES PA FOR THE
AFTRN AND EVE HOURS. THIS ONE LIKELY WILL SUPPORT ANTHR BATCH OF
RAINFALL INTO PA AFTER A LULL IN THE ACTION THIS MORNING.
ERN PA STANDS TO SEE THE HEAVIEST PRECIP GIVEN THE PRESENCE OF THE
LL THETA-E RDG WHICH STAYS PARKED IN ERN PA THRU 0000 UTC THIS EVE.
NEXT BATCH OF PRECIP LIKELY WILL EFFECT WRN PA... BUT PROBABLY
WON/T BE AS HEAVY.

AFTER THIS SECOND WAVE MVS N BY THIS EVE... COLD AIR AlLOFT WILL
COVER PA THRU FRIDAY WITH A LL WRLY FLO OF RATHER MOIST AIR TO
SUPPORT SCRTD SHRA... ESP FOR MTNS.

NICOSIA