Flash Flood in Pennsylvania, August 12 to 13, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
930 PM EDT SUN AUG 12 2001

BUSY EVE WITH FFW AND MULTIPLE FFS FOR YORK AND LANCASTER COUNTIES
AS MCS MOVED ACROSS OUR S COUNTIES. FRANKLIN AND ADAMS COUNTIES
RECEIVED HEAVY RAIN BUT IT FELL ON THIRSTY FARMLAND AND THERE WERE
NO PROBLEMS. AS THE MCS ROLLED INTO YORK COUNTY THOUGH...AN E/W BAND
OF TSRA DEVELOPED OVR LANCASTER AND EASTERN YORK COUNTIES. THIS
MATCHED UP PRETTY WELL WITH THE NORTHERN END OF THE SEA BREEZE FROM
THE CHESAPEAKE BAY. THE DEWPTS IN THE MARINE AIR WERE IN THE MID 70S
AND WERE BEING FED BY A SOUTHERLY FLOW ORIGINATING OFF THE GULF
STREAM S OF HAT. TO THE N OF THE BOUNDARY...DEWPTS WERE CLOSER TO
70. IT APPEARED THAT THE MCS WOULD PROPAGATE ALG THIS DEVELOPING
BOUNDARY. A FFW WAS ISSUED AND WAS VERIFIED IN LANCASTER COUNTY BUT
NOT IN YORK.

WE ARE STILL WATCHING THE PEQUEA AT PARADISE WHERE THE CREEK HAS
RISEN TO WITHIN A FOOT OF FLOOD STAGE. THE RISE IS SLOWING DOWN BUT
IT IS GETTING CLOSE. IF ANOTHER WARNING COMES OUT OF THIS OFFICE
TONIGHT IT WILL BE A FLOOD WARNING FOR THAT POINT.

OTHW...A NEW BKN LINE OF TSRA ARE DEVELOPING ALG BLUE MTN BETWEEN
SCHUYLKILL AND BERKS COUNTIES. THIS WILL NEED MONITORING AS WELL BUT
SO FAR RAINFALL HAS AMOUNTED TO UNDER AN INCH OVR 3 HRS AND IS BEING
SPLIT BY THE RDG INTO 2 SEPARATE BASINS. THE CELLS ARE SLOW MOVG BUT
ARE NOT AS PROLIFIC RAIN PRODUCERS AS THE STORMS FURTHER S HAVE
BEEN. THIS AREA IS EXPANDING/BACK BUILDING INTO THE HARRISBURG AREA

FURTHER N AND W...THERE ARE WIDELY SCT TSRA DEVELOPING THIS EVE OVER
OUR FAR NW COUNTIES. THERE IS NOTHING OVR THE LAURELS. AND ONLY ONE
SMALL SHRA OVR WESTERN JUNIATA COUNTY. SO I WILL UPDATE TO LOWER BUT
NO ELIMINATE POPS AND TAKE OUT THE HEAVY AT TIMES WORDING IN ALL
ZONES BUT THE LWR SUSQ WHERE I WILL LOWER POPS TO 50 PERCENT BUT
LEAVE IN A FEW MAY BE HEAVY WORDING.

CTP...NONE

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