Damaging Wind in Pennsylvania, August 31, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
155 AM EDT FRI AUG 31 2001

...SOME LOCALLY HEAVY RAINS POSSIBLE TONIGHT THEN DRYING...

THE COLD FRONT IS WELL TO OUR NORTH AND WEST THIS AFTERNOON...BUT THE
LEADING EDGE OF THE DRIER AIR IS ALREADY MOVING INTO THE REGION AND
TRIGGERING CONVECTION.   THE THETA FRONT IS ACTUALLY JUST BEHIND THE
LINE OF CLOUDS IN INDIANA TO SOUTHEASTERN MICHIGAN WHILE THE THETA-E
FRONT IS IN NW PENNSYLVANIA EXTENDING INTO OHIO.  WE WILL GET COOL
FROM THE FORMER AND THE RAIN WILL COME WITH THE LATTER.

THE MODEL MOISTURE FIELDS ARE ABOUT 1-2 STANDARD DEVIATIONS ABOVE
NORMAL THIS AFTERNOON AND TONIGHT.  THIS IMPLIES WE COULD SEE SOME
LOCALLY HEAVY RAINS UNDER ANY INDIVIDUAL THUNDERSTORM.  SOME
OROGRAPHICALLY FAVORED LOCATIONS COULD SEE 1-2 INCHES OF RAIN IN A
SHORT PERIOD OF TIME.  WIND PROFILES DO NOT RULE OUT A FEW HP
SUPERCELLS.

SREF DATA CONTINUES TO SHOW THREAT OF 0.25 AND GREATER RAINFALL OVER
THE WESTERN AND NORTHERN PARTS OF CENTRAL PA. HOWEVER...BY 6 AM
SATURDAY ALL QPF IS TO OUR EAST.  NO RAIN IS EXPECTED FROM STATE
COLLEGE WEST MUCH AFTER 9 PM TONIGHT.  THE BEST PERIOD FOR RAIN IS
BETWEEN NOW AND AND 4 AM SATURDAY. IN WESTERN SECTIONS THE RAIN
WILL END EARLIER. THE SREF POPS FOR 0.10 SUGGEST NO ACCUMULATED
RAINFALL WILL FALL AFTER 09Z SATURDAY.  BY SUNRISE ALL THE PRECIP
SHOULD BE OVER.

MODELS ALL SHOW QUICK AND STRONG DRYING FROM WEST TO EAST SATURDAY.
A CRISP LATE SUMMER AIR MASS WILL MARCH ACROSS PA. SHOULD BE ONE
NICE AFTERNOON SATURDAY FOR OUTDOOR ACTIVITIES. CRISP NIGHT FOR
EARLY SEPTEMBER SAT NIGHT INTO SUNDAY.  SOME COLDER VALLEYS WILL DIP
BELOW 40 AND INTO THE MID 30S BY SUNRISE SUNDAY.

...EXTENDED...

AFTER A TASTE OF AUTUMN THIS WEEKEND...SUMMER LIKE WEATHER WILL
SLOWLY RETURN TO THE REGION DURING THE WEEK.  MONDAY STARTS OUT WITH
SLIGHTLY BELOW NORMAL LOW-LEVEL TEMPS BUT BY TUESDAY WE REBOUND TO
NEAR NORMAL. INITIALLY...THE SURFACE HIGH WILL KEEP US DRY AND
PLEASANT. HOWEVER...ENSEMBLES SHOW A RIDGE...ABOUT +1.5 STANDARD
DEVIATIONS ABOVE NORMAL BUILDING OVER THE NORTHERN LAKES. THIS WOULD
LEND IT SELF TO AN INCREASE IN THE HUMIDITY AND DAILY TEMPS OVER THE
REGION TUESDAY INTO THURSDAY.  WITH 850 TEMPS AND THICKNESS VALUES NEAR
NORMAL WOULD EXPECT TO SEE NEAR NORMAL TEMPERATURES.

THE PATTERN IS NOT OVERLY CONDUCIVE FOR HEAVY RAINS.  THE
LOW-LEVEL AND UPPER LEVEL FLOW IS QUITE WEAK SUGGESTING UNLESS THERE
IS A BIG CHANGE...IT WILL BE A RELATIVELY DRY WEEK THROUGH AT LEAST
THURSDAY.  OUR ONLY HOPE FOR RAIN WOULD BE IF WE GET SOME NOCTURNAL
ACTIVE CONVECTION DOWNSTREAM OF THE RIDGE ONCE IT GETS ESTABLISHED
BY MID WEEK.

.CTP...NONE.

GRUMM/LACORTE

PAZ027-028-037-041-042-046-049>053-056>059-066-010100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
310 PM EDT FRI AUG 31 2001

...A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 900 PM EDT FRIDAY
EVENING FOR THE FOLLOWING COUNTIES IN CENTRAL PENNSYLVANIA...

LEBANON...MONTOUR...NORTHUMBERLAND...UNION...SULLIVAN...JUNIATA...
LYCOMING...PERRY...TIOGA...DAUPHIN...LANCASTER...SCHUYLKILL...
COLUMBIA... SNYDER AND MIFFLIN.

A SEVERE THUNDERSTORM WATCH MEANS THAT SEVERE THUNDERSTORMS ARE
POSSIBLE IN AND CLOSE TO THE WATCH AREA...PRODUCING DAMAGING
WINDS..LARGE HAIL..AND FREQUENT LIGHTNING.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH...
DESTRUCTIVE HAIL...FREQUENT LIGHTNING...AND VERY HEAVY RAIN. FOR YOUR
PROTECTION...MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAIN FLOODS ROADS QUICKLY SO DONT DRIVE INTO
AREAS WHERE WATER COVERS THE ROAD.

JUNG