Flash Flood Warning 1, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
847 PM EDT SAT MAY 23 2009

.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE LATE THIS
AFTERNOON AND INTO THE EVENING HOURS OVER THE SOUTH CENTRAL
MOUNTAINS AND LOWER SUSQUEHANNA VALLEY...SOUTH OF AN OLD FRONTAL
ZONE ORIENTED IN VICINITY OF INTERSTATE 80. A SLOW MOVING COLD
FRONT WILL MOVE ACROSS THE REGION ON SUNDAY AND TRIGGER ADDITIONAL
SHOWERS AND THUNDERSTORMS. THIS FRONT WILL EVENTUALLY BECOME
NEARLY STATIONARY SOUTH OF THE MASON-DIXON LINE EARLY NEXT WEEK.
MEANWHILE...HIGH PRESSURE WILL MOVE FROM CENTRAL ONTARIO INTO
NORTHERN NEW ENGLAND AND PROVIDE FAIR AND DRY WEATHER FOR MOST OF
THE AREA FOR MEMORIAL DAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
EVENING CONVECTION HAS PRETTY MUCH MET EXPECTATIONS WITH
RESPECTABLE BUT NOT IMPRESSIVE CAPES LEADING TO ELEVATED HEAT
SOURCE CONVECTIVE INITIATION AND DISSIPATION FOR MOST OF THE PAST
5 HOURS. WEAK MCV NOW APPEARS TO BE KEEPING CONVECTION OVER SOUTH
CENTRAL PA ALIVE BEYOND THE DIURNAL MAXIMUM...BUT IT APPEARS THIS
WILL DIMINISH AS IT FINALLY MOVES OFF THE HIGHER TERRAIN IN
FRANKLIN COUNTY.

CONVECTION HAS BEEN LIMITED TO TWO 850-700 MB THETA-E RIDGES...
MAIN ONE EXTENDING FROM THE LAURELS NEWD TO NRN PORTIONS OF THE
LOWER SUSQ...AND SECONDARY RIDGE OVER THE ENDLESS MOUNTAIN REGION.
ALL SIGNS POINT TO CONTINUED WEAKENING OF CURRENT ACTIVITY WITH
ONLY ISOLATED AT BEST SHOWERS IN THE AFOREMENTIONED AREAS
OVERNIGHT. SOME GOOD RAINERS THIS EVENING WILL LEAD TO FOG
FORMATION IN A FEW HOURS. OTHERWISE GOING FORECAST HAS THINGS WELL
IN HAND.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
WITH THE FRONT WAGGLING SLIGHTLY TO THE SOUTH TONIGHT...SCATTERED
EVENING TSRA SHOULD OCCUR IN THE EAST...BUT THESE SHOULD WANE AS
MIDNIGHT APPCHS. AGAIN...NO REAL LARGE SCALE TRIGGER SEEN THAT
WOULD CAUSE WIDESPREAD ACTIVITY...BUT CANNOT GUARANTEE IT WILL BE
TOTALLY DRY EITHER...ESP AROUND MDT/LNS AND WELL TO THE EAST OF
IPT. CHC POPS FOR THE EVENING WILL TAPER TO SLIGHT CHCS AFTER
MIDNIGHT. SHOULD BE A MILD NIGHT WITH VARIABLY CLOUDY SKIES NOT
ALLOWING FOR MUCH RAD COOLING.

SUNDAY LOOKING LIKE A MORE-ACTIVE DAY...WITH CONVECTION A LITTLE
MORE WIDESPREAD THAN TODAY...BUT STILL CONFINED TO THE S/ERN TWO-
THIRDS OF THE AREA. FRONT WILL BE ALONG OR JUST N OF THE MASON-
DIXON LINE. BUT STILL VERT MOTION AND VORTICITY ADVECTION WILL
WORK AGAINST DEEP CONVECTION. THE SHEAR IS STRONGER THAN SAT...AND
DEWPOINTS JUST AS HIGH IN THE SRN HALF. THIS SHOULD ALLOW SCT AFTN
CONVECTION WITH JUST A VERY LOW CHC OF HIGHER WIND GUSTS AND
SMALL HAIL AGAIN SUN AFTN/EVE. THE AREA MUST GET SOME SUNSHINE TO
REALIZE THE MODEST CAPES IN THE FCST SOUNDINGS. THIS MAY BE
POSSIBLE IN THE MORNING...ESP IN THE CENT COS.

DRYING SHOULD COME TO THE REGION FROM N TO S SUN NIGHT...AS THE
BOUNDARY SINKS SOUTHWARD INTO VA. CLEARING LIKELY IN THE NORTH
WHERE LOWS MAY TOUCH 40F IN THE COLDER VALLEYS. WILL LINGER JUST A
20 POP ALONG THE SRN BORDER...BUT DRYING AND NEG MOISTURE AND VORT
ADV WILL SPELL A SHORT RESPITE FROM THE ENDLESS SCT SHRA.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
SFC HIGH PRESSURE WILL MOVE ESEWD ACROSS CENTRAL ONTARIO AND INTO
NORTHERN NEW ENGLAND MON-TUE...IN THE WAKE OF A BROAD LOW-AMPLITUDE
UPPER LVL TROUGH. A SLOW MOVG CLD FNT FCST TO CROSS THE REGION ON
SUNDAY WILL BECOME Q-STNRY SOUTH OF THE MASON-DIXON LINE
MONDAY...THEN BEGIN TO WORK ITS WAY NWD AS A WARM FNT TUE-WED.
ANTICYCLONIC/NELY LLVL FLOW SHOULD KEEP THE NORTHERN 2/3RDS OF THE
CWA FAIR AND DRY FOR MEMORIAL DAY...WITH ONLY A SLGT SCHC FOR AN
AFTN SHRA OR ISOLD TSRA OVER THE SRN TIER /MAINLY SOUTH OF RT22/
WHERE PW/S WILL REMAIN ABOVE NORMAL AND DEWPOINTS HOLD IN THE
55-60F RANGE.

MDLS INDICATE THAT THE AREA OF LOW PRESSURE...CURRENTLY ALONG THE
CENTRAL GULF COAST INVOF MS/AL BORDER...WILL BECOME SLIGHTLY MORE
ORGANIZED AS IT DRIFTS NWWD OVER THE MID MS VLY BY MID-WEEK.
MEANWHILE THE LOW LEVEL FLOW WILL CONTINUE TO VEER AROUND TO THE
SOUTHEAST...ALLOWING PWS WILL SURGE TO +2-3SD OR BTWN 28-36MM
/1-1.5 INCHES/. WITH THE AFOREMENTIONED BNDRY DRAPED OVER THE
REGION...THE WEATHER LOOKS VERY UNSETTLED AS A SERIES OF SHRT/WV
DISTURBANCES TRANSLATE EWD WITHIN A LARGELY ZONAL/CONFLUENT MID TO
UPPER LVL FLOW REGIME. TUESDAY LOOKS RELATIVELY COOL /MID-UPPER
60S/ NORTH OF THE WARM FNT WITH A MOIST ONSHORE ELY FETCH. TEMPS
SHOULD REBOUND INTO THURSDAY AS THE AREA ENTERS THE WARM SECTOR
AHEAD OF THE NEXT FRONTAL SYSTEM MOVG THROUGH THE GRT LKS/OH VLY.
FROPA TIMING DIFFS ARE OBVIOUS AT THIS RANGE...BUT THE GEFS SHOWS
HIGH PRES BUILDING BACK INTO CENTRAL PENN BY THE START OF THE
WEEKEND. THE GEFS MEAN H5 HEIGHTS ALSO SUGGEST INCREASING
AMPLITUDE IN THE LARGE SCALE PATTERN BY WEEKS END...TRANSITIONING
TO AN WCENT NOAM RIDGE/ERN TROF CONFIGURATION.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
NEARLY STATIONARY COLD FRONT DRAPED ACROSS NORTHERN PA THIS
EVENING WITH DRIER AIR TO THE NORTH AND WARMER MORE HUNID AIR TO
THE SOUTH. CLUSTER OF TSTORMS HAS PERSISTED EARLY THIS EVENING
ESPECIALLY IN THE VICINITY OF KJST/KAOO IN THE SW...WITH VERY
ISOLATED CONVECTIVE ACTIVITY ELSEWHERE. ACTIVITY ACROSS THE SOUTH
LOOKS TO BE GRADUALLY WEAKENING AND TREND SHOULD CONTINUE THROUGH
MID EVENING. OUTSIDE OF STORMS...VFR WILL PREVAIL.

LATER TONIGHT SOME MVFR FOG/HZ WILL FORM WITH LIGHT WINDS AND LOW
LEVEL MOISTURE IN PLACE...ESPECIALLY WHERE IT RAINED EARLIER
TODAY...BUT CONVECTION SHOULD TAKE A BREAK FOR A WHILE.

A BIT MORE SHRA/TSRA EXPECTED ON SUNDAY WITH SLIGHTLY HIGHER
VERTICAL SHEAR PROFILE. DEWPOINTS REMAIN HIGH AND IT COULD BE A
BIT HAZY IN THE S. HEATING MAY BE A BIT WEAK DEPENDING ON HOW MUCH
SUNSHINE WE RECEIVE. THUS...STILL SOME VERY LOW CHC FOR A GUSTY
TSRA.

OUTLOOK...
MON...AM FOG PSBL...THEN VFR.
TUE-THU...OCCASIONAL MVFR IN SHRA/TSRA.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

SYNOPSIS...DANGELO
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO/RXR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1132 AM EDT SAT MAY 23 2009

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-241545-
WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD-
NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON-MIFFLIN-
JUNIATA-SOMERSET-BEDFORD-FULTON-FRANKLIN-TIOGA-NORTHERN LYCOMING-
SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR-
NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND-
ADAMS-YORK-LANCASTER-
1132 AM EDT SAT MAY 23 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
508 PM EDT SAT MAY 23 2009

PAZ024>026-033-034-232200-
BEDFORD PA-BLAIR PA-CAMBRIA PA-HUNTINGDON PA-SOMERSET PA-
508 PM EDT SAT MAY 23 2009

...THUNDERSTORMS WILL AFFECT NORTHEASTERN SOMERSET...NORTHERN
BEDFORD...SOUTH CENTRAL CAMBRIA...SOUTHWESTERN BLAIR AND SOUTHWESTERN
HUNTINGDON COUNTIES...

AT 504 PM EDT...A CLUSTER OF THUNDERSTORMS WAS LOCATED BETWEEN
BEDFORD AND PORTAGE. THESE STORMS WILL AFFECT INDIAN LAKE...CENTRAL
CITY...BLUE KNOB STATE PARK...WOODBURY AND SAXTON THROUGH 600 PM.

BRIEF HEAVY RAIN AND WIND GUSTS TO 30 MPH ARE POSSIBLE WITH THESE
STORMS. BRIEF PONDING OF WATER MAY OCCUR IN POOR DRAINAGE AREAS.

THE FOLLOWING CENTRAL PENNSYLVANIA INTERSTATES WILL BE AFFECTED...
THE PENNSYLVANIA TURNPIKE BETWEEN MILE MARKERS 134 AND 149...I-99
BETWEEN MILE MARKERS 0 AND 20. STORMS WILL ALSO IMPACT THE FOLLOWING
MAJOR ROADS...ROUTE 30...ROUTE 220.

LAT...LON 3997 7866 4006 7889 4036 7865 4032 7826
      4020 7815 4004 7835

EXPERIMENTAL

FORECASTER: DEVOIR

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
512 PM EDT SAT MAY 23 2009

PAZ028-050-232215-
JUNIATA PA-SNYDER PA-
512 PM EDT SAT MAY 23 2009

...STRONG THUNDERSTORMS WILL AFFECT NORTHEASTERN JUNIATA AND WESTERN
SNYDER COUNTIES...

AT 510 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 16 MILES
EAST OF LEWISTOWN TO 17 MILES EAST OF LEWISTOWN...MOVING NORTHEAST AT
10 MPH.

WIND GUSTS TO 30 MPH ARE POSSIBLE WITH THESE STORMS. BRIEF HEAVY RAIN
WILL FALL FROM THESE STORMS...AND MAY CAUSE WATER TO POND ON ROADS
IN POOR DRAINAGE AREAS.

THESE STORMS WILL BE NEAR BEAVER SPRINGS AROUND 540 PM...BEAVERTOWN
AROUND 550 PM AND RICHFIELD AROUND 555 PM.

THIS WILL IMPACT ROUTE 522.

LAT...LON 4058 7724 4068 7732 4071 7731 4084 7715
      4062 7700

EXPERIMENTAL

FORECASTER: DEVOIR

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
751 PM EDT SAT MAY 23 2009

PAZ035-036-240015-
FRANKLIN PA-FULTON PA-
751 PM EDT SAT MAY 23 2009

...STRONG THUNDERSTORMS WILL AFFECT SOUTHERN FULTON AND SOUTHWESTERN
FRANKLIN COUNTIES...

AT 749 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM
BREEZEWOOD TO 12 MILES SOUTH OF BREEZEWOOD TO 10 MILES NORTH OF
BERKELEY SPGS...MOVING SOUTHEAST AT 10 MPH.

VERY HEAVY RAIN AND SMALL HAIL WILL FALL FROM THESE STORMS...
POSSIBLY CAUSING WATER TO POND ON ROADS IN POOR DRAINAGE AREAS.

THESE STORMS WILL BE NEAR COVE MILLS AROUND 800 PM AND BIG COVE
TANNERY AROUND 815 PM.

THIS WILL IMPACT I-70 BETWEEN MILE MARKERS 156 AND 170.

THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 30...ROUTE
522.

LAT...LON 3974 7836 3984 7830 3986 7827 3998 7817
      3991 7787 3982 7791 3972 7799 3972 7813

EXPERIMENTAL

FORECASTER: DEVOIR