Flash Flood Warning 46, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
122 PM EDT FRI SEP 9 2011

.SYNOPSIS...
CURRENT RIVER FLOODING IS EXPECTED TO CONTINUE WITH SMALLER
STREAMS RECEDING OVERNIGHT FROM RECENT CRESTS. SHOWERY WEATHER
WILL CONTINUE ACROSS MUCH OF THE REGION FOR THE NEXT COUPLE OF
DAYS AS UPPER-LEVEL LOW REMAINS IN THE VICINITY. A STRONG NORTHERN
STREAM SYSTEM SHOULD USHER IN COOLER...DRIER AND MORE AUTUMN-LIKE
AIR INTO OUR REGION BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SEE HYDROLOGY SECTION FOR ALL THINGS WATER.

THUNDER HAS BEGUN OVER THE WEST...WITH STORMS MOVING ALONG A
SIMILAR TRACK AS EARLIER SHOWERS THIS MORNING...PRETTY MUCH RIGHT
OVER SHANKSVILLE WHERE THEY ARE PREPARING FOR THE MEMORIAL
ACTIVITIES. QPF ESTIMATES ARE LESS THAN A HALF INCH AT MOST PLACES
THOUGH. FFG IS MORE THAN AN INCH THERE DUE TO LESS RAINFALL THERE
IN THE LAST FEW DAYS THAN TO THE EAST. A EVER-THINNING BUT LONG-
LIVED PLUME OF MOISTURE MAKES A CONNECTION/FEED INTO THE SHOWERS
IN THE SC AND WRN COS. FLOW ALOFT IS A LITTLE MORE EASTERLY THAN
YESTERDAY. THE MOISTURE CONVERGENCE SHOULD SLIDE TO THE NORTH AND
INTO THE CENTRAL MTS THIS AFTERNOON...SO THE HIGHER CHCS OF
SHOWERS THIS AFTN WOULD BE THERE. BUT STILL LIKELIES ON ORDER FOR
THE SRN COS AS WELL.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE H5 LOW IS EXPECTED TO CONTINUE SLOWLY UNWINDING OVER THE OHIO
VALLEY/MID WEST KEEPING US ON THE EAST SIDE UNDER DIFFLUENT FLOW
ALOFT KEEPING US VULNERABLE TO THE CHANCE OF SHOWERS OR
THUNDERSTORMS RIGHT INTO THE WEEKEND. LOW LEVEL FLOW WILL BE
RATHER SLACK AND GENERALLY NORTHEAST TO EAST SUGGESTING ANY
SIGNIFICANT DRYING WILL BE HARD TO COME BY. WITH EXPECTED
CLOUDCOVER AND A MOIST AIRMASS IN PLACE...OVERNIGHT LOWS WILL NOT
DROP BACK MUCH. EXPECTED TO BOTTOM OUT IN THE 50S AND 60S..THESE
WILL BE SEVERAL DEGREES ABOVE NORMAL.

SCT SHRA EXPECTED INTO THE DAY SAT...BUT MAINLY IN THE AFTN.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
BY SUNDAY PROGS SHOW THE LOW BECOMING AN OPEN TROF THAT WILL
BEGIN LIFTING OUT WHICH SHOULD EQUATE TO DIMINISHING CHANCES OF
SHOWERS.

AS WE LOSE THE UPPER UPPER LOW...WE WILL TRANSITION INTO A MORE
MOBILE PATTERN WHERE A BROAD UPPER RIDGE WILL SLOWLY YIELD TO A
LONGWAVE TROF THAT EVENTUALLY CARVES OUT OVER THE EASTERN US. THIS
WILL BRING SOME MUCH COOLER AND DRIER AIR TO THE REGION STARTING
ABOUT MID WEEK WITH ANY CHANCE FOR PRECIP BEING SHOWERY AND
MAINLY ON THE LIGHT SIDE.

A SIGN OF THE SEASON TO COME IS THE APPEARANCE OF THE 850 ZERO
DEG ISOTHERM BEING FCST INTO NRN PA BY THE LATTER HALF OF THE
WEEK.

&&

.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
DRIER AIR IS SLOWLY IMPROVING CONDITIONS IN THE NORTHEAST...BUT
SHOWERS AND ISOLATED THUNDERSTORMS WILL AFFECT MAINLY THE SOUTHERN
AND WESTERN TAF SITES TODAY. BRIEF IFR CONDITIONS ARE
POSSIBLE...ESPECIALLY IN JST AND AOO...AS SHRA/TSRA MOVE THROUGH
THE AREA THIS AFTERNOON.

CEILINGS WILL REMAIN LOW AS DENSE CLOUD COVER CONTINUES OVER MUCH
OF THE STATE. RESIDUAL GROUND MOISTURE AND THE LACK OF SUNSHINE
ARE MAKING IT DIFFICULT TO BURN OFF FOG...REDUCED VISIBILITIES ARE
POSSIBLE THROUGHOUT THE TAF PERIOD IN THE WESTERN HALF OF THE CWA.

ALL TAF SITES WILL SEE REDUCED VISIBILITIES OVERNIGHT AS FOG
DEVELOPS. EXPECT THE FOG TO PERSIST THROUGHOUT THE LATE MORNING
HOURS SATURDAY.

EXPECT MAINLY MVFR CONDITIONS TOMORROW ACROSS THE COMMONWEALTH WITH
SIMILAR CONDITIONS AS TODAY AS A MOIST AIR MASS CONTINUES TO SIT
OVER THE STATE. SKIES WILL BE OVERCAST THE MAJORITY OF THE DAY
WITH SCATTERED SHRA/TSRA IN THE AFTERNOON.

OUTLOOK...
SAT-SUN...MAINLY MVFR AND VFR...ISOLATED IFR CONDITIONS ARE
POSSIBLE DUE TO SHRA/TSRA AND AM FOG.
MON- TUE...MAINLY VFR...MVFR AND IFR CONDITIONS POSSIBLE EARLY
WITH AM FOG.

&&

.HYDROLOGY...
MAINSTEM RIVER POINTS NEAR CREST OR SLOWLY FALLING AT MOST
LOCATIONS. LIGHT RAIN TODAY INTO SAT COULD RAISE SMALLER CREEKS
AND STREAMS A BIT...BUT IT WILL BE EXTREMELY DIFFICULT TO KEEP THE
FLOWS/VOLUMES AS HIGH AS THEY CURRENTLY ARE IN THE BIGGER
WATERWAYS. MINOR DOUBLE BUMP IS EXPECTED AT HARRISBURG/MARIETTA
WITH A SLUG OF WATER COMING DOWN THRU SUNBURY AND A BIT MORE RAIN
EXPECTED TODAY. THE WEST BRANCH PUSH IS MAINLY BELOW THE
HARRISBURG GAUGE. SOME OF THE SMALLER GAUGES LIKE LOYALSOCKVILLE
HAVE BEEN DAMAGED AND UNTIL THEY ARE FIXED OR REPLACED BY THE USGS
- THEY WILL NOT BE REPORTING.

ADDITIONAL INFORMATION CAN BE FOUND AT:
WWW.ERH.NOAA.GOV/ERH/MARFC

&&

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

&&

SYNOPSIS...LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO/LA CORTE
LONG TERM...LA CORTE
AVIATION...DANGELO/COLBERT
HYDROLOGY...

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
421 AM EDT FRI SEP 9 2011

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-100830-
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-
421 AM EDT FRI SEP 9 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY AND TONIGHT.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT RAINFALL
AND ANY ADDITIONAL FLOODING TO THE NATIONAL WEATHER SERVICE.