Flash Flood Warning 4, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
428 AM EDT SUN MAY 23 2010

.SYNOPSIS...

STALLED LOW-LEVEL FRONTAL BOUNDARY IN SOUTHERN PA HAS PROVIDED A
FOCUS FOR HEAVY RAINFALL OVERNIGHT. THIS RAIN SHOULD END LATER
THIS MORNING. LONGER TERM FORECAST SHOWS A LARGE SUBTROPICAL RIDGE
BUILDING TO OUR NORTH WHICH WILL PROVIDE WARMER WEATHER TUESDAY
THROUGH PERHAPS THURSDAY BEFORE THIS FEATURE RETROGRESSES ALLOWING
COOLER DRIER AIR INTO THE REGION FOR THE MEMORIAL DAY WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
21Z...3 KM HIGH RESOLUTION RAPID REFRESH MODEL SHOWS THE FOCUS FOR
HEAVY SHOWERS (AND PERHAPS SOME ELEVATED TSRA) JUST TO THE EAST OF
THE ALLEGHENY PLATEAU AND ACROSS THE CENTRA./SCENT MTNS. 3 HOURLY
RAINFALL AMOUNTS FROM THIS LATEST RUN ARE IN THE RANGE 0.5 -0.75
OF AN INCH FROM NEAR KUNV...SW TO KAOO. JUST OVER 0.60 OF AN INCH
FELL AT KAOO DURING THE PAST HOUR...WHICH AGREES VERY WELL WITH
THIS MODEL OUTPUT IN LOCATION AND AMT.

THIS RAINFALL AXIS SHIFTS NE...AND BECOMES LOCATED JUST TO THE
EAST OF A KUNV TO KHAKI LINE AROUND 05Z...IN THE VICINITY OF THE
TIGHTEST 925 MB LIFTED INDEX GRADIENT.

THE BAND OF HEAVIEST SHOWERS MAY SLOW ITS EWD PROGRESS FOR A FEW
HOURS BETWEEN 05Z-09Z WITHIN THE REGION BOUNDED BY A LINE FROM
KUNV...TO KHGR...KTHV...AND KIPT. LOCALIZED RAINFALL AMOUNTS OF
JUST OVER ONE INCH ARE LIKELY IN A 2 HOUR PERIOD. PERHAPS A FEW
PLACES BETWEEN KUNV AND KMDT SEEING 1.5 INCHES.

SHOWERS WILL BE SCATTERED AT BEST LATER TONIGHT ACROSS THE NW MTNS
AS THE MAIN AXIS OF 925-850 THETA-E CONVERGENCE...AND COOLEST
700-500 MB TEMPS SHIFT TO THE SOUTH AND EAST.

TEMPS WILL BE RATHER MILD OVERNIGHT...AND SHOULD ONLY FALL ANOTHER
3-5F BY DAYBREAK (FROM THEIR PRESENT 01Z VALUES) AS A RESULT OF
THE RELATIVELY HIGH DEWPOINTS IN THE 55-60F RANGE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
SUNDAY TEMPS AND POPS WERE UNCHANGED WITH THIS EVENING UPDATE.
THE BULK OF SHOWERS SHOULD BE OVER WITH BY 00Z MONDAY...BUT AN
ISOLATED SHOWER COULD LINGER ACROSS THE FAR S PAST 00Z MONDAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LOW WILL SLIP SLOWLY SOUTH INTO THE MID ATLANTIC REGION SUN
NIGHT INTO MON...BUT SCT SHOWERS WILL LINGER MAINLY ACROSS SE 1/2
OF CWA. TEMPS WILL BE IN THE 70S IN MON...BUT COOLEST IN THE SOUTH
AS CLOUDS/SHOWERS LINGER THE LONGEST.

THEN THE THE LARGE SUBTROPICAL RIDGE TO OUR NORTH AND WEST WILL
EDGE INTO PA FOR TUE AND WED. THIS SHOULD ALLOW NORTHWESTERLY
FLOW AND DRY WEATHER TO MOVE BACK OVER OUR REGION. TEMPS WILL BE
ABOVE NORMAL BY MIDWEEK.

COULD SEE IMPINGEMENT OF BACK DOOR FRONTS LATER IN THE WEEK WITH
THE FIRST ON WED. THIS MAY BRING ISOLATED TSTORMS AS IT SLIDES
THROUGH...BUT WILL MAINLY BRING A BIT MORE DRIER AIR TO THE
REGION...WHICH WILL ALLOW AIR TO WARM A BIT MORE DURING THE DAY
EDGING HIGHS UP A LITTLE MORE.

ANOTHER BACK DOOR FRONT SLIDES THROUGH FRI NIGHT/SAT...BRINGING A
LOW CHANCE FOR SHOWERS AS TEMPS SLIP BACK TO NORMAL.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
A MIX IF MVFR/IFR OVER THE REGION THIS MORNING. OVER EASTERN PA
THERE IS A N-S LINE OF SHOWERS WITH STEADY RAIN...POCKETS OF
MODERATE RAIN TOO WITH ISOLATED LIFR UNDER THESE HEAVIER N-S
ORIENTED BANDS. RAIN SHOULD CONTINUE TO SLOWLY MOVE TO THE EAST.

THE RAIN SHOULD MOVE TO OUR EAST SUNDAY...RAIN AND LIGHT WINDS
WILL PRODUCE IFR OVER MOST OF THE REGION A FEW HOURS EITHER SIDE
OF SUNRISE. CONDITIONS SHOULD IMPROVE DURING THE LATE MORNING AND
EARLY AFTERNOON SUNDAY. IMPROVEMENT SHOULD GENERALLY BE FASTER IN
THE WEST AND MOVE WEST TO EAST.

A BUILDING RIDGE TO OUR WEST AND SURFACE HIGH SHOULD IMPROVE
CONDITIONS FOR MONDAY. IF THE HIGH DOMINATES COULD BE A GOOD WEEK
FOR FLYING WITH VFR CONDITIONS LASTING INTO THU PERHAPS FRIDAY
DEPENDING ON WHEN THE FRONTAL SYSTEM ENDS OUR MID-WEEK WARM HUMID
EVENT.

OUTLOOK...
MON-FRI...MAINLY VFR. PERHAPS AM MVFR WITH HAZE FOG AROUND SUNRISE.

&&

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

&&

SYNOPSIS...GRUMM
NEAR TERM...LAMBERT
SHORT TERM...MARTIN
LONG TERM...GRUMM
AVIATION...GRUMM/GARTNER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
332 AM EDT SUN MAY 23 2010

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-240745-
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-
332 AM EDT SUN MAY 23 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.