Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 300553
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
153 AM EDT SUN AUG 30 2015

.SYNOPSIS...
INCREASING MOISTURE WILL BE CHANNELED NORTHEAST FROM THE OHIO
VALLEY TODAY...AND INTERACT WITH A STATIONARY FRONTAL BOUNDARY TO
PRODUCE SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS MAINLY
THE NORTHWESTERN HALF OF THE STATE. HIGH PRESSURE OFF THE MID
ATLANTIC COAST WILL BE MORE INFLUENTIAL ON KEEPING FAIR AND DRY
WEATHER INTACT ACROSS THE SOUTHEASTERN HALF OF PENNSYLVANIA.
VERY WARM AND INCREASINGLY HUMID WEATHER WILL CONTINUE INTO THE
MIDDLE OF THE UPCOMING WEEK.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
STABLE STRATIFICATION UNDER CLEAR TO PTLY CLOUDY SKIES WILL
CONTINUE ACROSS MUCH OF CENTRAL AND SOUTHERN PENN THROUGH THE MID
MORNING HOURS. OVER NWRN PENN.

SFC BASED CAPE WILL SLOWLY INCREASE TO BETWEEN 300-500 J/KG
ACROSS THE NW MTNS THIS MORNING WITH THE ADVECTION OF 1.5 INCH
PWAT AIR FROM THE OHIO VALLEY. THE PRESENCE OF A QUASI-STNRY
FRONTAL BOUNDARY AND THE INCREASING MOISTURE FROM THE OHIO
VALLEY...WILL LEAD TO NEWRD EXPANSION OF SHOWERS AND A FEW
ISOLATED TSRA EARLY TODAY.

PATCHY LIGHT RIVER VALLEY FOG EXPECTED ELSEWHERE AS SFC DEWPOINTS
SLOWLY RISE.

MIN TEMPS SHOULD RANGE FROM THE MID TO UPPER 50S OVER THE NORTH...
TO THE LOWER 60S IN THE SOUTHEAST.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM MONDAY/...
SOME EARLY MORNING FOG IN THE VALLEYS - WHICH SHOULD BE OF LESSER
COVERAGE THAN SAT MORNING. THEN...THE TEMPS RISE EVEN
BETTER...ADDING ANOTHER 3-4F ONTO SAT/S MAXES.

RIDGE AT THE SFC AND ALOFT IS STARTING TO GET PRESSED A LITTLE TO
THE EAST BY AN ADVANCING UPPER TROUGH AND SLIGHT FEED OF GULF
MOISTURE. THUS...SUPPORT IN THE FORM OF INSTABILITY AND MOISTURE
WILL BE AVAILABLE TODAY.

PLAN TO INCREASE POPS INTO THE LIKELY CATEGORY ACROSS THE NW MTNS
DURING THE MID TO LATE MORNING HOURS. THERE WILL BE A TRANSITION
TO VIRTUALLY NO CHC OF RAIN OVER THE SE COUNTIES OF OUR CWA.

CONVECTIVE ALLOWING HRRR MODEL SUGGEST EVEN CATEGORICAL ARE
WARRANTED ACROSS PARTS OF THE NW AND NCENT MTNS /AND EVEN FOR A
MORE BRIEF TIME PERIOD OF A FEW HOURS OVER THE LAUREL HIGHLANDS
CENTERED ON DAYBREAK/. THIS SECOND...AND MORE SIGNIFICANT CLUSTER
OF CONVECTION WILL IMPACT THE NW MTNS OF PENN BETWEEN 10-14Z.SOME
LOCATIONS WILL SEE BETWEEN 0.25 AND 0.50 INCH OF RAIN...WHERE TWO
OR MORE MDT-HVY SHOWERS OCCUR.

AFTER THE INITIAL...RATHER COMPACT SHORTWAVE ALOFT LIFTS INTO
SOUTHCENTRAL NEW YORK LATER THIS MORNING...THE ATMOS WILL RECHARGE
TO OVER 1000 J/KG CAPE IN SOME AREAS...AND BE CAPABLE OF FIRING
OFF SCTD SHRA/TSRA ACROSS THE CENTRAL MTNS...AND ALLEGHENIES THIS
AFTERNOON.

HIGHS THIS AFTERNOON WILL VARY FROM THE U70S ACROSS THE NRN AND
WRN MTNS...TO THE UPPER 80S ACROSS THE LOWER SUSQ VALLEY AND
SURROUNDING AREAS.


&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ANOMALOUS UPPER LEVEL RIDGE WILL DOMINATE THE OHIO VALLEY AND
EASTERN UNITED STATES MUCH OF THE UPCOMING WEEK...WITH 850HPA
TEMPS RUNNING 16-18C WHICH WILL TRANSLATE TO WELL ABOVE-NORMAL
SFC TEMPS. THIS WARMTH AND INCREASING HUMIDITY SHOULD ALLOW FOR
AT LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY...BUT THE
PROBABILITY OF WIDESPREAD RAINFALL IS LOW.

THERE ARE A COUPLE OF INTERESTING FEATURES THAT BEAR WATCHING FOR
LATE IN THE LONG TERM PERIOD. THE FIRST IS THE REMNANTS OF
ERIKA...WHICH ARE FCST TO BE IN THE VICINITY OF THE FL/GA COAST BY
THE MIDDLE OF NEXT WEEK. AS THIS MOISTURE DIFFUSES OVER THE
SOUTHEAST U.S....SOME OF IT WILL GRADUALLY CRAWL INTO THE MID
ATLANTIC REGION. THE OTHER INTERESTING FEATURE IS A BACKDOOR COLD
FRONT THAT SOME MODELS BRING INTO THE MID-ATLANTIC STATES NEXT
THURS/FRI. THESE FEATURES COMBINED WITH THE WARM AND INCREASINGLY
HUMID AIR THAT WILL ALREADY BE IN PLACE WILL KEEP MENTION OF AT
LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY. THE LATTER
FEATURE COULD HAVE AN IMPACT ON TEMPS LATE NEXT WEEK...TAPERING
BACK TEMPS A BIT.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SOME WEAK SHOWERS WILL MOVE ACROSS NORTHWESTERN PA BETWEEN 03 AND
06Z. VCTS IN KBFD. OTHERWISE PATCHY AREAS OF FOG MAINLY MVFR SOME
ISOLATED ARE IFR. MODELS SHOWS COULD BE SOME ISOLATED SHOWERS
BEFORE SUNRISE IN FAR WEST.

MOST MODELS SHOW HIGHEST CHANCE OF SHOWER ACROSS NORTHERN
PENNSYLVANIA SUNDAY IN THE MORNING. BY 16Z SHOWERS MOVE INTO
SOUTHWEST MOUNTAINS. USED MAINLY VCSH/VCTS TO HANDLE SHOWERS AS
THE PROBABILITIES ARE GENERALLY 20 TO 40 PERCENT. HIGHEST
PROBABILITIES OF SHOWERS/THUNDER IN NORTHWEST. KBFD WILL LIKELY
SEE A SHOWER SUNDAY.

OUTLOOK...

MON...STILL SOME SHRA/TSRA POSS.
TUE-THU...NO SIG WX EXPECTED AREAS MVFR OVERNIGHT PATCHY FOG.

&&

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

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...RXR
AVIATION...GRUMM



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