Area Forecast Discussion
Issued by NWS State College, PA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KCTP 221953
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
353 PM EDT MON SEP 22 2014

.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE OVER THE MIDWEST...WILL BUILD EAST
ACROSS THE MID ATLANTIC REGION TUESDAY BEFORE DRIFTING OVER THE
NEW ENGLAND STATES FOR THE LATTER HALF OF THE WEEK. THIS DOMINANT
WEATHER FEATURE WILL PROVIDE GENERALLY FAIR AND COOL WEATHER FOR
THE ENTIRE WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
DEEP...AND WELL-ALIGNED NWRLY FLOW AND ASSOCIATED LAKE EFFECT
CLOUDS/ISOLATED LIGHT SHOWERS ACROSS THE ALLEGHENIES WILL
CONTINUE THROUGH EARLY TONIGHT...BEFORE THE MEAN BOUNDARY LAYER
FLOW GRADUALLY WEAKENS BY 5 KTS OR SO AND CONTRACTS THE CLOUD
COVER BACK TWD THE SOUTH SHORE OF LAKE ERIE.

THE CLOUDS WILL BE TOUGH TO BREAK UP COMPLETELY...AND BASED ON
SEVERAL FACTORS INCLUDING MODEL FCST OF HIGH RH/S IN THE 925-850
MB LAYER...THE 850 MB RIDGE AXIS WELL TO THE WEST OF PENN THROUGH
12Z TUESDAY...AND ANOTHER /ALBEIT WEAKER/ 850 MB THERMAL TROUGH
DRIFTING SE ACROSS LAKE ERIE IN THE 06-09Z PERIOD TUESDAY...MVFR
CIGS MAY HANG ON FOR MOST OR ALL OF THE NIGHT INVOF KBFD AND
POINTS WEST. LLVL TRAJECTORIES APPEAR FAVORABLE TO KEEP PLENTY OF
CLOUDS ACROSS THE LAUREL HIGHLANDS AS WELL THROUGH THIS EVENING.

THE THINNER...AND MAINLY BKN STRATO CU THAT WILL BE PRESENT FOR
THE REST OF TODAY ACROSS THE CENTRAL AND SE ZONES SHOULD SCT OUT
EARLY TONIGHT...THANKS TO THE MEAN SFC-850 MB FLOW DECREASING TO
AROUND 10 KTS.

TEMPS SHOULD RISE JUST ANOTHER 1-3 DEG F THIS AFTERNOON...WITH MAX
TEMPS RANGING FROM 50-55F ACROSS THE NRN AND WRN MTNS...TO THE
MID AND UPPER 60S THROUGHOUT THE LOWER SUSQ VALLEY. THESE READINGS
WILL GIVE US AN EARLY TASTE OF AUTUMN THAT OFFICIALLY BEGINS HERE
AT 0229Z TUESDAY. THE HIGHS WILL BE A SOLID 6-10F BELOW NORMAL
/WITH THE GREATEST DEPARTURES OF 12-14F BELOW NORMAL ACROSS THE NW
MTNS.

LOW TEMPS EARLY TUESDAY WILL REACH FROSTY LEVELS ACROSS THE HIGHER
TERRAIN OF SOMERSET COUNTY...WHERE A FROST ADVISORY WAS POSTED
FROM 07-13Z TUESDAY. ELSEWHERE...PATCHY FROST IS POSSIBLE FOR
RURAL VALLEYS...EXCEPT FOR THE LOWER SUSQ VALLEY. LOWS WILL BE IN
THE U30S TO AROUND 40F IN MOST LOCATIONS THROUGHOUT THE CENTRAL
RIDGE AND VALLEY REGION...WITH LOWER 40S IN THE LARGER SERN PENN
METRO AREAS SUCH AS YORK...HARRISBURG...AND LANCASTER.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
HIGH PRESSURE WILL BUILD EAST FROM THE OHIO NE UP THE OHIO VALLEY
AND BECOME CENTERED RIGHT OVER THE REGION TUESDAY AFTERNOON.

AFTER SOME LOCALLY DENSE RIVER VALLEY FOG AND PATCHY FROST IN A
FEW OF THE COLDER SPOTS EARLY TUESDAY...EXPECT ABUNDANT SUNSHINE
AND LIGHT WIND FOR THE LATE MORNING AND AFTERNOON HOURS.

TUESDAY WILL BE A MUCH MILDER DAY WITH TEMPS RISING ABOUT 25F
DURING THE DAY...AND REACHING ABOUT 10F MILDER THAN MONDAY/S HIGHS
IN THE NW - BUT STAYING SIMILAR TO MONDAY IN THE LOWER SUSQ.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN THROUGH THE
REST OF THE WEEK AND INTO EARLY NEXT WEEK WITH HIGHER THAN NORMAL
MSLP ANOMALIES OVER THE REGION. THE MODELS ARE IN FAIR AGREEMENT
THROUGH MOST OF THE PERIOD...THOUGH THEY DIVERGE THIS WEEKEND AND
THROUGH NEXT WEEK. HOWEVER...ALL SOLUTIONS KEEP THE REGION DRY
DUE TO A BLOCKING 500 HPA ANTICYCLONE AND DRY MIDLEVELS.

THE BIG QUESTION IS THE EXTENT OF DIURNAL VALLEY FOG. EXPECT
PATCHY FOG WEDNESDAY AND THURSDAY MORNINGS WITH DENSE FOG AND LOW
CLOUDS POSSIBLE. THE GFS AND EC AND CANADIAN MODELS DIVERGE BUT
THE NEXT CHANCE FOR PRECIPITATION SHOULD/T BE UNTIL MID TO LATE
NEXT WEEK.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
EXTENSIVE MVFR TO VFR BKN-OVC STRATO CU CLOUD DECK CONTINUES TO
COVER ALL BUT PORTIONS OF SCENT PENN AT MID AFTERNOON. THE CLOUD
SHIELD IS STARTING TO ERODE TWD THE NW AND EXPECT THIS TREND TO
CONTINUE LATE THIS AFTERNOON AND THIS EVENING.

EXCEPTIONS WILL BE AT KJST AND KBFD WHERE MVFR CIGS AREA EXPECTED
TO CONTINUE UNTIL AT LEAST 07Z TUESDAY.

AFTERWARD...HIGH PRESSURE RIDGING IN FROM THE OHIO VALLEY /AND
BECOMING CENTERED OVER PENN TUESDAY AFTERNOON/ WILL BRING MAINLY
CLEAR SKIES AND LIGHT WIND LATER TONIGHT THROUGH TUESDAY.

THE LARGE SPREAD OF 25 DEG F OR SO BETWEEN THE AIR AND REGIONAL
STREAMS AND RIVERS /COUPLED WITH CURRENT SFC DEWPOINTS IN THE
LOWER 40S/ WILL LEAD TO LOCALLY DENSE VALLEY FOG FOR SEVERAL
HOURS EARLY TUESDAY. THE FOG SHOULD IMPACT MAINLY KIPT...KUNV AND
KAOO AIRFIELDS.

GENERALLY TRANQUIL WEATHER WITH MAINLY VFR CONDITIONS SHOULD
PREVAIL THROUGH WED...WITH THE EXCEPTION OF SOME PATCHY MORNING
VALLEY FOG.

OUTLOOK...
WED-SAT...MAINLY VFR...BUT WITH DAILY RESTRICTIONS IN MORNING FOG
POSSIBLE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM TO 9 AM EDT TUESDAY FOR PAZ033.

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...CERU
AVIATION...LAMBERT



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.