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 230926
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
526 AM EDT TUE SEP 23 2014

.SYNOPSIS...
HIGH PRESSURE WILL DRIFT EAST ACROSS PENNSYLVANIA TODAY THEN PASS
OFF THE NEW ENGLAND COAST WEDNESDAY. A LOW PRESSURE SYSTEM WILL
TRACK UP THE MID ATLANTIC COAST WEDNESDAY AND THURSDAY...THEN OUT
TO SEA BY FRIDAY. AN ANOMALOUS UPPER RIDGE WILL MIGRATE EASTWARD
FROM THE GREAT LAKES TO PENNSYLVANIA THIS WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY AM 11-3.9 MICRON SATL IMAGERY SHOWING DENDRITIC PATTERN OF
VALLEY FOG ACROSS NORTHERN AND WESTERN PA. RADIATIONAL COOLING
UNDER A MCLEAR SKY AND LGT WIND WILL RESULT IN FOG BECOMING MORE
WIDESPREAD AND LOCALLY DENSE TOWARDS DAWN IN THE VALLEYS OF THE
ALLEGHENY MTNS. A MORE PERSISTENT NWRLY BREEZE SHOULD PRECLUDE
WIDESPREAD FOG EAST OF THE ALLEGHENIES...BUT WILL MENTION AT LEAST
PATCHY FOG ALL THE WAY INTO THE SUSQ VALLEY.

DWPTS AT 09Z ARE STILL RUNNING IN THE U30S OVER MUCH OF THE
ALLEGHENY PLATEAU...A BIT HIGH FOR WIDESPREAD FROST.
HOWEVER...BASED ON CURRENT MESONET DATA...WILL MAINTAIN PATCHY
FROST IN THE EARLY AM FORECAST FOR THE NORTHERN MTNS AND LAUREL
HIGHLANDS.

HIGH PRESSURE WILL BE POSITIONED DIRECTLY OVR PA LATER TODAY. THE
RESULTING LACK OF MIXING COULD DELAY THE FOG BURN OFF UNTIL LATE
MORNING IN THE DEEP RIVER/STREAM VALLEYS OF THE ALLEGHENIES.

AFTER THE FOG LIFTS...EXPECT ABUNDANT SUNSHINE AND LIGHT WIND FOR
THE LATE MORNING AND AFTERNOON HOURS. GEFS MEAN 925 TEMPS BTWN
12-14C SHOULD TRANSLATE TO HIGHS BTWN 65-70F FROM NW TO SE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
TRANQUIL CONDS EXPECTED TONIGHT AS SFC HIGH REMAINS OVR THE AREA.
WEAKEST GRADIENT WILL BE OVR THE N MTNS...WHERE A CALM WIND AND
CLEAR SKIES SHOULD PROMOTE AREAS OF LATE NIGHT VALLEY FOG. FURTHER
SOUTH...A DEVELOPING EASTERLY BREEZE WILL LIMIT THE FOG POTENTIAL.
ALSO...WAA ALOFT AHEAD OF UPPER LOW OVR THE SE CONUS MAY SPREAD
INCREASING CIRRUS INTO SOUTHERN PA LATE TONIGHT.

ALTHOUGH MOST OF THE REGION SHOULD DAWN BRIGHT...EXPECT INCREASING
CIRRUS TO OVERSPREAD CENTRAL PA FROM THE SOUTH ON WEDNESDAY...AS
AFOREMENTIONED UPPER LOW OVR THE SE CONUS DRIFTS NORTH. ALL
CURRENT MDL DATA KEEPS ASSOC SFC COASTAL LOW/PLUME OF ATLANTIC
MOISTURE JUST SOUTH OF PA...SO CONFIDENCE IS HIGH THAT ANY RAIN
WILL HOLD OFF THRU THE DAYLIGHT HRS. TEMPS WED SHOULD BE FAIRLY
UNIFORM ARND 70F DUE TO THE THICKEST CLOUDS ARRIVING OVR THE
NORMALLY WARMER SOUTHERN COUNTIES.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
SIGNIFICANT CHANGES MADE TO THE WED NITE/THURSDAY FCST...AS ALL
MED RANGE GUIDANCE NOW TRACKS COASTAL LOW ACROSS THE DELMARVA.
THIS SCENARIO WILL LIKELY BRING A PERIOD OF RAIN TO AT LEAST THE
SE COUNTIES ON THURSDAY. TIGHT PRES GRADIENT BTWN HIGH EAST OF NEW
ENG AND SFC LOW RIDING UP THE E COAST IS RESULTING IN ANOMALOUS
EASTERLY WINDS/PWATS IN THE 00Z GEFS ACROSS SE PA WED NIGHT AND
THURSDAY. GEFS AND OPER MDL QPF ALL SUPPORT AT LEAST LIKELY POPS
ACROSS THE LOWER SUSQ VALLEY DURING THIS PERIOD AND A CHC OF RAIN
AS FAR WEST AS THE ALLEGHENY PLATEAU. SOME ENSEMBLE AND OPER RUNS
INDICATE A SUBSTANTIAL RAINFALL OF OVER AN INCH IS POSSIBLE ACROSS
PARTS OF SE PA. HAVE INCREASED MIN TEMPS WED NIGHT AND LOWERED MAX
TEMPS WED SIGNIFICANTLY DUE TO THE EXPECTED CLOUD COVER/RAIN.

GENERAL AGREEMENT AMONG MED RANGE GUIDANCE THAT COASTAL LOW WILL
EXIT THE MID ATLANTIC COAST FRIDAY...BRINGING A RETURN TO FAIR
AND MILD WX. ANOMALOUS UPPER LVL RIDGE OVR THE GRT LKS IS THEN
PROGGED TO SLIDE EAST INTO PA OVR THE WEEKEND...BRINGING THE AREA
A PERIOD OF FAIR AND WARM WX THAT SHOULD LAST INTO EARLY NEXT
WEEK. LG SCALE SUBSIDENCE BENEATH THIS SYSTEM SHOULD RESULT IN
MCLEAR SKIES THRU THE WEEKEND AS THE 00Z NAEFS CLOUD OUTPUT
SUGGESTS. GEFS AND ECMWF 925TEMPS NEAR 20C SHOULD SUPPORT HIGH
TEMPS ARND 10F ABOVE NORMAL...WITH AFTN READINGS BTWN 75-80F OVR
MUCH OF THE AREA.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
PATCHY FOG NEAR KBFD EXPECTED FOR NEXT SEVERAL HOURS. WILL LIKELY
SEE MORE PATCHY VALLEY FOG AROUND SUNRISE THIS MORNING...DISSIPATING
AROUND 13-14Z. OTHERWISE VFR CONDITIONS FOR THE NEXT 24-48 HOURS.
UPPER LEVEL LOW PRESSURE SYSTEM WILL BRING CLOUDY SKIES AND A
CHANCE FOR SHOWERS WED NIGHT AND THU TO AT LEAST KMDT AND KLNS.

OUTLOOK...
WED...PATCHY FOG IN THE MORNING...OTHERWISE VFR. THU...LOW CIGS
AND AREAS OF -RA/DZ PSBL. FRI-SAT...PATCHY FOG IN THE
MORNING...OTHERWISE VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ033.

&&

$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...ROSS


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