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Area Forecast Discussion
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000
FXUS61 KCTP 020627
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
227 AM EDT TUE SEP 2 2014

.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE INTO TUESDAY EVENING WHEN
A COLD FRONTAL PASSAGE BRINGS DRIER AND SLIGHTLY COOLER AIR TO
CENTRAL PENNSYLVANIA. HUMIDITY WILL RETURN TOWARD THE END OF THE
WEEK AHEAD OF THE NEXT FRONTAL SYSTEM THAT WILL BRING THE CHANCE
OF RAIN FOR THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
RADAR LOOP AT 05Z SHOWING A BKN LINE OF SHRA/TSRA ENTERING NW PA
AHEAD OF SHORTWAVE CROSSING THE E GRT LKS. MODEST FORCING AHEAD OF
THIS FEATURE...COMBINED WITH A VERY MOIST AND MARGINALLY UNSTABLE
ENVIRONMENT OVR PA...SHOULD SUPPORT SCT SHRA DURING THE EARLY
HOURS. WILL PLACE HIGHEST /LIKELY/ POPS IN THE NEAR TERM OVR THE
NW MTNS...CLOSEST TO SHORTWAVE. WANING UPPER LVL SUPPORT AND
COOLING BLYR SHOULD TRANSLATE TO ONLY A SLIGHT CHC OF SHRA ACROSS
THE EASTERN COS LATER THIS MORNING. RADAR TRENDS AND LATEST RAP
OUTPUT INDICATE THE THREAT OF SCT SHRA WILL SHIFT EASTWARD INTO
THE CENTRAL MTNS TOWARD DAWN...THEN THE EASTERN COUNTIES BTWN 12Z-
15Z.

LIGHT WIND...PTCLDY SKIES AND WET GROUND SHOULD YIELD AREAS OF
FOG DURING THE EARLY AM HOURS. LOW CLOUDS ARE ALSO POSSIBLE ACROSS
THE UPSLOPE REGIONS ALONG THE ALLEGHENY HIGHLANDS. TEMPS ON TRACK
TO BOTTOM OUT IN THE U60S TO L70S IN THIS MUGGY AIR MASS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
A WELL-DEFINED COLD FRONT /WITH SHARP MSTR- PW GRADIENT/ WILL DROP
ACROSS THE REGION TUESDAY AFTERNOON AND EVENING. A CONDITIONAL
RISK FOR STRONG TO ISOLATED SEVERE STORMS WILL EXIST FROM LATE TUE
MORNING THROUGH THE AFTERNOON WITH THE PRIMARY POTNL TSTM HAZARD
BEING DAMAGING WINDS.

CLOUD COVER FROM UPSTREAM CONVECTION LKLY ONGOING AT 12Z ALONG
WITH RESIDUAL OVERNIGHT LOW STRATUS/FOG SHOULD ACT TO LIMIT
DESTABILIZATION EARLY TOMORROW. ALTHOUGH 700-500MB LAPSE RATES
WILL GENERALLY REMAIN WEAK TO POOR...THE MODELS SHOW A BELT OF
STRONGER WESTERLY MID-LVL FLOW AND DEEP LYR SHEAR. THIS SHOULD
HELP TO SUPPORT AN INCREASE IN CONVECTIVE PCPN/INTENSITY AS
RENEWED DEVELOPMENT OCCURS ALONG OUTFLOWS/DIFFERENTIAL HEATING
ZONES BY LATE MORNING INTO THE AFTERNOON...WITH SOME ORGANIZATION
INTO LINE SEGMENTS/CLUSTERS. THIS SHOULD YIELD AT LEAST AN ISOLD
DMGG WIND THREAT...WARRANTING AN UPGRADE BY SPC TO A CATEGORICAL
/SLGT/ RISK DESIGNATION. THIS HAS BEEN REFLECTED IN AN UPDATED
HWO.

EARLY CLOUDS SHOULD BREAK FOR A WARM AND HUMID DAY WITH FCST
HIGHS EXPECTED TO RANGE FROM THE MID 70S OVER THE NW TO NEAR 90
OVER THE LOWER SUSQ VLY. THE SECOND HALF OF THE PERIOD ESPECIALLY
AFTER MIDNIGHT SHOULD FEATURE A COOLER/DRYING TREND BEHIND THE
FRONT WITH PWS FALLING AOB NORMAL BY 12Z WED.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
COLD FRONT EXITING TO THE EAST TUE NIGHT ALONG WITH NORTHWEST
FLOW AROUND BUILDING HIGH PRESSURE AREA OVER OHIO VALLEY WILL
BRING A TRANSITION TO A NOTICABLY DRIER AIRMASS FOR MIDWEEK.
DAYTIME HIGHS WILL REMAIN SLIGHTLY ABOVE NORMAL...BUT LOWER
DEWPOINTS WILL MAKE IT FEEL MORE COMFORTABLE. OVERNIGHT LOWS WED
NIGHT WILL DIP TO NEAR 50F IN THE NORTHERN MTNS TO AROUND 60F IN
THE SE. 

THE HIGH WILL MOVE OFF THE EAST COAST THU INTO FRI...ALLOWING MORE
HUMID AIR TO BEGIN RETURNING TO THE REGION. A SURFACE LOW SLIDES
FROM THE NORTHERN PLAINS ACROSS THE GREAT LAKES AND LIFTING INTO
S CANADA ON FRI...DRAGGING A COLD FRONT ALONG BEHIND. AS THIS
FRONT APPROACHES...AN AREA OF HIGHER PWATS /1-2"/ SURGES INTO THE
OHIO VALLEY...AND THEN INTO PA FRI NIGHT INTO SAT. AT SAME TIME A
BROAD UPPER TROUGH SAGS SOUTHWARD. THIS WILL BRING ELEVATED
CHANCES FOR SHOWERS/TSTMS STARTING FRI NIGHT IN THE NW AND
SPREADING AREAWIDE ON SAT. 

BEHIND THE FRONT...AIRMASS CHANGE WILL USHER IN MUCH COOLER AND
DRIER AIR FOR LATE WEEKEND INTO EARLY NEXT WEEK. HIGHS WILL FALL
BACK ABOUT 10F...RANGING FROM THE UPPER 60S TO MID 70S. AS LARGE
HIGH PRESSURE AREA TRACKS ACROSS NEW ENGLAND...MORNING LOWS SHOULD
DIP WELL INTO THE 40S ACROSS THE NORTHERN MTNS...AND IN THE LOWER
TO MID 50S ACROSS THE SOUTH.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL PA EARLY THIS MORNING. NGM SHOWS THIS AREA MOVING
EAST OF THE AREA IN A FEW HOURS.

ISOLATED SHOWERS ACORSS THE SOUTH. WAS STRONGER STORMS JUST
SOUTH OF THE PA BORDER WHEN I CAME IN AT MIDNIGHT.

MORE SHOWERS AND STORMS POSSIBLE LATER THIS AFT AND EARLY
EVENING...AS WEAK COLD FRONT DROPS SE.

06Z TAFS SENT.

EARLIER DISCUSSION BELOW.

VFR CONDITIONS EVERYWHERE AS THE LOSS OF HEATING RAISED THE
STABILITY AND PASSAGE OF A VERY WEAK WAVE HAS LEFT US IN A LULL.
ANOTHER WEAK WAVE IS APPROACHING FROM OHIO AND IS TOUCHING OFF
SOME SHOWERS TO THE WEST. NAM BLOSSOMS THIS AREA AS THE SWRLY FLOW
INCREASES SLIGHTLY OVERHEAD. BUT WILL LEAV IT MOSTLY DRY THROUGH
THE NIGHT EXCEPT IN THE NW. THE 70PLUS DEWPOINTS AND UPSLOPE INTO
THE WRN MTS WILL CREATE LOW CLOUDS AND FOG AGAIN TONIGHT. SOME
DRIZZLE IS ALSO POSSIBLE THERE. THE SERN HALF OF THE AREA WILL
BE MAINLY VFR.

A COLD FRONT MOVING SEWRD OVER THE LOWER LAKES LATER IN THE DAY
WILL MEAN THE AREA WILL STAY IN THE WARM-SECTOR AND THUNDERSTORMS
WILL BECOME SCATTERED OVER THE AREA IN THE AFTERNOON. THIS FRONT
WILL BE A BETTER FOCUS FOR NMRS SHWRS/TSTMS IN THE EVENING AS IT
MOVES SEWRD ACROSS CENTRAL PA. SOME OF THE STORMS COULD BECOME
SEVERE WITH STRONG WIND GUSTS.

OUTLOOK... 
WED-THU...PATCHY AM FOG...OTHERWISE VFR. 
FRI...MAINLY VFR. CHC OF PM TSTMS WEST. 
SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA.

&&

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

&&

$$
SYNOPSIS...STEINBUGL
NEAR TERM...FITZGERALD
SHORT TERM...STEINBUGL
LONG TERM...RXR
AVIATION...DANGELO/MARTIN



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