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Area Forecast Discussion
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000
FXUS61 KCTP 310010
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
810 PM EDT SUN AUG 30 2015

.SYNOPSIS...
A WEAK TROUGH DYING OVER THE REGION AND HIGH MOISTURE WILL RESULT
IN SCATTERED SHOWERS AND A FEW THUNDERSTORMS THIS EVENING.
DRIER WEATHER WILL OCCUR FOR THE FIRST PART OF THE WEEK...BUT
HIGH PRESSURE OFF THE EAST COAST WILL LEAD TO TEMPERATURES WELL
ABOVE NORMALS ALL WEEK...WITH HIGH HUMIDITY. IT WILL FEEL MORE
LIKE THE MIDDLE OF SUMMER THAN SEPTEMBER.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TWO AREAS OF FORCING...ONE SHEAR AXIS ALONG THE PA/NY BORDER AND
ANOTHER OVER NORTHERN AND CENTRAL VIRGINIA...HAVE HELPED TO
INITIATE AND MAINTAIN ISOLATED TO SCATTERED COVERAGE OF SHOWERS
LATE THIS AFTERNOON INTO THE EARLY EVENING. A FEW LIGHTNING
STRIKES OCCURRING WITH ACTIVITY OVER ADAMS COUNTY...WHICH IS THE
MORE INTENSE AREA OF CONVECTION AT THIS TIME. STILL...CORES ARE
NOT VERY HIGH...AND AT THE PRESENT TIME BRIEF DOWNPOURS AND WIND
GUSTS OF 25 TO 30 MPH ARE ALL THAT WE EXPECT.

UPPED POPS SLIGHTLY AND EXPANDED COVERAGE INTO AREAS THAT WEREN'T
PREVIOUSLY INCLUDED. THINK THE IDEA OF SHOWERS LINGERING LONGEST
IN THE SRN HALF OF THE AREA AND ESP SE IS GOOD...AS A WEAK SFC
TROUGH SLIDES EAST BUT STALLS. CLOUD COVER IS A DIFFICULT FORECAST
WITH RH PLOTS SHOWING A DECENT AMOUNT OF LOWER CLOUDS HANGING ON
THROUGH THE NIGHT. THIS SEEMS REASONABLE SINCE THE WAVE DOES NOT
GO THROUGH AND WE DO NOT GET INTO SUBSTANTIAL SUBSIDENCE.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM MONDAY/...
CLOUD COVERAGE WILL LIKELY REMAIN THE MOST DIFFICULT PART OF THE
FORECAST OVERNIGHT. NAM RUNS A VERY SMALL PATCH OF LIGHT RAIN
THROUGH THE NW BY MORNING...MOST LIKELY ASSOCD WITH UPSTREAM
CONVECTION. AGAIN...NOT UNREASONABLE GIVEN THE HIGH MOISTURE AND
BEGINNING OF THE RETURN FLOW IN WRN PA. JUST THE FAR SRN TIER HAS
THE OTHER SLIGHT CHC FOR PRECIP OVERNIGHT AS THAT TROUGH LINGERS.
HOWEVER...FORCING AND INSTABILITY WILL BE LACKING THERE. SOME FOG
MAY DEVELOP...ESP IN PLACES WHICH HAD RAINFALL AND THOSE WHICH
SEE MORE CLEARING THAN OTHERS. HOWEVER...DO NOT EXPECT WIDESPREAD
FOG AT THIS POINT. MINS WILL RUN IN THE 60S EVERYWHERE AS
DEWPOINTS SHOULD NOT GO ANY LOWER THAN 60F.

SUBSIDENCE DOES NOT REALLY COME DOWN SOUTH ENOUGH TO ALLOW US TO
DRY OUT ON MON. THE UPPER HIGH WILL CONTINUE TO SLIDE EASTWARD BUT
SOME SEMBLANCE OF TROFFINESS REMAINS ACCORDING TO MOST GUID. WITH
THE SFC HIGH RETURN FLOW INCREASING...A FEW SHRA/TSRA ARE STILL
POSSIBLE MON...BUT MAINLY IN THE FAR SOUTH AND FAR NORTH. HAVE
ALLOW FOR LINGERING SHRA S IN THE MORNING AND EARLY AFTN...AND
MORE IN THE WAY OF DIURNAL SHRA IN THE NRN TIER. MAXES WILL BE A
FEW DEGS HIGHER THAN TODAY - IF WE CAN GET RID OF MOST OF THE
CLOUDS FOR A SHORT TIME - BECAUSE 8H TEMPS WILL BE ABOUT 2C
WARMER.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
ANOMALOUS UPPER LEVEL RIDGE WILL DOMINATE THE OHIO VALLEY AND
EASTERN UNITED STATES MUCH OF THE UPCOMING WEEK...WITH LATEST
GUIDANCE REMAINING FIRM FOR AN EXTENDED RUN OF 850HPA TEMPS
PEAKING DAILY AROUND 16-18C. THIS 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
WARM MID-LEVELS WILL KEEP THE PROBABILITY OF WIDESPREAD RAINFALL
QUITE LOW.

BEST CHANCES FOR PRECIP WILL BE MIDWEEK /WED-THU-FRI/ WITH A
COUPLE SUBTLE FEATURES. FIRST...A WEAK UPPER LEVEL WAVE /BEST
PROGGED ON THE ECMWF/ SLIPS OVERHEAD ON WED AS BERMUDA HIGH
BRIEFLY RECEDES. AT SAME TIME A WEAK BACKDOOR COLD FRONT SLIPS
SOUTHWARD OFF THE EAST COAST. THIS COULD HELP POOL SOME LOW LEVEL
MOISTURE OVER THE MID ATLANTIC AND OHIO VALLEY AS MID LEVELS COOL
JUST A BIT...BRINGING POTENTIAL FOR SCT TSTMS. RIDGE BUILDS BACK
IN FOR FRI...BUT ANOTHER SURFACE BACKDOOR FRONT TRIES TO SLIP
ACROSS THE STATE AS SURFACE HIGH EXPANDS IN FROM THE NORTH. THIS
BOUNDARY SHOULD BRING SCT CONVECTION FOR FRI.

EXTENDED MODELS HINT AT POTENTIAL FOR DAILY CONVECTION CONTINUING
INTO THE WEEKEND ALONG SOUTHER BORDER...BUT OVERALL CONDITIONS
WILL BE MAINLY RAIN-FREE.

TEMPS PEAK MIDWEEK WITH READINGS APPROACHING 90F IN THE SE...AND
EVEN GETTING INTO THE 80S ELSEHERE...EASILY WELL ABOVE NORMAL FOR
THE FIRST WEEK OF SEPT. LOWS WILL ALSO REMAIN QUITE MILD MID/LATE
WEEK AS HIGH HUMIDITY AIR HANGS AROUND. SLIGHTLY COOLER BUT STILL
ABOVE AVERAGE TEMPS WILL CONTINUE THROUGH THE WEEKEND.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A WEAK AREA OF LOW PRESSURE PASSING TO THE NORTH OF PA HAS SPAWNED
SCT SHRA/TSRA ACROSS CENTRAL PA EARLY THIS EVENING. LOSS OF
HEATING SHOULD CAUSE MOST OF THE SHOWERS TO DISSIPATE SHORTLY
AFTER SUNSET. HOWEVER...RADAR TRENDS AND LATEST HRRR IMPLIES A
BRIEF VIS REDUCTION CAN/T BE RULED OUT AT KMDT/KLNS SOMETIME BTWN
01Z-04Z. 

FOCUS LATER TONIGHT WILL SHIFT TOWARD POTENTIAL OF FOG. LIGHT WIND
AND PTCLDY SKIES SHOULD PROMOTE LOCALLY DENSE VALLEY FOG AFTER
MIDNIGHT ACROSS NORTHERN PA. CLIMATOLOGY AND LATEST SREF/MOS
SUGGEST KBFD IS LIKELY TO EXPERIENCE IFR/LIFR VIS REDUCTIONS
LATE TONIGHT. ALSO...MAY HAVE TO CONTEND WITH DENSE FOG AT
KIPT...WHERE GROUND IS NOW WET FROM A PASSING SHOWER. COMPLICATING
FACTOR IS MID LVL CLOUDINESS OVERSPREADING THE SOUTHERN PART OF
THE STATE. FEEL CONFIDENT THESE MID LVL CLOUDS WILL BE THICK
ENOUGH TO DIMINISH THE RADIATIONAL COOLING AND ASSOC DENSE FOG
THREAT ACROSS SOUTHERN PA. HOWEVER...NOT AS CONFIDENT AT KIPT.

ANY AM VALLEY FOG ACROSS NORTHERN PA SHOULD BURN OFF BY LATE AM.
OTHERWISE...WIDESPREAD VFR CONDS AND LIGHT WIND APPEAR VERY
LIKELY MONDAY WITH ONLY ISOLD LATE DAY SHRA/TSRA POSSIBLE...AS
HIGH PRESSURE BUILDS OFF THE MID ATLANTIC COAST.

OUTLOOK...

TUE-FRI...PATCHY AM FOG POSS...MAINLY KBFD. ISOLD PM TSRA IMPACTS
POSSIBLE. 

&&

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

&&

$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD



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