216
FXUS61 KCTP 150148
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
948 PM EDT FRI AUG 14 2020
SYNOPSIS
A STATIONARY FRONT WILL REMAIN DRAPED ALONG AND SOUTH OF THE
MARYLAND BORDER FOR THE NEXT FEW DAYS. A WAVE OF LOW PRESSURE
WILL RIDE ALONG THIS BOUNDARY OVER THE WEEKEND, PASSING JUST
SOUTH OF THE STATE. A COLD FRONT IS THEN LIKELY TO PUSH ACROSS
THE REGION ON MONDAY.
NEAR TERM /UNTIL 8 AM SATURDAY MORNING/
ALL IS LOOKING GOOD. HIGH CLOUDS WILL PROBABLY CONTINUE TO
STREAM OVER THE AREA OVERNIGHT, AND SOME LOW CLOUDS OUT THERE,
TOO, SHOULD HELP PREVENT FOG FORMATION IN MOST PLACES. LITTLE
CHANGE TO WHAT IS GOING.
PREV...
RADAR ALMOST ENTIRELY QUIET, EXCEPT FOR A FEW PINPOINTS OVER
SRN SOMERSET AND CENTRAL YORK COS. ANY ADDITIONAL DEVELOPMENT
WILL BE SPARSE AND WEAK, AND NOTHING SHOULD BE PRODUCING RAIN
PAST 10PM. HAVE CONTINUED THE TREND OF REDUCING POPS. TEMPS
RUNNING A LITTLE WARMER THAN SCHEDULED, AND THE HIGH CLOUD COVER
MAY HELP TO KEEP THEM A LITTLE MILDER ON THE WHOLE THRU THE
NIGHT. SOME PATCHY FOG IS POSSIBLE IN THE NORTH, BUT LOTS OF
BENIGN CLOUD COVER - AND LOW DEWPOINTS - UP THERE RIGHT NOW.
THEY WOULD NEED TO CLEAR OUT FOR FOG TO BECOME POSSIBLE.
PREV...
EXPECT SCATTERED, DIURNALLY-DRIVEN CONVECTION TO FORM DURING
THE LATE AFTERNOON HOURS TODAY OVER THE SOUTHERN HALF OF THE
STATE, IN THE MODERATELY UNSTABLE AIR MASS (WITH SFC BASED CAPE
CLIMBING TO NEARLY 1500 J/KG) ALONG AND SOUTH OF REMNANT SFC-850
MB FRONTAL BOUNDARY.
HIGHEST POPS OF AROUND 50PCT WILL BE PAINTED ALONG THE MASON
DIXON LINE, WHERE PWATS ARE HIGHEST. WEAK WINDS ALOFT AND 0-6KM
SHEAR ONLY AROUND 15KTS INDICATE ANY STORMS WILL BE OF THE PULSE
VARIETY WITH LITTLE RISK OF SEVERE WEATHER.
THE DRY GROUND AND ABUNDANT SUNSHINE IN MOST PLACES HAD LED
TO ANOTHER WARM DAY RELATIVE TO CLIMATOLOGY ACROSS THE NORTHERN
HALF OF THE STATE, WITH HIGHS IN THE UPPER 80S POSSIBLE IN THE
VALLEYS ALONG I-80. MORE CLOUD COVER AND SCATTERED CONVECTION
SHOULD HOLD READINGS CLOSE TO AVERAGE ACROSS THE SOUTHERN
COUNTIES.
ANY SHOWERS/STORMS ACROSS SOUTHERN PA WILL DISSIPATE QUICKLY
WITH THE LOSS OF HEATING THIS EVENING, THEN EXPECT DRY WEATHER
THE REST OF THE NIGHT. AN APPROACHING UPPER TROUGH AND SURFACE
LOW OVER THE OHIO VALLEY WILL SPREAD INCREASING CLOUDS INTO THE
REGION OVERNIGHT, WITH AN OUTSIDE CHANCE OF A SHOWER REACHING
SOMERSET COUNTY BY DAWN.
SHORT TERM /8 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/
A SLOW MOVING SHORTWAVE AND ASSOCIATED WAVE OF SFC LOW PRESSURE
WILL TRACK EASTWARD FROM THE OHIO VALLEY THIS WEEKEND.
THERE REMAINS A RELATIVELY HIGH AMT OF MODEL SPREAD/FORECAST
UNCERTAINTY REMAIN WITH REGARD TO HOW FAR NORTH THIS FEATURE AND
ITS ASSOCIATED RAIN GET IN PA. HOWEVER, ALL GUIDANCE FAVORS THE
HIGHEST POPS ACROSS THE SOUTHERN TIER COUNTIES LATE SATURDAY
INTO EARLY SUNDAY IN ASSOCIATION WITH PASSAGE OF ANOMALOUS
EASTERLY LOW LEVEL JET.
WITH SURFACE LOW TRACKING SOUTH OF THE STATE AND ALL GUIDANCE
SHOWING RELATIVELY STABLE AIR OVER PA, ANTICIPATE A STRATIFORM
RAINFALL, RATHER THAN CONVECTION, AND LITTLE RISK OF FLOODING.
THE BULK OF LATEST GUIDANCE INDICATE 24HR RAIN AMOUNTS OF
AROUND AN INCH OR SO ARE POSSIBLE ACROSS THE SOUTHERN COUNTIES.
LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/
UNSETTLED CONDS PERSIST INTO SUNDAY AS A SLOW MOVING WAVE OF LOW
PRESSURE ALONG THE PERSISTENT FRONT OVER THE MASON DIXON LINE
MOVES OFF OF THE NJ/DE COAST BY MIDDAY SUNDAY. THIS WILL BRING
HIGHEST SHOWERS CHANCES TO THE SOUTHEAST, WITH PERHAPS SOME
HEAVIER DOWNPOURS WHERE THEY LEAST NEED IT (THOSE AREAS WHICH
RECEIVED SEVERAL INCHES FROM ISAIAS NEARLY TWO WEEKS AGO, AND
MANY ADDITIONAL STORMS SINCE). IN ITS WAKE A RELATIVE LULL IN
THE PRECIP IS SEEN LATER SUNDAY INTO MONDAY MORNING BEFORE
A COLD FRONT IS PROGGED TO SWEEP THROUGH THE COMMONWEALTH
MONDAY, USHERING IN COOLER AND DRIER WEATHER.
THE CLIMATE PREDICTION CENTER 6-10 TEMPERATURE OUTLOOK FAVORS
BELOW NORMAL TEMPERATURES IN CENTRAL PA. THIS WILL BE A WELCOME
RELIEF AFTER A PROLONGED STRETCH OF WARM WEATHER. ADDITIONALLY,
THE ARRIVAL OF HIGH PRESSURE BY THE MIDDLE OF NEXT WEEK SEEMS TO
FAVOR A DRIER THAN NORMAL STRETCH FOR A LITTLE BIT.
PRECIPITATION CHANCES RAMP UP AGAIN ACROSS THE SOUTHERN TIER BY
LATE WEEK, BUT NO SIGNIFICANT IMPACTS ARE EXPECTED.
AVIATION /02Z SATURDAY THROUGH WEDNESDAY/
AT 23Z, CUMULUS CLOUDS ARE ALREADY DISSIPATING ACROSS THE AREA,
AS WE LOSE THE HEATING OF THE DAY. SOME HIGH CLOUDINESS IS
DRIFTING EASTWARD OVERHEAD, WHICH IS DEBRIS FROM STORMS OVER
THE MIDWEST AND OHIO VALLEY.
EXPECTING GENERALLY VFR CONDS ACROSS CENTRAL PA OVERNIGHT, WITH
LITTLE MORE THAN SOME HIGH AND MID-LEVEL CLOUDS PASSING
OVERHEAD.
SATURDAY WILL START OUT WITH VFR CONDS AREA-WIDE, AND WILL
PROBABLY REMAIN THAT WAY ALL DAY ACROSS THE EAST. HOWEVER,
CLOUDS WILL BUILD THROUGH THE DAY AND SHOWERS ARE POSSIBLE BY
AFTERNOON ACROSS THE WESTERN HIGHLANDS.
OUTLOOK...
SUN...REDUCTIONS POSS IN SHOWERS/STORMS.
MON...STILL A SLIGHT CHANCE OF SHOWERS/STORMS.
TUE...GENERALLY VFR CONDS.
WED...A FEW SHOWERS AND BRIEF REDUCTIONS POSS ACROSS THE SE.
CLIMATE
A DAILY RECORD HIGH TEMPERATURE OF 87 DEGREES WAS TIED AT
BRADFORD ON 8/13. THE PREVIOUS RECORD WAS SET IN 1988.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/DANGELO
SHORT TERM...LAMBERT/FITZGERALD
LONG TERM...DEVOIR/GARTNER
AVIATION...EVANEGO
CLIMATE...
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