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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 182136
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
536 PM EDT TUE JUN 18 2013

.SYNOPSIS...
THE PERSISTENT JUNE PATTERN OF A BROAD THROUGH OVER THE MID-
ATLANTIC AND NORTHEAST STATES IS FORECAST TO TRANSITION AND BE
REPLACED BY A SUMMERTIME UPPER LEVEL RIDGE MIGRATING EASTWARD FROM
THE PLAINS. A SLIGHTLY COOLER AND LESS HUMID AIR MASS WILL FOLLOW
IN THE WAKE OF A COLD FRONT TONIGHT INTO THURSDAY. INCREASING HEAT
AND HUMIDITY WILL ARRIVE ON SCHEDULE WITH THE OFFICIAL START OF
ASTRONOMICAL SUMMER...AND LAST INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
BEST LLVL CONVERGENCE IS ALONG THE TURNPIKE AND SRN BORDER.
THUS...EXPECT HIGHEST CHCS FOR SHRA TO BE THERE EARLY THIS
EVENING. A FEW MORE CU ARE BUILDING OVER THE LOCAL AREA...WHERE
HEATING HAS THUS FAR BEEN HAMPERED BY THICK HIGH CLOUD COVER.
SO...CANNOT PULL ALL MENTIONS OF SHOWERS - ESP WITH THE RUC
INSISTING ON MAKING MORE/HEAVY SHOWERS OVER THE RIDGE AND
VALLEY/MID SUSQ BEFORE SUNSET. TALL CU OVER BFD WILL ALSO WARRANT
AT LEAST ISOLD POPS IN THE NRN HILLS FOR THE NEXT FEW HOURS AS
WELL. SUBSIDENCE AND CLEARING WILL COME TO THE AREA FROM N-S
THROUGH THE LATE EVENING AND OVERNIGHT. WINDS DO GO CALM IN MANY
LOCATIONS. SO A LITTLE FOG IS POSSIBLE - EARLY IN BFD BEFORE
DEWPOINTS TANK...AND AROUND THE REST OF THE AREA LATER AT
NIGHT...ESP THOSE PLACES THAT DID GET WET TODAY.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
LAST SHORTWAVE TO ENHANCE THE TROUGH OVERHEAD WILL RUN OVER THE
REGION AROUND SUNRISE...AND THEN THE HEIGHTS START TO RISE
STEADILY. SFC HIGH PRESSURE FINALLY PUSHES FAR ENOUGH TO THE SOUTH
AND INTO PA TO REMOVE MOST CLOUD COVER AND ALMOST EVERY BIT OF
POPS. WILL JUST HANG ONTO A SLIGHT CHC OVER THE HIGHEST TERRAIN OF
THE LAURELS/SC MTS WHERE ENOUGH MSTR AND ELEVATED HEATING SURFACES
MAY COMBINE TO POP OFF A SHRA OR TWO. TEMPS WILL BE A DEG OR TWO
LOWER WED THAN TUES.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
UPPER RIDGE OVER CENTRAL PLAINS WILL BUILD EASTWARD INTO PA WED
NIGHT THROUGH SATURDAY...AS 500 MB HEIGHTS RISE TO 588DM. CENTER
OF SURFACE HIGH SLIPS SE ACROSS GREAT LAKES AND IS LOCATED OVER
CENTRAL PA ON WED NIGHT...SETTING UP IDEAL RADIATIONAL COOLING
CONDITIONS. DEWPOINTS WILL STILL BE LINGERING IN THE 50S ACROSS
SOUTHERN PA...BUT MUCH LOWER DEWPOINTS NORTH OF I-80 WILL ALLOW
TEMPS TO DROP WELL INTO THE 40S.

STARTING THU...LLVL S-SWLY RETURN FLOW AROUND SFC HIGH /DRIFTING
OFF THE EAST COAST/ WILL BRING A GRADUAL INCREASE IN LLVL MSTR
THRU THE END OF THE WORK WEEK...WITH JUST A SLGT CHC FOR AN AFTN
POP-UP/AIRMASS TYPE TSTM ON FRI. OTHERWISE...SUNNY TO MOSTLY SUNNY
CONDITIONS WILL PREVAIL AS TEMPS CLIMB TO SEASONAL NORMALS ON THU
AND BEGIN A STRING OF ABOVE NORMAL DAYS ON FRIDAY.

HEAT AND HUMIDITY CONTINUE TO INCREASE HEADING INTO THE WEEKEND AS
HEIGHTS PEAK. BIGGER SURGE OF HIGHER DEWPOINTS SLIDES IN FROM THE
WEST AS HEAT CONTINUES TO BUILD...SO A SERIES OF VERY WARM AND
HUMID DAYS ARE IN STORE FOR SAT INTO TUES...WITH OVERNIGHT LOWS
REMAINING QUITE MILD AS WELL. WITH STAGNANT AIR AND INCREASING
HUMIDITY ON BACK SIDE OF SURFACE HIGH...HELD ON TO 20-30 POPS MOST
AFTERNOONS - WITH HIGHEST CHANCES OVER WESTERN HIGHER TERRAIN OF
ISOLATED DIFFERENTIAL HEATING INITIATED STORMS.

PATTERN ALSO HAS A RING-OF-FIRE LOOK TO IT SO WILL NEED TO WATCH
FOR MCS ACTIVITY/RIDGE ROLLERS SLIDING DOWN FROM THE NW...THOUGH
LATEST MODELS NOT QUITE AS BULLISH ON THAT. EC OVERALL PRODUCING
MORE CONVECTION THAN THE GFS...BUT GENERAL AREAS ARE SIMILAR.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...

-- Changed Discussion --
A WEAK SURFACE BOUNDARY CONTINUES TO ACT AS A LOOSE FOCUS FOR
SLOW MOVING SHOWERS AND THUNDERSTORMS OVER THE SRN HALF OF THE
FCST AREA. MOST SITES WILL REMAIN VFR INTO THE OVERNIGHT...BUT
SOME MVFR CONDITIONS ARE POSSIBLE FROM JST EASTWARD AS THE SHOWERS
MEANDER ABOUT.

ANY EARLY MVFR OVER SRN AREAS WILL IMPROVE SHORTLY AFTER SUNRISE
LEADING TO WIDESPREAD VFR WEDNESDAY AS HIGH PRESSURE BUILDS OUT OF
THE GR LAKES.

HIGH PRESSURE WILL CONTROL THE WX INTO THE WEEKEND.

OUTLOOK...

THU-FRI...NO SIG WX EXPECTED.

SAT-SUN...ISOLD PM TSRA IMPACTS POSSIBLE.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...DANGELO/LA CORTE