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000
FXUS61 KCTP 180942
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
542 AM EDT TUE JUN 18 2013

.SYNOPSIS...
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THE PERSISTENT JUNE PATTERN OF BROAD TROUGHING 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 AIRMASS 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.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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BELT OF STRONGER MID-LVL FLOW ON THE SRN EDGE OF SHORTWAVE TROUGH
MOVG EWD FROM QUEBEC TO THE MARITIMES WILL SHIFT EWD ACRS NEW
ENGLAND THIS MORNING. AN ATTENDANT SFC COLD FRONT DRAPED ALONG THE
LWR LKS IS TEAMING WITH A WELL-DEFINED 300MB JET ENTRANCE REGION
TO MAINTAIN A CLUSTER SHOWERS/TSTMS OVER NW PA...WITH A FEW LONE
CELLS CROSSING LK ERIE. THE LATEST MESO MODELS CONTINUE TO WEAKEN
THIS AREA OF PCPN AS IT SHIFTS EWD ACRS MCKEAN CO THRU 12Z. OUTSIDE
OF THE NW MTNS...MOST AREAS SHOULD REMAIN DRY THRU DAYBREAK.

IR SATL LOOP SHOWS A SHIELD OF LYRD MID-HIGH CLOUDS SPREADING NEWD
ACRS CNTRL PA. THESE CLOUDS ARE ASSOCD WITH A SHORTWAVE LIFTING
THRU THE TN VLY AND WEAK SFC LOW ADVANCING EWD TOWARD THE CNTRL
MID-ATLC COAST. ANOTHER COMPACT SHORTWAVE IS CURRENTLY ROTATING
ACRS MN..AND WILL TRACK SEWD INTO THE LWR-MID OH VLY BY THIS
AFTN. THE APPROACHING SHORTWAVE ENERGY /FROM THE SW/ AND
AFOREMENTIONED SFC COLD FRONT /FROM THE NW/ SHOULD PROVIDE
SUFFICIENT FORCING/LIFT TO FUEL SCT TO NMRS TSTM DEVELOPMENT INTO
THE AFTN. HOWEVER THERE IS SOME QUESTION AS TO WHERE THE BEST
LOCATION/AERIAL CVRG WILL BE. THE LATEST HRRR AND 00Z SPC WRF/SSEO
HIGHLIGHT THE AREA SOUTH OF I-80...WITH THE HRRR SHOWING A NOTABLE
INCREASE IN CONVECTION AROUND THE 17-18Z TIMEFRAME.

THE SVR THREAT APPEARS MARGINAL DUE TO WEAK/MODEST INSTABILITY.
HOWEVER I CANT RULE OUT A FEW ORGANIZED STORMS GIVEN 35-40 KT OF
EFFECTIVE BULK SHEAR. COULD ALSO SEE SOME LOCALLY HEAVY RAINS
WITH THE MAIN SURGE OF ANOMALOUS PWATS OVER SOUTHEAST PA. THE
LATER ARRIVING MESO GUIDANCE SEEMS TO BE FORMING A CONSENSUS THAT
THE SRN 1/2 OF THE CWA SHOULD SEE THE MOST ACTIVITY COINCIDENT
WITH PEAK HEATING. AS SUCH...EXPECT TSTM CVRG TO WANE/TAPER OFF
WITH THE ONSET OF NIGHTFALL/SWD MVMT OF COLD FRONT.

THE FRONT WILL PUSH SOUTH ACRS THE CWA BY LATER TONIGHT WITH MUCH
DRIER/BELOW NORMAL PWAT AIR ARRIVING FROM THE NORTH. WILL HOLD
ONTO SOME LOW POPS ALONG THE MASON DIXON LINE INTO EARLY WEDNESDAY
MORNING BUT MOST AREAS SHOULD BE DRY AFT 06Z...ESPECIALLY TO THE
NORTH OF THE TURNPIKE.
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&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
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HIGH PRES WILL PREVAIL ON WEDNESDAY BRINGING PLENTY OF SUNSHINE.
THE WEATHER SHOULD BE RATHER COMFORTABLE AND PLEASANT WITH
COOLER NLY WINDS AND LOW HUMIDITY...WITH TEMPS GENERALLY IN THE
70S. CLR/CALM CONDS WED NIGHT SHOULD ALLOW OVERNIGHT LOWS TO FALL
INTO THE LOW-MID 40S ACRS THE NRN TIER...AND LOW-MID 50S IN THE
SOUTH. SOME OF THE USUAL COLD SPOTS IN THE NRN MTNS COULD DIP
INTO THE UPPER 30S.
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&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
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A DEEP CLOSED LOW MOVG ACRS THE PACIFIC NW AND NRN ROCKIES WILL
ALLOW THE CENTRAL PLAINS UPPER RIDGE TO SLIDE EWD WITH RISING HGTS
EXPECTED DOWNSTREAM OVER THE ERN CONUS. CONSENSUS OF MODEL AND
ENSEMBLE DATA CONTINUES TO BUILD THE RIDGE TO 588+DM THRU THE
WEEKEND WITH THE FIRST TASTE OF SUMMERTIME HEAT/HUMIDITY ARRIVING
ON SCHEDULE.

LLVL S-SWLY RETURN FLOW AROUND SFC HIGH PRES DRIFTING OFF THE EAST
COAST WILL BRING AN INCREASE IN LLVL MSTR THRU THE END OF THE WORK
WEEK...WITH JUST A SLGT CHC FOR AN AFTN POP-UP/AIRMASS TYPE SHOWER
OR TSTM ON FRI.

ABOVE NORMAL 500 HPA HEIGHTS OVERSPREAD THE COMMONWEALTH THIS
WEEKEND. THIS SHOULD TRANSLATE INTO WARMER-THAN-NORMAL TEMPS WITH
THE GFS-BASED MOS GUID MORE BULLISH THAN THE EC MOS ON THE HEAT.
PATTERN ALSO HAS A RING-OF-FIRE LOOK TO IT SO WILL NEED TO WATCH
FOR MCS ACTIVITY/RIDGE ROLLERS.
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&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
REGIONAL RADAR LOOP THIS EVENING SHOWS SHRA/TSRA ACROSS THE LOWER
GRT LKS IN ASSOCIATION WITH A SLOW-MOVING COLD FRONT. AS THIS
FRONT WORKS SE...A LATE NIGHT SHRA IS POSSIBLE OVR NORTHERN PA.
HOWEVER...THE BIGGEST AVIATION CONCERN TONIGHT IS THE POSSIBILITY
OF FOG AT BFD...MDT AND LNS...ESPECIALLY AT THE MDT AND LNS WHERE
RAIN HAS FALLEN. COUPLE THIS WITH MCLEAR SKIES...A LGT WIND AND WET
GROUND ALL FAVOR DEVELOPMENT OF FOG OVERNIGHT.
CURRENT SAT SHOT SHOWS CIRRUS MOVING OVER THE REGION...THIS WILL
REDUCE THE DEVELOPMENT AND THE SEVERITY OF ANY FOG/MIST. THE
CLEARING SKIES OVER BFD HAVE ALLOWED FOR IFR CONDITIONS TO
DEVELOP...OUT AHEAD OF THE APPROACHING FRONT. MVFR CONTINUES AT
LNS AND MVFR SHOULD DEVELOP AT MDT. IFR REMAINS POSSIBLE AT
MDT...LNS AND IPT. A THICK LAYER OF MID CLOUDS HAS DEVELOPED OVER
THE CENTRAL TAF SITES AND SHOULD NEGATE ANY FOG FORMATION.

ANY FOG THAT MANAGES TO FORM OVERNIGHT SHOULD BURN OFF WITHIN A
COUPLE HRS AFTER SUNRISE. FOCUS WILL THEN SHIFT TOWARD SCT
SHRA/TSRA DEVELOPING TUES AFTN...AS COLD FRONT WORKS SOUTH ACROSS
THE STATE. ALTHOUGH VFR CONDS WILL PREDOMINATE...A BRIEF VSBY
REDUCTION IS POSSIBLE WITH ANY SHRA/TSRA. CURRENT MODELS SHOW ANY
PRECIPITATION COULD LINGER ALONG THE MASON DIXON LINE...AND AT
LNS...MDT AND JST THROUGH 06Z WEDNESDAY. IFR CIGS AND VSBYS WILL
AGAIN BE A POSSIBILITY TOMORROW NIGHT.

OUTLOOK...
WED...EARLY AM LGT RAIN/LOW CIGS POSSIBLE JST/AOO.
THU...NO SIG WX EXPECTED.
FRI-SAT...ISOLD PM TSRA IMPACTS POSSIBLE.

&&

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

&&

$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU