Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 261254
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
854 AM EDT TUE MAY 26 2015

.SYNOPSIS...
HIGH PRESSURE AT THE SFC AND ALOFT WILL REMAIN JUST OFF THE EAST
COAST THROUGH THE END OF THE WEEK. A COLD FRONT WILL LIKELY PUSH
ACROSS THE REGION NEXT WEEKEND...THEN STALL JUST SOUTH OF THE
STATE EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEEP SOUTH-SOUTHWESTERLY FLOW ON WESTERN PERIPHERY OF THE
DOMINANT COAST RIDGE WILL TRANSPORT GULF OF MEX MOISTURE
NORTHWARD INTO CENTRAL PA EARLY THIS MORNING. SAT-DERIVED PWATS NR
1.7 INCHES ACROSS NORTHERN/WESTERN PA AT 09Z. REGIONAL RADAR AT
1230Z SHOWING ISOLATED-SCATTERED SHRA DEVELOPING IN THIS MOIST
AIR MASS IN ADVANCE OF A MID LVL VORT MAX LIFTING NE OUT OF
SOUTHERN OHIO. BASED ON RADAR TRENDS AND LATEST HRRR OUTPUT...WILL
CARRY CHC OF SHRA ACROSS THE NW MTNS THIS MORNING. FOR AREAS
SOUTH AND EAST OF KJST/KUNV/KIPT...THE REST OF THE LATE MORNING
HRS SHOULD REMAIN DRY.

AFTER THE PASSAGE OF THE SHORTWAVE LATER THIS MORNING...LG SCALE
FORCING BECOMES QUITE VERY WEAK. HOWEVER...HEATING OF MOIST AIR
MASS WITH PWATS 2-3SD ABV CLIMO SHOULD YIELD SCT DIURNALLY-DRIVEN
SHRA/TSRA THIS AFTN WITH LATEST NAM AND SREF MEAN SFC-CAPES MAXING
OUT AROUND 1000 J/KG. THE BEST CHC FOR CONVECTION WILL LIKELY BE
ACROSS THE CENTRAL MTNS AND MIDDLE SUSQ VALLEY...WHERE 50 PCT POPS
PAINTED. EARLY CLOUDS/SHOWERS ACROSS THE NW SHOULD RESULT IN LESS
INSTABILITY AND A DIMINISHED CHC OF CONVECTION UP THERE. ACROSS
SOUTHEAST PA...WARMER TEMPS ALOFT SHOULD HELP SUPPRESS CONVECTION
OVR THE LOWER SUSQ VALLEY.

MEAN SREF/GEFS CAPES TOP OUT NR OR SLIGHTLY LESS THAN 1000 J/KG
THIS AFTN AND SHEAR NOT PARTICULARLY STRONG. THUS...SPC OUTLOOK
KEEPS THE MRGL RISK WEST OF OUR CWA.

EARLY AM IR LOOP SUGGESTS AREAS SOUTH OF I-80 WILL DAWN MSUNNY
TODAY. HOWEVER...A GOOD DEAL OF CU SHOULD DEVELOP BY MIDDAY BASED
ON MDL SOUNDINGS. TEMPS ARE LIKELY TO BE A BIT COOLER THAN MONDAY
DUE TO MORE CLOUDS...WITH MAXES FROM THE U70S OVR THE ALLEGHENY
PLATEAU...TO THE M80S ACROSS THE LOWER SUSQ VALLEY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
DIURNALLY-DRIVEN CONVECTION SHOULD DIE OFF AFTER SUNSET THIS
EVENING. THE REST OF THE NIGHT WILL LIKELY FEATURE WARM AND
TRANQUIL CONDS. HIGH PWAT AIR MASS WILL RESULT IN MID SUMMER MIN
TEMPS...WITH LOWS IN THE M/U60S MOST PLACES.

A POTENT SHORTWAVE LIFTING THRU THE GRT LKS WILL INTRODUCE A
BETTER CHC OF SHRA/TSRA ON WEDNESDAY. MDL TIMING OF THIS FEATURE
SUGGESTS SHOWERS COULD ARRIVE EARLY IN THE DAY ACROSS THE W
COUNTIES...WITH A GREATER RISK OF PM TSRA ACROSS EASTERN PA. GEFS
MEAN CAPES PEAK ARND 1200 J/KG ACROSS THE SE COUNTIES WED AFTN.
HOWEVER...MID LVL WINDS AND ASSOC DEEP LYR SHEAR NOT PARTICULARLY
STRONG IN MDL DATA...SO SVR WX THREAT JUST MRGL. MCLDY SKIES WILL
HOLD TEMPS DOWN A BIT...BUT CONSALL STILL SUGGESTS HIGH TEMPS BTWN
THE M70S-L80S...SEVERAL DEG ABV NORMAL FOR LATE MAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGH PRES AT SFC AND ALOFT JUST OFF THE EAST COAST SHOULD KEEP
WARM/HUMID AIR OVR CENTRAL PA THRU THE END OF THE WEEK. PASSAGE
OF MID LVL SHORTWAVE ON THURSDAY SHOULD SUPPORT ADDITIONAL SCT
SHRA/TSRA THURSDAY. BY FRIDAY...BULK OF MED RANGE GUIDANCE IMPLIES
DRIER WX /ESP NORTHERN PA/...AS LOWER PWAT AIR MASS WORKS INTO
CENTRAL PA IN ASSOC WITH HIGH PRES WORKING ACROSS S ONTARIO INTO N
NEW ENG.

A COLD FRONT WILL LIKELY BRING AN END TO THE SUMMERLIKE
WARMTH/HUMIDITY BY NEXT WEEKEND. A FAIR AMT OF AGREEMENT AMONG
MED RANGE GUIDANCE THAT A PERIOD OF RAINY WX COULD FOLLOW LATE
SUNDAY/MONDAY AS WAVE OF LOW PRES RIDES EASTWARD ALONG STALLED
FRONTAL BNDRY SOUTH OF PA.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
ISOLATED SHOWER ACTIVITY HAS DEVELOPED ALONG A SW TO NE LINE FROM
NEAR KJST TO NORTH OF KIPT. ACTIVITY IS LIGHT AND SHOULD NOT
CAUSE A DIRECT IMPACT. HOWEVER...MOISTURE FROM THE SHOWERS WILL
LEAD TO LOWERED CIGS OVER THE NEXT COUPLE OF HOURS ACROSS THAT
REGION.

VFR SHOULD CONTINUE AT MOST SITES OVER THE NEXT 24 HOURS. HIGHEST
CONFIDENCE IN BRIEF 1-3HR PERIOD OF 3-6SM VISIBILITY RESTRICTIONS
IN BR/HZ IS AT MDT/LNS AROUND DAYBREAK TUESDAY. GIVEN RELATIVELY
LOW PROBABILITY/EXPECTED COVERAGE...DECIDED NOT TO EXPLICITLY
MENTION TSTMS IN TERMINALS AT THIS TIME. LATER ISSUANCES SHOULD
INTRODUCE A VCTS FM GROUP WITH EITHER THE 06 OR 12Z ISSUANCE.

A SUMMER-TIME PATTERN WILL PERSIST THROUGH THE WEEK WITH REPLAY OF
PATCHY MORNING FOG GIVING WAY TO VFR AND AFTN ISOLD-SCT TSTMS. A
MORE DEFINED TSTM RISK SHOULD ARRIVE BY NEXT WEEKEND AS A COLD
FRONT PRESSES SEWD FROM THE GREAT LAKES.

OUTLOOK...

TUE-FRI...PATCHY A.M. MVFR FOG/BR. ISOLD-SCT P.M. TSTMS.

SAT-SUN...PATCHY A.M. MVFR FOG/BR. SCT-NMRS P.M TSTMS W/COLD
FROPA.

&&

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

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...FITZGERALD/LAMBERT
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...GARTNER/STEINBUGL


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