Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 231959
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
359 PM EDT WED JUL 23 2014

.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE COMMONWEALTH THIS
EVENING AND TONIGHT. A REFRESHING...COOLER AND LESS HUMID AIRMASS
WILL OVERSPREAD THE COMMONWEALTH FOR THE END OF THE WEEK INTO THE
WEEKEND.

&&

.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
A FEW TOWERS HAVE BROKEN THE CAP. HOWEVER...WARM AIR ALOFT IS
SUPPRESSING MORE-WIDESPREAD TSRA FOR NOW. PARAMETERS FOR SEVERE
ARE RATHER WEAK AND SPC OUTLOOK IS ONLY FOR VERY SMALL CHC OF
SVR WIND/HAIL. NOT MUCH SHEAR - WITH THE HIGHEST AMOUNTS TO THE
N/E. CAPES ARE HIGH IN THE CELLS THAT ARE BIG ENOUGH TO BREAK THE
CAP...SO PULSE STORMS AND VERY TRANSIENT/SHORT-LIVED SVR THREAT IS
WHAT IS EXPECTED THIS EVENING. NOT MUCH ORGANIZATION TO THE CELLS
YET...WITH THE TERRAIN SEEMINGLY THE GENESIS FOR THE FIRST
CUSTOMERS OF THE DAY.

EXPECT THE SHOWERS/STORMS TO COVER MORE OF THE RADAR SCOPE
SHORTLY...WITH MUCH OF THE AREA SEEING A LITTLE RAIN BEFORE THE
EVENING IS OVER. THE COLD FRONT HAS MOVED ONSHORE FROM LAKE ERIE
AND IS PRACTICALLY TO KBFD AT 1830Z. DRY AIR BEHIND IT IS ALSO
COOLING THE LOCATIONS ALONG THE LAKESHORE. THIS SHOULD PUT AN END
TO SHOWERS FOR THE NW AS IT MOVES TO THE SE THROUGH THE EVENING.
LATEST MESO GUIDANCE AGREES ON THE SPEED AND PROGRESSION OF THE
SH/TSRA THIS EVENING. THERE COULD BE A LIGHT SHOWER OR TWO POP UP
AS LITTLE POCKET OF COOLER AIR ALOFT MOVES THROUGH NY STATE AND
BRUSHES THE NRN TIER A FEW HOURS AFTER THE COLD FRONT GOES BY.
EXPECT ALMOST ALL SHOWERS TO BE TO THE S OF IPT/UNV/JST BY 00Z.
SOME SHOWERS WILL PROBABLY LINGER THROUGH MIDNIGHT IN THE SERN
COS/SRN TIER. BUT COVERAGE DIPS QUICKLY AFTER SUNSET.

&&

.SHORT TERM /MIDNIGHT THROUGH 6 PM THURSDAY/...
AS THE STORMS DIE OFF AND MOVE TO THE SOUTH...LOWER CLOUDS WILL
ENTER THE PICTURE FROM THE N/W. LATEST MODEL GUIDANCE IS NOW
JUMPING ON-BOARD WITH THE NAM IS PUSHING THE DRY AIR AND SHOWERS
OFF TO THE S OF THE MASON-DIXON LINE EARLY TONIGHT. CONTINUITY
BETWEEN MOST FCSTS HAS BEEN STRONG WITH SOME SHRA LINGERING IN THE
SRN TIER THROUGH THE NIGHT. SO WILL CONTINUE ON WITH THAT
SLIGHT CHC POP THERE...BUT DRY IT OUT AFTER SUNRISE THURSDAY. THE
GUIDANCE TEMPS TONIGHT DO DROP NICELY OVER THE NORTH - BUT WILL
TEMPER THAT FALL DUE TO THE ANTICIPATED LOWER CLOUD DECK THERE.
MID 50S SHOULD BE LOW ENOUGH EXCEPT FOR THE MOST RURAL VALLEYS.
THUS...THERE COULD BE A BIT OF VALLEY FOG TONIGHT...BUT THE AIR IS
VERY DRY. WILL THEREFORE NOT MENTION FOG FOR TONIGHT IN THE
GRIDS.

THURSDAY SEEMS LIKE A GREAT DAY FOR ANY OUTDOOR ACTIVITY WITH ANY
LOW CLOUDS BURNING AWAY IN THE MORNING. HIGHER CLOUDS ALONG THE
SRN BORDER MAY LINGER FOR A BIT LONGER...BUT NOT ENOUGH TO WARRANT
A MOSTLY CLOUDY FCST. DESPITE THE 8H TEMPS AS LOW AS +10C IN THE
MORNING ACROSS THE NORTHERN TIER...EVEN THEY SHOULD WARM BACK
INTO THE LOWER/MID 70S. 80F AND MAYBE A LITTLE WARMER IS EXPECTED
IN THE SOUTH.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
OVERALL SCENARIO REMAINS UNCHANGED IN THE LONG TERM PERIOD AS A
LARGE UPPER RIDGE BUILDING OVER THE FOUR CORNERS REGION IS
FORECAST TO EXPAND NORTH AND EAST INTO THE ROCKIES AND PLAINS
DURING THE PERIOD. DOWNSTREAM...THIS WILL LEAD TO MODERATE TO
STRONG LONG WAVE TROFFING OVER THE EASTERN THIRD OF THE COUNTRY.

UPPER LOW TO THE EAST OF HUDSON BAY WILL BE STRENGTHENED AT TIMES
BY SHORTWAVE ENERGY IN THE STRONGER JET STREAM FLOW ACROSS CANADA.
SOUTHWARD EXTENSION OF THIS LOW/TROF WILL AT TIMES DURING THE
PERIOD STRENGTHENING THE TROFFING ACROSS THE NORTHEASTERN U.S./OUR
REGION. THE TREND OF MEDIUM RANGE MODEL GUIDANCE IS FOR
STRONGER/DEEPER TROFFING DOWNSTREAM ACROSS THE EASTERN
U.S...DEVELOPING AN ALMOST FULL LATITUDE TROF EXTENDING FROM THE
EASTERN CANADA LOW SWD TO FLORIDA. THIS WILL LIKELY SERVE TO
EXPAND AND PROLONG THE CHANCES FOR PCPN THIS WEEKEND.

CONDS WILL BE IMPROVING AT THE START OF THE PERIOD AS COLD FRONT
EXITS. A SECOND...POTENTIALLY STRONGER SYSTEM WILL AFFECT THE
REGION LATE NEXT WEEKEND. THE TREND OF STRONGER TROUGHING
MENTIONED ABOVE HAS LEAD TO SLOWER ARRIVAL AND DEPARTURE OF THE
FRONTAL SYSTEM IN THE DAILY PROGS. THE ECMWF IN LATEST RUN HAS
SLOWED UP THE PROGRESSION OF THIS UPPER LEVEL LOW...WHERE THE GFS
OPERATIONAL AND ENSEMBLES HAVE SPED UP ITS PROGRESSION THROUGH THE
GREAT LAKES REGION. A WARM FRONT WILL BE ON THE DOORSTEP OF PA
SUNDAY...AS THE EC CONTINUES TO SLOW ITS PROGRESSION SO EXPECT THE
WARM FRONT TO MOVE IN CLOSER TO MIDDAY SUNDAY. HAVE THUS ADJUSTED
POPS/TIME.

ASSOCIATED COLD FRONT DOES NOT CROSS THE STATE TIL MONDAY...WHERE
SURPRISINGLY AT THIS POINT...THE EC AND GFS COME CLOSELY IN PHASE.
THIS LARGE UPPER LEVEL LOW COULD BECOME QUASI STATIONARY OVER
SOUTHERN CANADA...GREAT LAKES REGION WHICH COULD LEAD TO A
POTENTIAL PROLONGED PERIOD OF SHOWERS AND THUNDERSTORM THROUGH THE
MIDDLE OF NEXT WEEK.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
SCT TO NMRS TSRA SHOULD CONTINUE THROUGH 00Z...MOVING STEADILY TO
THE EAST AND SOUTH. MOST STORMS SHOULD BE OFF THE THE SE OF
SEG/AOO BY 00Z AND THROUGH LNS BY 04Z AS A COLD FRONT PUSHES
STEADILY SE THROUGH THE AREA. CIGS SHOULD BE VFR FOR MUCH OF THE
TIME THIS EVENING.

WINDS ARE OUT OF THE WEST BEFORE THE FRONT WHICH IS ON TOP OF
KBFD AT 1845Z. BUT THE WIND PROFILE IS NOT A SET UP FOR STRONG
GUSTS UNLESS A STORM GROWS VERY TALL THIS EVENING.

LOW MVFR AND EVEN SOME IFR CIGS WILL BE FOUND IN THE NWRN HALF OF
THE AREA TONIGHT AS THE COOLER AIR MOVES IN. FOG IS NOT
ANTICIPATED TO BE IFR TONIGHT...BUT MANY OF THE VALLEYS OF THE
NORTH COULD GET SOME FOG. WILL ONLY MENTION MVFR FOG IN A FEW
LOCATIONS. THE DRYNESS OF THE AIR WILL WIN OUT AFTER SUNRISE ON
THURSDAY...BREAKING THE CLOUDS UP. VFR SHOULD BE THE WORD FOR
THURSDAY INTO SATURDAY. JUST THE NRN VALLEYS WILL DROP COLD ENOUGH
TO MAKE THE FOG HAPPEN EACH NIGHT.

OUTLOOK...

FRI...PATCHY MORNING FOG...OTHERWISE VFR/NO SIG WX.
SAT...PATCHY MORNING FOG...OTHERWISE VFR. PM TSRA/MVFR POSS W.
SUN-MON...SHRA/TSRA AS WARM FRONT THEN COLD FRONT MOVE THROUGH.

&&

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

&&

$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/GARTNER
AVIATION...DANGELO



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