Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 041907
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
307 PM EDT FRI SEP 4 2015

.SYNOPSIS...
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK WITH
GRADUALLY DECREASING HUMIDITY LEVELS. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE INTO EARLY THIS EVENING. HIGH PRESSURE
WILL ENSURE FAIR AND DRY WEATHER FOR LABOR DAY WEEKEND.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
ISOLATED SHOWERS AND THUNDERSTORMS AGAIN POPPING THIS AFTN AS
EXPECTED...MAINLY ACROSS SRN PA. THIS WILL CONTINUE FOR THE NEXT
SEVERAL HOURS WITH ANY SLOW MOVING STORMS PRODUCING BRIEF HEAVY
DOWNPOURS.

GUIDANCE INCLUDING LATEST HRRR IMAGERY SHOWS A CONVERGENCE OF
ACTIVITY THROUGH THE LOWER SUSQ VALLEY SOUTH CENTRAL MTNS AS WEAK
BACKDOOR COLD FRONT DROPS SOUTH...AND EASTERLY FLOW ON SRN END OF
SFC HIGH CONCENTRATES MOISTURE WESTWARD INTO THE REGION.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
A RATHER LARGE AREA OF HIGH PRESSURE AT THE SFC...AND A SLOWLY
FLATTENING UPPER RIDGE OVER THE EASTERN U.S...SHOULD MAINTAIN DRY
WEATHER SATURDAY NIGHT THROUGH MONDAY. PRECIPITABLE WATER VALUES
WILL RANGE FROM BELOW NORMAL AND ONLY AROUND ONE-HALF OF AN INCH
ACROSS FAR NERN PENN...TO SLIGHTLY ABOVE NORMAL ALONG THE SE SHORE
OF LAKE ERIE SUNDAY SATURDAY NIGHT INTO SUNDAY NIGHT. A FEW SHOWERS
OR EVEN A BRIEF TSRA COULD BRUSH OUR FAR NW ZONES DURING THIS
INITIAL 24 HOURS OF THE LONG TERM PERIOD...BUT POPS WILL BE LESS
THAN 25 PERCENT.

AN INITIAL...WEAK...COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE
GREAT LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.

A SLOWLY AMPLIFYING...BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.

THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.

12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.

DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLYIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.

ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.

A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.

SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.

OUTLOOK...

SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.

SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.

WED...COLD FROPA WITH SCT SHRA/TSRA.

&&

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

&&

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


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