Skip Navigation Linkswww.nws.noaa.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service Forecast Office   NWS logo - Click to go to the NWS homepage
State College, PA banner image
 
 

Area Forecast Discussion
Latest Versions  [Current][-1][-2][-3][-4][-5][-6][-7][-8][-9]



000
FXUS61 KCTP 192007
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
307 PM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE WESTERN GREAT LAKES WILL SLIDE
EAST ACROSS PENNSYLVANIA THIS WEEKEND...BRINGING DRY WEATHER WITH
LIGHTER WIND. A DEEP UPPER TROUGH AND ASSOCIATED SFC LOW WILL LIFT
NORTHEAST THROUGH THE GREAT LAKES DURING THE MIDDLE OF NEXT WEEK
LIKELY BRINGING US RAIN AND WIND FOR CHRISTMAS EVE...THEN BLUSTERY
AND COLDER CONDITIONS FOR CHRISTMAS DAY WITH SCATTERED SNOW
SHOWERS.

&&

.NEAR TERM /THROUGH TONIGHT/...
STUBBORN...ALBEIT SHALLOW STRATO CU CLOUD DECK TRAPPED BELOW A
MODERATELY STRONG SUBSIDENCE INVERSION /BASED AT AROUND 2-3KFT
AGL/ WILL PERSIST ACROSS MUCH OF NORTHERN AND WESTERN PENNSYLVANIA
LATE TODAY INTO SATURDAY...WHILE PARTIAL CLEARING OCCURS ACROSS
THE LOWER SUSQ VALLEY AND SURROUNDING AREAS.

TEMPS WILL REMAIN STEADY THROUGH LATE THIS AFTERNOON UNDER THE
10-15 KT NWRLY FLOW. READINGS WILL VARY FROM THE MID TO UPPER 20S
ACROSS THE NORTHERN AND WESTERN MOUNTAINS...TO THE LOWER 40S IN
THE SOUTHEAST. 

A WEAK SFC RIDGE WILL MOVE TO NEAR THE PENN/OHIO BORDER BY 12Z
SATURDAY...BUT THE WEAK WESTERLY ISENTROPIC LIFT ALONG THE 285K
THETA SFC...AND SOME SHALLOW MOISTURE BEING ADVECTED SWD INTO THE
NRN MTNS OF PENN FROM LAKE ONTARIO...WILL MAINTAIN MOSTLY CLOUDY
TO CLOUDY SKIES. LITTLE MORE THAN A FEW FLURRIES OR SPOTTY -FZDZ
WILL FALL FROM THIS THIN CLOUD LAYER ACROSS THE HIGHER TERRAIN OF
THE LAURELS AND INVOF KBFD. 

AFTER A PTLY CLOUDY LATE AFTERNOON AND EVENING IN THE SE PART OF
THE CWA...A BKN LAYER OF STRATO CU IS EXPECTED TO DRIFT SE /OR
FORM/ ACROSS THE REGION OVERNIGHT.

DUE TO THE NW-SE GRADIENT OF DECREASING CLOUDS...LOW TEMPS AT
DAYBREAK SAT WILL BE IN A RATHER TIGHT RANGE...FROM THE UPPER
TEENS TO LOWER 20S ACROSS THE MOUNTAINS...TO THE LOWER 20S IN THE
SE

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
A RIDGE OF HIGH PRESSURE...LIGHTER WIND...AND ASSOC DRIER AIR
MASS WILL BUILD EAST ACROSS THE STATE SATURDAY...PROVIDING THE
AREA WITH FAIR WEATHER.

HIGH RES MODEL DATA CONTINUES TO PAINT A MOSTLY CLOUDY PICTURE FOR
MUCH OF THE REGION SATURDAY INTO SATURDAY NIGHT...THOUGH PERIODS
OF SUNSHINE ARE LIKELY THROUGHOUT THE CENTRAL RIDGE AND VALLEY
REGION...AND SUSQUEHANNA RIVER VALLEY. 

WAA ALOFT IN ADVANCE OF SHORTWAVE LIFTING OUT OF THE MISS VALLEY
WILL LIKELY SPREAD SOME THIN CIRRUS OVER THE LOWER/THIN STRATO CU 
CLOUD DECK PRESENT ACROSS THE REGION SATURDAY. ALL 12Z OPERATIONAL 
MODEL DATA CONTINUES TO SUPPORT A DRY DAY WITH SFC RIDGE AND LOW
PWAT AIRMASS OVR THE STATE. MAX TEMPS SHOULD BE FAIRLY CLOSE TO
SEASONAL NORMS NEAR 30 ACROSS THE MTNS...AND MID TO UPPER 30S IN
THE SE.

MOSTLY CLOUDY SKIES WITH LIGHT WIND SAT NIGHT WILL YIELD LOWS IN
THE LOWER 20S ACROSS THE MTNS...AND GENERALLY THE MID 20S
ELSEWHERE.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL SHIFT SLOWLY EASTWARD FROM THE GREAT LAKES
INTO NORTHERN NEW ENGLAND BY 12Z MONDAY. A MOISTURE-STARVED NRN
STREAM SHORTWAVE SHOULD PRODUCE A PERIOD OF CLOUDINESS SAT
NIGHT...BUT LIKELY NOT PRODUCE ANY PRECIP. LATEST MDL SOUNDINGS
POINT TOWARD A RELATIVELY BRIGHT SUNDAY IN THE WAKE OF THIS
FEATURE WITH NEAR SEASONAL TEMPS. SPLIT FLOW REGIME ACROSS THE
LOWER 48 WILL TRANSITION TO A HIGHLY AMPLIFIED PATTERN BY EARLY
NEXT WEEK ACROSS THE LOWER 48...WITH A DEEP NEGATIVELY TILTED
TROUGH EVOLVING OVER THE EASTERN 1/3RD OF THE CONUS.

THE MODELS SEEM TO BE FORMING A CONSENSUS ON THE PESKY LOW
THAT REFUSES TO BE WELL FORECAST...LIFTING IT SLOWLY FROM FL
PANHANDLE NNEWD JUST OFF THE EAST COAST SUN-MON ALONG A LOW LEVEL
BAROCLINIC ZONE THAT MAY NOT BUDGE PAST THE GULF STREAM AS THE
FLOW ALOFT TURNS SOUTHWESTERLY/PARALLEL TO THE COASTAL FRONT.
INCREASED POPS FOR MONDAY OVER THE SE BASED ON MULTI-MODEL/WPC
BLEND. COMPLEX SFC PATTERN WITH SOME HINTS AT LOW LEVEL CAD ALONG
WITH WAA ALOFT VIA SLY FLOW COULD MAKE FOR A MESSY MIXED PTYPE
TRANSITION.

AN INTENSE TRIPLE POINT SYSTEM DEVELOPING ON DEC 23-24 WILL
LIKELY STEAL THE HEADLINES GIVEN ITS TIMING AND LARGE PORTION OF
REAL ESTATE THAT WILL BE AFFECTED. WHILE THE DETAILS REMAIN
UNCLEAR AT THIS POINT...TEMPERATURES SHOULD BE WARM ENOUGH TO
SUPPORT RAIN ON THE FRONT SIDE OF THE SYSTEM BEFORE BRISK WNW
WINDS DRIVE STRONG CAA EAST OF THE APPALACHIANS. THE TIMING OF THE
COLD/OCCLUDED FRONT WILL BE KEY FOR PRECIPITATION TRANSITION FROM
RAIN TO SNOW SHOWERS. AS THE SYSTEM SPINS UP INTO EASTERN
CANADA...THE STRONG CAA CIRCULATING THROUGH THE GREAT LAKES AND OH
VLY SHOULD LEAD TO LAKE EFFECT/UPSLOPE/WRAP AROUND SNOW SHOWERS
OVER THE WESTERN ALLEGHENIES BY CHRISTMAS DAY. A PERIOD OF STRONG
GUSTY WINDS ARE HIGHLY PROBABLE AS THE DYNAMIC SYSTEM INTENSIFIES
SHIFTING NWWD FROM NEW ENGLAND INTO ONTARIO/QUEBEC.

THE TAKE HOME MESSAGE IS THAT A VOLATILE PERIOD OF WEATHER WILL
IMPACT THE AREA THROUGH CHRISTMAS DAY WITH POTENTIAL WIND...RAIN
AND SNOW IMPACTS ALL ON THE TABLE. STAY TUNED.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
LLVL NWRLY FLOW AND OROGRAPHIC FORCING OF A SHALLOW MOIST LAYER
WILL CONTINUE TO PRODUCE PLENTY OF CLOUDS ACROSS THE NW 1/2 TO
2/3RDS OF THE STATE WITH MAINLY MVFR BKN-OVC CIGS THROUGH
TONIGHT. KJST AND KBFD MAY TEETER ON THE UPPER END OF IFR FOR A
FEW HOURS LATER TONIGHT /AFTER 06Z/. IN CONTRAST...THE SE PENN
AIRFIELDS SUCH AS KMDT...KTHV AND KLNS WILL SEE MAINLY VFR...WITH
SKY CONDITIONS VARYING SCT-BKN030-040.

NORTHWEST WINDS OF 10-15 KTS WITH HIGHER GUSTS WILL DECREASE TO 8
KTS OR LESS LATER TONIGHT AND SATURDAY.

HIGH PRESSURE BUILDS EAST ACROSS PENN SATURDAY...WITH BKN-OVC CIGS
VARYING BETWEEN MVFR OVER THE HIGHER TERRAIN OF THE NORTH AND
WEST...TO SCT-BKN VFR IN THE VALLEYS. 

OUTLOOK...

SUN...NO SIG WX EXPECTED.

MON...LOW CIGS WITH LGT RAIN/SNOW POSSIBLE. BECOMING BREEZY.

TUE...LOW CIGS WITH RAIN LIKELY. BREEZY.

WED...MILD WITH PERIODS OF RAIN OF VARYINGY INTENSITY...LEADING
TO MVFR TO IFR. ALSO...WINDY WITH LLWS.

&&

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

&&

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



National Weather Service
Disclaimer Privacy Policy