264
FXUS61 KCTP 221751
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1251 PM EST WED JAN 22 2025
SYNOPSIS
A RIDGE OF HIGH PRESSURE EXTENDING ALONG THE ENTIRE LENGTH OF
THE APPALACHIANS WILL BRING THE COLDEST TEMPERATURES OF THIS
CURRENT ARCTIC OUTBREAK ACROSS THE REGION THIS MORNING. THIS
RIDGE WILL DRIFT EAST AND OFF THE MID ATLANTIC COAST TONIGHT
INTO THURSDAY. UPPER LEVEL TROUGHING WILL REMAIN OVER THE AREA
INTO EARLY NEXT WEEK WITH A SERIES OF WEAK SHORTWAVES PASSING
THROUGH WITH JUST SOME FLURRIES OR A FEW BRIEF SNOW SHOWERS.
NEAR TERM /THROUGH TONIGHT/
CLEAR SKIES ARE CURRENTLY OBSERVED ON RECENT SATELLITE IMAGERY
UNDER THE INFLUENCE OF SURFACE HIGH PRESSURE, ALLOWING FOR
TEMPERATURES TO INCREASE QUICKLY ACROSS THE FORECAST AREA, WITH
THIS TREND CONTINUING FOR THE NEXT COUPLE OF HOURS AS KBFD HAS
INCREASED FROM -17F AT 0753AM EST TO -3F AT 0930AM EST. THIS
SURFACE HIGH PRESSURE HAS ALSO BROUGHT A DECREASING TREND IN
WINDS, WHICH HAS LOWERED THE WIND CHILL THREAT FOR MUCH OF THE
AREA. COLD WIND CHILLS ARE STILL EXPECTED TO CONTINUE THROUGH
NOON, ESPECIALLY FOR AREAS UNDER THE EXTREME COLD WARNING
(SOMERSET/CAMBRIA COUNTIES); HOWEVER, EXPECT THESE CONCERNS TO
CONTINUE TO WANE WITH CURRENT HEADLINES EXPECTED TO EXPIRE
CLOSER TO THE 12PM TIMEFRAME.
WARMING LATER THIS AFTERNOON WILL BE (SLIGHTLY) HINDERED BY AN
APPROACHING DECK OF MID-LEVEL CLOUDS CURRENTLY STATIONED ALONG
A LINE GENERALLY EXTENDING NORTH-TO-SOUTH OVER COLUMBUS, OH AND
FURTHER SOUTH INTO NORTHERN KENTUCKY. THIS SLIGHT OBSCURATION
FROM PEAK- HEATING WILL ALLOW FOR MAXTS TO TOP OUT NEAR 10
DEGREES ACROSS THE COLDEST POCKETS OF NORTHERN PENNSYLVANIA TO
NEAR 18-19 DEGREES IN THE LOWER SUSQUEHANNA VALLEY.
THE BULK OF MODEL GUIDANCE CONTINUES TO INDICATE SOUTHERLY FLOW
ALONG WITH A MID-LEVEL CLOUD DECK, THAT WILL LIMIT POTENTIAL
FOR DANGEROUSLY COLD WIND CHILLS AT THIS TIME, WITH MINIMUM WIND
CHILLS STATIONED ACROSS THE VALLEYS OF NORTHERN PENNSYLVANIA
ALONG WITH THE LAUREL HIGHLANDS. CRITERIA, COUPLED WITH THE
CURRENT FORECAST, SUGGEST THAT ANY HEADLINES WOULD BE CONFINED
TO THE LAUREL HIGHLANDS; HOWEVER, LOWER CONFIDENCE ON ANY
PRODUCT ISSUANCE AT THIS TIME GIVEN LOWEST WIND CHILLS ARE
CONFINED TO THE HIGHER ELEVATIONS OF SOMERSET/CAMBRIA COUNTIES
WITH WIND CHILLS STAYING NEAR-OR-ABOVE 0F FOR MUCH OF THE
COUNTY.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
MARKEDLY LESS COLD CONDITIONS ARE ANTICIPATED THURSDAY, AS A
SOUTHWEST FLOW DEVELOPS BETWEEN HIGH PRESSURE OFF OF THE EAST
COAST AND AN UPSTREAM COLD FRONT OVER THE GRT LKS. SEE NO REASON
TO DEVIATE FROM NBM MAX TEMPS, WHICH ARE IN THE 20S. RH
TIMESECTIONS SUPPORT CLOUDS ARRIVING FROM WEST TO EAST DURING
THE AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. MODEL
SOUNDINGS INDICATE THE RETURN MOISTURE AHEAD OF THE FRONT WILL
BE SHALLOW, BUT COULD SUPPORT SOME OCCASIONAL LIGHT SNOW WHERE
THE SSW FLOW IS FORCED TO ASCEND THE NW MTNS LATE IN THE DAY
THROUGH MUCH OF FRIDAY.
IN FACT, THE CLOUD LAYER (INITIALLY UP TO 7-8 KFT AGL THURSDAY
AFTERNOON AND EVENING THEN ONLY UP TO 3-4 KFT AGL ON FRIDAY)
WILL BE OCCUPIED BY THE ENTIRE DGZ. PERFECT CONDITIONS FOR THE
OROGRAPHIC LIGHT SNOW. INCLUDED A 36 HOUR SNOW TOTAL GRID (12Z
THURSDAY THROUGH 00Z SAT) TO CAPTURE THE BULK OF THIS MINOR
WINTER PRECIP EVENT OVER THE WESTERN MTNS.
OUTSIDE OF THIS MINOR SNOWFALL, EXPECT MAINLY DRY AND COLD
CONDITIONS INTO THE WEEKEND. TOWARDS THE END OF THIS WEEK A WEAK
UPPER LEVEL SHORT WAVE WILL SWING OFF THE GREAT LAKES. A
SURFACE TROUGH WILL ARRIVE BY FRIDAY MORNING, BRINGING WITH IT
ANOTHER MOISTURE STARVED COLD FRONT. DESPITE THE SYNOPTIC
FORCING THERE WILL NOT BE ENOUGH MOISTURE TO ALLOW FOR MUCH
PRECIPITATION. EVEN WIND FLOW WILL REMAIN MOSTLY WESTERLY BEHIND
THIS FRONT MAKING LAKE EFFECT SNOW IN THE NORTHWEST UNLIKELY AT
THE BEGINNING OF THE EXTENDED PERIOD. STILL ENOUGH OF A CHANCE
TO ENTER SLIGHT CHANCE POPS ACROSS THE HIGHER TERRAIN.
LONG TERM /SATURDAY THROUGH TUESDAY/
LARGE SCALE FLOW PATTERN SUPPORTS CLIPPERS DROPPING SOUTHEAST
ACROSS THE GREAT LAKES NEXT WEEK. THE WARM WATERS OF THE GREAT
LAKES WILL LIKELY RESULT IN HIGH CENTERS SPLITTING INTO TWO
SECTIONS, WITH THE COLDEST AIR STAYING NORTH OF THE LAKES. THUS
WE WILL SEE TEMPERATURES CLOSER TO NORMAL. WITH THE OVERALL
PATTERN AND SNOW COVER, WILL BE HARD TO SEE ANY EXTENDED MILD
SNAPS.
UPPER LEVEL TROUGHS AND WIND SHIFT LINES WILL SUPPORT SOME SNOW
SHOWERS FROM TIME TO TIME INTO LATE SUNDAY, MAINLY ACROSS THE
FAR NORTHWEST.
A CLIPPER DROPPING SOUTHEAST BY MID WEEK MAY SUPPORT MORE SNOW
A BIT FURTHER EAST AND SOUTH.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
THERE IS HIGH CONFIDENCE IN VFR CONDITIONS CONTINUING THROUGH
THE 18Z TAF PERIOD AS HIGH PRESSURE OVER CENTRAL PA BEGINS TO
SHIFT TO THE EAST. MID AND HIGH CLOUDS WILL INCREASE IN
COVERAGE DURING THE AFTERNOON AND EVENING AS WARM ADVECTION
INCREASES AHEAD OF A MOISTURE-STARVED DISTURBANCE APPROACHING
FROM THE WEST. MODEL SOUNDINGS SUGGEST THAT MUCH OF THIS CLOUD
COVER WILL DISSIPATE DURING THE DAY ON THURSDAY AND PARTLY
CLOUDY TO MAINLY CLEAR SKIES ARE EXPECTED AFTER 12Z.
WINDS WILL SHIFT TO THE WEST-SOUTHWEST THURSDAY AFTERNOON WHICH
WILL LEAD TO CLOUDS DEVELOPING AT BFD AND JST. MOISTURE WILL BE
VERY LIMITED, AT LEAST INITIALLY, SO NOT EXPECTING ANY SNOW
SHOWERS PRIOR TO 18Z. MODEL RH PROFILES DO SUGGEST THAT LOWER
CEILINGS DEVELOP DURING THE LATE AFTERNOON AND A FEW LAKE EFFECT
AND UPSLOPE SNOW SHOWERS COULD LEAD TO VISIBILITY RESTRICTIONS
AT BFD AND JST INTO THE EVENING.
OUTLOOK...
THU NIGHT...RESTRICTIONS POSSIBLE AT BFD AND JST WITH -SHSN.
FRI...MVFR/IFR CONDITIONS POSSIBLE WITH -SHSN IN NORTHERN &
WESTERN PA MAINLY DURING THE DAY.
SAT...VFR/NO SIG WX.
SUN-MON...MVFR IN -SHSN POSSIBLE IN NORTHERN & WESTERN PA.
CLIMATE
RECORD LOW MAXIMUM TEMPERATURES FOR JANUARY 22:
HARRISBURG 14F IN 2014
WILLIAMSPORT 14F IN 1961
ALTOONA 10F IN 2014
BRADFORD 6F IN 2014
STATE COLLEGE 7F IN 1936
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT/FITZGERALD
NEAR TERM...NPB
SHORT TERM...GUSEMAN/LAMBERT/FITZGERALD
LONG TERM...MARTIN
AVIATION...BAUCO
CLIMATE...STEINBUGL
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