618
FXUS61 KCTP 221515
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1015 AM 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/
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 /FRIDAY NIGHT THROUGH TUESDAY/
MEDIUM RANGE GUIDANCE SUPPORTS MAINLY DRY AND SEASONABLY COLD
WEATHER THIS WEEKEND INTO EARLY NEXT WEEK, AS UPPER LEVEL
TROUGHING REMAINS OVER THE REGION DESPITE THE DEPARTURE OF THE
ANOMALOUS COLD. THE 18Z EPS INDICATES WEAK SHORTWAVE PASSAGES
EARLY SUNDAY AND AGAIN ON MONDAY WILL BRING THE CHANCE OF A FEW
SNOW SHOWERS OVER THE NW MTNS, FOLLOWED BY LAKE-ENHANCED
OROGRAPHIC SNOW SHOWERS OVER THE ALLEGHENIES. HOWEVER, A
LARGELY FROZEN LK ERIE SHOULD RESULT IN MINIMAL ACCUMULATIONS.
A MINORITY OF ENSEMBLE MEMBERS ARE A BIT DEEPER WITH THE MONDAY
SHORTWAVE, RESULTING IN A WAVE OF LOW PRESSURE PASSING SOUTH OF
PA. THIS SCENARIO WOULD RESULT IN A PERIOD OF SNOW OVER
PRIMARILY SOUTHERN PA. HOWEVER, THE BULK OF GUIDANCE CURRENTLY
SUPPORTS DRY WEATHER.
AVIATION /15Z WEDNESDAY THROUGH SUNDAY/
HIGH CONFIDENCE IN WIDESPREAD VFR FLYING THROUGH THE 22/12Z TAF
PERIOD.
OUTLOOK...
THU...VFR THEN MVFR/IFR POSSIBLE THURSDAY NIGHT WITH -SHSN IN
NORTHERN AND WESTERN PA.
FRI...MVFR/IFR CONDITIONS POSSIBLE WITH -SHSN IN NORTHERN &
WESTERN PA MAINLY DURING THE DAY.
SAT...VFR/NO SIG WX.
SUN...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
COLD WEATHER ADVISORY UNTIL NOON EST TODAY FOR PAZ004>006-
010>012-017>019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
EXTREME COLD WARNING UNTIL NOON EST TODAY FOR PAZ024-033.
SYNOPSIS...LAMBERT/FITZGERALD
NEAR TERM...NPB
SHORT TERM...GUSEMAN/LAMBERT/FITZGERALD
LONG TERM...FITZGERALD
AVIATION...STEINBUGL
CLIMATE...STEINBUGL
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