943
FXUS61 KCTP 211942
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
242 PM EST TUE JAN 21 2025
SYNOPSIS
* FRIGID TEMPERATURES WILL CONTINUE TO GRIP THE COMMONWEALTH
TODAY THROUGH WEDNESDAY
* MODERATING, BUT STILL SEASONABLY COLD TEMPERATURES WILL FOLLOW
FOR THURSDAY AND FRIDAY AND CONTINUE INTO THE WEEKEND
NEAR TERM /UNTIL 6 PM THIS EVENING/
TEMPERATURES STILL LARGELY IN THE SINGLE DIGITS AS WE APPROACH
THE NOON HOUR, BUT HAVE SEEN MUCH OF THE LOWER SUSQUEHANNA
VALLEY "WARM" INTO THE DOUBLE DIGITS AS HIGH CLOUDS STREAM
OVERHEAD DOWNSTREAM OF A MOISTURE-STARVED UPPER LEVEL TROUGH.
NOT EXPECTING MUCH MORE MOVEMENT THROUGH THIS AFTERNOON.
AS SURFACE RIDGING SHIFTS A BIT TO THE SOUTHEAST TODAY, AND THE
ABOVE UPPER LEVEL TROUGH APPROACHES FROM THE WEST, WE'LL SEE
THE WELL-MIXED/ BOUNDARY LAYER REMAIN AROUND 5 KFT AGL. THIS
WILL ALLOW FOR SOUTHWESTERLY WIND GUSTS IN THE 10-15 MPH RANGE,
PUSHING 20 MPH AT TIMES ACROSS THE ALLEGHENIES THIS AFTERNOON.
WITH WIND CHILLS ONLY IN THE SINGLE DIGITS ABOVE AND BELOW ZERO
AT BEST TODAY, HAVE KEPT THE EXTREME COLD WARNING IN EFFECT
UNTIL NOON WEDNESDAY FOR THE LAUREL HIGHLANDS AND COLD WEATHER
ADVISORIES COVER THE REST OF CENTRAL PA THROUGH THE SAME PERIOD.
SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/
THE MAIN WEATHER STORY FOR THE NEXT FEW DAYS CONTINUES TO BE THE
EXTENDED PERIOD OF FRIGID TEMPERATURES AND AT TIMES NOTABLY
LOWER WIND CHILLS.
COLD WEATHER ADVISORIES AND EXTREME COLD WARNINGS ARE IN EFFECT
THROUGH WEDNESDAY.
THE PASSAGE OF A MID-LEVEL TROUGH WILL BRING CLOUDS AND
SOME LIGHT SNOW SHOWERS/FLURRIES, PRIMARILY OVER THE
ALLEGHENIES/LAURELS THIS AFTERNOON INTO THE EARLY EVENING, BUT
ACCUMULATIONS WILL BE MINIMAL, IF ANY.
SFC-850 MB TEMPERATURES WILL LIKELY REACH THEIR LOWEST POINTS
TONIGHT/EARLY WEDNESDAY. EVEN IF THEY COME IN CLOSE TO WHAT WE
HAVE OUT THEIR EARLY THIS TUESDAY, IT WILL BE BECAUSE OF A
SLIGHTLY HIGHER WESTERLY BREEZE, WHICH WOULD ACT TO CREATE MORE
OF A BITE FROM A LOWER WIND CHILL. EITHER WAY, TONIGHT WILL BE
THE COLDEST IT WILL FEEL FROM THIS CURRENT ARCTIC OUTBREAK.
THE COLDEST APPARENT TEMPERATURES (AS COLD AS AROUND -20F) WILL
BE LATE TONIGHT AND EARLY WEDNESDAY OVER THE HIGHER TERRAIN OF
THE ALLEGHENIES/LAURELS.
CONDITIONS WILL BE MAINLY DRY ON WEDNESDAY, AS WINDS BEGIN TO
BACK INTO THE SOUTHWEST, AHEAD OF ANOTHER WEAK NORTHERN STREAM
SYSTEM OVER THE UPPER MIDWEST.
HIGH TEMPS WEDNESDAY WILL REBOUND TO THE TEENS FOR MOST PLACES,
BUT POSSIBLY HOLD AOB 10 DEGREES FOR MUCH OF THE DAY OVER THE
NORTHERN MOUNTAINS AND RIDGE TOPS OF THE LAUREL HIGHLANDS.
THURSDAY SHOULD SEE CONTINUED MODERATION IN TEMPS, BUT THEY'LL
STILL BE SEVERAL DEG F OR MORE BELOW NORMAL FOR LATE JANUARY,
WITH AFTERNOON HIGHS BACK INTO THE 20S, TO NEAR 30F IN THE
SOUTHERN VALLEYS.
EXPECT MAINLY DRY AND COLD CONDITIONS THROUGHOUT THE EXTENDED
PERIOD. 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 A 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.
LONG TERM /SATURDAY THROUGH MONDAY/
WEAK FRONTAL SYSTEMS WILL MOVE ACROSS THE REGION FROM TIME TO
TIME. AFTER ONE LATER TODAY AND AGAIN LATER ON THURSDAY INTO
EARLY FRIDAY, LOOKS LIKE THE NEXT ONE WOULD MOVE ACROSS THE AREA
LATE SUNDAY INTO MONDAY. GFS AND EC SHOW A STRONG JET STREAM
FROM THE CENTRAL PLAINS OF CANADA, SOUTHEAST ACROSS THE GREAT
LAKES AREA BY NEXT MONDAY. A LARGE HIGH PRESSURE SYSTEM BEHIND
THE SYSTEM MAY TRY TO BUILD INTO THE AREA LATER NEXT WEEK, BUT
THE TENDENCY WILLL BE FOR ANY HIGH PRESSURE SYSTEMS TO SPLIT IN
TWO, WITH THE REAL COLD AIR STAYING OVER SOUTHERN ONTARIO AND
QUEBEC, AND THE OTHER HIGH CENTER BEING FURTHER SOUTH. CAN THANK
THE GREAT LAKES WARMER WATERS TO AID IN HAVING THE HIGH CENTERS
SPLIT APART. ALSO WILL LIKELY HAVE SEVERAL CLIPPERS MOVE ACROSS
THE AREA BEFORE THIS.
TEMPERATURES WILL TREND TOWARD NORMAL BY LATE WEEK INTO SUNDAY,
WHICH WILL HELP EASE THE PROBLEMS THAT CAN DEVELOP WITH THE
EXTENDED COLD SPELL.
AVIATION /19Z TUESDAY THROUGH SUNDAY/
AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION OVERNIGHT.
MOISTURE IS LIMITED, SO EXPECT ANY SNOW SHOWERS AND MVFR AND
IFR CONDITIONS TO BE LIMITED TO BFD AND JST.
CONDITIONS WILL QUICKLY IMPROVE ON WEDNESDAY, AS WINDS SHIFT
BACK TO THE WEST AND SOUTHWEST.
NO MAJOR STORMS EXPECTED THE NEXT FEW DAYS.
OUTLOOK...
THU-SUN...PRIMARILY VFR WITH BRIEF RESTRICTIONS POSSIBLE ACROSS
NW PA THURS PM IN SCATTERED -SHSN.
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 WEDNESDAY 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 WEDNESDAY FOR PAZ024-033.
SYNOPSIS...GUSEMAN/LAMBERT
NEAR TERM...GUSEMAN/LAMBERT
SHORT TERM...GUSEMAN/LAMBERT
LONG TERM...MARTIN
AVIATION...MARTIN
CLIMATE...STEINBUGL
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