844
FXUS61 KCTP 191911
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
211 PM EST SUN JAN 19 2025
SYNOPSIS
* QUICK-HITTING, PLOWABLE/LOCALLY HEAVY SNOWFALL WILL TAPER OFF
FROM WEST TO EAST THIS EVENING.
* ARCTIC BLAST DELIVERS BITTER TO EXTREME COLD THROUGH
WEDNESDAY
* DEEP FREEZE ENDS LATE WEEK WITH TEMPERATURES MODERATING
CLOSER TO THE HISTORICAL AVERAGE FOR LATE JANUARY BY NEXT
WEEKEND
NEAR TERM /THROUGH TONIGHT/
NEAR TERM FOCUS IS ON THE DEVELOPMENT AND MOVEMENT OF HEAVY
BANDS OF SNOW. MAIN BAND AT 2 PM WAS RIGHT WHERE IT WAS
SUPPOSED TO BE...THE SOUTH-CENTRAL MTNS MOVING TOWARD THE
CAPITAL CITY AND THE SURROUNDING BURGS. SNOW OVER THE LAURELS
HAS PILED UP QUICKLY. ONE HIGH ELEVATION REPORT OF 5.5 INCHES
NEAR BLUE KNOB IN BLAIR CO, BUT LIKELY HALF OR JUST OVER (3")
THAT IN THE VALLEYS NEARBY THUS FAR. FALLING DOWN PRETTY GOOD
(1/2SM) OUT THE WINDOW, AND STEADY-STATE FOR 2 HRS. WE'RE
PROBABLY BETWEEN 1-2" AT THIS POINT AT THE OFFICE. FROM THE
LOOKS OF IT, TUSSEY MTN AND POINTS SOUTH INTO HUNTINGDON CO HAVE
BEEN GETTING 1+"/HR RATES IN THAT ONE BAND.
ANOTHER BAND IS SLIDING UP THRU ADAMS CO AND ANOTHER ONE SHOULD
SOON FROM MD, TOO. THESE MAY END UP MERGE INTO EACH OTHER AS A
PREVIOUS ONE DID TO MAKE OUR CURRENTLY-MAIN BAND. RATES OF
1-2"/HR STILL EXPECTED IN THOSE, AND THIS SHOULD GET THE LOWER
SUSQ UP TO THE EXPECTED AMOUNTS (OR MAYBE SLIGHTLY LESS IF THE
BANDS MOVE TOO QUICKLY). SNOWFALL FORECASTING IS THE HARDEST
THING WE DO.
THE MAIN FORCING CONTINUES TO SLIDE TO THE EAST, AND SNOW IS
PROJECTED TO TAPER OFF AND END BTWN 23-02Z IN THE EAST AS DRY
ARCTIC AIR IS DIRECTED INTO THE AREA. SOME LAKE ENHANCED/UPSLOPE
SNOW SHOWERS SHOULD LINGER OVER THE NW ALLEGHENIES AND LAUREL
HIGHLANDS WITH LITTLE ADDITIONAL ACCUMULATION THROUGH 12Z MON.
MIN TEMPS DIP INTO THE +SINGLE DIGITS TO MID TEENS WITH MIN WIND
CHILLS RANGING FROM -10F IN THE LAURELS TO +SINGLE DIGITS INT
THE LOWER SUSQUEHANNA VALLEY.
SHORT TERM /MONDAY THROUGH MONDAY NIGHT/
MINOR TWEAKS TO THE GOING SHORT TERM FCST PERIOD, AS THE COLD
IS FORECAST VERY WELL WITH PROPER PRODUCTS/ADVYS/WARNINGS.
PREV...
BITTER COLD AND FRIGID MLK DAY WITH HIGHS 15 TO 30 DEGREES BELOW
THE HISTORICAL AVERAGE. SNOW SHOWERS AND FLURRIES ARE EXPECTED
TO CONTINUE ACROSS THE ALLEGHENY PLATEAU WITH VERY LIGHT ACCUM.
BASED ON MINIMUM WIND CHILLS AND COLLABORATION WITH NEIGHBORING
OFFICES, WE TRANSITIONED TO A LONGER DURATION COLD WX ADVISORY
MONDAY NIGHT FOR MOST OF THE AREA WITH HIGH ENOUGH CONFIDENCE
FOR AN EXTREME COLD WARNING FOR THE LAUREL HIGHLANDS FOR WCS AS
LOW AS 20 BELOW ZERO. LATER SHIFTS COULD CONSIDER EXPANDING THE
COLD WX ADVISORY TO INCLUDE THE REMAINDER OF THE CWA WITH THE
COLDEST PERIOD OF WCS NOW LOOKING LIKE TUESDAY NIGHT-WED.
LONG TERM /TUESDAY THROUGH SUNDAY/
COLD WEATHER PRODUCTS CONTINUE. PRODUCTS UPDATED TO ADJUST
TIMING AND AREA OF CONCERN.
AS WAS THE CASE YESTERDAY, I DID TUESDAY ONWARD, SO NOT A LOT
OF CHANGE.
THE MAIN STORY CONTINUES TO BE THE LONG DURATION COLD THROUGH
THE MIDDLE OF THE WEEK. A NORTHWEST TO SOUTHWEST FLOW OF COLD
AIR WILL CONTINUE, AS HIGH PRESSURE BUILDS TO THE SOUTH AND
WEST OF CENTRAL PA, BEFORE RIDGING NORTHWARD BY THURSDAY.
FOR CENTRAL PA, HIGH TEMPERATURES TUE-WED WILL RUN 20-30 DEGREES
BELOW AVERAGE. CONSIDERING THAT LATE JANUARY IS CLIMATOLOGICALLY
THE COLDEST TIME OF THE YEAR, THIS WILL BE A SIGNIFICANT ARCTIC
OUTBREAK.
A WAVE OF LOW PRESSURE PASSING WELL TO OUR SOUTH COULD BRUSH
SOUTHEASTERN PA WITH SOME LIGHT SNOW FOR A VERY BRIEF TIME
LATER ON TUESDAY. THIS SYSTEM WILL COAT THE GULF COAST STATES
WITH SNOW AND ICE BEFORE IT LIFTS TOWARD US. NO WARM PLACE TO
GO FOR A WINTER BREAK FOR A BIT. 12Z EC HINTED YESTERDAY THAT
THE PRIMARY JET STREAM MIGHT LIFT MORE TO THE NORTH AND BECOME
MORE ZONAL BY THE END OF THE MONTH, BUT NOT REALLY A CLEAR CUT
SIGNAL IN THE GUIDANCE FOR THIS.
THUS AFTER SEVERAL VERY COLD DAYS, WE WILL HAVE TO TAKE WHAT
MOTHER NATURES PROVIDES, A BRIEF MODERATING TREND FOR LATE
WEEK. NOT SEEING MUCH IN THE WAY OF WEATHER AFTER TODAY AND
MONDAY.
AVIATION /19Z SUNDAY THROUGH FRIDAY/
NOONTIME UPDATE.
AS EXPECTED, MODERATE TO HEAVY SNOW INTO SOUTHERN SITES SUCH AS
AOO, JST, MDT, AND THV.
EARLIER INFORMATION BELOW.
MVFR CONDITIONS ARE OCCURRING ACROSS MUCH OF CENTRAL
PENNSYLVANIA AS OF 11Z, THOUGH JST CONTINUES TO REPORT LIFR
CEILINGS AND MDT REMAINS VFR. MOST GUIDANCE SUGGESTS THAT THIS
WILL LARGELY CONTINUE FOR THE NEXT FEW HOURS.
A DEVELOPING COASTAL LOW WILL BRING A ROUND OF SNOW TO THE AREA
TODAY. THE SNOW WILL OVERSPREAD THE AREA FROM SOUTH TO NORTH
THROUGH THE MORNING AND EARLY AFTERNOON HOURS. ONCE THE SNOW
BEGINS, VISIBILITIES SHOULD QUICKLY DROP TO IFR. ALL GUIDANCE
CONTINUES TO SHOW A PERIOD OF HEAVY SNOW OCCURRING AT MDT AND
LNS IN THE 18Z-00Z TIMEFRAME. THIS WILL LIKELY LEAD TO
VISIBILITIES FALLING TO AS LOW AS 1/4SM AT THOSE SITES.
THE STEADY SNOW WILL PULL EAST OF THE REGION SUNDAY EVENING
INTO SUNDAY NIGHT, ALTHOUGH LINGERING UPSLOPE SNOW REMAINS
POSSIBLE ACROSS THE WESTERN HIGHLANDS SUNDAY NIGHT. AS THE SNOW
EXITS THE REGION, CEILINGS WILL GRADUALLY RISE TO VFR EAST OF
UNV AND AOO, WHILE MVFR CEILINGS ARE EXPECTED TO PERSIST TO THE
WEST. WHILE WINDS WILL GENERALLY BE LIGHT MOST OF THE DAY, MODEL
SOUNDINGS SUGGEST THAT A FEW GUSTS TO 20-25 KNOTS WILL BE
POSSIBLE THIS EVENING.
OUTLOOK...
MON...MVFR TO IFR CONDS IN SNOW SHOWERS ACROSS MAINLY
NORTHWESTERN PA; COLDER AREAWIDE WITH GUSTY WEST WINDS.
TUE...NO SIG WX EXPECTED; VERY COLD.
TUES NIGHT-WED...SCATTERED SNOW SHOWERS POSSIBLE, BRINGING
LOCALIZED RESTRICTIONS; VERY COLD.
THU...NO SIG WX EXPECTED; CONTINUED COLD.
CTP WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY FROM 4 AM MONDAY TO NOON EST WEDNESDAY
FOR PAZ004>006-010>012-017-018-037-041-042.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR PAZ012-
017-018-041.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ019-024>028-034-035-042-045-046-049>052.
COLD WEATHER ADVISORY FROM 7 PM MONDAY TO NOON EST WEDNESDAY
FOR PAZ019-025>028-034-035-045-046-049>053.
COLD WEATHER ADVISORY FROM 4 AM MONDAY TO 1 AM EST TUESDAY FOR
PAZ024-033.
EXTREME COLD WARNING FROM 1 AM TUESDAY TO NOON EST WEDNESDAY
FOR PAZ024-033.
WINTER STORM WARNING UNTIL 8 PM EST THIS EVENING FOR PAZ033.
WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR PAZ036-
053-056>059-063>066.
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...DANGELO/STEINBUGL
LONG TERM...MARTIN
AVIATION...MARTIN/EVANEGO/BAUCO
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