397
FXUS61 KCTP 190054
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
754 PM EST WED DEC 18 2024
SYNOPSIS
RAIN AND SNOW ARE EXITING. A LITTLE LAKE EFFECT (AND EVEN SOME
PATCHY FREEZING DRIZZLE OVER THE HIGHER TERRAIN OF CAMBRIA AND
SOMERSET COUNTIES) WILL LAST THROUGH ABOUT SUNRISE. A CLIPPER
WILL BRING LIGHT SNOW TO MOST OF THE AREA ON FRIDAY, FOLLOWED BY
CONSIDERABLY COLDER CONDITIONS FOR THE WEEKEND.
NEAR TERM /UNTIL 7 AM THURSDAY MORNING/
LOW PRESSURE SHOULD BE JUST TO THE EAST OF THE CWA, NOW.
PRECIP IS EXITING TO THE EAST, AND IS BEHAVING AS EXPECTED.
JUST AN INCH OR TWO OF SNOW HAS FALLEN ACROSS THE NRN MTNS EVEN
THOUGH THEY HAD AIR TEMPS JUST ABOVE FREEZING IN MOST PLACES.
TEMPS ARE DOWN TO 32F IN SPOTS, NOW.
THE LOSS OF THICKER CLOUDS WILL TAKE AWAY THE ICE CRYSTALS FROM
THE UPSLOPE PRECIP IN THE LAURELS EARLY TONIGHT. THIS WILL
CREATE AREAS OF FREEZING DRIZZLE STARTING ABOUT NOW (SOMERSET
AWOS IS AT 32F). THE CONDITIONS REMAIN TOO COLD NORTH OF ABOUT
RTE 22, AND SHOULD REMAIN MOSTLY SNOW. NOT MUCH ADDITIONAL SNOW
ACCUMS ARE EXPECTED. BY 08-09Z, EVEN THE PRECIP OVER SOMERSET CO
SHOULD BE JUST FLURRIES. BUT, ANY ICE ACCRETION WILL STILL BE
UNDERNEATH THE SNOW THAT MIGHT FALL AFTER THE DRIZZLE HAS ENDED.
MIN TEMPS THERE WILL RANGE FROM 25-29F, SO THAT COULD KEEP IT
SLIPPERY INTO THE MORNING ON UNTREATED SURFACES. AFTER
COLLABORATION WITH PBZ/LWX, WE'VE SETTLED ON ISSUING A WINTER
WX ADVY FOR THE NIGHT FOR THE LAURELS.
THE LAKE EFFECT WILL BE OF LITTLE CONCERN, WITH JUST ANOTHER
DUSTING IN PLACES ACROSS THE NRN ALLEGHENIES. THE SNOW WILL BE A
DIFFERENT CHARACTER THAN HAS JUST FALLEN. IT SHOULD GET
LIGHTER/FLUFFIER AS TEMPS COOL AND THE TOPS OF THE CLOUDS DIP
INTO THE GOOD DGZ FOR A SHORT TIME BEFORE THE INVERSION DROPS
LOW ENOUGH TO END THE LAKE EFFECT (AROUND SUNRISE OR MID-MORNING
AT THE LATEST).
THE WIND DOES PICK UP FOR TONIGHT AS THE LOW GOES TO OUR EAST
WITH GUSTS INTO THE 20S IN THE LAURELS, BUT LOWER GUSTS ELSEWHERE.
SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/
TYPICAL NORTHWEST FLOW PATTERN ON THURSDAY WITH BREAKS IN THE
CLOUDS IN SE PA DURING THE AFTERNOON AND PERSISTENT
STRATOCUMULUS FARTHER NORTHWEST. HIGHS ON THURSDAY WILL TREND
CLOSE TO NORMAL WITH HIGHS IN THE LOW 30S TO LOW 40S. AN
APPROACHING CLIPPER SYSTEM WILL TURN WINDS EASTERLY THURSDAY
NIGHT, SUPPORTING A DRY BUT DREARY NIGHT WITH PLENTY OF LOW
CLOUDS AND PERHAPS SOME REDUCED VISIBILITY. LOWS IN THE MID 20S
WILL COOL THE GROUND ENOUGH TO ALLOW ANY SNOW THAT FALLS ON
FRIDAY TO STICK TO UNTREATED/ELEVATED SURFACES.
THAT CLIPPER SYSTEM COMING IN FOR FRIDAY IS MORE CERTAIN, NOW,
BUT AMOUNTS STILL LOOK LIGHT WITH A WIDESPREAD 1-2" N & W, AND
LESS THAN THAT FOR THE S. ONE WILDCARD IS IF A TROUGH LINGERS
ACROSS ERN PA. THAT WOULD SERVE TO INCREASE SNOW (REALLY THE
DURATION OF SNOW) THERE. CONFIDENCE IS TOO LOW TO BUMP SF
NUMBERS UP THERE JUST YET. SOMETHING TO WATCH OUT FOR.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
THIS WEEKEND WILL BE VERY COLD WITH FORECAST MAXES ONLY IN THE
20S-L30S SATURDAY AND MIDTEENS- MID20S SUNDAY. OVERNIGHT LOWS
LIKELY CHALLENGE 0F IN THE N (SUN AM). ALMOST EVERYONE WILL DROP
INTO THE SINGLE DIGITS MON AM. WIND CHILLS DO GET NEAR -10F SUN
AM IN THE NE, BUT NOT ON MON AM WHEN THE WIND IS LIGHTER/CALM
UNDER THE SFC HIGH DESPITE THE COLDER AIR TEMPS.
SPRAWLING HIGH PRESSURE WILL MAKE FOR DRY WEATHER INTO EARLY
TUESDAY WITH MODERATING BUT STILL SEASONABLY CHILLY TEMPS.
SEVERAL SHORTWAVES WILL BRING A WEATHER SYSTEM TOWARD THE STATE
CHRISTMAS EVE INTO CHRISTMAS DAY. PCPN AMOUNTS DO NOT APPEAR TO
BE SIGNIFICANT, BUT TIMING AND P-TYPE MAY POSE SOME TRAVEL
ISSUES OVER THE HOLIDAY.
AVIATION /00Z THURSDAY THROUGH MONDAY/
RAIN OVER THE LOWER SUSQ VALLEY SHOULD TAPER OFF LATE THIS
EVENING, AS LOW PRESSURE PASSES EAST OF THE STATE. THE MAIN
FOCUS FOR THE REST OF THE NIGHT WILL BE THE ALLEGHENY PLATEAU,
WHERE RESIDUAL LOW LEVEL MOISTURE ASCENDING THE HIGH TERRAIN
WILL RESULT IN IFR/LIFR CIGS, AS WELL AS SPOTTY VERY LIGHT SNOW
OR -FZDZ THROUGH LATE EVENING.
AN INCREASINGLY DRY NORTHWEST FLOW LATE TONIGHT, SHOULD RESULT
IN IMPROVING CONDITIONS AREAWIDE. MODEL SOUNDINGS AND ENSEMBLE
PLUMES INDICATE IFR CIGS ARE LIKELY TO PERSIST THROUGH DAWN OVER
THE LAUREL HIGHLANDS (JST). HOWEVER, A RETURN TO MVFR CIGS IS
LIKELY OVER THE REST OF THE ALLEGHENY PLATEAU AND A RETURN TO
VFR IS LIKELY DOWNWIND (EAST) OF THE ALLEGHENY PLATEAU.
FLYING CONDITIONS SHOULD CONTINUE TO IMPROVE THURSDAY WITH A
DIMINISHING NORTHWEST BREEZE, AS HIGH PRESSURE BUILDS INTO THE
STATE. FORECAST SOUNDINGS INDICATE LINGERING MVFR CIGS OVER THE
ALLEGHENY PLATEAU WILL GIVE WAY TO VFR CONDITIONS DURING THE
AFTERNOON.
OUTLOOK...
FRI...SPOTTY PM LIGHT SNOW/LOW CIGS LIKELY, MAINLY N AND W MTNS.
SAT...NW WINDS GUSTING TO AROUND 25KTS. AM SNOW SHOWERS
POSSIBLE N AND W MTNS.
SUN-MON...NO SIG WX EXPECTED.
CLIMATE
ASTRONOMICAL WINTER (SOLSTICE) BEGINS ON SATURDAY, DECEMBER 21ST
AT 4:19 A.M. EST.
CTP WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 8 AM EST THURSDAY FOR PAZ024-033.
SYNOPSIS...DEVOIR/BANGHOFF
NEAR TERM...DANGELO
SHORT TERM...DEVOIR/FITZGERALD/BANGHOFF
LONG TERM...GARTNER/BAUCO
AVIATION...FITZGERALD
CLIMATE...STEINBUGL
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