939  
FXUS61 KCTP 190008  
AFDCTP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE STATE COLLEGE PA  
708 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/
 
 
PRECIP SHIELD WORKING ITS WAY EAST ACROSS THE AIRSPACE HAS AND  
WILL CONTINUE TO LEAD TO DETERIORATING CONDS, MAINLY LOW CIGS  
THAT WILL PERSIST INTO THIS EVENING.  
 
AS PRECIP EXITS THE EASTERN TERMINALS 04-06Z, A WINDSHIFT TO  
280-320 DEGREES WILL FAVOR CONTINUED IFR/LIFR AT KBFD/KJST WHILE  
SITES TO THE EAST OF THE MTNS BEGIN TO IMPROVE TO MVFR OR LOW  
END VFR. SNOW SHOWERS AND PATCHY FREEZING DRIZZLE WILL LIKELY  
IMPACT KBFD AND KJST OVERNIGHT INTO EARLY THURSDAY MORNING.  
 
OUTLOOK...  
 
THU...SNOW SHOWERS AND FLURRIES ENDING BY THURSDAY NIGHT.  
MVFR/IFR WEST TO LOW VFR EAST.  
 
FRI...IFR LIKELY IN LIGHT SNOW.  
 
SAT-SUN...IFR/MVFR IN SNOW SHOWERS AT BFD/JST. MVFR TO LOW END  
VFR ELSEWHERE WITH FLURRIES.  
 
MON...PRIMARILY VFR.  
 

 
   
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...STEINBUGL/GARTNER  
CLIMATE...STEINBUGL  
 
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