249  
FXUS61 KPHI 192344  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
644 PM EST SUN JAN 19 2025  
   
SYNOPSIS  
 
THE LOW RESPONSIBLE FOR THE WINTRY PRECIPITATION ON SUNDAY WILL  
PROGRESS NORTHEASTWARD TO THE CANADIAN MARITIMES BY MONDAY MORNING.  
ARCTIC HIGH PRESSURE BUILDS INTO THE OHIO VALLEY LATER MONDAY, THEN  
INTO OUR AREA TUESDAY INTO WEDNESDAY. A SYSTEM TRACKS TO OUR SOUTH  
AND EAST TUESDAY NIGHT AND WEDNESDAY WITH POSSIBLY ANOTHER ONE AT  
THE END OF THE WEEK.  
 
 
   
NEAR TERM /THROUGH MONDAY/  
 
NO MAJOR CHANGES IN THE PREVIOUS FORECAST. AS EXPECTED, NOW THAT  
WE HAVE GOTTEN PAST SUNSET, AREAS THAT HAD NOT YET CHANGED OVER  
TO SNOW HAVE QUICKLY CHANGED OVER. THE BAND OF HEAVIEST SNOW HAS  
SHIFTED EASTWARD, OVER PORTIONS OF WESTERN AND NORTHERN NJ.  
UNDER THIS BAND, WE HAVE HAD REPORTS OF 2 INCHES PER HOUR OR  
MORE.  
 
THAT BEING SAID, THE BACK END OF THE PRECIP IS QUICKLY  
APPROACHING DELMARVA, AND SHOULD BE MOVING THROUGH THE REGION  
OVER THE NEXT 4 HOURS.  
 
AS THE COASTAL LOW DEPARTS TONIGHT, PRECIP WILL END FROM SOUTHWEST  
TO NORTHEAST AND OUR FOCUS WILL SHIFT TO THE DOWNRIGHT BLUSTERY AND  
COLD CONDITIONS. WINDS WILL BEGIN TO SURGE LATE THIS EVENING AND  
INTO THE OVERNIGHT HOURS FROM THE NORTHWEST WITH GUSTS AS HIGH AS 25-  
30 MPH (UP TO 35 MPH ACROSS THE POCONOS), USHERING IN OUR FRIGID AIR  
FOR THE WEEK. TEMPERATURES WILL CRATER OVERNIGHT WITH LOWS EXPECTED  
IN THE TEENS ACROSS THE REGION, EVEN A FEW SINGLE-DIGITS FOR THE  
HIGHER ELEVATIONS. COMBINED WITH THE GUSTY WINDS, WIND CHILLS ARE  
EXPECTED TO BE AROUND 0 DEGREES FOR AREAS NORTH AND WEST OF THE I-95  
CORRIDOR. THE POCONOS WILL CERTAINLY SEE THE WORST, HOWEVER, WITH A  
WIND CHILL VALUES AROUND -10 DEGREES (YES, WE DID MEAN TO SAY TEN  
DEGREES BELOW ZERO). FOR THESE AREAS WITH THE HAZARDOUS COLD, A COLD  
WEATHER ADVISORY HAS BEEN ISSUED. ELSEWHERE, THE WIND CHILLS WILL  
STILL BE DANGEROUSLY LOW AND IN THE SINGLE-DIGITS. THIS RAPID ONSET  
COLD IN THE WAKE OF OUR WINTER STORM WILL ALSO BRING UP THE CONCERN  
OF SLIPPERY AND ICY CONDITIONS POTENTIALLY PERSISTING EVEN AFTER  
PRECIPITATION HAS LONG ENDED. ADDITIONALLY, WINDY CONDITIONS ACROSS  
OUR HIGHER ELEVATIONS THAT SAW THE BULK OF THE SNOW EARLIER IN THE  
DAY COULD CAUSE AREAS OF BLOWING AND DRIFTING SNOW, POTENTIALLY  
COVERING STREETS AND SIDEWALKS THAT HAD ALREADY BEEN CLEARED BEFORE.  
 
THE COLD WILL CONTINUE TO SETTLE IN FOR MONDAY TEMPERATURES  
REMAINING WELL BELOW FREEZING FOR THE ENTIRE AREA. DESPITE A MIX OF  
SUN AND CLOUDS, HIGHS ARE ONLY EXPECTED TO REACH THE LOW TO MID 20S  
WITH ONLY TEENS FOR THE POCONO PLATEAU. WINDS WILL ALSO KEEP IT  
BLUSTERY THROUGH THE DAY WITH GUSTS OF 20-30 MPH OUT OF THE  
NORTHWEST. WIND CHILLS WILL BE IN THE TEENS TO SINGLE DIGITS AS A  
RESULT WITH OUR FRIENDS IN THE POCONOS GETTING THE SHORT END OF THE  
STICK WITH BELOW ZERO WIND CHILLS ALL DAY.  
 
 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/  
 
DANGEROUS COLD GRIPS THE REGION WITH COLD WEATHER ADVISORIES ISSUED.  
 
THE BIG WEATHER STORY MONDAY NIGHT INTO WEDNESDAY WILL BE THE  
DANGEROUSLY COLD CONDITIONS. STARTING WITH MONDAY NIGHT,  
TEMPERATURES DROP INTO SINGLE DIGITS ACROSS THE AREA WITH NEGATIVES  
FOR THE POCONOS. WINDS DURING MONDAY NIGHT WILL GUST UPWARDS OF 25  
MPH WHICH LEADS TO WIND CHILLS RANGING FROM NEAR ZERO IN DELMARVA TO  
THE NEGATIVE TEENS IN THE POCONOS. MOST WILL HAVE NEGATIVE WIND  
CHILLS MONDAY NIGHT. DUE TO THESE FORECASTED CONDITIONS, A COLD  
WEATHER ADVISORY HAS BEEN ISSUED FOR ALL OF THE AREA FOR THIS  
TIMEFRAME. TUESDAY IS QUITE THE COLD DAY WITH HIGHS REACHING TEENS  
TO LOW 20S FOR MOST. AS FOR THE WINDS, GUSTS REMAIN UPWARDS OF 15  
MPH. THE COMBINATION OF THOSE WINDS AND TEMPERATURES WILL RESULT IN  
WIND CHILLS IN THE NEGATIVES FOR THE POCONOS, SINGLE DIGITS FOR THE  
LEHIGH VALLEY WITH OTHER LOCATIONS BEING SOMEWHERE IN THE TEENS.  
ANOTHER DANGEROUSLY COLD NIGHT IS EXPECTED FOR TUESDAY NIGHT. LOWS  
TUESDAY NIGHT WILL BE IN THE NEGATIVES FOR THE POCONOS AND SINGLE  
DIGITS ELSEWHERE. WINDS REMAIN 5-10 MPH AND LEADS TO WIND CHILLS IN  
THE NEGATIVES AREAWIDE FOR TUESDAY NIGHT. WEDNESDAY HIGHS REACH THE  
TEENS FOR MOST AND WINDS ARE GENERALLY 5-10 MPH WHICH LEADS TO WIND  
CHILLS IN THE TEENS FOR MOST. ADDITIONAL COLD WEATHER HEADLINES WILL  
LIKELY BE NEEDED THIS WEEK GIVEN THESE FORECASTED CONDITIONS.  
 
AS FOR THE WEATHER FEATURES DURING THIS TIME PERIOD, WE HAVE AN  
ARCTIC HIGH PRESSURE SYSTEM BUILDING IN THROUGH TUESDAY. MEANWHILE,  
AT THE UPPER-LEVELS, A TROUGH MOVES INTO THE REGION FROM TUESDAY  
INTO WEDNESDAY MORNING. NOW THIS TROUGH WILL MAKE THINGS A LITTLE  
INTERESTING BECAUSE THERE IS A PIECE OF ENERGY ROTATING THROUGH  
TUESDAY NIGHT INTO WEDNESDAY MORNING. AT THE SURFACE, THIS IS A LOW  
PRESSURE SYSTEM WHICH MOST MODELS KEEP OFFSHORE WITH NO  
PRECIPITATION REACHING OUR AREA. RIGHT NOW, ONLY PART OF THE AREA  
HAS BEEN SHADED FOR SLIGHT CHANCE TO CHANCE FOR SNOW. THE MODELS  
THAT KEEP THE PRECIPITATION OFFSHORE HAVE A STRONGER HIGH IN PLACE  
WHILE THE ONES THAT SHOW SOME PRECIPITATION REACHING THE AREA SHOW  
WEAKNESS IN THE HIGH ALLOWING THE LOW TO GET CLOSER TO THE COAST.  
HIGH PRESSURE IS THE MAIN WEATHER FEATURE FOR WEDNESDAY AND KEEPS  
THINGS QUIET WITH WEAK UPPER-LEVEL RIDGING IN THE UPPER-LEVELS.  
 
 
   
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/  
 
TEMPERATURES START TO IMPROVE THURSDAY AND IT CONTINUES INTO THE  
WEEKEND.  
 
AFTER A VERY COLD FIRST HALF OF THE WEEK, TEMPERATURES START TO  
IMPROVE IN THE LONG TERM. HIGHS ON THURSDAY ARE IN THE UPPER  
TEENS TO UPPER 20S ACROSS THE AREA. FOLLOWING THURSDAY, EACH DAY  
BUILDS UPON THE PREVIOUS DAY IN TERMS OF HIGH TEMPERATURES.  
 
FOR WEATHER FEATURES, THERE IS STILL THAT HIGH PRESSURE SYSTEM  
HAVING ITS INFLUENCE ON OUR REGION. UPPER-LEVEL TROUGHING IS MOVING  
INTO THE REGION THURSDAY THROUGH FRIDAY NIGHT AND ANOTHER PIECE OF  
ENERGY IS HINTED TO ROTATE THROUGH. ONCE AGAIN, THIS WOULD BE IN THE  
FORM OF A LOW PRESSURE SYSTEM. THERE IS STILL A LARGE AMOUNT OF  
UNCERTAINTY GIVEN THIS BEING IN THE LONG TERM. MODEL GUIDANCE  
SHOWS THE POTENTIAL FOR SOME SNOW TO BRUSH PARTS OF OUR AREA  
THURSDAY INTO FRIDAY MORNING. GIVEN THE UNCERTAINTY, SLIGHT  
CHANCE TO CHANCE WERE THE EXTENT FOR ANY PRECIPITATION DURING  
THAT TIME PERIOD. FOR THE WEEKEND, SATURDAY LOOKS MAINLY DRY  
WITH A FEW SHOWERS POSSIBLE BY SUNDAY.  
 
 
   
AVIATION /00Z MONDAY THROUGH FRIDAY/  
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,  
KMIV, KACY AND SURROUNDING AREAS...  
 
TONIGHT...IFR AND MVFR CONDITIONS WILL LINGER FOR THE NEXT FEW  
HOURS. SHOULD SEE CONDITIONS IMPROVE TO VFR FOR MOST TAF SITES  
FROM SW TO NE STARTING AROUND 03Z. A POSSIBLE EXCEPTION IS KACY  
WHERE LOW CLOUDS MAY LINGER FOR A FEW HOURS BEYOND 06Z.  
NORTHWEST WINDS GENERALLY 10 TO 15 KT. GUSTS TO 25 KT ARE  
POSSIBLE, THOUGH HAVE BEEN MORE SPORADIC THAN PREVIOUSLY  
FORECAST SO FAR THIS EVENING.  
 
MONDAY...PRIMARILY VFR CONDITIONS. HOWEVER, AREAS OF BLOWING  
SNOW ARE POSSIBLE NEAR KABE AND KRDG. HAVE LOW CONFIDENCE ON THE  
DURATION OR EXTENT OF BLSN, BUT THERE IS ENOUGH OF A RISK TO  
INCLUDE A MENTION IN BOTH TAFS. WEST- NORTHWEST WINDS 10-15  
KNOTS WITH GUSTS UP TO 20-25 KNOTS.  
 
OUTLOOK...  
 
MONDAY NIGHT AND TUESDAY...VFR. WEST-NORTHWEST WIND GUSTS  
DIMINISHING SOME MONDAY NIGHT AND THEN ESPECIALLY TUESDAY.  
 
TUESDAY NIGHT THROUGH FRIDAY...PREVAILING VFR. SMALL CHANCE (20 -  
30%) OF MVFR OR IFR CONDITIONS IN SNOW TUESDAY NIGHT AND AGAIN  
THURSDAY NIGHT.  
 
 
   
MARINE  
 
GALE WARNING IN EFFECT. WINDS AND SEAS WILL RAMP UP THROUGH TONIGHT  
AS A LOW PRESSURE SYSTEM MOVES UP THE COAST AND OUT TO SEA. EXPECT  
SMALL CRAFT ADVISORY CONDITIONS THIS AFTERNOON WILL GIVE WAY TO A  
PERIOD OF GALE FORCE WIND GUSTS TONIGHT. RAIN WILL CHANGE TO SNOW  
OVER THE WATERS TONIGHT BEFORE ENDING. THEN FREEZING SPRAY BECOMES A  
CONCERN OVERNIGHT AS TEMPERATURES DROP WITH GUSTY WINDS.  
 
FOR MONDAY, WINDS AT SMALL CRAFT ADVISORY LEVELS CONTINUE ALONG WITH  
FREEZING SPRAY.  
 
A FREEZING SPRAY ADVISORY WAS ISSUED FOR ALL MARINE ZONES BEGINNING  
LATE TONIGHT THROUGH MONDAY.  
 
OUTLOOK...  
 
MONDAY NIGHT...SCA CONDITIONS. FREEZING SPRAY EXPECTED.  
 
TUESDAY AND WEDNESDAY...A PERIOD OF SCA CONDITIONS ARE POSSIBLE  
LATER TUESDAY NIGHT AND WEDNESDAY MORNING. FREEZING SPRAY AT TIMES.  
 
THURSDAY AND FRIDAY...WINDS AND SEAS SHOULD STAY BELOW SCA.  
 
 
   
PHI WATCHES/WARNINGS/ADVISORIES  
 
PA...COLD WEATHER ADVISORY FROM 6 PM MONDAY TO 6 AM EST TUESDAY FOR  
PAZ070-071-102-104-106.  
WINTER STORM WARNING UNTIL 1 AM EST MONDAY FOR PAZ054-055-  
060>062-070-071-101>106.  
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST  
TUESDAY FOR PAZ054-055-060>062-101-103-105.  
NJ...WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NJZ012>014-  
016>020-027.  
COLD WEATHER ADVISORY FROM 6 PM MONDAY TO 6 AM EST TUESDAY FOR  
NJZ010-012>027.  
WINTER STORM WARNING UNTIL 1 AM EST MONDAY FOR NJZ001-007>010-  
015.  
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST  
TUESDAY FOR NJZ001-007>009.  
DE...WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR DEZ001.  
COLD WEATHER ADVISORY FROM 6 PM MONDAY TO 6 AM EST TUESDAY FOR  
DEZ001>004.  
MD...WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR MDZ012-015.  
COLD WEATHER ADVISORY FROM 6 PM MONDAY TO 6 AM EST TUESDAY FOR  
MDZ012-015-019-020.  
MARINE...GALE WARNING UNTIL 6 AM EST MONDAY FOR ANZ430-431-450>455.  
FREEZING SPRAY ADVISORY FROM 1 AM TO 7 PM EST MONDAY FOR  
ANZ430-431-450>455.  
 
 
 
 
 
SYNOPSIS...JOHNSON  
NEAR TERM...JOHNSON/MJL  
SHORT TERM...GUZZO  
LONG TERM...GUZZO  
AVIATION...AKL/JOHNSON  
MARINE...JOHNSON/MJL  
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