176  
FXUS61 KPHI 220808  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
408 AM EDT MON OCT 22 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE CENTERED IN THE SOUTHERN APPALACHIANS EARLY THIS  
MORNING WILL MOVE EASTWARD TODAY AND OUT TO SEA TONIGHT. A COLD  
FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST ON TUESDAY. IT  
SHOULD PASS THROUGH OUR REGION ON TUESDAY NIGHT WITH A SECONDARY  
COLD FRONT ARRIVING ON WEDNESDAY. HIGH PRESSURE IS ANTICIPATED  
TO FOLLOW FOR THURSDAY AND FRIDAY. A COASTAL STORM MAY AFFECT  
OUR REGION OVER THE WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
THERE WAS A DECK OF STRATOCUMULUS OVER MUCH OF EASTERN  
PENNSYLVANIA AND NORTHERN NEW JERSEY EARLY THIS MORNING. THE SKY  
WAS MAINLY CLEAR OVER AREAS TO THE SOUTH AND EAST. THE CLOUDS  
EXTENDED BACK TO THE GREAT LAKES. THEY ARE TRAPPED UNDER A  
TEMPERATURE INVERSION AND SHOULD BE SLOW TO ERODE. WE ARE  
ANTICIPATING A VERY GRADUAL DECREASE IN CLOUDS FOR OUR NORTHERN  
COUNTIES TODAY WITH MOSTLY SUNNY CONDITIONS IN THE SOUTH.  
 
THE CLOUD COVER HAS KEPT TEMPERATURES FROM FALLING IN EASTERN  
PENNSYLVANIA AND NORTHERN NEW JERSEY. THE POTENTIAL FOR FREEZING  
TEMPERATURES IN SOUTHEASTERN PENNSYLVANIA NO LONGER EXISTS, SO  
WE HAVE CHANGED THE FREEZE WARNING THAT WAS IN EFFECT FOR  
LOCATIONS TO THE NORTHWEST OF PHILADELPHIA TO A FROST ADVISORY.  
IF THE CLOUDS BREAK, THERE IS THE POSSIBILITY OF FROST IN THOSE  
AREAS BEFORE SUNRISE. OTHERWISE, THE REMAINDER OF THE FROST  
ADVISORY, AS WELL AS THE FREEZE WARNING IN SOUTHERN NEW JERSEY,  
REMAINS IN PLACE.  
 
WE ARE EXPECTING ANOTHER CHILLY DAY, WITH AFTERNOON  
TEMPERATURES RUNNING ABOUT 10 DEGREES BELOW NORMAL. THE WIND  
SHOULD SETTLE INTO THE SOUTHWEST AROUND 5 TO 10 MPH.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/
 
 
HIGH PRESSURE WILL CONTINUE TO MOVE OUT TO SEA TONIGHT. SUBTLE  
WARM ADVECTION IS ANTICIPATED IN ADVANCE OF OUR NEXT WEATHER  
SYSTEM. WE ARE EXPECTING A DECK OF MID LEVEL CLOUDS TO DRIFT  
OVER MOST OF OUR REGION DURING THE NIGHT. THE CLOUDS, IN  
COMBINATION WITH A LIGHT SOUTHWEST TO SOUTH SURFACE FLOW, SHOULD  
KEEP TEMPERATURES FROM FALLING BELOW THE 40S, EXCEPT IN THE FAR  
NORTH WHERE LOWS SHOULD BE IN THE UPPER 30S.  
 

 
   
LONG TERM /TUESDAY THROUGH SUNDAY/
 
 
TUESDAY...THE COLD FRONT ARRIVES ON TUESDAY. MODELS CONTINUE TO  
SHOW A CLIPPER-LIKE SYSTEM MOVING OUT OF CANADA AND ACROSS THE  
GREAT LAKES BEFORE REACHING OUR AREA ON TUESDAY. IT'S A PRETTY  
FAST MOVING SYSTEM AND THE FRONT QUICKLY MAKES ITS WAY THROUGH  
THE REGION. STILL NOT SEEING MUCH MOISTURE WITH THE FRONTAL  
PASSAGE AND IT COULD VERY WELL END UP BEING DRY. HOWEVER, WITH  
ANOTHER STRONG UPPER LEVEL TROUGH CROSSING THE REGION, I AM  
INCLINED TO CONTINUE THE MENTION OF SOME SLIGHT CHANCE TO CHANCE  
POPS ACROSS AREAS TO THE NORTH AND WEST OF THE I-80 CORRIDOR AS  
A RECENT SIMILAR FRONT WAS PROGGED TO BE MOSTLY DRY AND ENDED  
UP BEING A FAIRLY ROBUST SYSTEM MOVING THROUGH.  
 
WEDNESDAY THROUGH FRIDAY...STRONG SURFACE HIGH PRESSURE BUILDS  
INTO OUR AREA ON WEDNESDAY AND PERSISTS THROUGH THE END OF THE  
WORK WEEK. WE SHOULD REMAIN NICE AND DRY THROUGH THE PERIOD. THE  
BIGGER STORY IS THE RETURN OF COLDER AIR AS IT DIPS DOWN FROM  
THE NORTH AND SETTLES OVER THE EASTERN US THROUGH FRIDAY.  
WINDIEST DAY LOOKS TO BE WEDNESDAY AS THE FRONT PULLS AWAY FROM  
THE AREA BUT IT DOESN'T LOOK NEARLY AS WINDY AS SUNDAY WAS.  
 
SATURDAY AND SUNDAY...MODELS ARE CONTINUING TO SHOW THE  
POTENTIAL FOR A STRONG COASTAL SYSTEM TO MOVE UP THE EASTERN  
SEABOARD, BRINGING WIND, RAIN, AND POTENTIALLY SOME SNOW (MAINLY  
HIGHER ELEVATIONS). ONE THING THE MODELS DO NOT SHOW IS A GOOD  
COLD POOL, WHICH WOULD HELP GIVE MORE CONFIDENCE TO SNOW IN THE  
FORECAST AREA. SO IT MAY END UP JUST BEING A COLD RAINSTORM.  
MANY OF THE DETAILS STILL NEED TO WORKED OUT AS THE SYSTEM  
DEVELOPS AND THE TRACK WILL PLAY A CRUCIAL ROLE AS IT HAS BEEN  
MOVING CLOSE TO AND AWAY FROM THE COAST OVER THE PAST SEVERAL  
MODEL RUNS.  
 

 
   
AVIATION /08Z MONDAY THROUGH FRIDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
TODAY...VFR WITH DECREASING CLOUDS. SOUTHWEST WIND 4 TO 8  
KNOTS.  
 
TONIGHT...VFR WITH AN INCREASE IN CLOUDS. BASES SHOULD REMAIN  
ABOVE 6000 FEET. VARIABLE WIND 5 KNOTS OR LESS.  
 
OUTLOOK...  
TUESDAY...VFR. SOUTHWEST TO WEST WIND AROUND 10 KNOTS.  
 
TUESDAY NIGHT...VFR. NORTHWEST WIND 5 TO 10 KNOTS.  
 
WEDNESDAY...VFR. NORTHWEST WIND 10 TO 15 KNOTS.  
 
WEDNESDAY NIGHT...VFR. NORTHWEST WIND 5 TO 10 KNOTS.  
 
THURSDAY...VFR. NORTHWEST WIND AROUND 10 KNOTS.  
 
THURSDAY NIGHT AND FRIDAY...VFR. VARIABLE WIND 6 KNOTS OR LESS.  
 

 
   
MARINE
 
 
HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE COASTAL WATERS OF  
NEW JERSEY AND DELAWARE TODAY, BEFORE MOVING OUT TO SEA  
TONIGHT.  
 
THE SMALL CRAFT ADVISORY HAS COME TO AN END. WE ARE  
ANTICIPATING THAT THE WIND WILL SETTLE INTO THE SOUTHWEST AT 10  
TO 15 KNOTS FOR TODAY, INCREASING AROUND 15 KNOTS FOR TONIGHT.  
WAVES ON OUR OCEAN WATERS SHOULD RANGE FROM 2 TO 4 FEET, WITH  
WAVES ON DELAWARE BAY AT 2 FEET OR LESS.  
 
OUTLOOK...  
TUESDAY THROUGH THURSDAY...A COLD FRONT WILL CROSS THE WATERS  
ON TUESDAY WITH A STRONG NORTHWEST FLOW BEHIND IT. WINDS WILL  
INCREASE STARTING ON TUESDAY AND GUSTS ABOVE 25 KNOTS WILL THEN  
CONTINUE THROUGH THURSDAY BEFORE STARTING TO SUBSIDE THURSDAY  
EVENING. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR MUCH  
OF THIS PERIOD.  
 
FRIDAY...SUB-ADVISORY CONDITIONS ARE EXPECTED ON THE AREA  
WATERS.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ060-061-070-  
071-101>106.  
NJ...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NJZ013-017>022-  
027.  
FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NJZ012-015-016.  
DE...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR DEZ001.  
MD...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MDZ008.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...IOVINO  
NEAR TERM...IOVINO  
SHORT TERM...IOVINO  
LONG TERM...MEOLA  
AVIATION...IOVINO  
MARINE...IOVINO/MEOLA  
 
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