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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