864
FXUS61 KPHI 202030
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
330 PM EST SUN JAN 20 2019
SYNOPSIS
HIGH PRESSURE OVER CENTRAL CANADA BUILDS SOUTH INTO THE GREAT LAKES
TONIGHT, THEN MOVES INTO THE MID-ATLANTIC ON TUESDAY BEFORE MOVING
OFFSHORE TUESDAY NIGHT. LOW PRESSURE WILL AFFECT THE REGION
WEDNESDAY THROUGH THURSDAY. A STRONG COLD FRONT PASSES THROUGH THE
REGION THURSDAY NIGHT. HIGH PRESSURE RETURNS TO CLOSE OUT THE
WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
LOW PRESSURE SYSTEM CONTINUING TO PULL AWAY AT THIS HOUR AS IT MOVES
EAST OF LONG ISLAND. IN ITS WAKE TEMPERATURES ARE FALLING BEHIND A
STRONG COLD FRONT WITH NW WINDS GUSTING 30-40+ MPH. A WIND ADVISORY
REMAINS IN EFFECT FOR THE ENTIRE CWA UNTIL 5Z WITH WINDS GUSTING 35-
45 MPH LATE THIS AFTERNOON THROUGH THIS EVENING. AS OF 2 PM, TEMPS
STILL ABOVE FREEZING MOST OF THE I-95 CORRIDOR BUT FALLING SO EXPECT
TEMPS TO DIP BELOW FREEZING HERE BY 4 PM WITH TEMPERATURES REACHING
THE TEENS AND LOW 20S ACROSS THE AREA BY EARLY THIS EVENING EXCEPT
SINGLE DIGITS IN SOUTHERN POCONOS. THIS WILL FREEZE ANY LINGERING
STANDING WATER AND SLUSH PRODUCING VERY ICY CONDITIONS.
FOR TONIGHT, THE BIG STORY WILL CONTINUE TO BE STRONG WINDS AND
FALLING TEMPERATURES AS DEEPENING LOW PRESSURE MOVES NORTHEAST INTO
THE CANADIAN MARITIMES. THE WINDS REMAIN STRONG AND GUSTY AT LEAST
THROUGH THIS EVENING AND MAY NOT EVEN COME DOWN THAT MUCH OVERNIGHT
AS THE STRONG GRADIENT PERSISTS OVER THE AREA. WINDS CONTINUING TO
BLOW 15 TO 25 MPH THROUGH TONIGHT WILL COMBINE WITH BITTER COLD
TEMPERATURES TO PRODUCE WIDESPREAD DANGEROUS, SUBZERO WIND CHILLS
REACHING THE -10 (SOUTH) TO -25 (NORTH) RANGE BY LATER TONIGHT. FOR
THIS REASON, WIND CHILL WARNINGS REMAIN IN EFFECT FOR CARBON AND
MONROE COUNTIES WITH WIND CHILL ADVISORIES FOR THE REMAINDER OF THE
CWA.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
FOR MONDAY, DEEP LOW PRESSURE CONTINUES TO DRIFT NORTHEAST THROUGH
ATLANTIC CANADA WHILE HIGH PRESSURE NOSES SOUTHWARD INTO THE
MIDWEST. THIS WILL KEEP THE TIGHT GRADIENT OVER THE AREA PRODUCING
CONTINUING STRONG WINDS AND VERY COLD TEMPERATURES WITH BITTER WIND
CHILLS DESPITE SKIES THAT WILL BE MAINLY SUNNY. EXPECT HIGH
TEMPERATURES TO ONLY REACH THE SINGLE DIGITS ACROSS THE SOUTHERN
POCONOS AND FAR NW NJ WITH TEENS FOR MOST OF THE REMAINDER OF THE
AREA EXCEPT NEAR 20 OVER THE SOUTHERN DELMARVA. THIS WILL MEAN THAT
EVEN DURING THE PEAK OF DAYTIME HEATING SUBZERO WIND CHILL VALUES
WILL PERSIST FOR AREAS ALONG AND NORTH OF THE I-95 CORRIDOR.
WINDS FINALLY EASE THROUGH MONDAY NIGHT INTO EARLY TUESDAY AS THE
CENTER OF HIGH PRESSURE MOVES EASTWARD INTO THE AREA. FOLLOWING
ANOTHER VERY COLD NIGHT MONDAY NIGHT (LOWS IN THE SINGLE DIGITS AND
TEENS) TEMPERATURES WILL MODERATE TUESDAY BUT STILL BE BELOW
AVERAGE. EXPECT HIGHS GENERALLY IN THE 20S TO LOW 30S BUT WITH
LIGHTER WINDS AND MOSTLY SUNNY SKIES AS THE HIGH CRESTS OVER THE
REGION. THIS HIGH MOVES OFFSHORE TUESDAY NIGHT WITH A DEVELOPING
SOUTHERLY FLOW AND INCREASING CLOUDS AHEAD OF THE NEXT SYSTEM. AS A
RESULT, TEMPERATURES TUESDAY NIGHT WON'T DROP TOO MUCH FROM
TUESDAY'S HIGHS.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
A DEEP UPPER TROUGH WILL CONTINUE TO TRACK EAST THROUGH THE CENTRAL
U.S. LOW PRESSURE DEVELOPS AT THE BASE OF THE TROUGH OVER THE GULF
COAST STATES BY WEDNESDAY MORNING AS A PRIMARY LOW MOVES THROUGH THE
GREAT LAKES. LOW PRESSURE LIFTS NORTH INTO THE REGION, AND LATEST
FORECAST MODELS HAVE THIS SYSTEM PRIMARILY TAKING AN INLAND TRACK,
WHICH WOULD ALLOW FOR A SURGE OF WARMER AIR ALONG THE EAST COAST.
INITIALLY, THOUGH, TEMPERATURES WILL BE COLD ENOUGH FOR PRECIP TO
START OUT AS SNOW ACROSS THE REGION WEDNESDAY MORNING, AND THEN THE
RAIN/SNOW LINE WILL LIFT NORTH THROUGH THE DAY. SNOW ACCUMULATIONS
SHOULD BE LIGHT, AND LOOK TO BE LIMITED TO AREAS NORTH AND WEST OF
PHILLY, WITH POSSIBLY UP TO 2" IN THE SOUTHERN POCONOS.
SURFACE LOW PRESSURE LIFTS NORTH THROUGH THE REGION WEDNESDAY NIGHT
THROUGH THURSDAY MORNING, AND THEN UPPER TROUGH FOLLOWS THROUGH
THURSDAY AFTERNOON. STRONG COLD FRONT AHEAD OF AN ARCTIC AIRMASS
THEN PASSES THROUGH THURSDAY NIGHT.
ABUNDANT LOW LEVEL MOISTURE WILL BE ASSOCIATED WITH THIS SYSTEM, AND
LATEST FORECAST CALLS FOR 1.5-2" LIQUID QPF OVER A 24-36 HOUR
PERIOD. SHOULD BE A LONG ENOUGH PERIOD TO KEEP WIDESPREAD FLOODING
ISSUES LIMITED, BUT WILL HAVE TO MONITOR AS THE HEAVIEST RAIN WILL
FALL WEDNESDAY NIGHT THROUGH THURSDAY MORNING.
TEMPERATURES THEN FALL OFF GOING INTO THE WEEKEND, THOUGH THE
COLDEST AIR WILL HOLD OFF UNTIL FRIDAY NIGHT. HIGHS ON FRIDAY WILL
GENERALLY BE IN THE 30S, THEN FALL OFF INTO THE SINGLE DIGITS/TEENS
FRIDAY NIGHT. HIGHS ON SATURDAY LOOK TO BE QUITE COLD, IN THE TEENS
TO MID 20S.
ANOTHER STORM MAY DEVELOP FOR SUNDAY.
AVIATION /20Z SUNDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REST OF THIS AFTERNOON...VFR CEILINGS AROUND, WHICH THEN SCATTER
OUT. NORTHWEST WINDS 18-24 KNOTS WITH GUSTS TO AROUND 35 KNOTS.
TONIGHT AND MONDAY...VFR. NORTHWEST WINDS 18-22 KNOTS WITH GUSTS
TO AROUND 35 KNOTS.
OUTLOOK...
MONDAY NIGHT AND TUESDAY...VFR. NORTHWEST WINDS 15-20 KNOTS WITH
GUSTS TO AROUND 30 KNOTS DIMINISH MONDAY NIGHT, THEN BECOMING
WEST TO SOUTHWEST LESS THAN 10 KNOTS TUESDAY.
WEDNESDAY AND THURSDAY...SUB-VFR CONDITIONS ALONG WITH A PERIOD OF
SNOW OR SNOW/RAIN MIX TO RAIN PROBABLE. SOUTHERLY WINDS AROUND 10
KNOTS WEDNESDAY, BECOMING WEST-NORTHWEST AROUND 10 KNOTS THURSDAY.
FRIDAY...SUB-VFR CONDITIONS AT TIMES POSSIBLE. WESTERLY WINDS 10-15
KNOTS.
MARINE
GALE WARNING EXTENDED THROUGH MONDAY EVENING. STRONG NORTHWESTERLY
WINDS WILL CONTINUE THROUGH MONDAY AS ARCTIC AIR OVERSPREADS THE
AREA RESULTING IN DEEPER MIXING. AS THIS OCCURS, FREEZING SPRAY WILL
DEVELOP AND BECOME MORE WIDESPREAD BY LATER TONIGHT AND CONTINUE
THROUGH MONDAY. A FREEZING SPRAY ADVISORY REMAINS IN EFFECT FOR
MODERATE RATES OF ICE ACCRETION, AND THIS ADVISORY HAS BEEN EXTENDED
THROUGH MONDAY EVENING TO MATCH UP WITH THE GALE WARNING. A LOW
WATER ADVISORY MAY BE NEEDED ESPECIALLY MONDAY AFTERNOON GIVEN
THE STRONG AND PERSISTENT OFFSHORE WINDS.
OUTLOOK...
TUESDAY...THE CONDITIONS (WINDS) ARE ANTICIPATED TO BE DROPPING
BELOW SMALL CRAFT ADVISORY EARLY.
WEDNESDAY AND THURSDAY...WINDS SHOULD INCREASE TO SMALL CRAFT
ADVISORY CRITERIA WEDNESDAY, THEN DECREASE DURING THURSDAY WITH A
WIND SHIFT FROM THE WEST. SEAS LOOK TO REMAIN AT 5 FEET OR HIGHER ON
THE OCEAN WATERS.
FRIDAY...SMALL CRAFT ADVISORY CONDITIONS PROBABLE.
TIDES/COASTAL FLOODING
THE LAST OF THE MINOR TIDAL FLOODING WAS COMING TO AN END ON THE
TIDAL DELAWARE RIVER AT MID AFTERNOON. ALSO, THERE WERE A FEW
LINGERING POCKETS OF MINOR FLOODING ON THE UPPER PART OF BARNEGAT
BAY WHICH SHOULD ALSO COME TO AN END SHORTLY.
A STRONG NORTHWEST WIND IS EXPECTED FOR TONIGHT AND MONDAY AND IT
WILL CONTINUE TO PUSH WATER AWAY FROM THE COAST. THEREFORE, NO
ADDITIONAL TIDAL FLOODING IS ANTICIPATED BEYOND THAT WHICH OCCURRED
TODAY.
THE STRONG OFFSHORE WIND MAY RESULT IN SOME LOW WATER ISSUES, MAINLY
ON PARTS OF THE LOWER DELAWARE RIVER AND THE UPPER DELAWARE BAY ON
MONDAY. WE WILL CONTINUE TO MONITOR GUIDANCE TRENDS FOR THE EARLY
MORNING AND ESPECIALLY FOR THE EVENING LOW TIDE ON MONDAY FOR A
POSSIBLE LOW WATER STATEMENT OR ADVISORY. THE MOST SUSCEPTIBLE AREAS
SEEMS TO BE NEW CASTLE COUNTY IN DELAWARE AND SALEM COUNTY IN NEW
JERSEY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ054-055-
060>062-070-071-101>106.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY
FOR PAZ060>062-070-071-101>106.
WIND CHILL WARNING FROM 11 PM THIS EVENING TO 1 PM EST MONDAY
FOR PAZ054-055.
NJ...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ001-007>010-
012>027.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY
FOR NJZ001-007>010-012>027.
DE...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DEZ001>004.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY
FOR DEZ001>004.
MD...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ008-012-015-
019-020.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY
FOR MDZ008-012-015-019-020.
MARINE...FREEZING SPRAY ADVISORY FROM 1 AM MONDAY TO MIDNIGHT EST
MONDAY NIGHT FOR ANZ430-431-450>455.
GALE WARNING UNTIL MIDNIGHT EST MONDAY NIGHT FOR ANZ430-431-
450>455.
SYNOPSIS...MPS
NEAR TERM...FITZSIMMONS
SHORT TERM...FITZSIMMONS
LONG TERM...MPS
AVIATION...GORSE
MARINE...GORSE
TIDES/COASTAL FLOODING...IOVINO
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