700
FXUS61 KPHI 152058
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
358 PM EST SAT DEC 15 2018
SYNOPSIS
LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE AREA
THROUGH EARLY MONDAY MORNING, BEFORE LIFTING OFF TO THE NORTHEAST. A
COLD FRONT WILL PASS THROUGH THE REGION MONDAY, USHERING IN COLDER
AIR. HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY AND WEDNESDAY.
BY LATE WEEK, ANOTHER EXPANSIVE AREA OF LOW PRESSURE LOOKS TO MOVE
TOWARD TO THE AREA.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
LIGHT RAIN CONTINUES THIS AFTERNOON OVER THE SOUTHERN PART OF OUR
FORECAST AREA - GENERALLY PHILLY SOUTHWARD - WHILE NORTHERN AREAS
REMAIN CLOUDY BUT RAIN FREE. WITH THE UPPER LOW NOW OVER THE TN
VALLEY, SW FLOW ALOFT CONTINUES BRING MOISTURE INTO OUR ARE, WHILE
NE WINDS AT THE SURFACE ARE MAINTAINING NEAR STEADY TEMPS AND
DEWPTS.
FOR TONIGHT, ELONGATED EAST-WEST LOW PRESSURE WILL REMAIN TO OUR
SOUTH WHILE HIGH PRESSURE TO THE NORTH OVER NEW ENGLAND MAINTAINS
THE NORTHEAST SURFACE FLOW. AS THE UPPER LOW MOVES EAST INTO VA,
UPPER DIFLUENCE AHEAD OF IT AND A JET STREAK ROUNDING THE SE QUAD
WILL RESULT IN STRONGER UVV OVERNIGHT. A BAND OF HEAVIER PRECIP IS
FORECAST TO MOVE GENERALLY SOUTH TO NORTH ACROSS THE AREA FROM
LATE EVENING THROUGH THE OVERNIGHT. ADDITION RAIN AMOUNTS ARE
EXPECTED TO BE AROUND A HALF INCH OR SO, AND NO SIG FLOOD ISSUES
ARE LIKELY.
P-TYPE IS A CONCERN UP NORTH HOWEVER, WITH COLDER SURFACE AIR
FILTERING INTO THE POCONOS AND FAR NW NJ OVERNIGHT. THIS IS EXPECTED
TO RESULT IN SOME FREEZING RAIN LATE TONIGHT AND SUNDAY, WITH HIGHER
ELEVATIONS ACCUMULATING PERHAPS A TENTH TO A QUARTER INCH OF ICE. A
WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THESE AREAS.
SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/
ON SUNDAY, THE UPPER LOW WILL SLIDE BY JUST TO OUR SOUTH WHILE
THE SURFACE LOW WILL RE-ORGANIZE JUST OFF THE NJ COAST. SOME
AREAS OR BANDS OF PRECIP WILL LIKELY CONTINUE THROUGH MUCH OF
THE DAY BUT AMOUNTS SHOULD BE LESS THAN OVERNIGHT. HIGH TEMPS ON
SUNDAY WILL NOT BE ABLE TO RISE MUCH ABOVE TONIGHT'S LOWS. A
WINTRY MIX MAY CONTINUE OVER HIGHER ELEVATIONS IN THE POCONOS,
AND MAY BEGIN TO SPREAD FARTHER SOUTH TOWARDS EVENING AS
TEMPERATURES BEGIN TO FALL.
LOW PRESSURE SURFACE AND ALOFT WILL MOVE NORTHEAST AND AWAY FROM OUR
AREA SUNDAY NIGHT. PRECIP SHOULD END FROM WEST TO EAST AND BE OVER
BY DAWN MONDAY EXCEPT FOR SOME LINGERING SNOW FLURRIES IN THE
POCONOS.
LONG TERM /MONDAY THROUGH SATURDAY/
MONDAY THROUGH WEDNESDAY NIGHT...BY MONDAY MORNING, THE WEEKEND
COASTAL STORM WILL BE CONTINUING TO PUSH OFFSHORE AND OUT TO
SEA. MEANWHILE, HIGH PRESSURE WILL BEGIN BUILDING ACROSS THE
OHIO VALLEY CREATING A MODEST PRESSURE GRADIENT WIND ACROSS THE
REGION THROUGH TUESDAY. OTHERWISE, THE BUILDING HIGH PRESSURE
WILL QUICKLY CLEAR THINGS OUT ACROSS MUCH OF OUR AREA. A FEW
ISOLATED LIGHT SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE ACROSS
THE POCONOS ON MONDAY, HOWEVER GUIDANCE HAS SHOWN A FASTER
DRYING TREND IN THIS ACTIVITY AS OF THE LAST FEW CYCLES. WINDS
WILL INCREASE THROUGH THE DAY MONDAY AND PERSIST THROUGH THE
OVERNIGHT HOURS AND INTO EARLY TUESDAY BEFORE RELAXING TUESDAY
NIGHT AS THE HIGH SHIFTS JUST SOUTH OF OUR AREA. WINDS COULD
POTENTIALLY GUST OVER 30 MPH ON MONDAY. EXPECTING TUESDAY TO BE
AN EXCEPTIONALLY CLEAR, BUT CHILLY DAY WITH HIGHS ONLY TOPPING
OUT IN THE UPPER 30S TO LOW 40S. CLEAR AND COLD WILL REMAIN THE
STORY TUESDAY NIGHT WITH TEMPS BOTTOMING OUT IN THE LOW TO MID
20S BY WEDNESDAY MORNING. FAIR WEATHER IS EXPECTED TO CONTINUE
INTO WEDNESDAY WITH CLOUDS MOVING BACK INTO THE REGION BY LATER
IN THE DAY. NOT AS COLD WEDNESDAY NIGHT WITH INCREASING CLOUD
COVER AND LOWS AROUND NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH SUNDAY...PLEASANT WEATHER THURSDAY WILL BEGIN TO GO
DOWNHILL AS THE NEXT AREA OF LOW PRESSURE TRACKS TOWARD OUR REGION
OUT THE GULF COAST STATES. UNFORTUNATELY, THIS WILL LIKELY LEAD TO
SIMILAR CONDITIONS TO THIS CURRENT WEEKEND IN TERMS OF WIDESPREAD
DREARINESS AND RAINFALL. LATEST GUIDANCE APPEARS TO BE IN GOOD
AGREEMENT WITH A SURFACE LOW TRACKING UP THE APPALACHIANS INTO THE
EASTERN GREAT LAKES REGION, STAYING OFF TO OUR WEST. THIS PLACES US
IN THE WARM SECTOR WITH MOIST SOUTHERLY FLOW THURSDAY AND FRIDAY.
HIGHS WILL TREND 5-10 DEGREES AVERAGE THESE DAYS, RANGING FROM NEAR
40 IN THE POCONOS TO MID 50S ACROSS SOUTHERN DELAWARE. GIVEN THE
FORECAST STRENGTH OF THE SYSTEM (CENTRAL PRESSURE DROPPING BELOW 980
MB) AND STRONG WARM AIR ADVECTION, WOULDN'T BE SURPRISED TO SEE THESE
FORECAST HIGHS NUDGE EVEN FURTHER UPWARDS. THE AMOUNT OF CLOUD COVER
WILL ULTIMATELY PLAY A PART TOO. FORECAST SOUNDINGS FROM THE GFS
SUGGEST SOME DRIZZLE AND/OR MIST MAY BE POSSIBLE AHEAD OF THE SYSTEM
ON THURSDAY, SO THIS MAY HOLD THINGS IN CHECK A BIT.
THE RAIN LOOKS TO MOVE THROUGH THE AREA IN TWO WAVES, AT LEAST
GIVING US SOMEWHAT OF A BREAK IN BETWEEN. THE FIRST ROUND LOOKS TO
MOVE THROUGH THURSDAY EVENING THROUGH THE DAY FRIDAY, WHILE THE
SECOND WILL LIKELY BE MORE SHOWERY BEHIND THE COLD FRONT SATURDAY.
SATURDAY WILL BE COOLER WITH HIGHS APPROACHING 50 ACROSS DELMARVA,
WHILE STAYING IN THE MID 30S ACROSS THE NORTHERN PORTIONS OF THE
AREA. THUS, SOME SNOW SHOWERS ARE POSSIBLE ACROSS THE POCONOS AND
INTO THE HIGHER TERRAIN OF NORTHWEST NEW JERSEY SATURDAY. THE
PRECIPITATION LIFTS OFF TO THE NORTH FOLLOWING THE SURFACE LOW
SATURDAY NIGHT.
AVIATION /21Z SATURDAY THROUGH THURSDAY/
IFR CONDITIONS REMAIN AT MOST OF OUR TAF SITES EXCEPT FOR ABE/RDG
WHERE SOME DRIER AIR HAS FILTERED IN AT LOW LEVELS. RAIN IS EXPECTED
TO RE-DEVELOP AND SPREAD NORTHWARD TONIGHT, BRINGING A RETURN TO IFR
AT ALL SITES. NORTHEAST WINDS WILL CONTINUE THROUGH SUNDAY AND FOR
PHL VCNTY AND EAST, THEY SHOULD INCREASE AND BECOME SOMEWHAT GUSTY
OVERNIGHT INTO SUNDAY MORNING. IFR CONDITIONS ARE EXPECTED THROUGH
MOST OF SUNDAY, WITH PERIODS OF LIGHT RAIN.
OUTLOOK...
MONDAY THROUGH MONDAY NIGHT...MOSTLY VFR CONDITIONS ARE EXPECTED.
WEST TO NORTHWESTERLY WINDS THROUGH MAY GUST UP TO 25 KT THROUGH THE
EVENING HOURS. A STEADY BREEZE IS EXPECTED TO LAST THROUGH THE
OVERNIGHT HOURS.
TUESDAY THROUGH TUESDAY NIGHT...VFR CONDITIONS EXPECTED. A STEADY
BREEZE IS EXPECTED WITH NORTHWESTERLY WINDS GUSTING UP TO 20 KT
DURING THE DAY.
WEDNESDAY AND WEDNESDAY NIGHT...VFR CONDITIONS EXPECTED WITH LIGHT
WEST TO SOUTHWESTERLY WINDS.
THURSDAY THROUGH SUNDAY...MAINLY VFR CONDITIONS EXPECTED. MVFR TO
IFR POSSIBLE WITH SNOW SHOWERS ACROSS THE NORTHERN PORTIONS OF THE
AREA SATURDAY. SOUTHERLY WINDS THROUGH FRIDAY 10-15 KNOTS, TURNING
WEST TO NORTHWESTERLY SATURDAY. GUSTS TO 25 KNOTS ARE POSSIBLE
FRIDAY, ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE AREA.
MARINE
SMALL CRAFT ADVISORIES FOR ALL FORECAST WATERS AND GALE WARNINGS FOR
NORTHERN NJ COASTAL WATERS REMAIN IN PLACE. LOW PRESSURE ORGANIZING
OFF THE NJ COMBINED WITH HIGH PRESSURE OVER NEW ENGLAND SHOULD
PRODUCE A NORTHEAST GALE STARTING LATE TONIGHT AND CONTINUING
THROUGH MUCH OF SUNDAY. SEAS WILL ALSO BUILD UP TO 7 TO 10 FEET
DURING THIS TIME. VSBYS WILL BE LIMITED IN AREAS OF RAIN AND FOG
THROUGH TONIGHT AND SUNDAY.
OUTLOOK...
MONDAY THROUGH MONDAY NIGHT...SCA CONDITIONS EXPECTED BY MONDAY
AFTERNOON AS NORTHWESTERLY WINDS INCREASE THROUGH THE DAY WITH GALE
FORCE GUSTS POSSIBLE MONDAY NIGHT. WAVES ARE EXPECTED TO BE IN
THE 5-7 FEET RANGE MONDAY.
TUESDAY THROUGH TUESDAY NIGHT...SCA CONDITIONS EXPECTED TO LAST
THROUGH TUESDAY EVENING WITH GALE FORCE GUSTS POSSIBLE IN THE
MORNING, OTHERWISE SUB-SCA CONDITIONS EXPECTED OVERNIGHT.
WEDNESDAY THROUGH WEDNESDAY NIGHT...SUB-SCA EXPECTED.
THURSDAY THROUGH SUNDAY...SUB-SCA CONDITIONS INITIALLY WILL LIKELY
REACHING SCA CRITERIA FRIDAY, LASTING THROUGH SUNDAY MORNING. WINDS
GUSTING FROM 25-30 KNOTS POSSIBLE DURING THIS TIMEFRAME. WAVES
BUILDING FROM 8-13 FEET WILL BE POSSIBLE.
PHI WATCHES/WARNINGS/ADVISORIES
PA...WINTER WEATHER ADVISORY FROM 5 AM TO 6 PM EST SUNDAY FOR
PAZ054-055-062.
NJ...WINTER WEATHER ADVISORY FROM 5 AM TO 6 PM EST SUNDAY FOR
NJZ001-007.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ452>455.
GALE WARNING UNTIL 6 PM EST SUNDAY FOR ANZ450-451.
SMALL CRAFT ADVISORY UNTIL 9 AM EST SUNDAY FOR ANZ430-431.
SYNOPSIS...DAVIS
NEAR TERM...AMC
SHORT TERM...AMC
LONG TERM...DAVIS/STAARMANN
AVIATION...AMC/DAVIS/STAARMANN
MARINE...AMC/DAVIS/STAARMANN
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