Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 270444
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1244 AM EDT FRI MAR 27 2015

.SYNOPSIS...
A STRONG COLD FRONT SWEPT THROUGH THE REGION ON THURSDAY EVENING.
LOW PRESSURE WILL FORM ALONG THIS FRONT EAST OF THE MID ATLANTIC
COAST FRIDAY AFTERNOON AND HEAD NORTHEAST OUT TO SEA LATE
SATURDAY. STRONG CANADIAN HIGH PRESSURE IS EXPECTED TO MOVE
THROUGH THE REGION ON SUNDAY INTO MONDAY BEFORE ANOTHER COLD FRONT
PASSAGE LATER ON MONDAY. ANOTHER SHOT OF HIGH PRESSURE FOR TUESDAY
AND WEDNESDAY IS EXPECTED AHEAD OF THE NEXT COMPLEX LOW PRESSURE
SYSTEM ON THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE COLD FRONT WAS THROUGH OUR ENTIRE FORECAST AREA AT 1230 AM.
THE BOUNDARY HAD JUST PASSED FENWICK ISLAND, DELAWARE.

AN AREA OF SHOWERS IN THE WAKE OF THE FRONT EXTENDED FROM
NORTHEASTERN MARYLAND AND CENTRAL AND NORTHERN DELAWARE
NORTHEASTWARD INTO THE PHILADELPHIA METROPOLITAN AREA, AS WELL AS
SOUTHERN, CENTRAL AND NORTHEASTERN NEW JERSEY. THE SHOWERS WERE
MOVING NORTHEASTWARD.

A NARROW BAND OF RAIN SHOWERS EXTENDED FROM THE LOWER SUSQUEHANNA
RIVER VALLEY, ACROSS THE LEHIGH VALLEY AND THE POCONOS TO THE
CATSKILLS. ANOTHER AREA OF SHOWERS LOCATED OVER VIRGINIA WILL
BUILD UP INTO OUR REGION OVERNIGHT.

COLD ADVECTION WILL CONTINUE DURING THE NIGHT AND THE
PRECIPITATION WILL LIKELY CHANGE TO SNOW AND PERHAPS SOME ICE IN
PARTS OF BERKS COUNTY, THE LEHIGH VALLEY, THE POCONOS AND NORTHERN
NEW JERSEY. SNOW AND ICE TOTALS SHOULD BE LIMITED. HOWEVER, THERE
COULD BE ENOUGH OF AN ACCUMULATION IN SPOTS TO CREATE SLIPPERY
CONDITIONS. SOME LOCATIONS MAY RECEIVE UP TO A HALF INCH OF SNOW
OR PERHAPS A TRACE AMOUNT OF ICE. UP TO AN INCH OF SNOW COULD
ACCUMULATE IN THE ELEVATED TERRAIN.

TEMPERATURES RANGED FROM THE UPPER 30S IN THE POCONOS TO AROUND
60 IN SOUTHERN DELAWARE AT 1230 AM. READINGS SHOULD DROP INTO THE
30S IN OUR NORTHERN AND CENTRAL COUNTIES AND INTO THE LOWER 40S
IN THE SOUTH BY DAYBREAK. THE WIND WILL REMAIN OUT OF THE
NORTHWEST AROUND 10 MPH.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SATURDAY/...
THE COLD FRONT MAKES ITS WAY FARTHER OFF THE COAST FRIDAY WITH
SOME LINGERING RAIN HANGING AROUND - PROBABLY MIXED WITH ICE
PELLETS OR WET SNOW AT DAYBREAK VCNTY I-95 NWWD IF PCPN IS ON-
GOING AT THAT TIME, WHICH AM EXPECTING. PCPN ENDING FROM NW TO SE
DURING THE AFTN AS A WAVE OF LOW PRESSURE FORMS OFFSHORE EAST OF
THE VA CAPES.

TEMPERATURES WILL BE MUCH COOLER ON FRIDAY IN MANY AREAS COMPARED
TO TODAYS MAX TEMPS. HIGHS WILL BE IN THE 40S TO NEAR 50 ACROSS
THE REGION ON FRIDAY WITH PLENTY OF CLOUD COVER AROUND. NORTHWEST
WINDS MAY BE GUSTY EARLY BUT SHOULD RELAX AS THE FRONT MOVES
OFFSHORE.

&&

.LONG TERM /SATURDAY THROUGH FRIDAY/...
5-WAVE MODEL GUIDANCE SHOWS BROAD TROUGHING IN THE EAST WITH
BROAD RIDGING ACROSS THE WESTERN STATES THROUGH MOST OF THE
LONG TERM PERIOD. THE PATTERN ALOFT HAS A FAST FLOW LOOK WITHOUT
MUCH BLOCKING WHICH ADDS TO A BIT OF THE UNCERTAINTY/TIMING OF
EMBEDDED SHORTWAVES WITHIN THE MID-LEVEL FLOW. TOWARDS THE END OF
THE PERIOD A NEARLY ZONAL FLOW LOOKS TO TAKE SHAPE.

FRIDAY NIGHT - SATURDAY...DEEP ANOMALOUS MID-LEVEL TROUGH WILL BE
OVERHEAD AS STRONGER NORTHERN STREAM ENERGY TRIES TO PHASE WITH
WEAKER, SLOWER MOVING, SOUTHERN STREAM ENERGY. EVEN WITH MINIMAL
PHASING SURFACE CYCLOGENESIS LOOKS TO OCCUR TO THE SOUTH OF OUR
REGION LATE ON FRIDAY. THIS WEAK INFLECTION WILL MOVE ALONG THE
AFOREMENTIONED COLD FRONT SITTING OFFSHORE ON SATURDAY AND COULD
THROW SOME LIGHT PRECIPITATION BACK ACROSS THE REGION DURING THE
DAY. THINKING THAT A MAJORITY OF THE LIFT AND MOISTURE WITH THIS
SYSTEM WILL REMAIN TO OUR NORTHEAST, OVER NEW ENGLAND, AND FARTHER
OFFSHORE. THE PASSAGE OF THE MID-LEVEL LOW COULD ALSO SPARK A FEW
INSTABILITY SHOWERS DURING THE AFTERNOON. THERMALLY WE WILL BE
DROPPING BELOW FREEZING THROUGHOUT THE COLUMN BY SATURDAY
AFTERNOON SO MOST OF THE PRECIPITATION SHOULD FALL AS SNOW. TRYING
TO COMBAT ANY DAYTIME HEATING, EVEN WITH A MULTITUDE OF CLOUDS AND
NORTHERLY WINDS, WILL BE TOUGH WITH BOUNDARY LAYER TEMPERATURES
EXPECTED TO BE IN THE MID TO UPPER-30S...THE ONE CAVEAT WOULD BE
STRONGER DYNAMIC COOLING WITH THE PLACEMENT OF AN INVERTED
TROUGH/MESOSCALE BANDING FEATURE...THOUGH IT IS ILL-DEFINED ACROSS
OUR AREA AT THIS TIME.

SUNDAY...RIDGING TO OUR SOUTH RE-ESTABLISHES IT SELF ACROSS THE
REGION FOR THE SECOND HALF OF THE WEEKEND. THIS WILL PROVIDE
MOSTLY CONDITIONS ACROSS THE REGION AS TEMPERATURES REMAIN WELL
BELOW NORMAL.

MONDAY...RIDGING SLIDES OFF THE SOUTHEAST COAST AND A RETURN FLOW
WITH LOW-LEVEL WARM AIR ADVECTION KICKS IN. TEMPERATURES MAY BE
ABLE TO WARM TO ABOVE NORMAL, AS WE CONTINUE THE TUMULTUOUS EARLY
SEASON TEMPERATURE SWINGS. THERE DOES NOT APPEAR TO BE A GREAT
DEAL IN MOISTURE SURGE WITH THIS NEXT SYSTEM, AS IT APPROACHES
FROM THE WEST. WITH THE LACK OF MOISTURE WE KEEP THE SLIGHT CHANCE
POPS IN THE FORECAST, THOUGH THE BETTER LIFT WILL ACCOMPANY THE
ADVANCING COLD FRONT LATER MONDAY AFTERNOON SO POPS MAY BE
INCREASED IN TIME.

TUESDAY - THURSDAY...THE FLOW ALOFT, AS MENTIONED ABOVE, REMAINS
QUICK AND ACTIVE. NUMEROUS EMBEDDED WAVES OF ENERGY SLIDE THROUGH
THE REGION DURING THIS TIME FRAME, EACH CARRYING THE CHANCE FOR
SHOWERY ACTIVITY. THE BETTER CHANCES FOR SHOWERS WILL BE WEDNESDAY
INTO THURSDAY AS ANOTHER SYSTEM PUSHES IN FROM THE WEST. ANOTHER
LOW- LEVEL MOISTURE SURGE IS EXPECTED WITH THIS SYSTEM AS
TEMPERATURES LOOK TO REMAIN AT OR SLIGHTLY ABOVE AVERAGE FOR THE
FIRST COUPLE DAYS OF APRIL...THIS COULD EASILY CHANGE WITH TIME.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY, AND SURROUNDING AREAS.

CONDITIONS WILL VARY BETWEEN VFR AND MVFR AS RAIN SHOWERS
CONTINUE TO LIFT NORTHEASTWARD THROUGH OUR REGION DURING THE
NIGHT. THE RAIN MAY CHANGE TO SNOW AROUND KRDG AND KABE AFTER
ABOUT 0800Z WITH LITTLE ACCUMULATION ANTICIPATED.

DRYING WILL TAKE PLACE ON FRIDAY WITH AN IMPROVEMENT MAINLY INTO
THE VFR CATEGORY ALONG WITH A DIMINISHING CHANCE FOR
PRECIPITATION.

A NORTHWEST WIND AROUND 10 KNOTS OVERNIGHT AND ON FRIDAY MAY
GUSTS NEAR 20 KNOTS AT TIMES DURING THE DAYLIGHT HOURS.

OUTLOOK...
FRIDAY NIGHT - SATURDAY...MVFR OR LOWER POSSIBLE IN RAIN/SNOW
SHOWERS. NORTHERLY WINDS.

SUNDAY - MONDAY...VFR. NORTHERLY WINDS VEER TOWARDS THE SOUTHWEST
AND BEGIN TO GUST MONDAY AFTERNOON.

TUESDAY...VFR. WINDS VEER TOWARDS THE WEST-NORTHWEST...GUSTS
EXPECTED.

&&

.MARINE...
A SMALL CRAFT ADVISORY REMAINS IN EFFECT ACROSS THE AREA WATERS,
ENDING ON THE DELAWARE BAY AT 12Z FRIDAY AND ON THE OCEAN FRONT AT
22Z FRIDAY.

WINDS SHIFTED TO NW WITH THE COLD FRONTAL PASSAGE. WINDS WILL
GUST BEHIND THE FRONTAL PASSAGE BUT SHOULD DIMINISH THROUGH THE
DAY.

SEAS ARE RUNNING AROUND 6 TO 8 FEET ON THE OCEAN AND WILL REMAIN
ELEVATED THROUGH FRIDAY. WAVES ON THE BAY ARE GENERALLY AROUND 2
TO 4 FEET.

OUTLOOK...
FRIDAY NIGHT - SATURDAY...SEAS WILL SUBSIDE LATE FRIDAY EVENING
BUT COULD INCREASE A TAD SATURDAY WITH A NORTHERLY SURFACE FLOW
DEVELOPING. COULD SEE SCA SEAS SATURDAY AFTERNOON.

SUNDAY - TUESDAY...POSSIBLE SCA CONDITIONS SUNDAY THROUGH
TUESDAY. WINDS VEER TOWARDS THE WEST AND THEN SOUTHWEST BY MONDAY
AS HIGH PRESSURE SLIDES OFFSHORE. A COLD FRONT SLIDES THROUGH ON
MONDAY EVENING AND WINDS MAY STAY ABOVE SCA THROUGH TUESDAY NIGHT.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
     ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ430-
     431.

&&

$$

SYNOPSIS...DRAG/HEFNERNEAR TERM...IOVINO SHORT TERM...DRAG/MEOLA
LONG TERM...HEFNER AVIATION...HEFNER/IOVINO
MARINE...DRAG/HEFNER/MEOLA


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