Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 262221
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
621 PM EDT THU MAR 26 2015

.SYNOPSIS...
A STRONG COLD FRONT SWEEPS THROUGH THE REGION THIS EVENING. LOW
PRESSURE WILL FORM ALONG THIS FRONT EAST OF THE MID ATLANTIC COAST
LATE FRIDAY 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 FRIDAY MORNING/...
WE WILL PROBABLY UPDATE SNOW AMTS IN NE PA AND NW NJ BY 630 PM FOR
A PERIOD OF SNOW BETWEEN 4 AM AND 8 AM.

TSTMS VCNTY HARRISBURG SW INTO N MD WITH CONSIDERABLE LIGHTNING IC
AND A FEW REPORTS OF PEA HAIL WITH VIL 20. HANDLING WITH SPS`S AND
NOWS PER INTENSITY AND STRUCTURE.

SHOWERS WILL CONTINUE TO MOVE THROUGH THE REGION THIS EVENING WITH
THUNDER REMAINING POSSIBLE IN SE PA, NE MD AND N DE.

THE COLD FRONT WILL CROSS THE REGION THIS EVENING BRINGING IN ANOTHER
ROUND OF RAIN. INSTABILITY LOOKS LIMITED ALONG THE FRONTAL BOUNDARY
BUT THERE IS ENOUGH THAT SOME THUNDERSTORMS MAY DEVELOP AS THE
FRONT IS CROSSING THE REGION.

THINGS TURN COLDER BEHIND THE COLD FRONT AS WE SEE STRONG COLD AIR
ADVECTION TAKING PLACE. TEMPERATURES WILL DROP QUICKLY BEHIND THE
FRONT, ABOUT 10 TO 20 DEGREES COLDER. TEMPERATURES WILL FALL INTO
THE 30S AND 40S OVERNIGHT, WITH SOME UPPER 20S ACROSS THE SOUTHERN
POCONOS. WITH THE COLDER TEMPERATURES, THERE MAY BE A CHANGEOVER TO
OR A MIX OF RAIN AND SNOW AS THE FRONT MOVES OFFSHORE AND THE
PRECIPITATION STARTS TO DIMINISH. RAINFALL AMOUNTS WILL GENERALLY BE
AROUND A HALF OF AN INCH OR LESS WITH LITTLE TO NO SNOW ACCUMULATION,
THOUGH WE`LL MONITOR THE FCST FOR THE POCONOS.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
THE COLD FRONT MAKES ITS WAY 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, WHICH WE THINK IT
WILL BE. PCPN ENDING FROM NW TO SE DURING THE AFTN AS A WAVE OF
LOW PRESSURE FORMS OFFSHORE.

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 /FRIDAY NIGHT THROUGH THURSDAY/...
5-WAVE MODEL GUIDANCE SHOWS BROAD TROUGHING IN THE EAST WITH BROAD
RIDGING ACROSS THE WESTERN STATES THROUGH MOST OF THE LONGTERM
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 TIMEFRAME, 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 /22Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY, AND SURROUNDING AREAS.

THROUGH TONIGHT...CURRENTLY MVFR-VFR CIGS PREDOMINANT
PHL/KILG/KRDG WHILE IFR CONDS VCNTY SHOWERS KMIV AND KACY AND IFR
CONDS PREVAIL ELSEWHERE. THE VARIED SUB VFR CONDS WILL CONTINUE
THROUGH THE NIGHT, BASICALLY DEGRADING BACK TO IFR WITH SHOWERS
BECOMING WIDESPREAD OVERNIGHT, ESPECIALLY THE CFP THIS EVENING.

THE CFP WILL PROBABLY BE ACCOMPANIED BY A BRIEF NW WIND GUST OF
25-30 KTS AND A HEAVY SHOWER AS PER THE HRRR. WE NOW HAVE UPGRADED
FOR THUNDER AT KRDG.

THE CFP IS BEING ADVANCED FASTER AND EXPECT THROUGH KRDG/KABE
NEAR 23Z, KPHL/KPNE/KTTN/KILG NEAR 02Z, AND KMIV/KACY BETWEEN
03Z-04Z/27. GUSTY SOUTHERLY WINDS THIS AFTERNOON WILL BECOME
BRIEFLY GUSTY NW TO 25-30 KT WITH THE CFP THIS EVENING...THEN
SETTLE BACK A BIT DURING THE NIGHT. ICING SHOULD DEVELOP IN PCPN
TOWARD DAWN NEAR AND NW OF THE I-95 CORRIDOR INCLUDING KPHL,
ESPECIALLY NEAR 5000 FT AS A SUB FREEZING LAYER IS MODELED TO
DRIVES SEWD WHILE PCPN IS ON-GOING.

FRIDAY...IFR OR MVFR CONDS AT DAYBREAK IN PCPN WILL IMPROVE TO
VFR CIGS ACROSS THE TERMINALS FROM NORTHWEST TO SOUTHEAST DURING
THE MORNING EXCEPT NOT REACHING KMIV AND KACY UNTIL SOMETIME
DURING THE AFTERNOON. WINDS WILL BE OUT OF THE NORTHWEST WITH
SPEEDS AROUND 10 KNOTS, A FEW GUSTS TO 20 KT.

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...
MWW UPDATED FOR GALE FORCE GUSTS. MWS ISSUED FOR GALE FORCE GUSTS
THROUGH ABOUT 8PM TODAY. HAVE HAD A NUMBER OF REPORTS OF GALE
FORCE GUSTS ALONG OUR COASTS THIS AFTN.

OTHERWISE 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.

SOUTHERLY WINDS ACROSS THE WATERS THIS AFTERNOON WILL START TO VEER
TO THE WEST AS A COLD FRONT APPROACHES THE WATERS. THE COLD FRONT
WILL REACH THE AREA WATERS IN THE 05-09Z TIME FRAME AND THEN MOVE
OFFSHORE, LEAVING US WITH NORTHWEST WINDS. WINDS WILL GUST BEHIND
THE FRONTAL PASSAGE BUT SHOULD DIMINISH THROUGH THE DAY.

WAVES ARE RUNNING AROUND 4 TO 6 FEET ON THE OCEAN THIS AFTERNOON 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 FRIDAY FOR ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ430-431.

&&

$$
SYNOPSIS...DRAG/HEAVENER
NEAR TERM...DRAG/MEOLA
SHORT TERM...MEOLA
LONG TERM...HEAVENER
AVIATION...DRAG/HEAVENER/MEOLA
MARINE...DRAG/HEAVENER/MEOLA



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