Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 051622
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1222 PM EDT THU MAY 5 2016

.SYNOPSIS...
LOW PRESSURE OFFSHORE WILL MOVE TOWARD THE CANADIAN MARITIMES
LATE TODAY AND TONIGHT. MEANWHILE ANOTHER LOW PRESSURE SYSTEM
DEVELOPS OFF THE MID ATLANTIC COAST TONIGHT AND FRIDAY, THEN
MEANDERS AND WEAKENS AROUND THE REGION INTO SATURDAY. A COLD FRONT
IS FORECAST TO MOVE THROUGH SUNDAY MORNING FOLLOWED BY HIGH
PRESSURE BUILDING IN FOR MONDAY INTO TUESDAY. A WARM FRONT SHOULD
THEN LIFT ACROSS OUR AREA LATE TUESDAY INTO WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE LOCATED OFF THE MIDDLE ATLANTIC COAST AROUND MIDDAY
WILL PROGRESS TO THE NORTHEAST TOWARD THE WATERS OFF NEW ENGLAND.
IT WILL LEAVE A DEVELOPING LOW PRESSURE SYSTEM IN ITS WAKE. THE
SURFACE PATTERN IS EXPECTED TO MAINTAIN A NORTHEASTERLY FLOW IN
OUR REGION FOR THIS AFTERNOON.

THE WIND TRAJECTORY IS ANTICIPATED TO BE MAINLY FROM NEW ENGLAND
FOR THIS AFTERNOON AND IT SHOULD DRAW A BIT OF DRY AIR INTO OUR
REGION IN THE LOW LEVELS. AS A RESULT, THE BASES OF THE LOW CLOUDS
SHOULD LIFT SOMEWHAT AND THERE MAY EVEN BE SOME BREAKS IN THE
OVERCAST, MAINLY OVER OUR NORTHERN COUNTIES.

WE ARE NOT EXPECTING A GREAT DEAL OF PRECIPITATION FOR THIS
AFTERNOON. BASED ON THE MIDDAY TRENDS AND THE LATEST GUIDANCE, THE
MOST LIKELY AREA TO RECEIVE SCATTERED LIGHT RAIN SHOWERS THIS
AFTERNOON WILL BE SOUTHEASTERN PENNSYLVANIA.

MAXIMUM TEMPERATURES ARE FORECAST TO BE IN THE 50S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
APPEARS THAT WARM AIR ADVECTION AND AN INSTABILITY BURST WILL BE
DEVELOPING NORTHWESTWARD AS A NEW AREA OF LOW PRESSURE ORGANIZES
NEAR DELAWARE. THUNDER POSSIBLE BY DAYBREAK FRIDAY NEAR DELAWARE.
SHOWERS MAY BE BRIEFLY HEAVY WHERE THEY DO OCCUR THOUGH PWAT ONLY
INCREASES TO NEAR 1 INCH. NORTHEAST WIND...GUSTS GENERALLY UNDER
20 MPH. POPS MAY NEED TO BE RAISED 15 PCT IN LATER FORECAST FOR
LATE TONIGHT.

330 AM FORECAST WAS BASED ON A 50 50 BLEND OF THE 00Z/5 GFS/NAM
MOS WITH THE POPS MODIFIED BY THE SREF PROBS. WPC QPF 00Z/5 QPF
GRIDS USED.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF A CONTINUATION OF AN OMEGA
BLOCK FRIDAY, THEN THIS BREAKS DOWN DURING THE COURSE OF THE
WEEKEND. THIS CHANGE OCCURS AS A STRONG SHORT WAVE TROUGH DIVES
SOUTHEASTWARD FROM CENTRAL CANADA FRIDAY, KICKING OUT THE EASTERN
PORTION OF THE OMEGA BLOCK. THIS INCOMING TROUGH AMPLIFIES ACROSS
THE NORTHEAST LATER SUNDAY BEFORE GRADUALLY LIFTING OUT MONDAY. A
WEAK RIDGE THEN ARRIVES FOR EARLY NEXT WEEK WITH A SURFACE WARM
FRONT ALSO MOVING THROUGH. THERE COULD BE SOME TRICKINESS THOUGH
NEXT WEEK AS THE NORTHBOUND WARM FRONT MAY STALL ACROSS OUR
NORTHERN AREAS AS INCOMING ENERGY SHEARS EASTWARD ALONG IT. AS OF
NOW, IT APPEARS OUR AREA GETS INTO THE TRUE WARM SECTOR NEXT WEEK
HOWEVER IT MAY BE CLOSE ACROSS THE NORTH STARTING WEDNESDAY. WE
USED A MODEL BLEND APPROACH FOR FRIDAY INTO SUNDAY, THEN BLENDED
IN THE 00Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN
MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING
OFFICES.

FOR FRIDAY AND SATURDAY...A CLOSED LOW CENTERED TO OUR SOUTH TO
START FRIDAY IS FORECAST TO MOVE OVER OUR AREA BY LATE IN THE DAY.
AS THIS OCCURS, STRONG SHORT WAVE ENERGY PIVOTS NORTH AND THEN
NORTHWESTWARD ACROSS OUR AREA FRIDAY. THE MODEL GUIDANCE INDICATES
A STRONG 500 MB JET STREAK ROUNDING THE BASE OF THE CLOSED LOW
WITH OUR AREA WITHIN THE LEFT EXIT REGION FOR A TIME FRIDAY. THIS
FEATURE THEN SHIFTS NORTHEASTWARD DURING THE DAY FRIDAY. AS THIS
OCCURS, WAVES OF STRONGER FORCING GENERALLY SHIFT FROM SOUTHEAST
TO NORTHWEST. THE PW VALUES ARE FORECAST TO BE BETWEEN 0.75-1.00
INCHES FRIDAY. AS A RESULT, PERIODS OF RAIN ARE EXPECTED TO
TRANSLATE FROM SOUTHEAST TO NORTHWEST DURING THE COURSE OF FRIDAY
WITH PERHAPS THE MORE WIDESPREAD ACTIVITY OCCURRING IN THE MORNING
PRIOR TO THE CENTER OF THE CLOSED LOW ARRIVING. DESPITE FORECAST
SOUNDINGS NOT SHOWING MUCH IN THE WAY OF INSTABILITY, THE PRESENCE
OF THE 500 MB JET STREAK AND A COLD CORE ALOFT /STEEPENING MID
LEVEL LAPSE RATES/ A SLIGHT CHC OF THUNDER WAS ADDED FOR FRIDAY
/PERHAPS SMALL HAIL OCCURS WITH ANY EMBEDDED THUNDER/. WE THEN
GRADUALLY TAPER OFF THE STEADY RAIN AND TRANSITION TO SOME SHOWERS
FRIDAY NIGHT AS THE CLOSED LOW SETTLES RIGHT OVER US AND THE
STRONGER FORCING MAY SHIFT WEST AND NORTH.

THE CLOSED LOW IS STILL FORECAST TO BE OVER OUR AREA SATURDAY
HOWEVER IT LOOKS TO GRADUALLY WEAKEN AND OPEN UP SATURDAY NIGHT.
GIVEN THE COLD CORE ALOFT STILL OVER OUR AREA SATURDAY, SOME
SHOWERS SHOULD STILL OCCUR. WE LOOK TO FINALLY LOSE THE ONSHORE
FLOW COMPONENT SATURDAY, THEREFORE SOME BREAKS IN THE CLOUDS ARE
ANTICIPATED WHICH COULD PROVIDE A LITTLE INSTABILITY FOR SOME LOW-
TOPPED CONVECTION. THE FORECAST SOUNDINGS DO NOT INDICATE MUCH
INSTABILITY AND THEREFORE HELD OFF INTRODUCING A THUNDER MENTION
ATTM.

A STRONG SHORT WAVE DRIVING SOUTHEASTWARD FROM THE GREAT LAKES
REGION SATURDAY NIGHT WILL PUSH A COLD FRONT INTO OUR AREA TOWARD
DAYBREAK SUNDAY. THIS TROUGH MAY START TO TAKE ON A NEGATIVE TILT
AND WITH A PLUME OF DEEPER MOISTURE THERE IS THE POTENTIAL FOR A
BAND OF HEAVIER SHOWERS ACCOMPANYING THE COLD FRONT. AS A RESULT,
WE INCREASED THE POPS TOWARD LATER SATURDAY NIGHT.

FOR SUNDAY...AN AMPLIFYING UPPER-LEVEL TROUGH THAT MAY TAKE ON A
NEGATIVE TILT MOVES ACROSS THE NORTHEAST. THIS DRIVES A COLD FRONT
ACROSS OUR AREA SUNDAY MORNING WITH SOME SHOWERS. THE GREATEST CHC
FOR SHOWERS LOOKS TO BE ACROSS ABOUT THE NORTHERN HALF OF THE CWA,
THEREFORE RAISED POPS TO HIGH CHC/LOW LIKELY EARLY ON. WHILE A
COLD FRONT MOVES THROUGH AND THE FLOW SHIFTS TO THE WEST-
NORTHWEST, A WARMER AFTERNOON IS EXPECTED AS MIXING DEEPENS ALONG
WITH AN INCREASING BREEZE.

FOR MONDAY THROUGH WEDNESDAY...SOME RIDGING SLIDES ACROSS THE
AREA MONDAY INTO TUESDAY, HOWEVER LOW PRESSURE MIGRATING FROM THE
PLAINS TOWARD THE GREAT LAKES WILL DRIVE DOWNSTREAM WAA. THIS WILL
PUSH A WARM FRONT INTO OUR AREA LATE TUESDAY WITH IT LIFTING
MOSTLY TO OUR NORTH BY EARLY WEDNESDAY. THE ENERGY WITH THE
AFOREMENTIONED SURFACE LOW MAY SHEAR EASTWARD INTO WESTERLY FLOW
ALOFT, THEREFORE THE WARM FRONT MAY STALL IN THE VICINITY OF OUR
NORTHERN ZONES WEDNESDAY. THE PLACEMENT OF THIS FRONT WILL HAVE AN
IMPACT ON OUR TEMPERATURES, HOWEVER PLENTY OF WARMTH SHOULD BE
ADVECTING IN FROM THE SOUTH. AS A RESULT, A MUCH WARMER TIME FRAME
IS EXPECTED ESPECIALLY WHEN COMPARED TO OUR CURRENT STRETCH OF
WEATHER. THE PRECIPITATION CHCS ARE NOT ALL THAT CLEAR ATTM AS IT
WILL DEPEND ON POTENTIAL SHEARING ENERGY RUNNING EASTWARD AS THE
WARM FRONTS NORTHWARD PROGRESS SLOWS.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

CIGS ARE FORECAST TO SETTLE BETWEEN 1500 AND 3000 FT FOR THE
EARLY AFTERNOON, POSSIBLY LIFTING TO VFR CIGS DURING THE MID TO
LATE AFTERNOON. NORTHEAST WIND GUSTY 20 TO POSSIBLY 25 KT I95
REGION EASTWARD AND LESS THAN 18 KT VCNTY KRDG AND KABE.

TONIGHT...VFR CIGS TO START BUT CONDITIONS SHOULD DEGRADE TO MVFR
OR IFR IN SHOWERS/DRIZZLE SOMETIME AFTER 03Z/6. NORTHEAST WIND...
GUSTS UNDER 15 KT.

OUTLOOK...
FRIDAY AND SATURDAY...MVFR/IFR CEILINGS FRIDAY INTO SATURDAY,
THEN THIS SHOULD IMPROVE TO VFR SATURDAY ESPECIALLY IN THE
AFTERNOON. PERIODS OF RAIN FRIDAY WILL RESULT IN AT LEAST MVFR
VISIBILITIES AT TIMES WITH THIS BECOMING MORE SHOWERY AT NIGHT,
THEN A FEW SHOWERS ARE STILL POSSIBLE SATURDAY. NORTHEAST WINDS
MAINLY AROUND 10 KNOTS FRIDAY AND FRIDAY NIGHT, THEN TURNING
SOUTHEAST TO SOUTH SATURDAY. SOME SHOWERS SHOULD ARRIVE LATE
SATURDAY NIGHT WITH A COLD FRONT.

SUNDAY...SUB-VFR CONDITIONS POSSIBLE IN THE MORNING AS SOME
SHOWERS MOVE THROUGH WITH A COLD FRONT, THEN VFR. SOUTHWEST WINDS
EARLY, BECOMING WEST-NORTHWEST AND INCREASING TO 10-15 KNOTS WITH
GUSTS TO AROUND 20 KNOTS.

MONDAY...VFR. WEST TO SOUTHWEST WINDS AROUND 10 KNOTS.

&&

.MARINE...
SCA CONTINUES ON THE ATLANTIC WATERS FOR OCCASIONAL GUSTS 25 TO
30 KT AND SEAS OF 6 TO 9 FEET. SCA FOR LOWER DE BAY IS MARGINAL
FOR A FEW GUSTS 25 KT MIDDAY.

OUTLOOK...
LOW PRESSURE MOVES INTO OUR AREA FRIDAY BEFORE MEANDERING AND
DISSIPATING THROUGH SATURDAY. AN INCREASE IN THE ONSHORE FLOW
FRIDAY ESPECIALLY ACROSS OUR NORTHERN ATLANTIC COASTAL WATERS WILL
ALLOW FOR GUSTS TO AROUND 25 KNOTS BEFORE DIMINISHING BY LATER IN
THE DAY. THE FLOW THEN DECREASES FRIDAY NIGHT BEFORE TURNING
SOUTHERLY SATURDAY AHEAD OF A COLD FRONT THAT THEN MOVES THROUGH
SUNDAY MORNING. BEHIND THE FRONT, A WEST-NORTHWEST WIND SHOULD
GUST TO AROUND 20 KNOTS BEFORE DIMINISHING SOME SUNDAY NIGHT INTO
MONDAY. SEAS ON OUR ATLANTIC COASTAL WATERS SHOULD BE AT OR ABOVE
5 FEET INTO SATURDAY, THEREFORE THE SMALL CRAFT ADVISORY HAS BEEN
EXTENDED THROUGH FRIDAY NIGHT. THEREAFTER SOME UNCERTAINTY EXISTS
AS THE WINDS LESSEN FOR A TIME AND TURN SOUTHERLY SATURDAY. THE
SEAS SHOULD THEN BE BELOW 5 FEET SUNDAY AND MONDAY.

&&

.TIDES/COASTAL FLOODING...
BASED ON THIS MORNING`S TIDAL SURGE OF +1.0 TO +1.5 FEET ALONG
THE COAST, WE HAVE CONTINUED THE COASTAL FLOOD ADVISORY FOR THIS
EVENING. SOME LOCATIONS COULD GET CLOSE TO THEIR MODERATE
THRESHOLD LEVELS ALONG THE COAST. MEANWHILE, THE SURGE HAS ALREADY
INCREASED TO AROUND +1.0 ON THE EXTREME LOWER PART OF THE TIDAL
DELAWARE RIVER, SO WE HAVE EXPANDED THE ADVISORY TO INCLUDE THE
TIDAL DELAWARE RIVER, AS WELL.

THE ASTRONOMICAL TIDES WILL CONTINUE TO RUN HIGH ON FRIDAY AND
SATURDAY DUE TO THE NEW MOON.

MINOR TIDAL FLOODING IS AGAIN EXPECTED ALONG THE COAST AROUND THE
TIME OF HIGH TIDE ON FRIDAY MORNING. WIDESPREAD MINOR FLOODING IS
LIKELY WITH FRIDAY EVENING`S HIGH TIDE AND SOME MODERATE FLOODING
IS POSSIBLE AT THAT TIME. WE SHOULD EXPERIENCE THE HIGHEST WATER
LEVELS OF THIS STRETCH ON FRIDAY EVENING. A COASTAL FLOOD WARNING
MAY EVENTUALLY BE NEEDED FOR THAT TIDE CYCLE. ADDITIONAL MINOR
TIDAL FLOODING IS POSSIBLE ON SATURDAY.

MINOR FLOODING IS ANTICIPATED FOR THE TIDAL DELAWARE RIVER ON
FRIDAY AND PERHAPS AGAIN ON SATURDAY.

NO FLOODING ISSUES ARE EXPECTED ALONG THE UPPER EASTERN SHORE OF
CHESAPEAKE BAY AT THIS TIME.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 3 AM EDT
     FRIDAY FOR PAZ070-071.
NJ...COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT
     TONIGHT FOR NJZ012>014-020>027.
     COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 3 AM EDT
     FRIDAY FOR NJZ017>019.
     COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO 1 AM EDT
     FRIDAY FOR NJZ016.
DE...COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT
     TONIGHT FOR DEZ002>004.
     COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO 1 AM EDT
     FRIDAY FOR DEZ001.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ431.

&&

$$

SYNOPSIS...GORSE
NEAR TERM...IOVINO
SHORT TERM...DRAG
LONG TERM...GORSE
AVIATION...DRAG/GORSE
MARINE...DRAG/GORSE
TIDES/COASTAL FLOODING...IOVINO



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