Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KPHI 050630
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
230 AM EDT THU MAY 5 2016

.SYNOPSIS...
LOW PRESSURE OFF THE MID ATLANTIC COAST WILL PASS EAST OF CAPE COD
LATE TODAY WHILE ANOTHER LOW LAGS BEHIND EAST OF THE VIRGINIA CAPES.
THAT SECOND LOW WILL PROCEED NORTHWARD TOWARD NEW JERSEY FRIDAY...
THEN SHOULD EDGE EAST OUT TO SEA SATURDAY. A COLD FRONT IS EXPECTED
TO MOVE SOUTHEAST THROUGH THE REGION SUNDAY MORNING. THIS WILL BE
FOLLOWED BY WELCOMED HIGH PRESSURE INTO THE REGION FOR THE FIRST PART
OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
CLOUDY. AREAS OF DRIZZLE EARLY THIS MORNING OTHERWISE A RAINFREE
DAY. TEMPS NEARLY STEADY THROUGH SUNRISE THEN ONLY SMALL RISES DURING
THE DAY WITH COLD AIR UNDERRUNNING NORTHEAST WIND ADVECTION FROM
THE RESERVOIR OF COOLER WET BULBS OVER NEW ENGLAND. MAX TEMPS
MAYBE 15 BELOW NORMAL. GUSTY NORTHEAST WIND 20 TO 25 MPH DURING
MIDDAY AND THE AFTERNOON.

FCST WAS A 50 50 BLEND OF THE 00Z/5 GFS/NAM MOS. POPS...USED THE
HRRR TO KEEP THE MORNING-MIDDAY DRY (EXCEPTING SPOTTY DRIZZLE S
PART OF THE FORECAST AREA). CONFIDENCE: ABOVE AVERAGE ON ALL BUT
WHETHER ANY SHOWERS WILL DEVELOP THIS AFTERNOON.

&&

.SHORT TERM /TONIGHT/...
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.

FORECAST 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.

AM AWARE WAS MUCH TOO HIGH ON POPS YDY DURING THE DAY KTTN SOUTHWEST
THROUGH PHL/ILG/ESN AND MISSED THE THUNDER COASTAL NJ/DE.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FRIDAY THROUGH SATURDAY: DUAL LOW PRESSURES WILL CONTINUE THE GRAY
AND DREARY PATTERN ACROSS THE REGION IN THIS TIMEFRAME. THE FIRST
AREA OF LOW PRESSURE WILL LIKELY BE DEPARTING TO THE NORTHEAST OFF
CAPE COD WITH THE SECOND LOW PRESSURE SYSTEM IN THE CAROLINAS.
THESE LOW PRESSURE SYSTEMS WILL PROVIDE LIFT AND MOISTURE WITH
ONSHORE FLOW LEADING TO ADDITIONAL PERIODS OF SHOWERS. THE HIGHEST
CHANCES CURRENTLY ARE LIKELY TO OCCUR ON FRIDAY WHEN THE TRAILING
LOW PRESSURE SYSTEMS LOCATED JUST TO OUR SOUTHWEST. RIGHT NOW
MODELING IS FOCUSING THE HEAVIEST AND STEADIEST SHOWERS ACROSS
NORTHERN PORTIONS OF THE REGION ON FRIDAY. QPF COULD REACH HALF AN
INCH BY FRIDAY NIGHT IN NORTHERN PARTS OF THE REGION. WITH THE
EXCESSIVE CLOUD COVER IN PLACE WENT A LITTLE COOLER IN THE DAYS
WITH HIGHS THAN WHAT MET/MAV GUIDANCE WOULD SUGGEST AND WARMER AT
NIGHT,HIGHS WILL LIKELY STAY IN THE 50`S FOR MOST OF THE REGION.

THERE IS SOME OPTIMISM THAT SATURDAY AFTERNOON/EVENING COULD BE
DRIER THAN INDICATED IN THE VARIOUS ENSEMBLE PACKAGES. HOWEVER, AN
EQUAL POSSIBILITY IS PRESENT THAT THE SECOND LOW WILL LINGER
OFFSHORE THROUGH SATURDAY. THE CLOUDS AND SHOWERS SHOULD KEEP LOW
TEMPERATURES WARMER AT NIGHT AND COOLER IN THE DAY THAN WHAT VARIOUS
GUIDANCE PACKAGES INDICATE. TEMPERATURES WILL START A GRADUAL
WARMING TREND ON SATURDAY.

SATURDAY NIGHT THROUGH SUNDAY NIGHT: A COLD FRONTAL BOUNDARY WILL
LIKELY BE THE ULTIMATE KICKER FOR THE STUBBORN LOW PRESSURE JUST
OFFSHORE. HOWEVER, TIMING REMAINS UNCERTAIN AT THIS POINT. THE COLD
FRONT WILL BE A FOCUS FOR YET ADDITIONAL SCATTERED LIGHT SHOWERS LATE
SATURDAY NIGHT AND SUNDAY. A BREAK BETWEEN SYSTEMS WITH SOME
CLEARING IS LIKELY TO OCCUR BEFORE THE NEXT ROUND OF SHOWERS
ARRIVES.

MONDAY THROUGH WEDNESDAY: ON MONDAY HIGH PRESSURE WILL BUILD
NORTHEAST INTO THE REGION. THIS WILL ALLOW FOR A FEW DRY DAYS AND A
GRADUAL WARMING TREND THROUGH THE FIRST HALF OF NEXT WEEK AS A
NORTHWESTERLY FLOW GRADUALLY BECOMES SOUTHERLY BY WEDNESDAY. THE
CHALLENGE IN THIS PERIOD WILL BE A WARM FRONT DIVIDING A COOLER
MORE MARINE AIRMASS AND SOUTHERLY FLOW SENDING MORE SUMMERLIKE
TEMPERATURES INTO OUR REGION. RIGHT NOW THE LOCATION AND TIMING OF
THIS WARM FRONT EARLY NEXT WEEK IS STILL UNCERTAIN. HOWEVER, IT DOES
LOOK LIKE THE FRONT MAKES IT NORTH OF THE REGION. THIS WOULD
POTENTIALLY RESULT IN HIGH TEMPERATURES INTO THE 80`S BY WEDNESDAY.
FOR NOW, HAVE TEMPERED THIS CHANGE IN MODELING KEEPING SOME
CONTINUITY GIVEN THE UNCERTAINTY. LOW PRESSURE ALONG THE FRONT WILL
MOVE TOWARD OUR REGION ON WEDNESDAY. THERE IS A POTENTIAL FOR
OVERLAP OF INSTABILITY AND OVER 30 KNOTS OF 0-6 KM BULK SHEAR,
BUT IT`S TO EARLY TO ACCESS THE DEGREE OF ANY SEVERE WEATHER.

&&

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

THROUGH 12Z...CIGS VARIABLE BETWEEN 500 AND 1500 FT WITH POCKETS
OF 2MI DRIZZLE. IFR CONDS MAINLY VCNTY KPHL/KILG/KMIV/KACY.
NORTHEAST GUSTS UNDER 15 KT.

AFTER 12Z...CIGS GENERALLY IMPROVE TO BETWEEN 1500 AND 3000 FT BY
MIDDAY AND POSSIBLY TO VFR CIGS DURING THE AFTERNOON. ANY LINGERING
DRIZZLE EARLY IN THE DAY SHOULD QUIT BY 14Z. 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 THROUGH SATURDAY: FREQUENT MVFR/IFR CEILINGS AND VSBYS
WITH SCATTERED SHOWERS. EASTERLY WINDS UP TO 10 KNOTS WITH HIGHER
GUSTS UP TO 20 KNOTS ON FRIDAY.

SATURDAY NIGHT THROUGH SUNDAY NIGHT: MAINLY VFR WITH SCATTERED
SHOWERS. SOUTHWEST WINDS INCREASING WITH GUSTS AROUND 20 KNOTS
SUNDAY AFTERNOON. WINDS SHIFTING TO NORTHWEST DURING THE DAY SUNDAY.

MONDAY: VFR, WEST TO NORTHWEST WINDS AROUND 10 KNOTS WITH HIGHER
GUSTS.

&&

.MARINE...
SCA CONTINUES ON THE ATLANTIC WATERS FOR OCCASIONAL GUSTS 25 TO 30
KT AND SEAS OF 6 TO 9 FEET. WILL ADD AN SCA TO LOWER DE BAY IN THE
330 AM FORECAST ISSUANCE WHERE GUSTS TO 25 KT WILL OCCUR.

OUTLOOK...

AN SCA IS NOW IN EFFECT THROUGH FRIDAY AFTERNOON. SEAS WILL REMAIN
AT OR JUST OVER FIVE FEET THROUGH SATURDAY. SEAS WILL DECREASE FOR
THE EARLY PART OF NEXT WEEK. A PERIOD OF EASTERLY WIND GUSTS AROUND
20 KNOTS IS LIKELY FRIDAY ALONG WITH A PERIOD OF NORTHWESTERLY WIND
GUSTS AROUND 20 KNOTS ON SUNDAY.

&&

.TIDES/COASTAL FLOODING...
MAXIMUM WEDNESDAY EVENING TIDES WERE WITHIN 1 INCH OF THE MINOR
TIDAL INUNDATION FLOOD THRESHOLD WITH SURGE VALUES OF 1 TO 1.2
FEET ALONG THE NJ AND DE ATLC COASTS.

THE PERSISTENT NORTHEAST FLOW WILL CAUSE THE TIDAL SURGE TO BE
AT LEAST 1.0 TO 1.5 FEET FOR BOTH OF TODAYS HIGH TIDE CYCLES.
AND WILL NECESSITATE ANOTHER ADVISORY ISSUANCE AT 330 AM. THOSE
VALUES ALONG WITH THE INCREASING ASTRONOMICAL TIDES AS WE APPROACH
FRIDAY`S NEW MOON WILL RESULT IN MINOR TIDAL FLOODING ALONG THE NEW
JERSEY AND DELAWARE COASTS AT HIGH TIDE, ESPECIALLY THIS THURSDAY
EVENING.

WE HAVE A MORNING AND AN EVENING HIGH TIDE CYCLE ADVISORY PLKANNED
FOR DE.

MINOR TIDAL FLOODING IS ALSO LIKELY TO EXTEND INTO THE FRIDAY NIGHT
HIGH TIDE CYCLE.

ADDITIONALLY, THE DAY SHIFT MAY BE EXTENDING THE CF ADVISORY TO THE
TIDAL DE RIVER DOWNSTREAM FROM THE COMMODORE BARRY BRIDGE AND THE
EXTREME UPPER PART OF DE BAY (REEDY POINT LINK) FOR THE LATE THURSDAY
EVENING HIGH TIDE CYCLE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT FRIDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...DRAG/GAINES
NEAR TERM...DRAG/NIERENBERG 230A
SHORT TERM...DRAG 230A
LONG TERM...GAINES
AVIATION...DRAG/GAINES 230A
MARINE...DRAG/GAINES 230A
TIDES/COASTAL FLOODING...230A



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.