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Office: PHI

FXUS61 KPHI 180321

Area Forecast Discussion
National Weather Service Mount Holly NJ
1121 PM EDT Tue Jul 17 2018

A strong cold front will cross our area tonight. High pressure from
the Great Lakes will follow for Wednesday and remain over our area
into Friday night. A broad, slow moving upper level low will move
into the east this weekend and affect our weather through early next


The line of showers and thunderstorms that was near the front
has all but dissipated. The front appears to be making very fast
progress now, already off shore along the New Jersey shore.

Under clearing skies, overnight lows will reach the upper
50s/low 60s across the north and remain closer to 70 over
Delmarva and south NJ. The dry air will overspread the N/W areas
tonight, but likely not move much into the S/E areas until
closer to dawn. Winds will become northwest after the frontal


The front will be well offshore Wednesday morning and
with high pressure beginning to build in, a fair weather day is
expected. The new airmass will be much drier so even though
temperatures will still be very warm, it will be much more comfort
able. Highs will be in the mid/upper 80s in most areas.


Wednesday thru Friday... High pressure will be across the Great
Lakes Wednesday and build across the Mid-Atlantic Thursday before
moving offshore Friday. The high will bring mostly sunny skies along
with seasonable temperatures. No precipitation expected.

For the period, normal temperatures for PHL are in the mid 80s and
around 70 for lows. For MPO, normal highs are in the upper 70s with
lows in the upper 50s. For Wednesday, temperatures will be near
normal, and below normal for Thursday and Friday.

Next weekend through Tuesday...Turning unsettled with an
unseasonably strong upper level trough moving towards the region. A
deep south to southwest flow aloft will become established and
abundant moisture from the south will arrive across the region.
There are however some differences in the models regarding how
quickly the moisture and resulting showers/storms affect the area
with the ECMWF keeping things dry here through Saturday and the GFS
not showing much precip either. For this reason, keeping only low
chances for showers/storms Saturday as the day could end up being
mostly dry. However, by Sunday into Tuesday, widespread showers and
thunderstorms will become more likely. Temperatures are expected to
be at or below normal. Significant heat is not expected with the mid-
level ridge well established on the west coast. Latest GFS runs have
suggested a coastal low may form and move northward along the New
Jersey Shore Saturday night into Sunday, though confidence is low at
this point as previous runs were not as suggestive.


The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Tonight...Aside from KMIV and KACY where some low clouds may
linger for the next few hours, VFR conditions are expected at
the rest of the TAF sites overnight. Skies will become clear to
partly cloudy late tonight. Winds have mostly switched to
northwesterly at all the TAF sites already, although wind speeds
are light (generally less than 10kt).

Wednesday...VFR conditions expected with mostly sunny skies. Winds
will be mostly N to NW around 10 knots.


Wednesday night through Friday...VFR expected.

Friday night and Saturday...Mainly VFR. A few showers and
thunderstorms possible.

Saturday night and Sunday...Showers and thunderstorms becoming more
widespread...leading to greater chances of MVFR.


Winds and seas have diminished. There may still be locally
higher winds and seas in the vicinity of a cluster of
thunderstorms off the Delaware Beaches. Otherwise, winds and
seas should stay below Small Craft advisory conditions for the
remainder of tonight and Wednesday. Therefore, the SCA has been


Wednesday night thru Friday...Sub-SCA with fair weather.

Friday night thru Saturday...Scattered showers and tstms
possible with seas potentially building to SCA levels.

Saturday night and Sunday...Showers and thunderstorms becoming more
numerous. SCAs possible.

Rip Currents...
The moderate risk of rip currents is expected to continue on
Wednesday. This is due to a lingering underlying southeasterly
long period swell.




Near Term...Johnson/Miketta/O'Hara
Short Term...O'Hara
Long Term...Davis/Kruzdlo

Office: OKX FXUS61 KOKX 180538 AFDOKX Area Forecast Discussion National Weather Service New York NY 138 AM EDT Wed Jul 18 2018 .SYNOPSIS... High pressure builds across the region through Thursday and slides offshore on Friday. A frontal system approaches Saturday night into Sunday with a prolonged period of unsettled weather possible into early next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Showers and a cold front will continue to shift out of the tri- state area during the overnight hours. Showers will now be confined to Long Island and CT. The sky will then begin to clear out. Dewpoints will begin to lower, but it will still feel humid for the rest of the night. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... Drier and less humid conditions are tap for Wednesday with a northerly flow and a highs in the 80s. Readings will be a few degree above normal but it will feel much more comfortable as dewpoints drop into the 50s. Lows Wednesday night will be near seasonable levels. Aloft, the upper trough axis swings across the area Wednesday into Wednesday night. Lack of moisture though will keep the region dry. There is a moderate risk of rip currents on Wednesday due to a 3 to 4 ft southerly swell and offshore flow maintaining waves around 3 ft in the surf zone. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... The long term period will begin will tranquil conditions as middle and upper trough axis moves offshore. Ridging will build aloft Thursday into Friday along with surface high pressure. Near seasonable temperatures are expected on Thursday and Friday. There is good agreement among the models for the ridge to move offshore late Friday into the weekend as a shortwave digs and amplifies across the eastern states. This could potentially set the stage for an unsettled period into early next week. As the surface high moves offshore on Saturday, there will likely be enough surface ridging to keep the area dry. However, a frontal system associated with the shortwave/upper trough will approach the region on Saturday. The latest models show the warm front approaching Saturday night into Sunday morning. There continues to be indications of a wave forming on the warm front as a strong vort max moves up the coast. This will need to be watched for any early morning strong thunderstorms with the approaching warm front. Otherwise, showers and thunderstorm chances continue into early next week overall as the frontal system lingers nearby with a blocking ridge over the Atlantic. Temperatures this weekend and into early next week will ultimately be determined by how much clouds and precipitation occur, but should be near or slightly above normal. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... HIgh pressure builds towards the region from the Great lakes through tonight. VFR, with SCT 050-070 ft cloud deck in the late afternoon/evening. N/NNW gusts of 15 to 20 kt likely developing during the morning push and continuing into early afternoon. Winds should remain right of 310 magnetic an left of 040 magnetic through the day. .OUTLOOK FOR 06z THURSDAY THROUGH SUNDAY... .Wednesday-Saturday...VFR. .Sunday...MVFR or lower in showers and thunderstorms. && .MARINE... Winds and seas remain below SCA overnight, as a S to SW swell continues overnight. Seas will gradually diminish through Wednesday with a lingering southerly swell around 4 ft on the ocean waters. Sub SCA criteria through Saturday morning. Seas will build on a southerly flow on the ocean waters Saturday, with 5 ft waves by Saturday night. Wind gusts should remain below 25 kt for the weekend. With an approaching complex frontal system to affect the waters by Sunday and a prolonged southerly flow, expect SCA conditions to exist into early next week. && .HYDROLOGY... Dry weather for today through at least most of Saturday. An extended period of unsettled weather is forecast starting Saturday night into next week. Hydrologic impacts are uncertain with this period still a few days away. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JC/PW NEAR TERM...JC SHORT TERM...JC LONG TERM...PW AVIATION...NV MARINE...JC/PW HYDROLOGY...JC/PW EQUIPMENT...