Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 182200
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
600 PM EDT Mon Sep 18 2017

.SYNOPSIS...
Hurricane Jose will continue to move northward well east of our area
through Wednesday. It will then move towards New England while
weakening Thursday and Friday. What is left of JOse will remain well
north and east of our area this weekend. Meanwhile, high pressure
will build across the Middle Atlantic area and remain into the
weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
The Tropical Storm Watch that was in effect for the land areas
of New Jersey and Delaware has been cancelled. Please continue
to pay attention to the forecast, as local effect from Hurricane
Jose will still be felt, especially along the coasts. Although
it will be windy, especially along the coast, we no longer
expect sustained Tropical Storm Force winds.

A narrowing upper-level ridge is located just to our west this
afternoon and this evening. Meanwhile, the main focus is northbound
Hurricane Jose as it will continue to parallel the East Coast well
offshore. The combination of a high pressure system in the Canadian
Maritimes and the hurricane will continue to result in a northeast
wind. This onshore wind will be strongest closest to the coast as
frictional effects diminishes it quite a bit inland. The water vapor
imagery shows plenty of dry mid level air, which was sampled well by
the 12z raobs from Sterling, VA and Upton, NY. There remains a layer
of moisture though in the lower levels that is helping to maintain
areas of lower clouds. These clouds are lifting some along with more
breaks in them as they try to become more convective looking. As we
go through the night, we anticipate clouds to expand and lower for
much of the area once again given the onshore flow and influx of
some additional low-level moisture overnight. Overall low clouds are
anticipated with the fog more limited to perhaps the far
northwestern zones.

Hurricane Jose continues to look like it is taking on some non-
tropical characteristics with a well defined mid level dry slot on
its south and east sides. The less organized satellite imagery is
also due to increased shear. Some model guidance shows some showers
spinning westward from the ocean later this afternoon and this
evening as some strung out short wave energy is nearby in addition
to a weak convergence area and instability. Confidence on the
development of these showers, especially related to coverage, is on
the lower side and therefore we maintained just some mainly slight
chance PoPs.

As we go through the overnight and especially near daybreak, some
increasing lift on the northwest side of Jose within a zone of
perhaps developing deformation, should result in a band of
developing showers. This should be nearing the coast toward daybreak
and therefore the PoPs start to ramp up as we approach this time
frame. We trimmed back the PoPs farther west as much of the area may
end up dry through the night. The winds will increase some during
the night mainly closest to the coast, however the main wind
increase is not expected until during Tuesday.

Low temperatures are mostly a MOS/continuity blend, and with the
idea of cloudiness through the night we did not lower below
guidance. The temperature, dew point and wind grids were adjusted
based on the 19z observations, then the LAMP and some high-res
guidance was blended in especially for the temperatures.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
The main focus through Tuesday night will be the northward movement
of Hurricane Jose. It is forecast to be moving over cooler water
within an area of stronger southwesterly shear, thus gradually
weakening it. The center of this storm is still expected to parallel
the East Coast well offshore, however the overall wind field is
larger as it gains latitude. The model guidance overall has
diminished the wind threat especially for the land areas under a
tropical storm watch. Since frictional effects will diminish the
wind quite a bit from the coast inland, we are expecting the
strongest winds right along the coast. In addition as the center
tracks northward, the winds will start to turn from the northeast to
the north-northwest by late Tuesday.

Regarding the shower potential, much of the guidance still showing
an area of showers well west of the center. This is within an area
of potentially developing deformation as a zone of strengthening
convergence focuses shower development. There continues to be
differences between the guidance on just how far west this area gets
during Tuesday and then shifts northeastward Tuesday night. The main
showers should be closer to the coast as frictional convergence
might enhance the lift for a time. We therefore trimmed the PoPs
back across the western areas (tightened up the gradient some), with
the highest PoPs (likely to categorical) across the eastern areas
for a time. This system looks to start slowing down though during
the course of Tuesday night as the steering flow weakens, leaving
the center of the storm sitting well to our east. This should
maintain at least some showers and wind all the way through Tuesday
night especially for our eastern zones. It is good to note though
that some guidance has little rain on land with this system.

High temperatures are a MOS/continuity with minor tweaks, and we are
expecting a cooler day given the anticipated cloud cover, onshore
wind and at least some showers.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Any of the remaining effects with Jose will be ending across the
northern and eastern parts of the area Wednesday morning. This will
be mainly in the form of showers and gusty winds. Pops for Wednesday
will be in the chc range across ern NJ and these will decrease thru
the day. Gusty winds up to 25 mph will be possible during the
morning across these ern areas, but then they will decrease thru the
day. Over the rest of the area, fair weather with slightly above
normal temperatures expected for Wed.

A prolonged period of nice weather is expected for Thursday and into
the weekend as high pressure builds at the sfc and aloft. Generally a
rain-free period with temperatures near normal, or perhaps a degree
or two above. Patchy overnight fog is possible, mostly in rural
areas. Rather low confid fcst next Monday. Its possible that
enough low level moisture may be around for some showers, a
slight chc was kept in the grids for that period attm.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

This afternoon...MVFR ceilings should lift some to locally VFR for a
time. A few isolated brief showers cannot be ruled out.
Northeasterly winds 6-10 knots, however 10-15 knots closer to the
coast.

Tonight...MVFR to IFR ceilings. A band of showers should start to
move onshore toward daybreak, however the timing and coverage is
less certain. Some MVFR fog possible late especially at KRDG.
Northeast winds 5-8 knots at KABE and KRDG, and 10-15 knots at the
other terminals with the highest winds at KACY.

Tuesday...IFR/MVFR conditions mostly due to ceilings, which may
improve to near VFR for a time in the afternoon especially west of
KACY and KMIV. Some showers are expected to occur, however the
timing and especially coverage is less certain. We only included
showers with restrictions for KACY and KMIV for now with a VCSH for
the I-95 corridor terminals.

Tuesday night..MVFR/IFR with some showers especially from near KPHL
on eastward, should improve to VFR for some areas. North to
northwest winds 10-20 knots with gusts up to 30 knots, with much
less wind near and north and west of KPHL.

OUTLOOK...
Wed thru Saturday...VFR except for patchy morning fog.

&&

.MARINE...
Northeasterly winds will increase through late Tuesday as Hurricane
Jose slowly weakens and parallels the East Coast well offshore.
There is the potential still of 35-40 knot winds especially during
Tuesday into Tuesday night, however this may be less now especially
for lower Delaware Bay. For now, any changes to the headlines will
be made after the 4 PM NHC conference call. Seas continue to be slow
to build, therefore delayed this some more at least into this
evening. A more significant increase in the seas on the ocean will
be later tonight and Tuesday with the arrival of stronger winds.
A high surf advisory remains in effect starting this evening.

OUTLOOK...
Wed thru Saturday...Fair weather expected. Low end SCA
  conditions for seas on the ocean expected.

Rip Currents...

High risk of rip currents continues due to building swells/waves
from Hurricane Jose through at least mid week.

&&

.TIDES/COASTAL FLOODING...
A coastal flood advisory has been issued starting this evening.
See the CFW product for more details. A coastal flood warning may be
needed for tomorrow night.

Coastal flooding is expected with the Atlantic coast high tide
cycles tonight through Wednesday due to the passage of Hurricane
Jose. A period of east to northeast winds due to Hurricane Jose will
force water to build along the shores. In addition, there is a new
moon on Wednesday, September 20th, so astronomical tide levels will
be running high.

For tonight`s high tide, spotty minor flooding is expected for much
of the NJ coast. With the NE flow, the minor flooding might be a
little bit more widespread across our DE waters. No flooding is
expected on the Delaware River nor Chesapeake.

For Tuesday morning, minor tidal flooding is expected along
both the NJ and DE coasts. Spotty minor may work it`s way up the
Delaware River. Nothing is expected across the Chesapeake.

A Coastal Flood Watch has been issued for the high tide cycles
Tuesday night, as minor to moderate flooding is expected for
the ocean-facing zones of DE and NJ as well as the lower DE
Bay. Spotty minor to minor flooding is expected further up the
DE Bay and the Delaware River. Once again, coastal flooding is
not expected across the Chesapeake.

&&

.EQUIPMENT...
KSMQ metar is not being sent out attm. Problem is being looked
into.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Watch from Tuesday afternoon through Tuesday
     evening for NJZ012>014-020>027.
     High Surf Advisory until 6 PM EDT Tuesday for NJZ014-024>026.
     Coastal Flood Advisory until 5 PM EDT Tuesday for NJZ012>014-
     020>027.
     Coastal Flood Advisory until 1 AM EDT Wednesday for NJZ016.
DE...Coastal Flood Watch from Tuesday afternoon through Tuesday
     evening for DEZ002>004.
     High Surf Advisory until 6 PM EDT Tuesday for DEZ004.
     Coastal Flood Advisory until 5 PM EDT Tuesday for DEZ002>004.
     Coastal Flood Advisory until 1 AM EDT Wednesday for DEZ001.
MD...None.
MARINE...Tropical Storm Watch for ANZ450>455.
     Small Craft Advisory from midnight tonight to 6 AM EDT
     Wednesday for ANZ430.
     Gale Warning from 2 AM Tuesday to midnight EDT Tuesday night
     for ANZ431.

&&

$$
Synopsis...O`Hara
Near Term...Gorse/MPS
Short Term...Gorse
Long Term...O`Hara
Aviation...Gorse/O`Hara
Marine...Gorse/O`Hara
Tides/Coastal Flooding...
Equipment...



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