Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 180727
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
327 AM EDT Mon Sep 18 2017

.SYNOPSIS...

Hurricane Jose will continue moving northward well off the Mid
Atlantic coastline over the next couple of days. By Wednesday,
it will begin to weaken and move slowly northeastward near
southeastern New England through the remainder of the week. A
ridge of high pressure will also become established to our north
through the mid and late week time period.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

This is the final day in a stagnant pattern that we have been in
over the last several days. The mid and upper level trough that has
been over our region will fill through the day. Onshore flow,
reinforced by the approaching Jose, will help to keep low clouds in
for much of the region through the day.

As for precip, we could see a few showers develop under what is left
of the mid and upper level trough, generally west of the dry line,
and a few of the very outer rain bands of Jose may reach the coast
late in the day, but mostly we are expecting dry conditions.

Temperatures will be dependent on when or if we see breaks in the
stratus (it seems unlikely that we will see much clearing east of
the fall line). Stayed close to the previous forecast with highs
ranging from the mid 70s to lower 80s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...

Tonight, we start to see more influence from Hurricane Jose, both in
terms of increasing winds (along the shore) and increasing chances
for outer rain bands to reach our Coastal Plains. Based on the
current forecast from the National Hurricane Center, it doesn`t look
like we will have many outer rain bands through the overnight hours,
so kept rain amounts generally less than a half of an inch (at least
through the tonight period).

Persistent clouds should limit radiational cooling, so lows are
forecast to range from the upper 50s to mid 60s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...

Hurricane Jose to have an impact on our weather Tuesday and
Wednesday but still expected to track well offshore. Please
refer to NHC for track and intensity forecasts. Expected impacts
to our region discussed below.

Tuesday through Wednesday night:

Coastal flooding: Right now model guidance continues to hone in on
the Tuesday morning and evening high tides when Jose makes it`s
closest pass to the region for coastal flooding. Tidal
departures are still modeled to be one to two feet above normal
which would result in some moderate coastal flooding. With Jose
further away Wednesday and Thursday, any flooding would likely be
more of the minor or spotty minor variety.

Winds: Most of the region will have a windy period Tuesday and
Tuesday night with top wind gusts 20-30 mph inland and 40-45 mph
along the coast. These wind gusts may down a few trees and wires.

Rainfall: General rainfall of an inch or less is expected with
locally higher amounts on the coast. The 00z RGEM/UKMET and GFS have
come in fairly dry early this morning which gives some pause to the
wetter EC suite and the NAM. Trends of being slightly further
offshore this morning has allowed for the trim back of some
pops and QPF with this forecast update.

Also, clouds will keep temperatures down in the 70`s at least
Tuesday and possibly Wednesday as well. Overnight lows will be
warm, mainly in the 60`s due to the clouds and increased wind.

Thursday through Monday:

Right now about one-third of all ensemble guidance shows Jose making
a loop back to the southwest by the end of the week. A slightly
higher amount of 00z GEFS members are doing this than with
previous runs though. Any southwest movement will depend on the
strength of mid- level ridging developing to our west and north
throughout the remainder of the week. For now, the forecast
will go with the mainstream idea that Jose will continue to be
located east enough of the region to limit impacts besides
coastal flooding past Wednesday.

With the ridging building to our north, mid-level temperatures will
warm even more than we have seen so far allowing highs to make a run
into the 80`s most days with above normal lows as well in the 60`s.
A further east Jose will also allow for ample sunshine. This
forecast went a few degrees warmer than mean ensemble guidance most
days.

If Jose were to trend back to the southwest, it would be much weaker
but bring clouds along with somewhat cooler temperatures.

In conclusion...

Please refer to the NHC for the latest track and advisory and to the
TCV for a more detailed summary of impacts from Jose.

While uncertainty is decreasing on Jose, a westward shift could
still increase the potential impacts our region sees.

Hurricane Maria will have to be watched closely as well but
anything in that regard is still +7 days away.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Low stratus has already moved in over most of the TAF sites,
resulting in IFR conditions. Even if we see some breaks in the low
stratus as indicated on Satellite imagery, any improvement in flight
categories will likely be short lived as dew point depressions are
quite low so fog is likely to form if the low stratus clears.

With building on shore flow in advance of Hurricane Jose passing off
the coast, expect additional low clouds to build over the region
through the day. Though ceilings may increase after 12Z with
increasing mixing, it is unlikely based on the prevailing pattern
that we will improve to VFR conditions (except at KRDG and KABE
which will have less of an influence of the onshore flow).

Winds will generally be out of the northeast at or below 10 KT
through the day, but late tonight, expect a shift to northerly and
increasing speeds especially at KMIV and KACY.


Outlook...

Tuesday and Tuesday night: MVFR or IFR possible with showers,
particularly from KPHL to the east. Wind gusts 20-25 knots
inland and around 30 knots on the coast at times.

Wednesday through Friday: VFR. Northerly or Northwesterly winds
around 10-15 knots Wednesday then decreasing to under 10 knots
for Thursday and Friday.

&&

.MARINE...

Winds and seas will begin building late today in advance of
Hurricane Jose passing off shore. Wind gusts above 25 KT will be
possible by mid afternoon today on the Atlantic Coastal waters.
Winds and seas will continue to build through the overnight hours
with gusts near or above 40 KT and seas above 10 ft possible by
early Tuesday morning.

Outlook...

A tropical storm watch is in effect. Details in the MWW.

Late Monday night through Wednesday...Tropical storm conditions
will be possible. Although winds will begin to diminish Wednesday,
it will take time for seas to subside.

Wednesday night through Friday...Northeast to east swells of 5
feet may continue hazardous seas advisory because of the
meandering and slowly decaying remains of Jose.

Rip Currents...

High surf due to Hurricane Jose will continue to create dangerous
rip current conditions through at least mid week.

&&

.TIDES/COASTAL FLOODING...

Coastal flooding is expected with the Atlantic coast high tide
cycles Tuesday through Wednesday due to the passage of Hurricane
Jose. A prolonged 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.

The high tide cycle of greatest concern at this point is the Tuesday
evening high tide, especially Sandy Hook to Cape May. Otherwise,
mostly widespread minor coastal flooding is expected with the high
tide cycle early Tuesday, and those early Wednesday. The tropical
HLS will contain information on coastal flooding.

&&

.EQUIPMENT...
KSMQ transmission of data continues ots.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Tropical Storm Watch for NJZ013-014-020-022>027.
DE...Tropical Storm Watch for DEZ003-004.
MD...None.
MARINE...Tropical Storm Watch for ANZ431-450>455.
&&

$$
Synopsis...Gaines
Near Term...Johnson
Short Term...Johnson
Long Term...Gaines
Aviation...Gaines/Johnson
Marine...Gaines/Johnson/Drag
Tides/Coastal Flooding...Johnson
Equipment...



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