Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 181101

Area Forecast Discussion
National Weather Service Mount Holly NJ
701 AM EDT Fri Sep 18 2020

Light rain moves off the coast today as high pressure builds in over
the Mid-Altantic and New England states. High pressure will
weaken slightly before reestablishing itself across the
Appalachian mountains early in the week.


The cold front has tracked through portions of the region this
morning and has kept much of the remnants of Sally to the south of
the forecast area. Light rain will continue to slide offshore
through the rest of the morning hours. As cold air advection
starts to intensity through the day today anticipate below
normal temperatures and rather brisk winds. The CAA will steepen
low level lapse rates and we should see 15 to 20 mph winds
through much of the afternoon. Temps top out in the upper 60 to
low 70s with dewpoints that should end up in the low to mid 40s
by late afternoon.


Cold air advection continues this evening with high pressure
over the region. Anticipate our first "chilly" night of the Fall
with the potential of some frost formation over portions of the
Poconos. Lows will be in the mid to low 40s with mid 30s
expected for the Poconos. Some light patchy frost may develop
over portions of Carbon and Monroe county in PA but isn`t
widespread enough to warrant justification for a full county

Saturday should be a pleasant albeit "chilly" day with highs in
the low to mid 60s and modest gusts up to 20 mph out of the


Dry weather continues through the weekend with high pressure
cresting to the north and east. Winds should be gusty as times as a
modest pressure gradient force remains in place with high pressure
located over the Great Lakes and low pressure to our south.
Northerly winds should weaken during the overnight hours allowing
for modest longwave radiational cooling through at least Monday

Heading towards the middle of the week, the high pressure system
starts to sag south over the Appalachian region with an upper
level trough digging into New England. This could be enough to
cause some spotty showers if any shortwave are able to track
this far south but will be highly dependent on available
moisture. As of the 00z suite, the forecast remains dry through
late Thursday with only a 15- 20% chance of showers for the
northern tier of the forecast area.


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

Today...VFR/MVFR ceilings, improving to VFR/SKC in the
afternoon. North wind 10 to 15 knots with gusts around 20 knots.
High confidence.

Tonight...VFR conditions expected with north to northeasterly
winds 8-12kts.


Saturday-Saturday night...VFR conditions expected. North to
northeast winds may gust around 15-20 knots at times. High

Sunday-Sunday night...Mostly VFR conditions expected. Northeast
winds may gust 15-20 knots at times. High confidence.

Monday-Tuesday...Generally VFR conditions expected. Northeast
Monday, become north to northwest Monday night into Tuesday.
Winds may gust around 15-20 knots at times. Moderate confidence.


Small Craft Advisory begins at 6 AM as northeast winds will
ramp up to 20 to 25 with gusts of 25 to 30 knots and seas build
to 5 to 8 feet by later today into tonight.


Saturday through Saturday night...The Small Craft Advisory
continues through this period as northeast winds continue
generally at 15 to 25 with gusts of 25 to 30 knots. Seas
continue in the 5 to 8 foot range.

Sunday through Tuesday...Extended period of Small Craft Advisory
conditions likely to continue due to persistent northeast winds.
Seas may build as high as 10 feet by Monday due to swell from
Hurricane Teddy


There is an enhanced risk for the development of dangerous rip
currents for today right into the early part of the new week as
a strong north to northeast wind and rough seas develop along
the coast. For today, we`ve issued a High Rip current risk for
the Delaware Beaches as there will be a strong onshore component
to the swell as it`s directed against the shore from the


The new moon was yesterday (Thursday), so astronomical tides
will continue to be higher than normal for the next couple days.

For the Atlantic coast: As the flow shifts to northeasterly this
morning, surge above the astronomical tide should gradually
increase. The high tide this morning should be relatively
unaffected as the wind shift will be mostly coming too late to
affect those high tides (though spotty minor flooding is
possible around high tide). However, beyond this time widespread
minor flooding becomes increasingly likely so we`ve issued a
Coastal Flood Advisory that starts this evening for most
counties (exception being Middlesex County) and continues
through midday Saturday to account for the Saturday morning high
tide as well. Can`t rule out a few spots mainly south of
Barnegat Bay getting close to or just touching Moderate
flooding levels with the Saturday morning high tide but this is
not the most likely scenario so a Coastal Flood Watch or
Warning is not warranted at this time.

For the Delaware Bay and tidal Delaware River: The wind
direction is less likely to lead to tidal flooding (as opposed
to an E or SE direction). The one exception is along the
southern shores of the Delaware Bay (primarily along the bay
shores in Kent and Sussex County DE), where we`ve issued a
Coastal Flood Advisory that also begins with this evening`s high

For the Northeast Chesapeake Bay: Despite higher astronomical
tides, tidal flooding is not expected at this time as the NNE
wind direction does not typically lead to water being slow to
evacuate the bay.


NJ...Coastal Flood Advisory from 8 PM this evening to 2 PM EDT
     Saturday for NJZ013-014-020-022>027.
     Coastal Flood Advisory from 8 AM to 2 PM EDT Saturday for
DE...Coastal Flood Advisory from 8 PM this evening to 2 PM EDT
     Saturday for DEZ002>004.
     High Rip Current Risk through this evening for DEZ004.
MARINE...Small Craft Advisory until 6 AM EDT Sunday for ANZ430-431-


Near Term...Deal
Short Term...Deal
Long Term...Deal
Tides/Coastal Flooding...WFO PHI is the U.S. government's official web portal to all federal, state and local government web resources and services.