Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Home | 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
FXUS61 KPHI 210225

Area Forecast Discussion
National Weather Service Mount Holly NJ
925 PM EST Tue Nov 20 2018

A cold front will swing across the area on Wednesday, then high
pressure builds across the northeast later Thursday, then
offshore Friday. A low pressure system and associated frontal
boundary will affect the Mid Atlantic region around Saturday and
Saturday night, followed briefly by weak high pressure Sunday.
Another frontal boundary and associated low pressure system is
forecast to affect the area late Sunday into Monday.


930pm update: Showers from earlier this evening have weakened.
Adjusted sky cover to match current obs and satellite trends.
Clouds across the northern part of our area should continue to
diminish over the next few hours and mostly clear skies can be
expected overnight.

A quick update was sent around 430 PM to add in a mention of
rain/snow showers across the far northwest zones through early
this evening. Radar data shows some showers approaching the
Poconos, and some high-res guidance indicates these arrive into
the Pocono region. In addition, increased the cloud cover for
much of the area into this evening.

Otherwise, a deck of stratocumulus with some altocumulus above
it lingered over much of our region at mid afternoon. A mid
level short wave trough is forecast to pass over our region
early this evening and the cloud cover is expected to decrease
in its wake for much of tonight. Another batch of mid level
clouds is anticipated to begin advecting over our region from
the northwest toward daybreak.

The gusty west to northwest wind is expected to diminish to
less than 10 MPH around dusk.

Minimum temperatures are forecast to be in the upper 20s and
lower 30s along and to the southeast of the Interstate 95
Corridor. Readings should drop solidly into the 20s in areas to
the northwest.


Clouds are expected to overspread our region from the northwest
on Wednesday. The clouds will be ahead of a mid level short
wave that is forecast to approach our region from the northwest
late in the day, along with an associated surface cold front.

A westerly wind is forecast to increase to 10 to 15 MPH with
gusts around 20 MPH. Afternoon temperatures will be a few
degrees colder than those of today. Highs should range from the
30s in the Poconos and far northern New Jersey to around 50 in
southern Delaware.


The long term forecast starts off with way below normal
conditions for the Thanksgiving holiday and day after. Cold high
pressure will build southward out of Canada and across our area
Thursday into Friday. Daytime highs will be at least 15-20
degrees below normal both days, in fact, the actual highs
Thursday and Friday may not reach the normal low. The
overnight/morning lows Wednesday night/Thursday morning and
again Thursday night/Friday morning are forecast to be at least
10-15 degrees below normal as well. Dry conditions are forecast
due to the high pressure across the area. However, this dry
weather is not expected to last long.

An Saturday, a storm system is forecast to affect the area
later Saturday into Saturday night. One area of low pressure is
expected to be moving across central Canada, likely pulling a
cold front across the Mid Atlantic region. Meanwhile, an area of
low pressure will strengthen across the Gulf coast and move
offshore of the southeast, before a third low develops across
the central Appalachian and move across our area Saturday into
Saturday night, along the boundary that will affect the area.
This is expected to bring the potential for a period of moderate
to heavy rainfall to the area Saturday and Saturday night.

This system will move to our northeast Sunday, and weak high
pressure will move in behind this system later Sunday into
Sunday night. This should bring a brief period of dry weather,
but this will not last long either.

On Monday, an area of low pressure is forecast to lift into the
Great Lakes region, while a frontal boundary lifts toward our
area. Another low pressure is forecast to develop along this
frontal boundary to our south and lift across the Mid Atlantic
region. This will bring another potential period of moderate to
heavy rainfall.

Temperatures over the weekend into early next week look like
they should be warm enough for mostly or all rain to occur. The
one exception to this would be if precipitation starts early
enough Saturday, a wintry mix could be possible before changing
to all rain.

Another concern with both storm systems will be the potential
for gusty winds; especially the storm system early next week
which looks to have the strongest winds.


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

Tonight...VFR. Lingering ceilings around 5000 feet should dissipate
into the overnight. Northwest winds around 10 knots, diminishing to
6 knots or less to locally light and variable.

Wednesday...VFR with an increase in cloud cover. West winds
increasing to 10-15 knots with gusts up to 25 knots, becoming
northwest later in the day.

Wednesday night-Friday night...VFR conditions
expected. Gusty winds Wednesday night into early Thursday.

Saturday-Saturday night...Conditions lowering to MVFR an IFR
with periods of rain.

Sunday...Conditions likely to improve to VFR.


The Small Craft Advisory for Upper Delaware Bay has been cancelled
as winds have dropped off enough. Another advisory however may be
needed starting Wednesday evening. Otherwise, the remaining Small
Craft Advisory remains unchanged for now.

Otherwise, wind speeds are forecast to diminish a bit for late
tonight and Wednesday morning, before increase again late on
Wednesday as an arctic front arrives from the northwest. There
should be enough of a gap between the current Small Craft Advisory
winds and those expected late on Wednesday to indicate a break in
the advisory for Delaware Bay and for the ocean waters off Delaware
and far southern New Jersey. However, we will simply run the Small
Craft Advisory through all of tonight and Wednesday for our ocean
waters off Ocean County and Monmouth County in New Jersey, being
that the respite there should be only a few hours.

Wednesday night-Thursday night...Small Craft Advisory
conditions expected through Thursday, before diminishing
Thursday night.

Friday-Friday night...Conditions expected to be below advisory

Saturday-Saturday night...Conditions may increase to Small
Craft Advisory levels.

Sunday...Conditions expected to be below advisory levels.


There is the potential for near record low maximum AND low
minimum temperatures for the Thanksgiving holiday. Here are the
record coldest high and low temperatures across our climate
sites for Thanksgiving day, accounting for the change in date.
(Note, this is not records for November 22 itself):

Thanksgiving record low minimum:
Atlantic City, NJ: 10 (1989)
Allentown, PA: 16 (2000)
Georgetown, DE: 20 (1996)
Mount Pocono, PA: 1 (1903)
Philadelphia, PA: 20 (1901)
Reading, PA: 15 (1903)
Trenton, NJ: 20 (1930)
Wilmington , DE: 18 (1996)

Thanksgiving record low maximum:
Atlantic City, NJ: 31 (1996)
Allentown, PA: 27 (1996)
Georgetown, DE: 27 (1989)
Mount Pocono, PA: 20 (1901)
Philadelphia, PA: 27 (1901)
Reading, PA: 30 (1989)
Trenton, NJ: 30 (1930)
Wilmington , DE: 29 (1996)


MARINE...Small Craft Advisory until 4 AM EST Wednesday for ANZ431-
     Small Craft Advisory until 6 AM EST Thursday for ANZ450-451.


Near Term...Gorse/Iovino/Staarmann
Short Term...Iovino
Long Term...Robertson
Climate... is the U.S. government's official web portal to all federal, state and local government web resources and services.