Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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
000
FXUS61 KPHI 291948
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
348 PM EDT MON AUG 29 2016

.SYNOPSIS...
A frontal boundary extended from around Cape Cod, across the
waters off Long Island to central New Jersey and southeastern
Pennsylvania at mid afternoon. The front will slowly dissipate as
it drifts southward. Weak high pressure is forecast to build
across New York and New England from tonight into Tuesday.
Tropical Depression Eight is expected to pass well to our
southeast on Wednesday as a strong cold front approaches from the
northwest. The front is anticipated to pass through our region
early on Thursday followed by high pressure for Friday into the
upcoming holiday weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A weak cold front will move offshore tonight with high pressure
building southeast behind the front into the region. Winds be from
the northwest tonight behind the cold front but will become light
in the evening. With mostly clear skies and an even drier air mass
working into the region it should be a favorable setup for
radiational cooling but not fog. Given the players on the field
tonight, opted to go a couple of degrees cooler than what most of
the MOS guidance has tonight, particularly the ECMWF. In rural
areas across northern NJ and PA along with the Pine Barrens
temperatures should fall fairly quickly with lows in the 50`s and
low 60`s for many. Lows should end up a few degrees warmer in the
urban corridor.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Tomorrow, high pressure will move eastward through the region
allowing for another sunny late summer day. Temperatures will
rebound quickly with another run at 90 likely for Philly. Winds
will likely be light and variable, under 10 mph throughout most of
the day and not much potential for mixing is showing up on
soundings. Winds will be more of an easterly direction from
Philadelphia to the southeast resulting in an onshore flow another
risky day for swimming in the ocean (see rip current section).

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
The forecast continues to keep Tropical Depression Eight well
enough to our southeast on Wednesday as not to impact our weather.

A strong cold front is expected to extend from southern Ontario
to the middle Mississippi River Valley on Wednesday morning. It
should reach central New York and western Pennsylvania late in the
day. We will continue to mention a chance of showers and
thunderstorms in our northwestern counties for Wednesday
afternoon. The potential for scattered showers and thunderstorms
will overspread the remainder of our forecast area on Wednesday
night.

The front is expected to work its way though our region early on
Thursday. The guidance continues to linger showers through the
morning hours, especially on the coastal plain. Maximum
temperatures on Thursday are anticipated to be in the 70s in the
elevated terrain of the Poconos and northwestern New Jersey and in
the lower and middle 80s elsewhere. Dew point readings should drop
into the lower 60s and 50s.

High pressure is forecast to build from Ontario and the Great
Lakes on Thursday to the northeastern states on Saturday before
drifting off the coast. The air mass will be noticeably cooler and
less humid than the one that it will be replacing.

We will need to keep an eye on the tropical activity to our south
and east over the weekend.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

VFR throughout the TAF period with some scattered mid and high
level clouds from time to time. Northwest winds around 10 knots
becoming light and variable tonight and staying under 10 knots
tomorrow. Winds shifting to easterly from Philadelphia and points
SE on Tuesday. Little to no chance of fog formation at any TAF
site.

OUTLOOK...
Tuesday night and Wednesday morning...Mainly VFR. Late night and
early morning visibility restrictions are possible.

Wednesday afternoon into Wednesday night...Mainly VFR. However,
there is a chance of showers and thunderstorm.

Thursday...Mainly VFR with a chance of showers.

Thursday night through Saturday...Mainly VFR.

&&

.MARINE...
Wave heights close to three feet will likely build slowly to
between three and four feet given the onshore flow by tomorrow.
Winds will start from the west and northwest tonight before
becoming more easterly on Tuesday, around 10 knots.

OUTLOOK...
Tuesday night through Saturday...No marine headlines are
anticipated. However, long period swells may create rough
conditions in and around the inlets along the coasts of New Jersey
and Delaware.

RIP CURRENTS...
The rip current risk is moderate for the remainder of today. This
is largely in part due to swells from tropical systems offshore
and well out to sea. Long periods of around 13 seconds have been
predominant today and will likely continue to be through tomorrow.
With an onshore flow tomorrow and slightly higher seas, another
moderate risk day looks likely. If the onshore easterly winds
increase a bit more than forecasted or the waveheights are
slightly higher than forecasted conditions then may be favorable
for a high risk.

Wednesday: GFS and tropical modeled swell/period wave groups
strongly suggest a moderate risk for the formation of dangerous
rip currents continues.

In terms of safety, follow the advice of local lifeguards who
will be observing. There may be some beach closures, all dependent
on the reality that develops. This is not a time to swim on your
own without lifeguard presence. Additionally, waders are cautioned
not to turn their backs to the waves when coming out of the water.
Wave knock down can result in upper torso injury
(dislocations/spinal cord injuries).

A beach hazards statement was issued to alert for the rough surf
for this week into the coming weekend, this in part based on NHCs
outlook compared with the GFS/EC operational cycles.

&&

.CLIMATE...
This section is up to date through 435 AM Today-Monday August 29.
Today`s data have yet to be finalized.

A top 4 warmest August appears assured most of our forecast area
with record monthly warmth likely at PHL.

A top 3 warmest June-July-August for Philadelphia, Allentown and
possibly Atlantic City.

Philadelphia will establish its warmest August on record (dating
back to 1874). More than 4 degrees above normal.

This Philadelphia August ranking includes our forecast temps (SFT
specific values) through the 31st. The 30 year normal is 76.6
Records date back to 1874.

1. ~81.0 2016
2. 79.9 1980
3. 79.8 2001 and 1995

Regarding whether August can tie its record of 17 90F days. Its
possible but not probable. Foresee an additional 2 to 3 more 90
degree days to add onto the 13 we have so far this month. The
record of 17 was set in 1995. The mean for the month is only 5.
Tuesday is the possible day for breaking a modest heat wave and
eliminating a chance at a record equaling 17, 90 degree days in
August.

Allentown will rank #2 warmest August. Records date back to 1922.
Normal is 71.7 and we are projecting a positive departure of
around 5 degrees.

1. 78.2 1980

2. 76.6 2016

3. 76.0 1937

Atlantic City records date back to 1874. The August monthly
normal is 74.4 and we`re projecting a positive departure of nearly
4 degrees. As it stands, Atlantic City will rank #1 or #2 warmest
August with very little chance of slipping to #3. The forecast and
climate for Atlantic City has greater variability than Allentown
and Philadelphia due to proximity to water on sea breeze days and
notable radiational cooling on some nights.

1. 78.2 2016

2. 77.9 2005

3. 77.1 2009

Seasonal: This summer 2016 for Philadelphia will probably be the
2nd warmest June-July-August (JJA) in the period of record dating
back to 1874.

1. 79.6 2010
2. 78.8 2016
3. 78.6 1995
4. 78.3 1994

Allentown seasonal avg is projecting 75.0 or a ranking of around
#2 in the por.

1 75.3 1949

2 75.0 2016

3 74.6 2005 and 1980

Atlantic City seasonal average is projecting 75.8...4th warmest
in the por.

1. 77.5 2010

2. 77.0 2011

3. 75.9 2005

4. 75.8 2016

5. 75.5 2008

90 degree days through the 28th.

season       mean  Aug  Aug       Aug      Season
                        mean      rer      rer

abe  33      17    12   4         16-1980  41-1966

acy  27      10    10   3         11-2010  46-2010

phl  38      21    14   5         17-1995  55-2010

ilg  32      20    13   5         23-1895  59-1895

Rainfall: Considerable uncertainty exists regarding additional
rainfall in August, so this part of the climate is stated with
caution.

Presuming no further measurable rain this month of August...the
current ACY value of 1.10 would rank the 6th driest August on
record, after a 6th wettest July.

For Philadelphia, the June-August seasonal total of 7.45 inches
is so far, the 12th driest summer...again this presumes no further
measurable rain in August.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Beach Hazards Statement through Wednesday evening for NJZ014-
     024>026.
DE...Beach Hazards Statement through Wednesday evening for DEZ004.
MD...None.
MARINE...None.

&&

$$
Synopsis...Iovino
Near Term...Gaines
Short Term...Gaines
Long Term...Iovino
Aviation...Gaines/Iovino
Marine...Drag/Gaines/Iovino
Climate...Drag



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.