Area Forecast Discussion
Issued by NWS Mt. Holly, NJ-- Remove Highlighting --
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FXUS61 KPHI 290409
Area Forecast Discussion
National Weather Service Mount Holly NJ
1209 AM EDT MON AUG 29 2016
-- Changed Discussion --A weak frontal boundary over western New York State will slide down
into our area later today, then slowly dissipate on Tuesday. Tropical
Depression Eight is anticipated to pass well to our southeast of our
area on Wednesday as a strong cold front nears our region from the
northwest. The front is expected to pass through eastern Pennsylvania,
New Jersey, northeastern Maryland and Delaware early on Thursday
followed by high pressure for Friday, Saturday and Sunday.
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.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Primary concerns this evening are chances for precip across the
Poconos and the development of fog.
In terms of precip, thunderstorms to our west will struggle to
make it east into our County Warning Area. Sufficient moisture,
lift, and instability are lacking. However, we have noticed some
mid-level clouds develop across the Poconos, where there is weak
low-level convergence and resultant moisture pooling. Some of
the high res guidance, mainly the HRRR, bring some very light
precip into Carbon and Monroe Counties, which the 12Z Euro also
hints at. For now, we have brought slight chance POPS into the
aforementioned areas between 02Z and 06Z, for sprinkles. Given
the lack of instability, no thunder is anticipated.
Patchy dense fog is also possible again tonight, but should be
confined further south into Delmarva, as cloud cover streams
into the Poconos, portions of the Lehigh Valley and northern
New Jersey. Nevertheless, some of the typically prone locations
may fog a bit, prior to the thicker cloud cover moving in.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
The cold front starts to make its way into our area on Monday
morning. However, there seems to be very limited moisture
associated with the front. Not expecting much in the way of
showers across the region and only mention an isolated shower or
thunderstorm for the late afternoon time frame.
Temperatures will again be similar to the weekend, with highs
into the mid to upper 80s to around 90 across the region. Shore
points will be slightly cooler and remain closer to the lower 80s.
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A weak short wave trough traveling in the mid level flow is
forecast to pass over the northeastern states on Tuesday. The
feature will bring additional drying to to region. As a result, we
are anticipating a mostly sunny sky on Tuesday. High temperatures
should approach 90 degrees except in the elevated terrain and
right along the coast where readings will likely not get above the
lower and middle 80s.
It appears as though Tropical Depression Eight will remain well
enough to our southeast on Wednesday as not to impact our land
areas. Meanwhile, a cold front is forecast to approach from the
northwest. Temperatures will remain quite warm ahead of the front.
Highs on Wednesday should be similar to those expected for
Tuesday. We will mention a chance of afternoon showers and
thunderstorms from the Interstate 95 corridor northwestward in the
developing lift in advance of the cold front.
The chance for showers and thunderstorms will overspread the
remainder of our forecast area on Wednesday night with some
lingering precipitation possible near the coast into Thursday
morning. The front is expected to work its way though our region
early in the day with the wind shifting to the northwest. 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 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.
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...Predominantly VFR conditions expected. Some patchy fog
is possible once again overnight, particularly at TTN, RDG, ACY,
and MIV, which may result in brief MVFR/IFR restrictions late.
Monday...Predominantly VFR conditions. Light west to southwest
winds around 10 knots or less will veer to the northwest late in
the afternoon, generally north of ILG, ACY, and MIV. An isolated
shower or thunderstorm is possible during the afternoon/evening.
Monday night through 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 through Friday...Mainly VFR.
Sub-advisory conditions continue on the area waters through
Monday. Easterly winds tonight will veer to the west across
the New Jersey waters, but an easterly component will remain
across the Delaware waters. Seas will remain around 2 to 4
Monday night through Friday...No marine headlines are
anticipated. However, long period swells may create rough
conditions in and around the inlets along the coasts of New Jersey
The much anticipated long period swells from Tropical Cyclone
Gaston have arrived this evening. These 12 to 15 second swells,
combined with waves in the surf zone around 3 feet, will lead to a
moderate risk for the formation of dangerous rip currents for
Monday along the NJ shore and Delaware beaches.
Looking ahead, the long period 12 to 15 second swells are forecast
to become more pronounced along the coasts of New Jersey and
Delaware on into Tuesday. We continue to expect an enhanced
threat for the development of dangerous rip currents for much of
the week, and in particular on Tuesday, due to onshore winds.
In terms of safety, follow the advice of local lifeguards who
will be observing. 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.
-- Changed Discussion --This section is up to date through 1205 AM Today-Monday August
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 is on its way for 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 3 to 4 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.
Allentown will probably 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
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.
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