Area Forecast Discussion
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FXUS61 KPHI 271938
Area Forecast Discussion
National Weather Service Mount Holly NJ
338 PM EDT SAT AUG 27 2016
High pressure centered over southern Quebec this afternoon will
drift to the east. The high will continue to influence our weather
into Sunday. A frontal boundary approaching from the northwest is
forecast to arrive during the afternoon and evening hours on
Monday. The front is expected to stall and slowly dissipate on
Tuesday on Wednesday. A cold front from the northwest is
anticipated to pass through our region early on Thursday followed
by high pressure for Friday and Saturday.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
High pressure remains across the region and we have another
relatively nice night in the works.
Winds will diminish this afternoon and evening and should become
calm to light and variable across the region. Skies will remain
clear early on but with a light easterly flow across the region,
some low level cloudiness will start to work its way into the area
overnight. Expect cloudier skies towards the coast with less
cloudiness as you head to the north and west of Philadelphia. Some
patchy fog is also possible late tonight towards morning.
Temperatures will drop off tonight and into the 60s across the
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
High pressure will continue to influence our weather for Sunday.
Low clouds that move in from the east overnight should clear
during the morning and another relatively sunny day will had
across the region. Easterly winds will be light through the day,
around 10 mph or less.
Temperatures will be similar to today, with highs into the mid to
upper 80s to around 90 across the region. With an easterly flow in
place, shore points will be slightly cooler and remain in the
upper 70s to lower 80s.
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
A mid level short wave trough is anticipated to move across New
York State and New England during the afternoon and evening hours
on Monday. It should push a surface frontal boundary into our
region at that time. The guidance continues to suggest only a
limited potential for precipitation. A band of precipitable water
values around 1.7 inches is forecast to precede the front and
there should be marginal instability. We will keep the mention of
a slight chance of showers and thunderstorms.
It appears as though the boundary will dissipate slowly over or
near Maryland, Delaware and southern New Jersey. Drying is
expected to work its way into our region from the north for
Tuesday so we are not anticipating any precipitation at that time.
Temperatures are forecast to remain above normal for Monday,
Tuesday and Wednesday with highs around 90 and lows ranging from
the middle 60s to the lower 70s. Readings will be lower than those
values in the elevated terrain of the Poconos and northwestern New
A cold front is expected to approach from the northwest on
Wednesday. It looks as though our best chance of showers and
thunderstorms during the coming week will be on Wednesday
afternoon into Wednesday night in advance of the front. The
boundary should pass through our region early on Thursday.
High pressure is forecast to build from Ontario and the Great
Lakes on Thursday to the northeastern states on Saturday. The air
mass will be noticeably cooler and less humid than the one that it
will be replacing.
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...VFR conditions expected. Easterly winds will become
light this evening, going calm in some locations. Skies will
remain mostly clear through this evening. Guidance indicates that
low clouds will start to move in from the east overnight. Have
higher confidence in these clouds reaching KACY and KMIV and have
added BKN015 for late tonight into early Sunday morning. Lesser
confidence as you head to the west and only indicate a SCT015
group inland. Some patchy fog is also possible overnight.
Sunday...low clouds are expected to clear out by 14-15Z with VFR
conditions expected through the remainder of the TAF period. Light
southeast winds around 10 knots or less.
Sunday 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.
Sub-advisory conditions are expected to continue on the area
waters through Sunday. Easterly winds around 10 to 15 knots across
the area waters. Seas around 2 feet tonight, increasing to 2 to 4
feet on Sunday as we start to see the swells arrive from distant
Tropical Storm Gaston.
Sunday night through Thursday...No marine headlines are
There is a moderate risk for enhanced rip currents today. The
swells from distant tropical systems have yet to arrive. Winds are
onshore today creating some enhanced surf conditions.
The long period swells from Tropical Cyclone Gaston should arrive
Sunday as the cyclone nears 55 degrees west longitude. However,
the long period 12 to 15 second swells are forecast to become more
pronounced along the coasts of New Jersey and Delaware on Monday
and Tuesday, even as Gaston makes its turn northeastward. Momentum
in the swells reaching our coast due to the original westward
motion of the tropical system should result in an enhanced threat
for the development of dangerous rip currents for much of the
Presuming these swells occur as outlined above, this will
eventually impact beach behavior. Follow the advice of local
lifeguards who will be observing and your safety net. 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.
This section will be reviewed daily through Wednesday morning but
unless there is some sort of major change in the ranking...am not
anticipating a repost until Monday or Tuesday morning.
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 3 to 5 more 90 degree days to
add onto the 12 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 at least 5 degrees.
1. 78.2 1980
2. 76.7 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.
1. 78.0 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. 78.9 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 26th.
season mean Aug Aug Aug Season
mean rer rer
abe 31 17 10 4 16-1980 41-1966
acy 27 10 10 3 11-2010 46-2010
phl 36 21 12 5 17-1995 55-2010
ilg 31 20 12 5 23-1895 59-1895
Decided not to post dry rainfall statistics due to uncertainty
regarding shower amounts, if any Monday and Wednesday.