Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
352 PM EDT sun Aug 28 2016
high pressure centered in the Nova Scotia vicinity this afternoon
will lose its influence over our weather tonight. A weak frontal
boundary approaching from the northwest is forecast to arrive on
Monday. The front is expected to stall and slowly dissipate on
Tuesday. Tropical Depression Eight is anticipated to pass well to
our southeast 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
Near term /until 6 am Monday morning/...
high pressure continues to influence our weather through tonight.
The high has shifted to the east and is presently sitting over the
Canadian Maritimes. Meanwhile, a cold front will be making its way
through Pennsylvania during the overnight hours.
With the high in control, we anticipate another dry night across
the region. Showers and thunderstorms are developing across
central Pennsylvania but they are expected to dissipate as they
move to the east and even more so as the sun sets.
There is still enough low level moisture around that patchy fog
is possible late tonight towards early morning.
Skies will remain mostly cloud free through much of the night but
we will start to see some clouds moving in from the west, mainly
towards Monday morning across our northern and western areas.
Temperatures will be kind of similar to last night but milder as
some moister and warmer air pushes in on the developing southerly
flow. Expect upper 50s to lower 60s across the northern areas with
mid 60s to around 70s across the southern and urban areas.
Short term /6 am Monday morning through 6 PM Monday/...
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 /Monday 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 /20z Sunday through Friday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
Tonight...mainly VFR conditions expected. The light winds that we
have had today will remain light overnight but will start to veer
more to a south to southwesterly direction. Skies will remain
mostly clear through this evening but some high clouds may start
to arrive late tonight. Some patchy fog is also possible once
Monday...low clouds/fog are expected to clear out by 14-15z with
VFR conditions expected through the remainder of the taf period.
Light west to southwest winds around 10 knots or less. 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 around 10 to 15 knots this afternoon will
turn more to south tonight. Seas will remain around 2 to 4 feet.
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
there is a moderate risk for enhanced rip currents into tonight.
The swells from distant tropical systems have yet to arrive. Winds
are onshore creating some enhanced surf conditions.
The long period swells from tropical cyclone Gaston should become
noticeable Monday as the cyclone turns northeastward from near 55
degrees west longitude. 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. We continue to expect an
enhanced threat for the development of dangerous rip currents for
much of the week with onshore winds Tuesday enhancing the risk.
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 is up to date through 5 am today-Sunday August 28.
Today's data are not finalized and have not been included.
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. 78.1 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... 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 27th.
Season mean Aug Aug Aug season
mean rer rer
Abe 32 17 11 4 16-1980 41-1966
Acy 27 10 10 3 11-2010 46-2010
Phl 37 21 13 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.