Scientific Forecaster Discussion
fxus61 kphi 211024
Area forecast discussion
National Weather Service Mount Holly New Jersey
624 am EDT Sat Sep 21 2019
high pressure located in North Carolina early this morning will
drift eastward and out to sea today and Sunday. A cold front is
expected to approach from the northwest on Monday and it should
pass through our region on Monday night. Another area of high
pressure is anticipated to follow for Tuesday and Wednesday. The
next cold front from the northwest is forecast to arrive late
on Thursday with high pressure expected for Friday.
Near term /until 6 PM this evening/...
the sky was clear overnight and the wind was light. Valley fog
developed in parts of eastern Pennsylvania and northern New
Jersey. The fog will lift and dissipate by mid morning.
A mid level ridge will remain over the eastern states today.
Surface high pressure located in North Carolina early this
morning will drift off the coast. The high will continue to
bring dry weather conditions to our region. We are anticipating
a mostly sunny sky with a few cumulus and some patchy cirrus
A light southwest to south wind will develop in our region on
the back side of the high. Maximum temperatures will favor the
lower and middle 80s. The readings will be about 8 to 10 degrees
above normal for September 21.
Short term /6 PM this evening through 6 am Sunday/...
a short wave trough is expected to ride over the mid level
ridge tonight. The axis of the trough is forecast to approach
our region from the west late tonight. The feature will not have
much moisture associated with it. As a result, we are
anticipating only some scattered cloud cover. Meanwhile, the
surface high will continue to move slowly out to sea.
The wind is forecast to become light and variable for tonight.
Low temperatures are expected to be mainly in the upper 50s and
the lower 60s.
Long term /Sunday through Friday/...
the mid level ridge over the eastern states will continue to
flatten on Sunday and Monday, as a trough moves from the Dakotas
to the Great Lakes. The axis of the trough is forecast to pass
over the northeastern states from Monday night into Tuesday. The
surface cold front associated with the mid level feature is
expected to move through our region on Monday night.
Surface high pressure will begin to lose its influence over our
weather on Sunday and Sunday night but not before bringing
another mostly sunny and warm day. The southwest to south
surface flow will result in a noticeable increase in humidity.
Monday will be very warm and humid with an increase in cloud
cover. As the cold front approaches from the west, there will be
a chance of showers in the afternoon, mainly in eastern
Pennsylvania and northern New Jersey. The chance of showers will
likely spread eastward into central and southern New Jersey,
northeastern Maryland and Delaware on Monday evening. Marginal
instability is anticipated, so we will keep the slight chance of
The cold front is forecast to push to our east and southeast
during the mid week period. High pressure is expected to build
from the Ohio River valley on Tuesday to the waters off the
southeast coast on Wednesday, bringing a couple of additional
dry days to our region.
Another mid level trough is forecast to pass across the Great
Lakes and the northeastern states from Wednesday night into
Thursday. It should pull a moisture starved cold front through
eastern Pennsylvania, northeastern Maryland, Delaware and New
Jersey late on Thursday. Surface high pressure is expected to
follow for Friday.
Above normal temperatures are anticipated for Sunday and
Monday. Readings should return near normal with lowering
humidity for Tuesday before both creep upward again from
Wednesday through Friday.
Aviation /12z Saturday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
Today...local MVFR/IFR conditions early this morning around
krdg and kilg, otherwise VFR under a mostly clear sky. West to
south wind 4 to 8 knots.
Tonight...VFR with scattered clouds developing. Variable wind 6
knots or less.
Sunday and Sunday night...mainly VFR. Southwest wind 5 to 10
Monday...mainly VFR. A chance of afternoon showers. Southwest
wind around 10 knots.
Monday night...mainly VFR. A chance of showers. Southwest wind
5 to 10 knots becoming northwest.
Tuesday...mainly VFR. Northwest wind around 10 knots.
Tuesday night...mainly VFR. Northwest wind 5 to 10 knots.
Wednesday...mainly VFR. Northwest wind 5 to 10 knots becoming
high pressure will continue to influence the coastal waters of
New Jersey and Delaware into tonight. The wind should settle
into the southwest and south around 10 to 15 knots.
Waves of 4 to 6 feet this morning should subside gradually to 3
to 4 feet during the course of the day. A Small Craft Advisory
remains in effect until noon for our coastal waters north of
Atlantic City, and until 4:00 PM for our coastal waters from the
Atlantic City area down to Fenwick Island, Delaware.
Sunday...no marine headlines are anticipated.
Sunday night into Monday night...southwest to south wind
gusting around 25 knots at times. Waves on our ocean waters may
build around 5 feet.
Tuesday through Wednesday...no marine headlines are
a long period easterly swell with a wave period of 12 to 14
seconds is expected to continue for today. Breaking waves are
forecast to be in the 3 to 4 foot range. As a result, there is a
high risk for the development of dangerous rip currents for
today along the coasts of Delaware and New Jersey.
The long period easterly swell is anticipated to persist into
Sunday. Wave heights will likely subside a bit, so we are
expecting a moderate risk of rip currents at that time.
New Jersey...high rip current risk through this evening for njz014-024>026.
Delaware...high rip current risk through this evening for dez004.
Marine...Small Craft Advisory until 4 PM EDT this afternoon for
Small Craft Advisory until noon EDT today for anz450-451.