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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 250118
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
918 PM EDT Sat Jun 24 2017

.SYNOPSIS...
High pressure will attempt to build into the mid- Atlantic
region overnight and Sunday. However some trofiness will
persist over the Great Lakes and New England through Tuesday.
Stronger high pressure is forecast to build in for Wednesday and
then move offshore Thursday and Friday. A frontal system
approaching from the northwest may bring a chance for showers
Friday and Saturday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A shortwave surface ridge is expected to build close to the
region overnight. That combined with the continued dry air
advection in the wake of the cold front this morning means dry
conditions and clearing skies through the overnight hours.

Thanks to the drier conditions and clearing skies, temperatures are
expected to drop off a bit more than what we have seen the last few
nights. Low temperatures are expected to range from the upper 50s to
near 70.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
The surface ridge will weaken quickly as a mid and upper level
shortwave trough digs southeast towards New England. The lift
associated with this feature may be enough for convective
initiation across the Poconos and NW NJ, but we aren`t expecting
any widespread precipitation as we will remain quite dry
through the day tomorrow.

Temperatures tomorrow are expected to be near or just below
temperatures today as the northwesterly flow regime redevelops.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Monday and Monday night...Another cold front is expected to
move through the region through this period. In the mid and
upper levels, a positively tilted short wave trough will be
trailing close behind. Despite ample lift and upper level
support, do not expect too much in the way of precipitation
across the region primarily because we are not expecting any
significant moisture advection before this period.

An upper level trough remains over the eastern US on Tuesday
with some associated surface trofiness as well. Guidance
supports just a slight chance for showers or an isolated
t-storm. Then stronger surface high pressure builds in over the
mid-Atlantic region on Wednesday as the upper trof moves
offshore. At this time Wednesday looks to be dry with slightly
below normal temperatures continuing from Tuesday.

On Thursday and Friday the high pressure moves offshore and low
pressure moves across the Great Lakes. This sets up a southwest
flow around the sub-tropical ridge with increasing heat and
humidity towards the end of the week. A frontal system is
forecast to approach from the northwest but is not expected to
reach the area. However the increasing low-level moisture and
typical surface trof in the lee of the mountains will make
conditions favorable for afternoon showers and t-storms,
especially north/west of PHL. High temperatures a few degrees
above normal are expected Thursday through Saturday.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

VFR conditions are expected through the TAF period. Some mid level
clouds near or above 5000 ft AGL may move over the region after 03Z.

Winds are expected to subside to near or below 10kt by 00Z. Wind
direction may back to westerly overnight. Around 18Z tomorrow,
expect wind speeds to once again increase with 10g20kt possible for
much of the afternoon at all TAF sites.

OUTLOOK...

Sunday night through Monday night...Mostly VFR conditions are
expected. There is a small chance for showers and thunderstorms
Monday and Monday night. If any move over the TAF sites, MVFR or
lower conditions will be possible.

Monday and Tuesday...Mostly VFR but a chance for tempo lower
conditions in isolated thunderstorms, mainly for ABE and RDG.
West wind mainly 10 kt or less.

Wednesday and Thursday...VFR condions expected. Light west winds
on Wednesday become southwest on Thursday with gusts to 20 kt
possible in the afternoon.

&&

.MARINE...
Winds and seas have subsided below SCA criteria across the
Delaware Bay and the coastal waters south of Little Egg Inlet.
However...seas remain just over the 5 foot critera north of
Little Egg so a SCA continues in those locations through most of
the overnight hours. Below SCA conditions are expected
everywhere on Sunday.

OUTLOOK...

Sunday night through Monday night...Winds and seas should
stay below SCA criteria.

Tuesday and Wednesday...Winds and seas are forecast to remain
below SCA conditions.

Thursday...SCA conditions may develop in the afternoon.

&&

.TIDES/COASTAL FLOODING...
Water levels at the time of high tide this evening are expected
to approach but not quite exceed minor threshold
levels...especially considering the offshore flow...so no
coastal flood advisories have been issued. A similar situation
may develop again with Sunday evening`s high tide.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 5 AM EDT Sunday for ANZ450-451.

&&

$$
Synopsis...AMC
Near Term...Johnson/Miketta
Short Term...Johnson
Long Term...AMC/Johnson
Aviation...AMC/Johnson/Miketta
Marine...AMC/Johnson/Miketta
Tides/Coastal Flooding...Miketta