Area Forecast Discussion
Issued by NWS Mt. Holly, NJ-- Remove Highlighting --
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FXUS61 KPHI 311739
Area Forecast Discussion
National Weather Service Mount Holly NJ
139 PM EDT TUE MAY 31 2016
A frontal boundary will stall over the area today before dissipating
late tonight into Wednesday morning. High pressure builds in from
eastern Canada Wednesday and Thursday. A cold front will approach
from the west Thursday night and move through the Mid-Atlantic
region on Friday. High pressure briefly builds in Saturday. An area
of low pressure is forecast to move across the Great Lakes region
late in the weekend and then pass to our north early next week. A
cold front associated with this low pressure system will move
through during this time.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A weak cold front is dissipating across the area late this
morning and is along the i-95 corridor. Some cu development across
the Delmarva and srn NJ points to where the richer sfc moisture is
beginning to mix out with the sun. Sct showers will probably
develop across srn Delaware later this afternoon, so we will
continue with the low chc/slgt chc pops for these areas. The
temps/dew point and winds grids are mostly ok too. Wind direction
is rather variable across the Delaware Valley. Generally
srly/serly winds further south and mostly north or northeast
across ern pa and nrn nj. wind speeds mostly 5 to 10 mph.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
The high to our north will continue to influence our weather through
tonight. The remnant moisture will exit the region for good and all
areas should remain dry overnight. Enough low level moisture across
the region may result in some patchy fog forming, especially across
the southern zones.
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Wednesday and Thursday...High pressure builds down from Hudson
Bay Wednesday morning. The high will then shift eastward toward
the Canadian Maritime with it`s ridge axis extending southwestward
along the New England coast and Mid-Atlantic states Wednesday
afternoon through Thursday. With moisture returning back northward
around the periphery of the high, there is a potential for showers
to develop across eastern PA/MD during peak heating both Wednesday
and Thursday. Kept coverage of showers isolated and confined to
our far western forecast zones since models are showing a lack of
organized /larger-scale lift over us while the low-level theta-e
ridge and axis of convective instability develops farther inland.
Temps will be cool in the coastal plain and at the beaches on
Wednesday thanks to the onshore flow that develops under this
setup. There is an opportunity for highs to reach the lower 80s
from the Delaware Valley, westward with a fair amount of sunshine
to start the day. Slightly cooler temps (at or just below climo)
anticipated for Thursday as the onshore flow persists for a second
day, allowing for the marine layer and accompanied stratocu deck
to become better established across the entire area, even inland
Friday...High pressure along East Coast retreats offshore late in
the week as a cold front approaches from the west. The front looks
to make slow progress through our region Friday, perhaps not
moving offshore until Friday night. Meanwhile, the remnants of
Tropical Storm Bonnie that was stalled near the Southeast Coast is
forecast to finally lift northeastward and out to sea. Some of its
tropical moisture could be drawn poleward up the Eastern Seaboard
within the pre- frontal warm sector ahead the cold front. This
could enhance coverage of showers and storms as well as rainfall
amounts. The risk of locally heavy rainfall will depend on the
interaction between these systems and other environmental factors
on the mesoscale. Opted to keep any mention of a flooding threat
out of HWO for now given the limited support in the QPF fields
from forecast guidance and the limited predictability inherent
with determining the finer details on the mesoscale several days
Saturday through Monday...The first half of the weekend looks to
be dry assuming the cold front has already moved offshore and high
pressure builds in from Canada. Precip chances increase later in
the weekend into early next week as an area of low pressure is
forecast to move into the Great Lakes on Sunday and the Northeast
on Monday. There is a chance for showers and thunderstorms during
this time along and ahead of the attendant cold front that is
forecast to move through our area. Near-normal temps will prevail
during the extended part of the forecast period.
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
VFR has returned to the Delaware valley and Lehigh Valley
terminals. Winds rather light and variable. This should continue
into the afternoon.
With light winds expected, a sea breeze will likely develop along
the coast and will make it inland to KACY and possibly reach KMIV.
A few showers may develop this afternoon but are expected to
remain to the south of the terminals. Fog may form again tonight,
especially south and east of KPHL.
Wednesday and Thursday...Light east to southeast winds. Marine
stratocu deck may result in MVFR cigs along the coast Wednesday
afternoon/night that expands inland by Thursday. IFR cannot be ruled
out along the coast overnight Wednesday and then overnight Thursday
across any of the terminals. Low confidence in timing/coverage of
these CIG restrictions.
Friday...MVFR with low clouds and fog at the start of the day
improves to mainly VFR by midday. Chance of showers and storms.
Temporary flight restrictions possible in heavier activity.
-- Changed Discussion --We have discontinued the Dense Fog Advisory that was in effect
earlier. The recent webcams and visible satellite images reveal
that the fog has diminished. More fog may redevelop tonight.
Winds and seas will remain below SCA flag conditions this
afternoon and tonight. Winds near the coast will be onshore at 5
to 10 knots.
Wednesday through Saturday...Winds and seas below SCA criteria
through much of the outlook period. Winds will be under 20 kt and
generally onshore through Friday. They may briefly become more
northerly behind a front Friday night or Saturday. Seas in our
coastal Atlantic zones will mainly be between 2 and 4 ft throughout
-- End Changed Discussion --
Onshore flow is expected to develop on Wednesday and continue
into Friday. We will need to monitor the possibility of minor
tidal flooding at times of high tide along the coast late this
week owing to the persistent onshore flow and the approaching new
moon this Saturday.
-- Changed Discussion --PA...None.
-- End Changed Discussion --