Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 200556

Area Forecast Discussion
National Weather Service Mount Holly NJ
156 AM EDT Sun May 20 2018

A warm front will continue lifting northward through our region
this evening. A cold front approaching from the northwest is
forecast to arrive late on Sunday. The boundary is anticipated
to stall to our south on Monday. Weak low pressure is expected
to move from the eastern Great Lakes to New England on Tuesday
and Tuesday night and it should pull another cold front through
our region early on Wednesday. The front is forecast to stall to
our south as weak high pressure influences our weather on
Thursday and Friday. The boundary may return northward as a warm
front next weekend.


The warm front is continuing to lift northward across the area.
South of the frontal boundary, the dense fog is lifting. For the
areas where the dense fog has dissipated, we will cancel the
Dense Fog Advisory, although there will remain areas of light
fog and low clouds overnight. For areas north of the frontal
boundary, especially across far eastern Pennsylvania and north-
central New Jersey, there remains some patchy dense fog, so we
have extended the Dense Fog Advisory there. These areas should
have improving visbilities in the next couple of hours as the
front continues lifting northward as well.

Otherwise, cloudy conditions will continue across the area with
areas of light fog, drizzle, and scattered showers through the
remainder of the night.


For Sunday, area will be firmly in the warm sector to start the
day as low pressure moves northeast through Quebec. Don`t
really expect any sun though as low levels will remain quite
saturated in southerly flow and there will continue to be some
showers, mist, and drizzle around. Heading into the late morning
through the afternoon, the cold front will push south with
time...reaching the I-95 corridor by mid afternoon and southern
NJ across the Delmarva by evening. This front will be the focal
point for more scattered showers and storms to
develop...especially during the afternoon from the I-95 corridor
S/E. Some good news is the the mid and upper levels will be
drying out and the upper forcing will be shifting off to the
east. This may tend to limit the coverage of showers and storms
but nevertheless, PWATs will still be quite high (1.7+ inches)
and with the saturated ground any showers/storms will be a
concern for additional hydro issues...mainly of the urban and
small stream variety. Temperatures will be much warmer as there
will also be some sun developing by afternoon...highs will be
mainly in the upper 70s to low 80s except cooler in the far
north across the southern Poconos. Dew points will also be in
the upper 60s ahead of the front so it will feel very humid
until the front clears the area by tomorrow night.


The long-term forecast period will begin with a mid level
trough over eastern Canada and the northeastern states on Sunday
night. The feature is expected to progress slowly eastward
during the course of the week. A ridge is anticipated to build
overhead from the west on Friday and Saturday.

Conditions are expected to remain in flux during the first half
of the work week. Dry air is forecast to push down from the
north for Monday in the wake of a frontal boundary. However, the
boundary and moisture should build back to the north on Monday
night and Tuesday. We will keep the forecast rain-free for
Sunday night and most of Monday, then we will indicate a chance
of showers and an increasing potential for thunderstorms from
Monday night into Tuesday.

Weak low pressure is forecast to pass to our north on Tuesday
night and it should pull a cold front through our area early on
Wednesday. We will keep a chance of showers and thunderstorms
for Tuesday night in advance of the front.

A more substantial shot of dry air is expected for the second
half of the work week. We are not anticipating any precipitation
from Wednesday through Friday as the frontal boundary stalls
well to our south and as ridging begins to build overhead from
the west.

The forecast for Saturday could go either way at this point. We
will not mention any precipitation at this time. However, with
a southerly flow becoming established and with the mid level
ridge axis moving to our east, we may eventually need to
introduce a chance of afternoon showers and thunderstorms.

Temperatures for the period from Sunday night through Saturday
are expected to be typical for this time of the year with highs
mainly in the 70s and lower 80s, and lows in the 50s and 60s.


The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...IFR/LIFR CIGs/VSBYs with areas of light fog, and dense
fog remaining at TTN. Light/variable winds may become
predominantly southerly late. Moderate confidence.

Sunday...IFR CIGs may persist through much of the morning,
though VSBYs are forecast to improve gradually to MVFR/VFR after
12Z. MVFR to VFR conditions are expected everywhere by mid
afternoon (though exact timing is quite uncertain) as southwest
winds increase to 10 to 15 kts with occasional gusts to 20 kts
possible. Low confidence.

Sunday night and Monday...Mainly VFR. Some late night and early
morning visibility restrictions are possible.

Monday night through Tuesday night...A chance of showers and
thunderstorms. Conditions varying between VFR and MVFR. Brief
periods of IFR may occur in precipitation.

Wednesday through Thursday...Mainly VFR. Some late night and
early morning visibility restrictions are possible.


730 pm update: Dense fog advisory issued for the coastal NJ
zones, as webcams are indicating dense fog hovering just off the
coast. With dew points increasing atop the cold ocean waters, do
not expect this fog to dissipate through much of the morning

Previous discussion...

A Small Craft Advisory remains in effect. While winds continue
to see a lull in many areas expect them to increase again by
later this evening through tonight. Also, there will be some
showers around tonight along with patchy fog, especially for the
northern waters, and this may lead to reduced visibilities.

For Sunday, SCA conditions continue over the ocean waters as SW
winds gust up to 25 knots and seas will be around 5 ft.
Conditions should be below SCA levels over the Delaware Bay.
There will be some scattered showers around with the chance of
thunderstorms, especially in the afternoon.

Sunday night...A Small Craft Advisory is in effect until 10:00
PM Sunday for our ocean waters to allow wave heights to fall
below 5 feet. West wind around 10 knots becoming north.

Monday through Thursday...No marine headlines are anticipated.


PA...Dense Fog Advisory until 6 AM EDT early this morning for
NJ...Dense Fog Advisory until 6 AM EDT early this morning for
MARINE...Dense Fog Advisory until noon EDT today for ANZ450>453.
     Small Craft Advisory until 10 PM EDT this evening for
     Small Craft Advisory until 6 AM EDT early this morning for



Near Term...CMS/Fitzsimmons/Robertson
Short Term...Fitzsimmons
Long Term...Iovino
Marine...CMS/Fitzsimmons/Iovino is the U.S. government's official web portal to all federal, state and local government web resources and services.