Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
FXUS61 KPHI 241941
Area Forecast Discussion
National Weather Service Mount Holly NJ
341 PM EDT FRI JUN 24 2016
A cold front over Northern Delaware and southern New Jersey will
continue to gradually push south into this evening. This weekend, a
high-pressure system will build over the region. A frontal system
will move through our area by mid-week. A high-pressure system will
build over our region later in the week.
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Scattered convection has developed in the heat of the
day across the Delmarva and Srn NJ. There are also more isolated
showers across ern and se PA too. The activity has been moving
rather slow, prompting a SVR and some FFWs for the area. These
showers/tstms should continue for the next few hours before
decreasing this evening. The onshore flow will continue overnight
with high pressure building down from the north. Low clouds and
patchy fog will be across the area, especially where the present
rains are. We will mention fog across the north too, where more of a
patchy radiation fog is psbl. Low temperatures tonight will be in
the upper 50s to low 60s in most areas and mid 60s over the Delmarva
and metro Philadelphia.
.SHORT TERM /6 AM SATURDAY THROUGH 6 AM SATURDAY/...
High pressure will continue to build in Saturday. There will
likely be some lingering clouds and fog, especially along the NJ
shore areas during the morning. After the mid-morning, mostly
Sunny skies are expected. Winds will continue to be from the E or
NE at 5 to 10 mph. High temperatures will reach into the low to
mid 80s in most areas.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
Saturday night: A clear night with light winds and conditions
favorable for radiational cooling. Some patchy fog is possible as
well just before sunrise when higher RH values correspond with the
Sunday and Sunday night: High pressure will be moving eastward and
offshore resulting in another dry but hotter day. A look at actual
model data shows the ECMWF to be several degrees warmer than the
GFS. Boundary layer temperature output on both occasions supports
the model output. Given the dry conditions from Philadelphia and
points north this forecast and recent cool biases with model data,
this forecast is in line with the warmer ECMWF. High temperatures
will push the mid and upper 80`s in most of the region, with the
highest readings in the Lehigh valley and the cooler readings down
by the shore. Southerly flow will result in a warmer and muggy night
as well Sunday night.
Monday through Wednesday: A cold frontal boundary will move from the
Great lakes southwestward through the region in this time frame. A
few mid-level shortwaves ahead of this front will likely serve as
triggers for scattered showers and thunderstorms in a warm and humid
air mass. The most likely window for rain based on current ensemble
data stretches from Monday night through Tuesday night. However,
given uncertainty in timing and coverage will continue with chance
pops. This will likely not dent the drought across the northern half
of the region. The actual cold front will likely move through on
Wednesday with a cooler and drier airmass moving in behind the
front. Winds will be southerly from 5 to 15 mph throughout the early
part of the week.
Wednesday night through Friday: High pressure will build
southeastward into the region with a cooler and drier airmass.
Leaned at or warmer than ensemble guidance here given the dry
ground and recent temperature biases the past few weeks. Winds
generally westerly to southwesterly at around 10 mph.
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Most of the area remain under VFR conditions early this afternoon.
The southern TAF sites have lower clouds and scattered tstms nearby.
We have kept a mention of tstms and low mvfr conditions at KACY/KMIV
and KILG into the afternoon. The shower activity is moving very
slowly with the weaker winds aloft. A few showers could develop
further north in the Lehigh Valley according to some of the local
fcst models. We have left any shower activity out of the tafs attm
with amds possible later. Winds will remain erly at 10 to 15 kts.
Tonight...The showers will diminish this evening then skies will
clearing from N to S. We will likely hold onto some low clouds across
the srn areas. Any breaks will result in fog development across the
srn areas. Low clouds could affect KPHL/KPNE and up into KTTN also.
We have decided to preserve some of the earlier clouds in the fcst.
The guidance doesn`t mention much in the way of low clouds, but the
pattern seems to favor it. Winds tonight light from the NE or E.
Sat...VFR conditions expected after any low clouds or morning fog
dissipates. Winds will be east at around 10 knots by early
Sunday and Sunday night: VFR. Southwest winds around 10 knots.
Monday through Tuesday night: Mainly VFR. Some scattered
thunderstorms will reduce vsbys and ceilings to MVFR and IFR at
times. The highest chances for any storms are on Tuesday. Southwest
winds from 5 to 15 knots, highest Monday and Tuesday afternoon.
Wednesday: VFR. Northwest winds around 10 knots.
Onshore flow will continue tonight and Saturday with high
pressure building in from the north. Scattered thunderstorms across
the srn NJ and DE waters this afternoon will diminish this evening.
patchy fog is possible tonight. Seas have been steady around 3-4 ft
so far today and this will continue tonight. Seas will tick up
closer to SCA criteria seas Saturday. Confid is still not the
greatest however, we`ll just mention 4 ft seas attm and hold on the
SCA flag for now. Fair weather expected Saturday.
Saturday night through Wednesday:
Seas will remain under five feet throughout the period. The
highest seas around four feet are likely to occur into Sunday then
again on Tuesday. Top wind gusts will top out around 20 knots both
Monday and Tuesday afternoons from the south.
Moderate risk for rip currents the rest of today
and probably Sat also. High pressure will bring lighter winds and
lowering seas Sun. Risk on Sun will likely be less than Sat.