Area Forecast Discussion
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FXUS61 KPHI 250152
Area Forecast Discussion
National Weather Service Mount Holly NJ
952 PM EDT FRI JUN 24 2016
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/...
The remaining showers over Chester County and Cecil County will
will dissipate shortly. The light northeasterly flow should bring
dry air into our region. However, we continue to think that low
clouds and fog will expand tonight in areas that received heavy
Minimum temperatures should be mainly in the upper 50s and lower
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM 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 NIGHT 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 /02Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Low clouds remained over KACY and KMIV this evening. The low
clouds are forecast to expand northward overnight and they should
impact KILG, KPHL and KPNE. There seems to be a lesser chance that
they will reach KTTN, KABE and KRDG. However, we have maintained
their mention at those three locations for the sake of
continuity. Conditions are expected to improve rapidly on
Saturday morning with the sky becoming mostly clear by 1400z. VFR
conditions are then anticipated for the balance of the day.
A light northeast to east wind is expected for overnight and
Saturday with the wind direction forecast to veer toward the
southeast late in the day.
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
Wednesday: VFR. Northwest winds around 10 knots.
Onshore flow will continue overnight and Saturday with high
pressure building in from the north. Seas have been steady around
3-4 ft 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 on Sat with the onshore flow. High
pressure will bring lighter winds and lowering seas Sun. Risk on
Sun will likely be less than Sat.