Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 290148
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
948 PM EDT TUE JUN 28 2016

.SYNOPSIS...
Low pressure along a cold front was crossing the mid Atlantic
states this evening. That front drifts offshore on Wednesday. Weak
high pressure builds in for Thursday. A cold front approaches from
the west on Friday and moves offshore Saturday. High pressure
follows later Saturday into Monday. A strong warm front should be
moving northeast toward our area on Tuesday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Severe Thunderstorm Watch 305 has been cancelled in our forecast
area. While scattered showers and thunderstorms will persist into
the overnight hours, the threat for damaging wind gusts and hail
has ended.

An outflow boundary from the earlier convection over the Lehigh
Valley and northwestern New Jersey was pushing down into
southeastern Pennsylvania and central New Jersey around 930 pm. As
the boundary continues to move southward, additional showers and
thunderstorms will develop in its wake. Locally moderate to heavy
rain is possible. Meanwhile, a cold front will continue to drift
into our region from the northwest.

The shower and thunderstorm activity is forecast to diminish
gradually late tonight leaving a fair amount of low level
moisture. There will not be much wind associated with the cold
front so we are anticipating low clouds and patchy fog to develop.

Minimum temperatures should be mainly in the 60s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Wednesday should be a very nice day. The cold front will either
be offshore, or moving offshore at the start of the day. We are
not expecting any showers to be affecting the area, but if there
was any showers, it would be near the frontal boundary.

After any morning fog/low clouds burns off, a nice day should
develop across the area. Some scattered cumulus cloud build up is
expected during the day, but we`ll be precipitation free. We are
expecting close to normal, or slightly above normal temperatures
for Wednesday, even with the light northwest flow.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
500MB: A -1SD short wave trough over the eastern Great Lakes
Tuesday night weakens during mid week at the expense of a more
significant trough (-2SD) developing over southeast Canada late
Friday and Saturday. Eventually ridging follows into the northeast
USA early next week.

Temperatures: June, through the 27th has averaged 1 to 2 degrees
above normal at PHL, RDG, ABE, and TTN, near normal at ILG/ACY,
0.6F above normal at GED and surprisingly a degree below normal at
MPO. Calendar day averages the next week or so should be within 3
degrees of normal... nothing notable. So the monthly average
should be very close to the monthly departures posted above and
also available in our preliminary CF6 within the MT Holly climate
web link.

Forecast basis: Unless otherwise noted, a 50 50 blend of the
12z/28 GFS/NAM MOS guidance Wednesday night - Thursday night,
thereafter the 12z/28 GFS MEX MOS for Friday and WPC Guidance
Friday night- Tuesday. I did take into account the 12z/28 ECMWF op
run and added several degrees to some of the max`s Thu-Mon,
especially north of PHL near I78 north to the northern border.
Saturday: raised temps almost all the way to the coast where near
90F possible on a west or west southwest wind.

The dailies...

Wednesday night through Thursday...High pressure briefly builds
in, in the wake of the cold front. Nice seasonable summer weather.
Confidence: Above average.

Thursday night...waa may still bring a shower or thunderstorm to
the DE coast. Patchy fog probable parts of the area, especially
favored nw NJ valleys. Confidence: average.

Friday...a chance of showers and thunderstorms ahead of the next
cold front, otherwise partly to mostly sunny, very warm and more
humid. Heat index lower 90s. Confidence: average.

Saturday...Rainfree and very warm, lower dewpoints. Confidence:
above average.

Sunday through Monday Independence Day...Weak high pressure
should build in for Sunday and Independence Day. Thus at this
point, we still expect this period to be dry. Nice summer weather
for the outdoor celebrations. Confidence: Average. the reason its
only average is that am a little concerned about thunderstorms
moving into the area Monday afternoon ahead of a developing strong
warm front.

Tuesday...Depending on how quickly the high shifts off shore, low
level flow will shift to southerly sometime on Tuesday, bringing
warm air and moisture advection. Forecast is rainfree at this time
but warm frontal thunderstorms are a concern. Confidence: below
average.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Scattered showers and thunderstorms will persist in our region
and they should diminish gradually after midnight (0400Z). A good
deal of lingering low level moisture will likely result in the
development of low clouds and patchy fog.

Conditions are forecast to improve rapidly between about 1200Z
and 1400Z with VFR expected for the balance of the TAF period.

A light and variable wind overnight is forecast to settle into
the northwest and west for Wednesday around 5 to 10 knots.

Outlook...
Confidence on the days listed below is generally above average.

Wednesday night through Thursday...VFR. Light northwest wind
become southerly late day. Confidence: above average.

Thursday night through Friday...MVFR and brief IFR conditions
will be possible with any showers and thunderstorms that move
through the region during this time...probably mainly Friday.
Patchy IFR stratus/fog possible early Friday morning.

Saturday...VFR. west to northwest wind.

Sunday...VFR.

&&

.MARINE...
Sub-Small Craft Advisory conditions will prevail across the
waters tonight through Wednesday. A cold front will move across
the waters early Wednesday, so southerly winds today/tonight will
become westerly/northwesterly on Wednesday.

A period of showers and possible thunderstorms will affect the
waters overnight, before dissipating.

Outlook...
Wednesday night through Sunday...winds and seas should remain
below SCA criteria. Although gusty winds are possible in the
vicinity of any thunderstorms Thursday night or Friday.

RIP CURRENTS...
Wednesday: at this time we are expecting a low risk with an
offshore wind and a southeast or east southeast swell of 2 to 2.5
feet at about 5 to 7 seconds.

Thereafter, the rip current risk will be low to possibly moderate
at times during the balance of this week through the weekend, in
part dependent on the amount of onshore wind. In other words, not
much change from the somewhat active month of June. AWARENESS:
weak swimmers for their own safety should swim only in the
presence of lifeguards. It is not worth being a rip current victim
by swimming near jetties, or after the lifeguards go home, or with
untrained weak swimming bystanders who wont be capable of saving a
distressed swimmer, except to call 911, which then could be too
late.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$
Synopsis...Drag
Near Term...Iovino
Short Term...Robertson
Long Term...Drag
Aviation...Drag/Iovino
Marine...Drag/Robertson


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