Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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961
FXUS61 KPHI 231403
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1003 AM EDT Wed Aug 23 2017

.SYNOPSIS...
A cold front was moving slowly southeastward to the southeast
of the Delmarva Peninsula today. High pressure is then expected
to build towards the northeastern U.S. and remain over our region
into early next week. A low pressure system off the East Coast
could affect our weather mid week next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
930 AM ESTF: adjusted temps, dews and sky a bit this morning
otherwise little change to the overall forecast and messaging.

Today...considerable cloudiness is still expected for extreme
southern NJ and the Delmarva today with a possible shower or
thunderstorm. Otherwise partly to mostly sunny north.
Seasonable temps and slowly drying dewpoints.

Tonight...Clearing skies and cold air advection with nearly calm
wind will promote below normal temperatures across the region.
The one question will be if we will see any fog development
overnight. At this point, have not mentioned it in the forecast
as we should also see considerable dry air advection behind the
front.

&&

.SHORT TERM /THURSDAY/...
Thursday...Fair. Scattered light showers still possible late
in the day in e PA with considerable afternoon cloudiness.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
This forecast was not changed since 330 PM yesterday due to the
overnight thunderstorms.

500 MB: a -2SD trough begins the long term period in the Great
Lakes region, then weakens slightly as it moves into the
northeast Friday-Monday. Thereafter, we will monitor the
northeastward progress of what should be a split flow low of
tropical origins, having moved ashore along the Gulf Coast by
early next week.

Temperatures: Calendar day averages 2 to 6 degrees below normal
daily Friday-Tuesday.

Forecast basis: a 50 50 blend of 12z/22 GFS/NAM MOS was used
Wednesday night-Thursday night, then the 12z/22 GFS MEXMOS was
applied Friday and thereafter the 15z/22 WPC D4-8 gridded
elements of max/min T, 12 hr POP 6 hourly dew/wind/sky.

Friday-Monday...High pressure shifts southeastward into the
Great Lakes Thursday through Saturday,then eastward into
southeastern Canada/Northeast U.S. Sunday and Monday. This
expansive high will control our regional weather pattern across
the Mid Atlantic during this time. The trough aloft could result
in a shower north of I-78 Friday afternoon and there should be
considerable cloudiness at that time. Otherwise, for now, good
weather is predicted.

Tuesday...WAA overrunning clouds, if not rain, from a potential
tropical remnant moving northeastward from the Gulf coast.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today... VFR with sct-bkn clouds aoa 5000 ft. Generally a light
northwest wind with possible gusts 15 kt.

tonight...VFR clear. nearly calm wind.

Thursday...VFR sct-bkn clouds aoa 5000 ft. light mostly
northwest wind may sea breeze along the coast.


Outlook...
Thursday night through Sunday...VFR. Generally light winds from
the N or NW, possibly becoming N-NE on Saturday and Sunday.
small chance of a light shower vicinity KABE/KTTN/KRDG Thursday
afternoon and Friday afternoon.

&&

.MARINE...
No headlines through Thursday. Northwest winds today may sea breeze
later this afternoon. Winds become light north overnight and again
northwest tomorrow morning before sea breezes are seemingly more
likely to develop Thursday afternoon.

Outlook...
Thursday night through Saturday...Winds and seas below SCA
criteria.

Sunday...For now, no SCA headline but chance that northeast
flow will increase and cause hazardous seas to develop along the
S NJ and DE coasts Sunday afternoon (5 feet).


Rip Currents...
We are forecasting a low risk for the formation of dangerous rip
currents today as earlier elevated seas are slowly diminishing.
Conditions are expected to improve (i.e. the risk should lower)
through the day.

Outlook for Thursday through Saturday is currently indicating LOW
risk. That doesn`t mean NO risk but sensible decision making
for swimmers with ultimate safety, swimming within the watchful
gaze of the life guards. Stay away from jetties/piers.

Early next week... the risk for the formation of dangerous rip
currents may increase depending on the the actual development-
building of 8 second easterly swells

&&

.CLIMATE...
KABE monthly rainfall is now 8.34 inches...still ranked #12 for
the month of August. The record is 13.47 inches in 2011.

&&

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

&&

$$
Synopsis...Johnson
Near Term...Drag/Johnson 1003
Short Term...Drag/Johnson 1003
Long Term...Drag 1003
Aviation...Drag/Johnson 1003
Marine...Drag/Johnson 1003
Climate...1003



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