Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 231938
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
338 PM EDT Wed Aug 23 2017

.SYNOPSIS...
A cold front will continue to move well south of the region
tonight as high pressure begins to build in from the north and
west. The high will continue to build over the region through
early next week as it slowly shifts eastward, before it finally
shifts offshore by mid week. Around the same time, a low
pressure system will pass off the East Coast, to the south.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...

Remainder of this afternoon...considerable cloudiness for
extreme southern NJ and the Delmarva with scattered showers or
sprinkles. Otherwise partly to mostly sunny north. Seasonable
temps and slowly drying dewpoints.

Tonight...Clearing skies and cold air advection with nearly calm
or light north to northwest wind will allow temperatures to
drop to minimums of 0 to 4 degrees below normal.

Forecast is a 50 50 blend of the 12z/23 GFS/NAM MOS.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
Thursday...Probably a sunny start then considerable cu/sc
developing during mid afternoon. Scattered sprinkles are still
possible late in the day in ne and e central PA. light northwest
to northeast wind.

Max temp forecast is normal to 5 below normal.

Forecast is a 50 50 blend of the 12z/23 GFS/NAM MOS checked
against the 12z/23 ECMWF temps and multi operational model
qpf`s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Overall not much in the way of sensible weather for the long
term forecast as strengthening confluence aloft allows surface
high pressure to strengthen and build into the area. Forecast
soundings suggest perhaps some cumulus development each day,
then increasing onshore flow by Sunday as the high passes to the
north and low pressure begins to deepen off the Southeast coast.
Despite the overall drier air mass, will have to watch for
coastal stratus development into early next week with increasing
moisture beneath the inversion in onshore flow.

Much more uncertainty exists by mid week as low pressure passes
well to the south. One scenario if the low passes farther north
is some light overrunning precipitation. A more concerning
potential scenario to consider is how moisture from the remnants
of T.C. Harvey interact with an upper trough expected to move
into the area by mid week. Southwest-west flow may advect
tropical moisture northeastward, and despite model forecast
showing little in the way of QPF at the moment, there is
certainly potential for a wet mid-late week. Have edged a little
higher than deterministic guidance at this time. Both systems
will need to be closely monitored in the week ahead.

Temperatures will be close to or a few degrees below normal
through mid week.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of this afternoon...VFR with sct-bkn clouds aoa 5000 ft.
Generally a light northwest wind with possible gusts 18 kt.

Tonight...VFR clear or mostly clear. Light northwest to north
wind or calm.

Thursday...VFR clear to start, then sct-bkn clouds aoa 5000 ft
during the afternoon. Light mostly northwest wind may sea breeze
along the coast. Small chance of a sprinkle late in the day
vicinity of KRDG/KABE.


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 with spotty
southerly sea breezes late this afternoon. Winds become light
north overnight and again north to northwest tomorrow morning
before sea breezes are seemingly more likely to develop Thursday
afternoon.

Scattered mostly light showers late this afternoon s tip of NJ
and the lower DE waters.

Outlook...
Thursday night through Saturday...Winds and seas below SCA
criteria as high pressure builds across the area.

Sunday through Monday...As high pressure moves north of the
area then gradually eastward, onshore flow will begin to
strengthen. The increasing pressure gradient and prolonged
period of onshore flow will resulting in seas building to 5 ft
or higher along the S NJ and DE coasts.


Rip Currents...
Low risk rest of today for the formation of dangerous rip
currents as early morning elevated seas are slowly diminishing.
Conditions are expected to improve (i.e. the risk should lower)
through the afternoon. A northwest wind helps keep this
southerly 2 to 3 foot 6 second swell, manageable.

Outlook for Thursday through Saturday is currently indicating LOW
risk. That doesn`t mean NO risk, but REQUIRES sensible decision
making for swimmers with the 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...99
Near Term...Drag 338
Short Term...Drag 338
Long Term...99
Aviation...Drag 338
Marine...Drag 338
Climate...338



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