Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 240139

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

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.


KDOX radar continues to show some light sprinkles moving off the
Delmarva. Should last another hour or so.

In the more rural parts of NJ and up in the Poconos, the
combination of clear skies and light winds along with relatively
low dewpoints has resulted in pretty decent radiational cooling
this evening. Temps in these areas have dropped into the low to
mid 60s, and into the mid 50s in the Poconos. Temps will
continue to fall off tonight, and as a result, lowered overnight
lows a bit. Expecting overnight min temps to range from the mid
60s in the Philly metro area, and in the upper 50s to low 60s
across much of SE PA and NJ. Lows will be in the low 60s in the
Delmarva and in the low 50s in the Poconos.


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


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.


The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR. Any BKN-OVC mid-deck at KMIV/KACY will scatter
out and will become SKC later this evening. SKC otherwise.
LGT/VRB to nearly calm winds.

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.


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.


No headlines through Thursday. NW winds 10-15 KT will become N
5-10 KT tonight through Thursday morning. Sea breezes are
seemingly more likely to develop Thursday afternoon.


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...
There is Low Risk for the development of dangerous rip currents
at NJ and DE ocean beaches on Thursday.

Outlook for Friday 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

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


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




Near Term...Drag/MPS
Short Term...Drag
Long Term...99
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