Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 281321
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
921 AM EDT Tue Mar 28 2017

.SYNOPSIS...
Weak low pressure will move across the Middle Atlantic region today
and then offshore tonight. Large high pressure will build across the
area Wednesday and then move east of the area by Friday morning. A
low and its associated fronts will push across our region Friday and
remain into Saturday. More high pressure will be over the area
Sunday and into Monday. Another disturbance may affect the area Next
Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Cluster of showers and thunderstorms currently over central and
southern NJ and over extreme SE PA (generally in/around Philly),
and tracking to the northeast. Heavy rain, small hail, and
lightning with these storms, and the heaviest of the rain has
dropped a quick 3/4" QPF across parts of salem county before
departing. These storms moving into Bucks, Mercer, and Monmouth
counties.

A secondary wave of showers and thunderstorms developing over
the Delmarva and tracking to the northeast. So far, not nearly
as developed as the other storms in the CWA, but will monitor
their development. If they follow a similar track to previous
storms, then training could result in poor drainage flooding.

Otherwise, cloudy and murky with areas of fog giving way to
patchy fog this afternoon. Warm front lies right along the
NJ/PA/DE borders. South of the front, instability likely to
increase today, where best MLCape of less than 800J. Weak speed
shear so svr not expected. PWAT 1.25 so brief torrents of rain
possible in any shower.

Please follow later PHI discussions and those of SPC regarding
SVR potential.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
Any remaining showers end from west to east with a slightly
faster modeled end to the rain than 24 hours ago.

There could be some patchy fog, especially early at night in
the still moist boundary layer with a light north wind
increasing a bit late at night and trending northwest.

FCST Basis was a 50 50 blend of the 00z/28 GFS/NAM MOS.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A rather steady progression of disturbances in the extended period
with a 2 day (or so) return period. Fair weather is expected for
much of Wednesday and Thursday as high pressure across Canada ridges
southward across the area. Temperatures will be close to normal with
highs in the mid/upper 50s south and low/mid 50s north. Lows will be
in the mid/upper 30s north and low 40s south. It will be dry and
breezy Wednesday, but with wet ground conditions, fire weather
hazards will probably not be a big concern.

The first of two disturbances in the long term will affect much of
the area for much of Friday and Saturday. Low pressure will move up
the Ohio Valley Friday and then off the VA Tidewater area Saturday.
Our region will remain on the cooler nrly part of the system.
Occasional showers should occur much of the time. Depending on what
computer model, the rains could begin Thu night. Temperatures should
remain near or a little below normal thru the period. A couple
snowflakes across the highest elevations of the southern Poconos are
possible.

Fair weather returns over the region for Sunday and persist into
Monday as high pressure to the north ridges across the area.
Temperatures will be a little above normal with upper 50s to low 60s
for highs in most areas. Another disturbance may approach for Tue
with the latest EC model having a soaker system across the area and
the GFS much slower with the low and a fair weather day for Tue. We
just have chc pops for now.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Today...variable conditions with general deterioration to IFR
conds in st/fog by 12z in the light northeast flow. The southerly
winds TAFS of MIV and ACY could remain VFR much of the day except
lower in showers. Then considerable deterioration ACY and MIV
late today when the wind turns decidedly northeast.

Bands of showers and isolated tstms, some with brief heavy rain.
light wind, mostly east or northeast at the TAF locations
except southeast to south at KMIV and KACY at least this
morning.

Tonight...MVFR/IFR conditions possible in showers and fog
early...becoming VFR late. Light north winds will become north
to northwest overnight around 10 knots.

OUTLOOK...

Wed/Thu...VFR expected. Gusty north winds Wed.
Fri/Sat...lower cigs/vsbys expected. Showers.

&&

.MARINE...
Will cancel the Dense Fog Advisory for NJ coastal waters as
conditions on local web cams seem to be improving. Patchy fog
with VSBYs down to 1 NM still possible through late morning.

Winds/seas will be under advisory criteria through Tonight.

Scattered showers/isolated thunderstorms through today, with
showers ending this evening.

OUTLOOK...

Wed...Sub-SCA conditions.
Wed night/Thu morning...Low end SCA near the NJ coastal waters.
Thu afternoon thru Fri...Sub-SCA expected. Showers Fri.
Fri night thru Sat...SCA possible. Showers.

&&

.EQUIPMENT...
KNEL appears to be reading 10F too warm the past several days.

&&

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

&&

$$
Synopsis...O`Hara
Near Term...Drag/MPS
Short Term...Drag
Long Term...O`Hara
Aviation...Drag/O`Hara
Marine...Drag/O`Hara
Equipment...



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