Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kphi 281624 
afdphi

Area forecast discussion
National Weather Service Mount Holly New Jersey
1224 PM 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/...
currently...weak low pressure is forming along a stationary
boundary just across the Delmarva. Light east-NE flow across
northern and central New Jersey and into southeast PA is ushering in cooler and
more stable air into that part of the cwa, and most of the
convection seems to be winding down as thunderstorms track to
the north and east, with thunderstorms becoming more isolated.
Showers continue, and are producing locally heavy rainfall.

South of that boundary, across extreme southern NJ, de, and MD,
warmer and more unstable air is in place, and will likely be
where any future thunderstorms develop. Cold front to the west,
across western New York/PA, will begin to track to the east, and as it
does, additonal showers and possible thunderstorms will develop
later this afternoon and into the early evening.

Pwats will range from 1-1.25", so can expect heavy downpours at
times.

&&

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.

Forecast 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 Virginia 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 /16z 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...
winds/seas will be under advisory criteria through tonight.

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

Outlook...

Wed...sub-sca conditions.
Wed night/Thu morning...low end Small Craft Advisory near the New Jersey coastal waters.
Thu afternoon thru Fri...sub-sca expected. Showers Fri.
Fri night thru Sat...Small Craft Advisory possible. Showers.

&&

Equipment...
knel appears to be reading 10f too warm the past several days.

&&

Phi watches/warnings/advisories...
PA...none.
New Jersey...none.
Delaware...none.
Maryland...none.
Marine...none.

&&

$$
Synopsis...O'Hara
near term...drag/mps
short term...drag

National Weather Service Glossary of Abbreviations