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fxus61 kphi 291614 
afdphi

Area forecast discussion
National Weather Service Mount Holly New Jersey
1214 PM EDT Wed Mar 29 2017

Synopsis...
high pressure near hudson's Bay will build into our region
through Wednesday night. Low pressure moving through the Ohio
Valley on Friday will redevelop near the New Jersey coast
Friday night and move offshore on Saturday. High pressure
will move into the area for Sunday and Monday. Low pressure
over the Ohio Valley and its associated fronts will approach
our region on Tuesday.

&&

Near term /until 6 PM this evening/...
mid and low clouds right along the New Jersey shore and across southern
and coastal Delaware will continue to erode and drift away through the
afternoon as high pressure builds in from the north and west.
Some diurnally driven mid-level cu will spread into PA/New Jersey later
this afternoon as well.

Winds beginning to diminish, and north-northwest winds 10-15 miles per hour on tap for
the rest of the afternoon. Winds may back a bit more to the west-northwest
late in the afternoon, and this may provide just enough of a
downsloping component to the winds to allow temps to warm up
late in the day.

Max temps in the mid 40s in the Poconos, and in the low 50s
across northern New Jersey. Otherwise, highs in the upper 50s to low 60s
across central/southern NJ, southeast PA, and in the low to mid 60s in
MD/de.

&&

Short term /6 PM this evening through 6 am Thursday/...
clear or mostly clear skies, a few fragments of SC in the early
eve and possibly a little cirrus. Some radiational cooling
expected. Light north wind. Normal or slightly below normal
mins.

Forecast basis: 50 50 blended 00z/29 GFS/NAM MOS guidance. Applied
minor 1-2f cooler than guidance adjustments in our 330 am fcst
for tonight.

&&

Long term /Thursday through Tuesday/...
the primary players during the long term will be two southern
stream systems that are expected to impact our region in the
Friday-Saturday and Tuesday time frames.

The first system may produce 1 to 1.5 inches of rain across
portions of the region, especially in the Delaware valley. While
there could be some urban and poor drainage flooding, we do not
expect any major impacts on rivers and streams. There is also a
consistent signal in the models for mixed precip north of I-80,
with sleet and freezing rain the primary concerns, during the
Friday night and Saturday morning period. We have mentioned this
in the severe weather potential statement.

Looking ahead to early next week, the next system is expected to
bring more precip to our region Monday night into Tuesday. This
setup looks warmer, given the absence of high latitude blocking,
and would favor predominantly rain.

&&

Aviation /16z Wednesday through Sunday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.

Today...MVFR cigs at kacy will give way to VFR conditions no
later than 18z. Otherwise, VFR. Diurnally driven scattered clouds at
3500 ft possible this afternoon.

Northwest winds 10-15 knots with gusts up to 20 knots for the rest of the
afternoon.

Tonight...VFR with fragments of SC in the evening and maybe some
thin cirrus at times. Light north wind.

Outlook...

Predominantly VFR, except MVFR possible Friday into Saturday.

&&

Marine...
sub-Small Craft Advisory conditions on the waters with northwest flow 10-15 knots with
gusts up to 20 knots through this afternoon. Seas will average 3-4
ft on the ocean, and 1-2 ft on Delaware Bay.

Small Craft Advisory may be needed for anz450-51 (nnj tonight).
Elsewhere...gusty north wind through the night to around 20-22
kt.

Outlook...

Small Craft Advisory likely Friday into Saturday, with the potential for gale
force southeasterly wind gusts Friday night, mainly across the
northern New Jersey waters. Otherwise, sub-sca.

&&

Tides/coastal flooding...
though astronomical tides will be gradually diminishing through
the week now that we are past the new moon, the threat of minor
tidal flooding along the New Jersey and Delaware Atlantic coasts increases
late in the week. This is a result of a low pressure system
bringing a prolonged period of onshore flow. The tide of most
concern at this point is the high tide on Friday evening/late
Friday night. By this tide cycle, it will take a surge of 0.8 to
1.0 feet to reach minor flooding thresholds, which is possible
but still uncertain (it will be dependent on how quickly the on
shore flow develops and how strong it will be by then). At least
one source of guidance shows water levels reaching minor tidal
flooding thresholds with the Thursday evening/night high tide,
but that seems unlikely as the latest forecast depicts onshore
flow either developing right around or just after the time of
that high tide.

We have mentioned the potential of minor flooding along the
northern New Jersey coast in the hwo, where the threat is greatest
during the Friday evening/late Friday night high tide cycle.

&&

Climate...
MO avg temps

March dep Feb dep
Abe 38.0 -1.1 39.2 +8.5

Acy 41.6 -0.6 43.0 +7.7

Ilg 41.7 -1.3 43.1 +8.0

Phl 42.2 -1.3 44.2 +8.5



This March will be a below normal month for temps.... one of
the very few the last two years.

We appreciate that this is possibly old news, but March temperatures
will average colder than the Feb average at all 4 long term climate
locations. The last time this occurred, 1984.

&&

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

&&

$$
Synopsis...franck
near term...mps
short term...drag
long term...franck

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