Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kphi 230145 
afdphi

Area forecast discussion
National Weather Service Mount Holly New Jersey
945 PM EDT Wed Mar 22 2017

Synopsis...
large high pressure across the upper Great Lakes region this
evening will slide southeast and crest over our region on Thursday.
A warm front will lift to our northwest Friday, while a backdoor
cold front pushes through the area Saturday. This front is
forecast to stall near the southern portions of the area or just
to our south into early next week. A couple of low pressure
systems may form along the boundary and move eastward as well.

&&

Near term /until 6 am Thursday morning/...
930 PM estf: small modifications to temp trends were made.
Overall impact on the general forecast...almost nil.

From 330 pm:

Winds will slowly diminish as the surface high builds closer
and the pressure gradient decreases. This, combined with the dry
air that is already in place will lead to efficient radiational
cooling. As a result expect lows tonight to be 10 to 20 degrees
below normal. We could get close to record lows (see climate
section below).

&&

Short term /6 am Thursday morning through 6 PM Thursday/...
high will pass almost directly overhead leading to light and
variable winds for much of the region. Despite the sunny conditions,
temperatures will remain 10 to 15 degrees below normal as the
Continental polar air mass will be entrenched over the region.

&&

Long term /Thursday night through Wednesday/...
high pressure will have moved east of the area by Thursday night. A
warm front will inch towards the area from the west causing clouds
to increase over the region. Rains and some mixed precipitation will
arrive across the far north/west Friday morning. The models seem to be a
bit slower with the arrival time, and this could make the difference
in p-type with even a few hours later favoring more rain over mixed.
We will continue with a mention of some sleet/freezing rain attm.
Other than that, mostly rain north/west with low likely pops by afternoon
over the srn Poconos. Limited clouds/precip S/east with temperatures
near 60 degrees by afternoon.

The weekend looks to be a split with Sat being the better weather
day and Sunday looking rather wet. The front will remain to the
north Sat with only small chc or slgt chc pops across the far north.
The front then sags southward Sunday while low pressure moves along
it and approaches from the west. We will carry low likely pops in
most areas Sunday. Temperatures well above normal Saturday with 60s
north and low 70s south/east. Readings closer to normal Sunday.

Unsettled conditions early next week with an upper low and sfc front
lingering across the area. We will carry chc pops for both Monday
ad Tuesday with this fcst. The north/west counties will be favored
for the better chcs for measurable rain. Temperatures early next
week should remain a little above normal for late March.

&&

Aviation /02z Thursday through Monday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

VFR conditions are expected through the taf period with few, if any,
clouds. Northwest winds will slowly diminish, dropping below 10
kt no later than 06z. By 18z tomorrow, winds especially at
Delmarva and south New Jersey sites (ilg, Acy, and miv) could become
light and variable as the center of the high passes almost
directly overhead.

Outlook...

Thu night...in general VFR. Low clouds psbl far northwest late.
Fri...VFR most areas but restrictions psbl with rain and a
chance for sleet and freezing rain far north/west Fri morning.
Fri night and Sat...mostly VFR.
Sat night thru Monday...showers. Restrictions for ceiling and visibility
psbl.

&&

Marine...
930 pm: converted remaining gale to Small Craft Advisory New Jersey waters and ended Small Craft Advisory
upper de Bay.



Northwest to north winds will slowly diminish overnight. By
sunrise Thursday, winds and seas should be below Small Craft Advisory criteria.



There is a chance for light freezing spray overnight. Still
considerable uncertainty as by the time the air temperature gets
cold enough to support freezing spray, winds will be dropping off.

Outlook...

Thursday night...sub-sca conditions expected.
Fri-Fri night...Small Craft Advisory conditions likely on the ocean. Sub-Small Craft Advisory on
del. Bay. Showers mostly north.
Sat-Sat night...conditions diminishing below Small Craft Advisory conditions.
Sun-Mon...Small Craft Advisory expected on the ocean. Sub- Small Craft Advisory on del Bay. Showers.

&&

Climate...
one or 2 of the following are vulnerable record equaling lows
Thursday morning March 23, primarily Abe. Others are listed for
reference

Acy-13 1875

Phl-14 1885, 1875

Ilg-14 1934

Abe-13 1934

Ttn-13 1934

Ged-16 1959

Ridge-14 1906

Mpo- minus 8 1912

&&

Phi watches/warnings/advisories...
PA...none.
New Jersey...none.
Delaware...none.
Maryland...none.
Marine...Small Craft Advisory until 6 am EDT Thursday for anz450>453.
Small Craft Advisory until 4 am EDT Thursday for anz431-454-
455.

&&

$$
Synopsis...drag/O'Hara 945
near term...drag/Johnson 945
short term...Johnson

National Weather Service Glossary of Abbreviations