Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 211430
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
930 AM EST Fri Feb 21 2020

.SYNOPSIS...
High pressure slowly builds across the region today and through
the weekend before exiting Sunday afternoon. Low pressure will
track through the Mississippi Valley early in the week towards
New England by Wednesday. A deeper and more intense low pressure
system will develop by the middle of next week tracking into
the Saint Lawrence Valley towards the end of the week and looks
to impact the region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High pressure extending from the southern Great Plains to the
Ohio River Valley this morning will continue to build to the
east. We are anticipating an abundance of sunshine for today
with two minor exceptions.

A weakening cloud streamer off Lake Ontario extended southward
over parts of Monroe County around 9:00 AM. It should continue
to dissipate as the northerly flow lessens during the balance of
the morning. Also, there was a deck of stratocumulus off our
coast. It was due to the cold northerly flow passing over the
relatively warm ocean waters. That area of clouds should also
begin to erode as the northerly flow decreases.

Today`s high temperatures are expected to favor the middle and
upper 30s in northeastern Maryland, Delaware, New Jersey,
southeastern Pennsylvania and the Lehigh Valley. Readings should
not get above freezing in the elevated terrain of the Poconos
and far northern New Jersey.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
Really not much change in the weather this evening as the
center of high pressure tracks over the intersection of
TN/GA/AL. With the high tracking just to the south anticipate
light westerly flow and a better chance of the winds decoupling
Friday night. Overnight lows should fall to the teens to low
20s.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
High pressure builds through the weekend leading to quiet
weather under mostly clear skies. As the flow becomes more
southern and western, the area will start to have a warming
trend with highs increasing to above normal and increasing about
3-5 degrees each day. By Monday, anticipate temps in the low to
mid 50s. We may see some high clouds filter through over the
weekend but with low level (1000mb-700mb) RH`s progs less than
30% I dont think it will amount to any sort of low or mid level
clouds.

High pressure finally starts to break down Monday night as the
center of the high drifts offshore. A weak upper level shortwave
starts to track through the central plains with a low pressure
system tracking through Missouri Monday afternoon. The low then
tracks quickly to the north and east and ends up moving towards
the Saint Lawrence Valley on Tuesday. This brings a warm front
into the Mid Atlantic along with some modest rainfall. With
surface temps in the mid to upper 40s there`s almost a nil
chance any wintry precip will fall over NJ or DelMarVa.

A stronger upper level trough will follow that low pressure
system as a vort max tracks into the Carolinas with some decent
850mb FGEN. The low will undergo fairly rapid cyclogensis
deepening from 1008mb Wednesday to 980mb centered over Lake
Ontario. This should bring widespread precipitation to the
region, which as of right now would be mostly rain in the warm
sector. Time will tell for that system but on the surface the
late week system looks significantly stronger than the early
week system.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR under a mostly clear sky. North wind 10 to 15
knots, becoming northwest 5 to 10 knots. High confidence.

Tonight...VFR. Southwest wind less than 10 kts. High
confidence.

Outlook...
Friday night...VFR. Southwest wind less than 10 kts. High
confidence.

Saturday...VFR. West wind around 10 knots. High confidence.

Saturday night...VFR. Southwest to west wind less than 10 kts.
High confidence.

Sunday...VFR. Southwest wind 5 to 10 knots. High confidence.

Sunday night...VFR. Southwest wind 6 knots or less, becoming
south toward morning. High confidence.

Monday...Mainly VFR. Increasing cloud cover through the day
with a slight chance of rain late in the day. South wind 5 to 10
knots. Medium confidence on timing of any rainfall.

Monday night...MVFR likely. A chance of rain. South wind 5 to
10 knots. Medium confidence on timing and coverage of any
rainfall.

Tuesday...MVFR with periods of IFR possible in rain. Southeast
wind 5 to 10 knots. Medium confidence.

&&

.MARINE...
Small Craft Advisory conditions will continue as northerly
winds of 20 to 25 kts with gusts near 30 kts eventually subside
this afternoon.

Sub-SCA conditions are expected tonight as winds become
westerly 10 to 15 kts and seas of 1 to 3 feet.

Outlook...

Saturday through Saturday night...Sub-SCA conditions expected
through the period with seas generally running 2-3 ft and gusts
up to 20 kts.

Sunday through Monday...Sub-SCA conditions expected with seas
generally running 2-3 ft and gusts of 10 to 15 kts.

Monday night and Tuesday night...Sub-SCA conditions expected
with seas increasing to 3-4 ft and gusts 15 kts or less.

Wednesday and Wednesday night...SCA conditions expected with
southerly winds increasing to 10 to 20kts and seas ramping up to
4 to 6 feet by Wednesday evening.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 4 PM EST this afternoon for
     ANZ452>455.
     Small Craft Advisory until noon EST today for ANZ430-431-450-
     451.

&&

$$

Synopsis...Deal
Near Term...Iovino
Short Term...Deal
Long Term...Deal
Aviation...Deal
Marine...Deal


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