Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 110714
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
314 AM EDT Tue May 11 2021

.SYNOPSIS...
Strong high pressure will build into the central United States
and will be the primary influence on our weather through the
workweek. A weak trough will pass through the region today, and
a couple weak systems will approach the area this weekend as the
High slowly weakens and shifts offshore.

&&

.NEAR TERM /THROUGH TONIGHT/...

The period starts with low pressure aloft centered over the Great
Lakes. This feature will pivot east and be centered over Nova Scotia
late tonight. A weak shortwave will swing around the base of trough
and approach our region this afternoon. At the same time, a weak
surface trough will set up along or near the I95 corridor.

Northwest winds will increase this afternoon and gust in the 20 to
25 mph range. Winds will back more west tonight and diminish to 10
mph or less.

Temperatures will be about 5 to 10 degrees below normal topping out
in the mid 50s north and west with the 60s elsewhere. More 30s can
be expected tonight north and west of the I95 corridor and maybe
in the NJ Pines. Otherwise lows will be in the 40s.

With low to mid level lapse rates steepening this afternoon along
with an increase of moisture, some skinny CAPE develops. As a
result, widely scattered showers are possible. The chance of thunder
isn`t zero, but is low enough to keep out of the forecast attm.
Can`t rule out a rumble here or a rumble there along with a few
reports of graupel. Any showers will move west to east across the
region and end in the evening. Skies will become mostly clear by
daybreak Wednesday.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...

The mid-week period will be uneventful as mid-lvl ridging and
resultant sfc. High Pressure are positioned upstream of the
area, in the vicinity of the Upper Midwest. Given the position
of the High a dry NW flow will prevail Wed/Thu, with
temperatures slowly moderating through the period but still
remaining 5-10 degrees below normal (i.e. Highs largely in the
mid to upper 60s). Given clear skies and light winds on
Wednesday night can`t rule out some frost in colder spots in the
Poconos, but most of the area should remain warm enough to
avoid any frost/freeze concerns.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...

The upstream mid-lvl ridge will deamplify and progress east of
the area late this week, with several transient shortwaves
likely passing through the region in its wake. These waves
coupled with diurnal destabilization will result in increased
shower/thunderstorm potential late this week into the weekend.
That being said the positioning of the weakening sfc. High will
continue to inhibit low-lvl moisture return until Sunday/Monday
when it finally shifts offshore. Therefore feel that sChc- Chc
PoPs sufficiently cover the precip threat at this time.
Temperatures should warm up to near normal by the weekend with
uncertainty increasing towards early next week as the low-lvl
flow potentially acquires more of an onshore component.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR. Northwest winds around 10-15 knots with gusts 20 to 25
knots. Can`t rule out a shower. High confidence with the VFR and
winds, but the showers will be widely scattered.

Tonight...VFR. West to northwest winds less than 10 kt. Can`t rule
out an early evening shower. High confidence again with the VFR and
winds, but the showers will be widely scattered.

Outlook...

Wednesday...VFR. NW winds 10-15 kt with gusts up to 20 kt.
High confidence

Thursday...VFR. NW winds 5-10kts, with sea breezes possible in
the afternoon particularly at KACY/KMIV. Moderate confidence.

Friday through Saturday...VFR. with some potential for afternoon
showers/thunderstorms particularly W of the I-95 terminals.
Winds generally 5kts or less with variable direction (sea
breezes also possible in the afternoon). Moderate confidence.

&&

.MARINE...

Today...Conditions are expected to remain below SCA levels although
winds will likely approach 20 kts.

Tonight...A brief period of SCA winds are possible toward dawn, but
will hold off on any headlines at this time.

Outlook...

Wednesday-Saturday... Some chance for borderline SCA conditions
Wed AM, but then sub-SCA conditions are expected to prevail
through Saturday. Seas will likely run 2 ft or less with wind
gusts decreasing to 15kts or less Thursday-Saturday.


&&

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

&&

$$
Synopsis...Carr
Near Term...Kruzdlo
Short Term...Carr
Long Term...Carr
Aviation...Carr/Kruzdlo
Marine...Carr/Kruzdlo


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