279
FXUS61 KPHI 020705
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
305 AM EDT Thu May 2 2024

.SYNOPSIS...
A cold front moves through tonight, with high pressure building in
for the end of the week. A weakening cold front approaches on
Saturday, stalling out on Sunday. The front lingers through early
part of next week, before lifting north as a warm front by the
middle of next week.


&&

.NEAR TERM /THROUGH TONIGHT/...
One area of high pressure lies offshore, and is resulting in an
onshore flow. Another area of high pressure lies over the Mid-
Atlantic and Southeast, and a warm front lies in between these two
systems.

The onshore flow is resulting in a cool and increasingly humid
airmass. Stratus and fog is developing as that warm, moist air
overrides the colder ocean waters. Fog and stratus will be in place,
mainly for most of New Jersey and into the southern Poconos and
Lehigh Valley. That warm front lifts north through the region
shortly after sunrise, and fog and low clouds will scatter out
through the morning.

Unseasonably warm air spreads into the region today under mostly
sunny to sunny skies, at least away from the coast. Clouds may
persist right along the coasts and at the beaches, where it will be
much cooler compared to inland. Highs will generally top off in the
mid to upper 80s, possibly touching 90 in some spots for most of the
region, and highs will be in the 70s in the mountains and along the
coasts.

A cold front approaches from the west and passes through the region
this evening. No precipitation is expected with its passage. Winds
turn go the north this evening, then eventually to the northeast,
then east tonight. Temperatures tonight will not be much cooler
compared to this morning, but surface dew points will begin to drop
as drier air filters in from the north.&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Dry conditions will persist for Friday as an upper level ridge
slides overhead. A little bit of a tricky high temperature forecast
for Friday though as high pressure over New England will result
in an onshore flow and a backdoor cold front setting up near
the I-95 corridor. Still some uncertainty where exactly this
boundary sets up, but temperatures west of the front (primarily
the Lehigh Valley) will get into the 70s, with upper 50s/60s
near and east of the backdoor front. Temperatures on Friday
Night will fall into the upper 40s/low 50s.

For Saturday, upper level ridging and high pressure begin to move
offshore. A cold front will slowly move across Pennsylvania with
some showers moving in ahead of it. The bulk of the rain will come
for the back half of the weekend, but a small chance (15-25%) of
showers are expected west of the I-95 corridor for Saturday.
Otherwise, it will be mostly cloudy and cool with temperatures in
the low to mid 60s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Weakening cold front approaches on Saturday night with numerous
shortwaves moving over the region through Sunday. A solid push of
moisture works in from the southwest as well and PWATs climb into
the 1.3-1.5 in. range which is around the 90th percentile for early
May. Periods of rain are expected for Sunday, some of which could be
heavy at times. Not overly concerned at the moment with flooding
given dry antecedent conditions however. Instability is lacking
overall as well, so the threat for thunderstorms is rather low.
Temperatures will hover in the 60s, with lower 70s in lower
Delmarva.

The early and middle portions of next week look rather unsettled,
though not expecting any significant impacts at this time. A stalled
boundary looks to set up over the southern portion of the region
with several waves of low pressure riding along the stationary
front. High pressure nudging in from the northwest could limit
shower activity, depending on how much influence it has over the
region. Temperatures Monday/Tuesday will hover near/slightly
above seasonal levels for early May, with mid to upper 70s
expected. That boundary looks to eventually lift north as a warm
front by midweek and we should return to the 80s by Wednesday.

&&

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

Today...Fog and stratus will continue to impact at least
KACY/KMIV/KTTN this morning with IFR/LIFR CIGs. IFR VSBYs also
possible in fog, but predominant restrictions should be from low
CIGs. Improvements to VFR expected by 14Z. VFR elsewhere. LGT/VRB
winds, becoming SW 5 to 10 kt this morning, then W 10 to 15 kt with
18 to 23 kt gusts this afternoon. Winds turn N 5 to 10 kt prior to
00Z. Moderate confidence overall.

Tonight...VFR, though restrictions possible at KACY/KMIV late
tonight. NE to E winds 5 to 10 kt. Moderate confidence.

Outlook...

Friday through Friday Night...Primarily VFR, though sub-VFR
conditions possible (30-50%) later in the day at KMIV/KACY with
marine stratus working in.

Saturday through Saturday Night...sub-VFR conditions possible (30-
50%) with CIG restrictions. Slight chance (15-25%) of showers for
the I-95 and Lehigh Valley terminals.

Sunday through Monday...sub-VFR conditions likely (60-80%) with
periods of rain.

&&

.MARINE...
Sub-Small Craft Advisory conditions today and tonight. SW winds will
increase to 10 to 15 kt with gusts up to 20 kt this afternoon, then
winds turn N around 10 kt tonight. Seas will average 2 to 3 ft.

Low stratus and fog will reduce VSBYs to 1 to 3 NM this morning.
Localized marine dense fog is possible. VSBYs will improve later
this morning.

Outlook...

Friday through Saturday Night...No marine headlines anticipated.

Sunday...SCA conditions possible (20-30%) as seas near 5 feet on the
ocean.

Sunday through Monday...No marine headlines anticipated.

&&

.FIRE WEATHER...
Warm, dry, and breezy conditions on tap for today under sunny skies.
Minimum RH values will drop to 25 to 35 percent across the region
this afternoon due to the combination of highs in the mid to upper
80s and surface dew points in the mid and upper 40s in the southern
Poconos and Lehigh Valley, and in the mid to upper 50s elsewhere.
Southwest winds will increase to 10 to 15 mph with 20 mph gusts this
afternoon. While a wetting rainfall occurred on Tuesday across the
Lehigh Valley, southern Poconos, and northern New Jersey, remaining
areas of southeastern Pennsylvania, New Jersey, and Delmarva have
not experienced a wetting rainfall in well over a week now. This
will result in some concerns for wildfire spread today. Coordination
will be needed with our fire weather partners to determine if any
products will be needed to highlight this potential threat.


&&

.CLIMATE...
Near record breaking high temperatures are expected today. Records
for our climate sites are listed below:

Record High Temperatures
                            May 2
Site                  Record/Year
Allentown (ABE)           90/2001
AC Airport (ACY)          91/2018
AC Marina (55N)           85/1913
Georgetown (GED)          90/2018
Mount Pocono (MPO)        83/1913
Philadelphia (PHL)        89/2010
Reading (RDG)             89/1899
Trenton (TTN)             88/2010 & 2018
Wilmington (ILG)          90/1894

&&

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

&&

$$

SYNOPSIS...Hoeflich
NEAR TERM...MPS
SHORT TERM...Hoeflich
LONG TERM...Hoeflich
AVIATION...Hoeflich/MPS
MARINE...Hoeflich/MPS
FIRE WEATHER...MPS/Staarmann
CLIMATE...Staarmann