525
FXUS61 KPHI 021908
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
308 PM EDT Thu May 2 2024

.SYNOPSIS...
A cold front will push south across the region tonight before
stalling to our south and west on Friday. A weakening cold front
will move into the region Saturday while a stronger front moves
in later Sunday. After a couple of mostly dry days another front
will approach towards midweek.

&&

.NEAR TERM /THROUGH FRIDAY/...
145 PM...As of early this afternoon, low pressure was moving
into western New England with a trailing cold front extending
west from this feature back into upstate NY and northern PA.
Meanwhile a surface trough extended to the south and west right
across the mid Atlantic I-95 corridor. As this trough continues
to move through, winds will shift from southwest to more
westerly across the area this afternoon with a drop in dew
points. However actual air temperatures will remain quite warm
with highs still expected to top out in the mid to upper 80s
across much of the region. The exceptions will be over the
Poconos and right along the coast where it will be cooler.
However winds becoming mainly offshore will keep any sea breezes
from really getting inland so while right at the shore
temperatures will be in the upper 60s to low/mid 70s, just a
couple miles inland it will be in the 80s. Otherwise, it will be
a mainly sunny and precipitation free afternoon across the
area.

As we head into this evening, the cold front moves southward
through the region as low pressure moves southeastward off the
coast of New England and high pressure builds into eastern
Canada. This setup will cause the winds to shift to an
east/northeast direction over the mid Atlantic and it`s likely
this will eventually bring in some marine stratus along the
coast by Friday morning. Expect overnight lows mainly in the
50s...ranging from low 50s over the southern Poconos, NW NJ, and
and the NJ coast to mid/upper 50s near the urban corridor of SE
PA extending south into interior portions of Delmarva.

For Friday, ridging aloft will keep the area dry for at least
one more day as it helps to keep the approaching system from
the west at bay. Meanwhile the front will be stalled to our
south but then arcing back to the north and west into PA just
west of our region. The upshot of this is it will be a much
cooler day with continuing easterly winds and variable cloud
cover. Through the morning, marine stratus near the coast will
try to push inland for a time and could get to near the I-95
corridor before starting to retreat. Meanwhile by afternoon
there will be some clouds moving in from the west. So not a
completely sunny day but much of the region should see at least
a little sun at some point except perhaps right along the coast.
Speaking of which, expect highs near the coast will only get
into the upper 50s to low 60s with warmer temperatures the
farther west you go. Eastern PA should see highs mainly in the
upper 60s to low 70s except some mid 70s over portions of Berks
County.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Wedge of Canadian high pressure will continue nosing
southwestward along the coast Friday night through Saturday
night, keeping the frontal boundary which moves through tonight
stalled to our southwest with a cooler maritime air mass in
place over our region. A weakening cold front will be moving
into the area from the west, but it will be too weak to dislodge
the maritime air in place, and the front will wash out. Showers
and thunderstorms associated with said front will develop to
our west, especially Saturday and Saturday night, but are
expected to weaken and eventually die out as they continue
advecting eastward into the stable maritime air mass. Thus, POPS
are highest in the far west/Poconos and much lower along the
coast. Clouds will dominate thanks to the maritime influence and
temps will be in the upper 40s to lower 50s, with highs
Saturday in the upper 50s to 60s.

By Sunday, another, stronger cold front will be approaching from
the west. This one looks likely to bring enough of a
southwesterly push ahead of it to at least partially dislodge
the stalled boundary to our southwest, which may bring 70s back
into the Delmarva. Further north, it looks likely to stay stuck
in the martime air, with 50s and 60s more likely, along with
continued mostly cloudy conditions. This stronger boundary from
the west, however, looks more likely to spread showers and
perhaps some mostly elevated thunderstorms into the region, so
POPs are much higher on Sunday compared to Saturday. That said,
still not expecting a lot of rain, mostly in the half inch rain,
though locally more could be had with any heavier storms,
especially NW of I-95.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The stronger cold front moving in Sunday will try its best to
dislodge the marine layer for the balance of the week, though
a boundary of some sort will remain nearby through the entire
week. This boundary will continue to form the basic path of
additional waves of low pressure moving eastward across the
northern US. Given uncertainty about exactly where the boundary
ends up each day, which will depend on passing low pressure
waves and high pressures building in behind each one, have kept
temps relatively stable in the 70s for highs and 50s to 60s for
lows. Chance of precip appears to ebb behind the front Monday
and Tuesday, but will return with additional waves of low
pressure Wednesday and Thursday. Still a lot of uncertainty
regarding timing of waves so confidence is not great regarding
details.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

This afternoon...VFR with west to WNW winds around 10 to 15
gusting upwards of 20 to 25 knots. High confidence.

Tonight...Mainly VFR except some MVFR cigs possible towards 12z
at ACY. Winds diminishing early this evening to 5-10 knots and
becoming northwesterly before veering to northeasterly by the
late evening through the overnight. Moderate confidence.

Friday...Mainly VFR except a period of MVFR cigs possible in the
morning at ACY (60 percent chance) and MIV (40 percent chance)
due to marine stratus. Winds generally easterly around 10 knots.
Moderate confidence.

Outlook...

Friday night...MVFR cigs possible esp toward coastal sites.

Saturday...MVFR cigs possible.

Sunday...MVFR conds likely with IFR conds possible.

Monday...VFR likely.

Tuesday...VFR likely.

&&

.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 veer to northeast around 10 kt tonight.
Seas will average 2 to 3 ft through tonight and then 3 to 4 ft
by later Friday.

Outlook...

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

Saturday nihgt through 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 through the rest of 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 dropping
into the 40s over much of eastern PA into northern NJ with 50s
south further south. Southwest winds shifting to northwest will
increase to 10 to 15 mph with 20 to 30 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
through the rest of the day.

&&

.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...Fitzsimmons/RCM
NEAR TERM...Fitzsimmons
SHORT TERM...RCM
LONG TERM...RCM
AVIATION...Fitzsimmons/RCM
MARINE...Fitzsimmons/RCM
FIRE WEATHER...PHI
CLIMATE...PHI