560
FXUS61 KPHI 150021
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
821 PM EDT Wed May 14 2025

.SYNOPSIS...
Low pressure will linger across the Mid Atlantic through the
Thursday, resulting in mild, humid, and showery conditions.
Brief period of ridging comes in Thursday Night, with a warm
front coming through on Friday morning. Unsettled weather
continues through Saturday until a strong cold front comes
through on Saturday Night. Drier high pressure will settle into
the region by Sunday into early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Cloudy, mild, showery, and humid conditions persisting through
Thursday.

A decaying upper low over the Midwest will slowly push a
negatively tilted trough axis slowly through our region locally
through Thursday. Weak surface low pressure will remain across
the Mid Atlantic through this period as well.

A lull in shower activity is expected overnight, however areas
of fog are anticipated to develop across much of the area along
with continued low clouds and light winds. Humid with lows in
the mid 50s (north) to mid 60s (south). Main thing with the
evening update was cutting down PoPs overnight and a touch
tomorrow. Some fog could be dense at times, so a Dense Fog
Advisory was issued for the New Jersey coast.

For Thursday, the low clouds and fog will dissipate as the
morning progresses, and some breaks of sun may even occur by
afternoon, especially across Delmarva. With the mid level
trough axis remaining in the vicinity and the weak surface low
nearby as well, some diurnal instability should result in some
isolated to scattered showers/storms into the afternoon. With
PWats around 1.25-1.50", heavy downpours will be possible as
well as gusty winds and small hail. Severe thunderstorms are
unlikely, but can`t totally rule one out. High temperatures will
be mainly in the 70s and a bit muggy.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
A brief period of quiet weather comes Thursday night as a brief
period of ridging moves overhead. Skies may actually clear out
some Thursday evening into the first half of Thursday Night
before a warm front moves in late Thursday/early Friday morning.
Mainly dry through Thursday Night though but still mild, with
lows in the upper 50s/low 60s.

A warm front lifts through Friday morning, bringing some light
showers as warm air advection ramps up. This will allow
temperatures to climb into the 80s on Friday, with more
instability in place as well. Forcing looks rather weak though
with ridging not far away and only a weak shortwave coming in
and no advancing cold front until Saturday. Thus, thinking it
will be just unsettled with scattered showers, primarily in the
afternoon with a few thunderstorms mixed in. It`s possible a
decaying MCS impacts the region in the morning sometime Friday,
but the severe threat with this would be low. Showers diminish
in coverage with the loss of daytime heating on Friday Night,
but still cannot rule out some light sprinkles through the
night. Mild pattern continues with low to mid 60s for lows.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Saturday looks to be the day to monitor for any severe weather.
Forcing strengthens with an incoming potent shortwave digging
from the Great Lakes. At the surface, an area of low pressure
slides by to the north Saturday into Saturday Night, with a cold
front advancing towards and eventually through the region.
Temperatures will climb into the 80s and it will feel quite
muggy ahead of the front. Instability looks to be on the order
of around 1000 J/kg with relatively favorable shear. Thinking
any showers and thunderstorms will come in the afternoon and
evening as the front arrives. Main concern would be damaging
wind gusts and heavy downpours, but still a good amount of
uncertainty being a few days out. Coverage in showers and
thunderstorms diminishes into the night with the loss of daytime
heating and passage of the front.

Sunday and beyond actually looks pretty nice for now. With the
front coming through, it should result in dry conditions and
seasonable weather to close out the weekend and start next week.
Perhaps a little gusty on Sunday, but nothing that looks too
significant.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...Lehigh Valley terminals start out of MVFR/IFR but
should come down to LIFR overnight with very low ceilings and
patchy fog. I-95 and South Jersey terminals are currently LIFR
and it should stay that way through most, if not all, of the
night. More widespread fog around these terminals could drop
visibility as low as 1/4-1/2SM overnight. Easterly winds around
5 kt or less. Moderate4 confidence.

Thursday...IFR and LIFR early. Visibility improvement by 15-18Z,
with ceilings scattering out to VFR by 18-21Z. ENE winds 5 kts
or less early, shifting southerly around 5-10 kts as conditions
improve. Isolated SHRA/TSRA after 18Z. Low confidence on timing
of improvement.

Thursday Night...Most likely VFR to start but restrictions could
return overnight with low clouds and patchy fog. Low confidence.
Winds light and variable.

Outlook...

Conditions expected improve for Friday and Saturday with
prevailing VFR likely during the day, aside from any showers and
thunderstorms move in. VFR conditions look to come Saturday
Night and beyond.

&&

.MARINE...
A Marine Dense Fog Advisory was issued through 06z for coastal
waters south of Manasquan Inlet and for the lower Delaware Bay.
May need to extend in time and to ANZ450, but will see how
things develop overnight. A Small Craft Advisory remains in
effect for all Atlantic coastal waters through tonight, and
through Thursday morning north of Ocean City, NJ. Winds under 10
kt but seas 5 to 8 feet.

Some isolated showers/storms possible Thursday afternoon.

Outlook...

Sub-SCA conditions should then take hold by Thursday evening
and continue through Sunday However, showers and spotty
thunderstorms may continue to be a risk through Saturday,
especially during the afternoon and evening hours.

&&

.TIDES/COASTAL FLOODING...
A new Coastal Flood Advisory was issued for the tidal Delaware
River for the high tide late tonight into early Thursday
morning. Elsewhere, no additional coastal flooding is expected.

Minor coastal flooding is forecast with the overnight high
tides Thursday night and Friday night as well, especially along
the upper reaches of the tidal Delaware River. Additional
advisories may be needed.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 2 AM to 7 AM EDT Thursday for
     PAZ070-071-106.
NJ...Dense Fog Advisory until 7 AM EDT Thursday for NJZ013-014-020-
     022>027.
     Coastal Flood Advisory from 2 AM to 7 AM EDT Thursday for
     NJZ017>019.
DE...None.
MD...None.
MARINE...Dense Fog Advisory until 2 AM EDT Thursday for ANZ431-450>455.
     Small Craft Advisory until noon EDT Thursday for ANZ450>452.
     Small Craft Advisory until 6 AM EDT Thursday for ANZ453>455.

&&

$$

SYNOPSIS...Hoeflich/Staarmann
NEAR TERM...Hoeflich/Staarmann
SHORT TERM...Hoeflich/Staarmann
LONG TERM...Hoeflich/Staarmann
AVIATION...Hoeflich/Staarmann
MARINE...Hoeflich/Staarmann
TIDES/COASTAL FLOODING...