349
FXUS61 KPHI 141852
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
252 PM EDT Sat Jun 14 2025

.SYNOPSIS...
A stationary front will remain situated across near the Chesapeake
region through Tuesday yielding unsettled weather conditions. The
front will then begin to lift northward as a warm front on Tuesday
night into Wednesday across our area as an area of high pressure
settles near Bermuda mid-week. A low pressure system begins to
approach the area on Thursday with a cold frontal passage Thursday
night. High pressure returns for Friday into next weekend.

&&

.NEAR TERM /THROUGH SUNDAY/...
A frontal boundary remains draped from low pressure over the Great
Lakes, through the Ohio Valley, and into the Delmarva Peninsula.
That low slowly tracks east tonight and will be over the Ohio and
Tennessee Valleys by Sunday morning, then will approach the Mid-
Atlantic late Sunday. Several waves of showers associated with mid-
level shortwave energy will spin off ahead of that low.

Unsettled conditions on tap through the period, though it will not
be a washout. The first wave of rainfall is moving through the
northern half of the forecast area, and the bulk of the rain should
taper off by this evening.

The next wave of showers will approach Delmarva by this evening.
Since Delmarva is south of the frontal boundary, there is some
instability with SB CAPE values of 1000 to 1500 J/kg, and SPC has a
Marginal Risk (1 out of 5) for severe weather. PWATs are over 2
inches, and WPC has a Marginal Risk (1 out of 4) for Excessive
Rainfall. Some stronger storms will be capable of stronger winds
gusts and locally heavy rain that could lead to localized flooding.
This threat should end by midnight or so.

Overnight, cloudy and foggy conditions continue. Lows tonight will
be in the 60s.

Another wave of showers approaches late tonight and may pass through
the region late tonight through Sunday morning.

Cloudy, damp, and cool conditions continue on Sunday. Highs will be
in the 60s to low 70s. Another wave of showers will approach late
Sunday.

The Mines Sprung Wildfire in Wharton State Forest in Shamong
Township, NJ, continues, though progress has been made in containing
it. As of 2:30 pm, the fire is 5000 acres and 60% contained. With
east to northeast winds, smoke from this fire will spread inland
towards Philadelphia and Wilmington. With an inversion developing
overnight once again, smoke will get trapped across portions of
southern New Jersey, and possibly as far back as the I-95 corridor
in the Philadelphia metro area and northern Delaware. Air Quality
alerts remain in effect until midnight tonight.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Little change in the forecast has been made for the Sunday night and
Monday period as the stalled frontal boundary be displaced well
south of the region. A weak wave of low pressure will ride along the
boundary Sunday night into Monday causing a period of light rain
showers and perhaps an isolated thunderstorm to occur (20-40%),
especially to the south of Philadelphia. For areas north of
Philadelphia, perhaps a spotty shower shall occur, but largely
should remain dry (PoPs less than 20%). The boundary will gradually
start to work its way back north Monday night and more so on Tuesday
and Tuesday night as it will then be located within the vicinity of
the southern Delmarva. Another weak disturbance will ride along the
boundary yielding another period for some rain showers and isolated
thunder to occur (PoPs 20-40%) across the entire region as the front
is in closer proximity to the area.

All in all, unsettled weather conditions are to continue through the
beginning of the week, but will not be a washout by any means as
there will be breaks in between rounds of precipitation. However, it
will remain mostly cloudy with limited sunshine throughout the
period. Highs will mainly be in the upper 60s to mid 70s on Monday
with mid to upper 70s on Tuesday. Lows will remain uniform mainly in
the 50s and 60s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
An upper level ridge will be located over the Southeast US on
Wednesday as a trough develops over the Great Lakes region on
Thursday. This pattern will shift east on Friday with the base of
the upper trough located over the East Coast. At the surface, the
`stalled` frontal boundary will lift north as a warm front on
Wednesday across our area. Surface high pressure will be located
near Bermuda where it will persist through the end of the week. Low
pressure will also be tracking through the Great Lakes on Thursday
tracking and into New England on Friday with a cold front trailing
to the southwest, crossing through late in the week.

For Wednesday, we`ll begin to see the beginning of a considerable
warm-up as the warm front lifts north of the area. Some spotty
thunderstorms may occur due to the combination of the passage of the
front and diurnal heating. Otherwise, attention then turns to the
cold front that will approach the area on Thursday into Thursday
night. Forcing does appear to be quite strong with the deepening
trough, so at this point it does seem plausible for there to be at
the very least some strong thunderstorms around Thursday afternoon
and evening. This is supported quite well by the machine learning
guidance by UCAR/NCAR which has a targeted area of severe weather
potential over the Mid-Atlantic and Northeast. Obviously, this is
still 5-6 days away, so a lot can change between now and then.
Regardless, the front will likely bring some showers and
thunderstorms to the area as it crosses through. Improving weather
should return by Friday and into next weekend as high pressure
returns.

In terms of temperatures, above normal temperatures are expected
throughout the period, with the warmest day of the week appearing to
be Thursday where highs will be around/in excess of 90 degrees
across the Coastal Plain. With the area being located well into the
warm sector (and a very muggy airmass in place), this will likely
result in heat indices in excess of 95 degrees in spots. Suppose if
this holds true, our first set of heat headlines may be warranted.

&&

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

Rest of Today...Generally MVFR/IFR CIGs, though there may be
some brief VFR CIGs from time to time. -SHRA and BR will reduce
VSBYs to MVFR/IFR. There is a wildfire in the Pine Barrens of
southern NJ, and smoke from that fire will spread west towards
KPHL/KILG/KMIV. VSBY restrictions in FU are possible, though
restrictions may be more likely due to BR. A few TSRA possible
towards KILG, but any lightning will be brief and isolated. NE winds
5 to 10 kt. High confidence overall, low confidence on timing.

Tonight...IFR/LIFR CIGs. MVFR/IFR VSBY in BR. Some -SHRA possible
late. A few TSRA possible this evening towards KILG, but any
lightning will be brief and isolated. E winds 5 to 10 kt.
Moderate confidence.

Sunday...IFR CIGs, possibly lifting to MVFR late in the day.
MVFR VSBYs in the morning, giving way to VFR VSBYs in the
afternoon. E winds 5 to 10 kt. Moderate confidence.

Outlook...

Sunday night through Tuesday night...Primarily sub-VFR conditions
expected with several rounds of rain showers and isolated
thunderstorms possible.

Wednesday through Thursday...Primarily VFR expected with at times
periods of sub-VFR conditions possible in thunderstorms.

&&

.MARINE...
E-NE at 10 to 15 kt may result in winds gusting to 25 kt from time
to time late tonight along with seas around 5 feet on the NJ ocean
waters. The Small Craft Advisory remains in effect through Sunday
morning. Otherwise, sub-SCA conditions.

VSBY restrictions in showers and fog from time to time.

Outlook...

Sunday night through Thursday...No marine headlines are expected.
Winds will generally remain below 20 kt with seas of 2-4 feet.
Several rounds of rain showers and thunderstorms are expected
through Thursday.

Rip Currents...

For today, northeast winds will increase through the day to
around 15-20 mph by late afternoon. Breaking wave heights
remain around 1-2 feet with a continued weak southeasterly swell
around 1 foot at 9-10 seconds in length. Will maintain a LOW
risk for dangerous rip currents at all beaches given light winds
and low breaking wave heights.

For Sunday, stronger onshore flow will remain with a 15-20 mph
northeast wind. Wave heights increase to around 2 to 3 feet or
higher and with multiple swell groups in the surf zone, there
will be a MODERATE risk for dangerous rip currents at all
beaches.

For specific beach forecasts, visit weather.gov/beach/phi

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Air Quality Alert until midnight EDT tonight for PAZ070-071-
     101>106.
NJ...Air Quality Alert until midnight EDT tonight for NJZ016>019-
     021>025.
DE...Air Quality Alert until midnight EDT tonight for DEZ001.
MD...Air Quality Alert until midnight EDT tonight for MDZ012-015.
MARINE...Small Craft Advisory from 6 PM this evening to noon EDT Sunday
     for ANZ450>452.

&&

$$

SYNOPSIS...DeSilva
NEAR TERM...MPS
SHORT TERM...DeSilva
LONG TERM...DeSilva
AVIATION...DeSilva/MPS
MARINE...DeSilva/MPS