976
FXUS61 KPHI 151043
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
643 AM EDT Sun Jun 15 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 TONIGHT/...
Cloudy, showery, drizzly, and humid conditions expected to
close out the weekend along with below normal temperatures.
Continuing with Saurday`s theme, nothing of particular interest
to note as far as impacts go with the convective activity in our
region, however the lousy conditions won`t be good news for any
outdoor activities.

Quasi zonal and relatively weak flow will continue to prevail
aloft, though we will remain in the vicinity of the right
entrance region of a zonal jet toward our northeast. This mid
level diffluence will continue to provide a prolonged period of
modest ascent through tonight, which will lead to prevailing
cloudy skies and periods of showery weather. At the surface, a
stalled to slowly moving frontal boundary will remain in place
to our southwest, with surface ridging extending into the region
from southern New England.

As far as precipitation chances go, not great confidence
through tonight regarding any details of timing and coverage of
showers. There will continue to be a lot of mesoscale factors at
play. Long story short, there will be at least some chance of
showers through tonight. PWats will be high (1.25-1.75"), so any
robust and persistent convection that can develop will produce
efficient rainfall rates. Any heavier rainfall will be very
brief, and thus the flood threat is low.

With the frontal boundary now well displaced to our southwest,
we`ll have much less diurnal influence on convection. The latest
guidance still varies considerably in timing and coverage of
precipitation today through tonight, which isn`t surprising
given the subtle forcing at play. The overnight showers should
wane toward mid morning, then another round of showers may
develop by midday into the afternoon, but again, low confidence
on this. We`ve stuck with NBM PoPs through tonight for the
forecast. The main idea is scattered showers can be expected. An
isolated rumble of thunder is possible, but the chance of
lightning is quite low overall as the instability is to our
southwest where the frontal boundary is located. Areas of
drizzle or fog may develop across the coastal plain as well.

Temperatures will be mainly in the 60s to perhaps near 70
degrees in Delmarva. Lows tonight in the mid 50s to low 60s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
There continues to be little overall chance to the beginning of
the workweek as a low pressure system will ride along the
stationary boundary located to our south. The bulk of the shower
threat will be displaced to the south but there does appear to
be a brief period when we`ll see some light rain develop with
perhaps a rumble of thunder. For areas north of Philadelphia, it
should largely should remain dry (PoPs less than 20%). On
Monday evening, the boundary will gradually start lift north as
a modest warm front leading to warming temperatures hading into
the work week. 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 Tuesday into
Tuesday evening.

As the previous shift discussed, by no means do we anticipate a
washout but there will be periods of unsettled weather with
light rain/drizzle coming through in rounds. 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/...
High pressure starts building through the middle of the week
with warm air advection pushing into the region. 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
will push temps well into the upper 80s to low 90`s for areas
south and east of I95.

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. Will continue to monitor
for trends in the guidance but regardless, the general idea that
a front will bring showers and thunderstorms to the area is
consistent with the guidance. Improving weather should return by
Friday and into next weekend as high pressure returns.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...Any IFR ceilings early will improve to MVFR for most
terminals by 15Z or so. MVFR visibilities in scattered showers
and drizzle/fog at times. Otherwise, mainly prevailing VFR
visibility. East to northeast winds near 10 kts. Low confidence
on the timing/details, but high confidence in prevailing
restrictions.

Tonight...IFR ceilings likely developing, with some LIFR
possible. Fog development is possible as well, but lower
confidence on this. Scattered showers possible. Northeast winds
5-10 kts. High confidence in prevailing IFR, but low confidence
on details.

Outlook...

Monday through Tuesday night...Primarily below 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...
Conditions will remain fairly stead state through tonight. ENE
winds remaining near 10-20 kts. Seas around 3-6 feet, greatest
near and north of Atlantic City through this morning. Seas
should gradually diminish into the afternoon. The Small Craft
Advisory remains in effect through noon today north of Great Egg
Inlet. Periods of showers, drizzle, and fog could cause
visibility reduction at times.

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 and Monday, winds will be out of the northeast and
nearly perpendicular to shore around 10-20 MPH, with 2 to 4 foot
waves within the surf zone. Multiple swell groups are expected
as well, with the longest period being around 8 to 9 seconds.
This will result in a MODERATE risk for the development of rip
currents for all beaches both days.

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

&&

.TIDES/COASTAL FLOODING...
With onshore flow continuing over multiple tide cycles, water
will pile up within back bays and inlets. This will result in
some spotty minor tidal flooding along the Atlantic coastline
for areas in Atlantic and Cape May County, New Jersey and Sussex
County in Delaware. Cannot rule out some spotty minor tidal
flooding within the Delaware Bay and tidal Delaware River. The
overnight high tide cycle tonight looks to bring the highest
tides, with slowing declining water levels getting into next
week.

&&

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

Record Coldest High Temperatures
                          June 15
Site                  Record/Year
Allentown (ABE)           57/1971
AC Airport (ACY)          63/1965
AC Marina (55N)           61/1884 & 1916
Georgetown (GED)          69/2007
Mount Pocono (MPO)        55/1971
Philadelphia (PHL)        64/1912
Reading (RDG)             61/1912
Trenton (TTN)             60/1971
Wilmington (ILG)          67/1933 & 1950

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until noon EDT today for ANZ450>452.

&&

$$

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