308
FXUS61 KPHI 131024
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
624 AM EDT Wed May 13 2026

.WHAT HAS CHANGED...
Updated the aviation section for the 12z TAFs.

&&

.KEY MESSAGES...
1. Low pressure passing across our region will bring showers and
isolated thunderstorms later today through Thursday.

2. Becoming very warm to hot this weekend and early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Low pressure passing through the region will bring
showers and isolated thunderstorms later today through Thursday.

An upper trough extending from a closed H5 low over central Canada
will move through the Great Lakes and into the Ohio Valley tonight.
Surface low pressure associated with this low will stay well north
of the area, but the closed low will sag down into the Northeast by
Thursday. Behind the departure of the surface low, a cold front
slides through the region. Unsettled weather on tap during this
period.

The timing of precipitation seems to have slowed down a bit, with
scattered showers moving into far northern and western zones by
midday Wednesday, but the bulk of the showers will hold off until
evening.

Thunderstorms are possible later today and tonight, but the latest
guidance points to a later start with the rains and CAPE values are
rather low, so coverage will not be scattered at best. According the
the SPC outlook, severe thunderstorms are not expected.

Storm total QPF continues to trend lower with overall totals of a
tenth to a quarter inch. The higher totals will be across the
southern Poconos and North NJ. Any tstm will be capable of producing
locally higher totals.

It be seasonably mild today ahead of the system with highs reaching
the low/mid 70s in many areas with some 60s across the far N/W
areas. Readings will be some 5 to 7 cooler on Thursday with highs
mostly in the 60s.


KEY MESSAGE 2...Becoming very warm to hot this weekend and early
next week.

As a closed low  departs to our east on Friday, a ridge starts to
build across the East Friday night and especially this weekend into
early next week. This along with high pressure becoming centered
across the western Atlantic and strengthening some will result in
southerly flow advecting in a much warmer air mass across our area.
As a result, high temperatures get into the 70s to mid 80s Saturday
with widespread 80s on Sunday (some inland areas touching 90
degrees). Given a southerly wind component though, it should be
cooler along the coast. The heat looks to build into early next week
with even hot conditions. Highs Monday are forecast to be well into
the 80s with even some areas reaching the low 90s (again cooler
along the coast). Given the presence of the ridge aloft, no
precipitation is currently anticipated. Some convection to our
northwest and west more removed from the ridge could try and make a
run into parts of our area later Monday. On Tuesday, the heat
continues to build with highs forecast to reach the upper 80s to low
90s (remaining cooler along the coast). The surface dew points will
increase Monday and Tuesday, peaking in the low to mid 60s for much
of the area. This will boost the heat indices above the air
temperatures some, and the urban I-95 corridor could be very close
to Heat Advisory criteria Tuesday (lower heat index criteria
starting at 96F through June).

The northwest side of the ridge aloft may start to weaken as an
upper-level trough approaches from the west later Tuesday. This may
start to allow for some convection to develop as we go deeper
through Tuesday. The greater chance for some convection may not
occur until after Tuesday with more of a trough arriving along with
a cold front. This will all depend though on how quickly the ridge
weakens and also the timing of an incoming trough and cold
front.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Today...VFR with increasing clouds. Some showers and lower
ceilings (low-end VFR) for KABE/KRDG for later this afternoon.
Increasing south to southwest winds 15-20 knots with gusts
25-30 knots. Winds at KACY/KMIV may turn southeast by late
afternoon. Moderate confidence overall.

Tonight...Lowering ceilings then visibilities as showers
overspread most areas. MVFR expected, but IFR possible by late
evening. A few thunderstorms are possible, but not included in
the TAFs given low probability. South winds 10-15 knots,
becoming southwest late. Low confidence.

Outlook...

Thursday...VFR ceilings overall. Some lingering showers however could
result in times of sub-VFR conditions. Northwest to west-northwest
winds 10-15 knots with some gusts 20-25 knots.

Friday...Mostly VFR. An isolated shower possible.

Saturday and Sunday...VFR.

&&

.MARINE...
No changes to the present SCA flag that`s already out. Winds and
seas will continue to build thru the morning with gusts reaching 25
to 30 kts and seas on the ocean reaching 4 to 6 ft today. The
highest winds and seas will be found close to the northern NJ
waters. Fair today and then showers arriving after sunset with a
chance for a tstm.

Outlook...

Friday...The conditions are anticipated to be below Small Craft
Advisory criteria.

Saturday...A period of Small Craft Advisory conditions possible.

Sunday...The conditions are anticipated to be below Small Craft
Advisory criteria.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ430-
     431-450>455.

&&

$$

DISCUSSION...Gorse/OHara
AVIATION...Gorse/OHara
MARINE...Gorse/OHara