Haverford, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

019
FXUS61 KPHI 131019
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
619 AM EDT Wed Aug 13 2025

.SYNOPSIS...
High pressure will continue to move east today while a surface
trough arrives later today. This trough will give way to a cold
front crossing our area from the northwest during Thursday. The
front then settles just to our south into Friday before dissipating
by Saturday. High pressure arrives for Saturday into Sunday, then
a cold front crosses our area late Sunday into Monday. High pressure
starts to build in from the north on Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Bermuda high pressure lies over the western Atlantic. Return flow
will allow for a warmer and more humid airmass to spread into the
region. Upper level ridging over the area will break down as a cold
front approaches from the west. This front passes through the
region this evening.

In terms of sensible weather, fog and stratus will develop over the
area in the late night/early morning hours. While some locally dense
fog is possible, do not this it will be widespread enough to warrant
a Dense Fog Advisory. Any fog will lift and dissipate through the
morning, and should be gone by 10 am.

A hot and humid day is on tap. Surface dew points will generally be
in the low to mid 70s owed to a southerly flow. With highs in the
upper 80s to low 90s, the max heat index values will be in the upper
90s, but should fall just short of 100, and a Heat Advisory will not
be issued. Still, it may feel quite uncomfortable given how pleasant
the weather has been the last week or so.

A cold front with strong shortwave energy approaches from the west
and will trigger late day and evening showers and thunderstorms.
CAPE values will be in excess of 1500 J/kg, possibly even in excess
of 2000 J/kg. 0-6 km Bulk Shear will be less than 20 kt. PWATs will
range from 2.0 to 2.3 inches. SPC has a Marginal Risk (1 out of 5)
for severe weather, and WPC has a Marginal Risk (1 out of 4) for
Excessive Rainfall. Given how high the PWATs will be, and given the
relatively light mid-level flow, these storms should be slow-moving,
and Flash Flooding looks to be the primary threat, followed by
damaging winds.

Showers and thunderstorms mostly taper off by midnight, but with the
front getting hung up over the Mid-Atlantic, some lingering showers
and thunderstorms may continue over portions of Delmarva and
southern New Jersey. Otherwise, patchy fog is possible once again.
Lows tonight will generally be in the upper 60s to low 70s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The upper trough/surface front lingers across our forecast area Thursday
with pops in the high chance/low categorical range attm. Clouds will
be across the area for much of the day, keeping temps a few degrees
cooler than recent days. Highs will still mostly be 85 to 90 most
areas. The breaks in the clouds and daytime heating will still allow
enough instability to develop to continue with tstms for Thu. Severe
weather is not anticipated but locally heavy rains will occur.

The system from Thu. slowly moves offshore Thu night allowing a ridge
from the north to move towards our area for Friday. Pops will lower
to the 10% to 20% range with just isolated activity expected. Highs
will continue a little above normal with readings approaching 90 in
many areas (again), the humidity will be a little less that Thu,
especially across the N/W areas.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The continuation of a hot and humid pattern with mostly zonal flow
aloft will be across the area Saturday. A change in the upper air
pattern beginning late this weekend and continuing into next week
will cause a break in the hot weather. A weak upper ridge will move
back towards the Plains states leaving a shallow trough across the
Northeast and northern Middle Atlantic. The last hot day in the
latest heat will be on Sunday when we still have maxs in the upper
80s/low 90s in many areas. After that, the highs will be cooler each
day with mostly low/mid 80s by Tue. The humidity will still be
uncomfortable Sunday, but that too will moderate into next week.

There are no strong organized systems for the weekend or into next
week, mostly just a few shortwaves and a front later Sunday. We will
go along with the NBM pops which are mostly 20% to 30% for the
NW areas and 10% to 20% elsewhere for Sat/Sun. Pops Mon/Tue are
mostly around 20% for most areas.

&&

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

Today...Spotty IFR/LIFR CIGs improve to VFR by 14Z to 15Z. Late
day SHRA/TSRA will result in brief sub-VFR conditions. S to SW
winds 5 to 10 kt. Moderate confidence overall.

Tonight...Lingering SHRA/TSRA will taper off in the evening,
though may persist at KMIV/KACY for most of the night.
Conditions lower to MVFR/IFR, possibly LIFR in fog/stratus once
again late tonight. LGT/VRB winds. Low confidence.

Outlook...

Wednesday thru Thursday... sub-VFR at times with scattered
showers and tstms. Areas of fog overnight Wed night.

Thu night... Except for areas of fog overnight, mostly VFR.

Fri thru Sunday... Mostly VFR with a few scattered
showers/tstms.

&&

.MARINE...
Sub-Small Craft Advisory conditions through tonight. South to
southwest winds generally 10 to 15 kt with occasional gusts up to 20
kt. Seas 2 to 3 feet.

Late day and evening showers and thunderstorms will result in VSBY
restrictions and locally higher winds and seas.

Outlook...
Conditions will largely remain below SCA levels. A few tstms
Wed thru Thu could bring localized higher winds and seas.

Rip currents...

For today, winds will generally be out of the south at 10-15
mph with higher gusts at times. Wave heights will be 2-3 feet
with an easterly swell of 2 feet. The period will be around 8
seconds. All of these factors have resulted in a MODERATE risk
for rip currents for the Jersey Shore and a LOW risk for the
Delaware Beaches.

For Thursday, winds will be more out of the southwest at 5-10
mph with a wave height of 1-2 feet. The period will be 7-9
seconds. Due to these factors, a LOW risk of rip currents is in
place for all of the Jersey Shore and Delaware Beaches.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Gorse
NEAR TERM...MPS
SHORT TERM...OHara
LONG TERM...OHara
AVIATION...MPS/OHara
MARINE...MPS/OHara