Lansdowne, Pennsylvania Weather Forecast Discussion

197
FXUS61 KPHI 092112
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
512 PM EDT Tue Sep 9 2025
.SYNOPSIS...
High pressure across New England will shifting eastward tonight
and Wednesday. An area low pressure off the Southeast U.S.
coast tracks north and northeastward today through Wednesday. A
front may develop across portions of our area Sunday and Monday,
with an area of low pressure located off the Southeast U.S
coast.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Clouds continue to filter in through the remainder of today and into
tonight. It is a breezy day, especially as you head east to the
coastal areas as we have a northeast wind with gusts occasionally
for some of the coastal areas reaching up to 20-30 mph. In terms of
dry time, much of today will feature that. Shower chances start to
creep upwards for the coastal areas by dinner time and this
continues to increase through tonight. By the overnight hours
and into Wednesday, PoPs are 15-20% for areas west of I-95 and
for the Poconos at times. For the I-95 corridor, it is 25-30%
and then as you head east it increases up to 40%. The coastal
areas and Sussex county Delaware will at times see PoPs up to
40-60%. This all aligns well with the coastal low bringing in
moisture and setting off showers that will be isolated to
scattered in coverage. There are some indications that local
enhancements from areas of convergence and elevation may lead
to an increase in precipitation at times across parts of our
area. An isolated thunderstorm also cannot be ruled out for
mainly the coastal areas.
This coastal low will stay offshore but will also lead to an
increase in our winds. A high pressure system to our north/northeast
along with the coastal low moving north and eventually to the
northeast will lead to a tightening pressure gradient which
increases our winds. Our winds will stay breezy into Wednesday with
sustained winds generally up to 10 mph or 15 mph for the coast and
gusts 10-20 mph for most and 20-30 mph for the coast.
In terms of temperature, we see lows tonight in the low 50s to
mid 60s. Highs on Wednesday are in the upper 60s to low 70s. We
trend drier by the late afternoon and into the evening on
Wednesday as the coastal low moves away but it will take a bit
for the winds to decrease given the tighter pressure gradient.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Any residual showers will dissipate by Wednesday evening as the low
offshore stretches out and moves farther out to sea. Dry
weather will persist for Thursday into Friday night as high
pressure builds well to our north Thursday in eastern Canada,
before shifting across New England Friday. This will keep a
northerly flow across the area Thursday, before shifting to
northeast and easterly Friday. Even with the northerly and
easterly flow, temperatures will be close to normal at night,
and a couple of degrees above normal during the day through
Friday.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
For Saturday, high pressure shifts offshore and gets squeezed
offshore and weakens through Sunday, before a cold front moves into
the area later in the weekend into early next week. This front may
be mostly dry for most areas as it moves through, so we will keep
with only a slight chance of rain Sunday into Tuesday. Temperatures
over the weekend into Monday are forecast to be near or above
normal, then near normal for Tuesday.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Rest of Today...VFR with increasing clouds, especially
KMIV/KACY. NE to ENE winds increasing to 10-15 knots with some
gusts to 20 knots. High confidence.
Tonight...Clouds continue to increase with sub-VFR conditions likely
to develop for all terminals. Mainly MVFR conditions expected
at KRDG and KABE by around 08Z. There looks to be a period of
prevailing IFR conditions for the I-95 terminals and KMIV/KACY
with rain showers and low ceilings. NNE winds around 10 knots,
gusts up to 20 knots remain possible at KMIV/KACY. A PROB30
group was put in for KACY late tonight for the potential of
thunderstorms. Moderate confidence.
Wednesday...Sub-VFR ceilings for all terminals Wednesday with
MVFR ceiling at KABE/KRDG. IFR Ceilings through 18Z for the I-95
terminals and KACY/KMIV. Even LIFR possible for KACY at times.
Ceilings should improve late Wednesday from west to east along
with any showers coming to an end as well. The best potential
for gradual improvement is after 18Z Wednesday. Northeast to
north winds less than or around 10 knots for most terminal with 10-15
knots and gusty for KMIV/KACY. Winds diminish late in the
afternoon and through the evening.
Outlook...
Wednesday night through Sunday...VFR conditions expected with no
significant weather.
&&
.MARINE...
Small Craft Advisory remains in effect due to winds and waves.
Northeast winds of 20-25 kts with gusts up to 30 kts, along
with seas up to 5-7 feet will continue into Wednesday.
Outlook...
Wednesday night...Small Craft Advisory remains for the first half of
the night due to seas.
Thursday through Sunday...Conditions expected to remain below
advisory levels.
Rip Currents...
A RIP CURRENT STATEMENT REMAINS IN EFFECT THROUGH WEDNESDAY.
For Wednesday, northeasterly winds around 15 to 25 mph with
occasional gusts around 30 mph will gradually diminish through
the afternoon. Breaking wave heights around 3-5 feet. An
easterly swell around 7-8 seconds shall continue with choppy
waters around 4-5 seconds. As a result, have maintained a HIGH
risk for the development of dangerous rip currents for all
beaches.
For Thursday, north-northeast winds subside to around 5-15 mph.
Breaking wave heights lower to around 2-3 feet. An easterly
swell around 7-8 seconds will persist as choppy waters abate. As
a result, have opted to post a MODERATE risk for rip currents
for all beaches.
For specific beach forecasts, visit weather.gov/beach/phi
&&
.TIDES/COASTAL FLOODING...
Strong and persistent northeasterly flow continues through
Wednesday, before lingering albeit weakening into Thursday.
Despite being two-three days removed from the Full Moon,
astronomical high tides are still high enough with water pushing
into the coast for minor tidal flooding to occur at most of our
tidal gauges.
The greatest potential for minor tidal flooding looks to occur
with the high tide cycle tonight and on Wednesday. Therefore,
have issued a Coastal Flood Advisory for all coastal zones along
the ocean, backbays and as well as the Delaware Bay through
Wednesday afternoon. Have also included New Castle and Salem
Counties into the Advisory through Wednesday as a result of
minor tidal flooding. Additional tidal flooding may occur with
future high tide cycles on Thursday and possibly lingering into
Friday as well.
For the tidal Delaware River, confidence is still low and less
compared to areas further south. However, can anticipate at
least spotty minor tidal flooding to occur with tonight`s high
tide cycle. For Wednesday`s high tide cycles and beyond, minor
tidal flooding appears possible, but will allow future shifts to
evaluate if Advisories are needed.
No tidal flooding is expected along the northeast coast of
Chesapeake Bay.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Advisory from 11 PM this evening to 4 PM EDT
     Wednesday for NJZ016.
     Coastal Flood Advisory from 8 PM this evening to 3 PM EDT
     Wednesday for NJZ012>014-020>027.
     High Risk for Rip Currents through Wednesday evening for NJZ014-
     024>026.
DE...Coastal Flood Advisory from 11 PM this evening to 4 PM EDT
     Wednesday for DEZ001.
     Coastal Flood Advisory from 8 PM this evening to 3 PM EDT
     Wednesday for DEZ002>004.
     High Risk for Rip Currents through Wednesday evening for DEZ004.
MD...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ430-
     431.
     Small Craft Advisory until 6 AM EDT Thursday for ANZ450>455.
&&
$$
SYNOPSIS...Gorse
NEAR TERM...Guzzo
SHORT TERM...Robertson
LONG TERM...Robertson
AVIATION...Guzzo/Robertson
MARINE...DeSilva/Guzzo/Robertson
TIDES/COASTAL FLOODING...PHI

NWS PHI Office Area Forecast Discussion