740
FXUS61 KPHI 150747
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
347 AM EDT Wed May 15 2024

.SYNOPSIS...
Several waves of low pressure will slowly pass by the area through
tonight. These waves will consolidate into one low pressure that
meanders offshore on Thursday. Weak high pressure briefly builds
into the region Thursday night and Friday. Another slow moving low
pressure system will cause unsettled conditions through the weekend
lingering potentially into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A gray day ahead as surface low pressure near the mouth of the
Chesapeake will meander northward into tonight. Although it will
only slightly strengthen, it will still produce a widespread
rainfall across the forecast area. The rain will be over much of the
area today and then be more focused closer to the New Jersey coast
this evening and tonight. Rainfall totals have increased over the
next 24 hours. I`ve painted about 0.25 inches well north and
west to about an inch south and east.

Highs today will be in the 60s. Lows tonight will be in the 50s.

Mainly a southeast/east wind to start the day. We`ll finish the
forecast period with northeast winds. We`re expecting the winds to
be noticeable today into tonight gusting up to 20 or 25 mph.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
Coastal low pressure will meander off the Mid-Atlantic coast on
Thursday as the waves of low pressure merge into one system. The low
then drifts east into the western Atlantic on Friday. Weak high
pressure also approaches on Thursday, but it doesn`t really build
fully into the region until Thursday night and Friday.

Thursday will consist of periods of light rain being thrown back
around the northern side of the low primarily across Delaware, New
Jersey and the Poconos. To the south and west, dry air will begin to
filter in from the approaching high which will allow PoPs to be less
across southeast Pennsylvania and eastern Maryland. However, with
the low still in relative close proximity to the area, low clouds
and stratus will likely be difficult to erode. Some breaks will be
found the further west you are, but with onshore flow, it will feel
quite damp and cool. Highs on Thursday will be in the 60s areawide.

Thursday night will feature drying conditions across the area with
just some lingering showers near the coast. Decreasing clouds
overnight with lows in the 50s. Friday at this point looks like the
"pick of the week" considering the entire forecast. Surface high
pressure will be in control causing a mix of sun and clouds along
with seasonable temps in the upper 60s to mid 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The long term period continues to remain highly variable due to the
timing differences amongst forecast guidance with regards to the
next low pressure system.

The surface high over the region on Friday will retreat to the
northeast on Friday night. Another slow moving low pressure system
will move along the southern Appalachians on Saturday, over the Mid-
Atlantic on Sunday, and eventually offshore into early next week.
The biggest forecast challenge at this point is the timing of the
system as it works its way across the area though. Guidance
continues to struggle and vary from run to run. To avoid a
windshield wiper effect to the forecast, have continued to base the
long term forecast strictly off the NBM. This generally includes a
slight chance of rain showers Friday night, increasing and peaking
on Saturday into Saturday night before decreasing on Sunday. For
now, it still looks like the weekend will be fairly unsettled, but
it may not entirely be raining the entire time. Precip chances
reduce on Monday and Tuesday as the low exits the region. Temps are
expected to be below average for Saturday and Sunday, before making
a return closer to average on Monday and Tuesday depending on the
progression of the low.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Rest of the overnight...A mix of VFR and MVFR becoming either MVFR
or IFR as both ceilings and visibilities lower in rain. Moderate
confidence.

Today...A mix of MVFR and IFR conditions in rain...becoming IFR. SE
winds 5 to 10 kts becoming NE around 10 to 15 kts with gusts up to
20 or 25 kts. LLWS concerns arise late this morning and persist
through the afternoon near the NJ coast where the center of the low
will track. High confidence with the MVFR, lower confidence on the
extent and duration of IFR conditions.

Tonight...MVFR and IFR in the evening becoming MVFR. Rain likely
across the I95 terminals and eastward. A chance of rain at KRDG and
KABE. Decreasing chances of rain as we move through the overnight. N
to NE winds 10 to 15 kts gusting to 20 or 25 kts. Moderate
confidence.

Outlook...

Thursday...Sub-VFR conditions continue with periods of light rain.

Thursday night through Friday night...Sub-VFR conditions possible on
Thursday night, improving to VFR on Friday. No significant weather
expected.

Saturday through Sunday...Sub-VFR conditions return with periods of
rain.

&&

.MARINE...
Today...SCA conditions developing from south to north on our ocean
waters and lower Delaware Bay. E to SE winds gusting up to 25 or 30
kts. Seas building to 5-7 feet on the ocean.

Tonight...SCA conditions on our ocean waters. The SCA will also
continue on the lower Delaware Bay through at least the evening
hours. NE winds 15 to 25 kts. Seas 5-7 feet on the ocean.

Outlook...

Thursday through Friday...The SCA for all ocean waters is in
effect until 6 PM on Thursday. Due to elevated seas lingering
into Friday, the SCA will likely need to be extended. Conditions
will remain below SCA thresholds on the Delaware Bay.

Friday night through Saturday night...No marine headlines expected.

Sunday...Small Craft Advisory level conditions possible.


&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory from 10 AM this morning to 10 PM EDT this
     evening for ANZ431.
     Small Craft Advisory from 6 PM this evening to 6 PM EDT
     Thursday for ANZ450.
     Small Craft Advisory from 1 PM this afternoon to 6 PM EDT
     Thursday for ANZ451-452.
     Small Craft Advisory from 10 AM this morning to 6 PM EDT
     Thursday for ANZ453>455.

&&

$$

SYNOPSIS...Desilva/MPS
NEAR TERM...Kruzdlo
SHORT TERM...Desilva
LONG TERM...Desilva
AVIATION...Desilva/Kruzdlo
MARINE...Desilva/Kruzdlo