041
FXUS61 KPHI 112033
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
433 PM EDT Tue Jun 11 2024

.SYNOPSIS...
High pressure will be in control through Thursday. A gradual warming
trend is expected for the remainder of this week ahead of a cold
frontal passage on Friday into Friday night. High pressure will then
return on Saturday and build across the region through early next
week with above normal temperatures.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
200 PM...An upper level low remains situated to our north over
eastern NY State with a SW to NE oriented surface trough
offshore and an area of high pressure west of us over the
midwestern states into the lower Great Lakes. The upshot of this
is that there`s considerable cloud cover across the area due to
the upper low and associated cold pool aloft combined with
diurnal heating. There`s also some low level convergence that`s
been setting up near the coast due to a generally NE flow coming
onshore (aided by sea breezes) with NW winds trying to build in
from the west with the high pressure. This will bring some
isolated to scattered showers and perhaps even a few
thunderstorms developing this afternoon over southern NJ,
Delmarva, and perhaps as far north as the I-95 corridor by later
in the day. These won`t be too widespread though as POPs are
only in the 20 to 30 percent or so range for these areas. Our
northwest zones from Berks County into the Lehigh Valley and the
southern Poconos remain precip free. It will be an otherwise
relatively cool afternoon (by June standards) with low humidity
levels.

Tonight, the upper low starts to migrate to the northeast and
heights rise rapidly. This should cause convection to die
quickly by sunset with mostly clear to partly cloudy skies
overnight. Lows will be mostly in the 50s to low 60s. Enjoy it,
as we`re about to flip the page to summer in a big way.

For Wednesday, high pressure will be centered near the area
early in the day before starting to shift offshore causing
winds to turn light westerly. Expect a partly to mostly sunny
day with highs mainly in the low to mid 80s as our warming trend
begins. Humidity levels will remain comfortable though as dew
points will still be in the 50s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Quasi-zonal flow will develop through the end of the week with
increasing heights and thicknesses. Another trough axis will
approach and cross through the region by Friday night. At the
surface, high pressure will shift offshore on Wednesday night but
remain in control through early Friday. A cold front will then
arrive from the north and west on Friday into Friday night.

This pattern will translate to a gradual increase in temperatures
and dewpoints each day along with a dry forecast until Friday. Highs
on Thursday will be in the 80s to around 90 degrees for most inland
locations. Temps on Friday will be a bit warmer with a mix of 80s
and low 90s away from the shore, however with the earlier arrival of
the cold front, temps have trended a bit downward compared to
yesterday. Near the shore temps will mostly be in the 70s to around
80 degrees both days. While dewpoints will be on the rise, they
should top out in the 60s. This will keep heat indices close to the
air temperature, so at this point, it looks like we will remain
below Heat Advisory Criteria on Friday.

With respect to the cold front on Friday and Friday night...there
continues to be support from medium range guidance that there will
at least be some convection around in the afternoon and evening.
Exact convective details remain unclear especially since we are
outside the timeframe of the CAMs. However, CSU-MLP guidance does
have most of our area highlighted in a 5-14% corridor of severe
probs. So, we will need to keep an eye on Friday`s heat and
potential severe weather threats over the coming days.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The upper trough will depart the region by Saturday giving way to a
large and expansive upper ridge that will build across the eastern
CONUS through early next week. High pressure will be located near
the Great Lakes on Saturday and over the Mid-Atlantic on Sunday.
This will result in near-normal temperatures for the weekend with
mostly sunny skies.

Surface high pressure will shift offshore early next week as upper
ridge builds further resulting in increasing temps through the
middle of next week. This is supported quite well by both the
Climate Prediction Center and most ensemble guidance where temps may
flirt with records. Little in the way of precipitation is expected
other than a stray thunderstorm during the afternoon.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

This afternoon...VFR overall. Scattered showers may impact all
terminals except KRDG/KABE, with an isolated t-storm possible as
well, most likely at KMIV. A heavier storm could briefly reduce
vsby to MVFR or even IFR, but it should be very transient
should it occur. Winds this afternoon becoming mainly light NW,
at around 5 knots or less, except east to southeast at KMIV and
KACY. Moderate confidence.

Tonight...VFR. Winds becoming NW 5 kts or less. High
confidence.

Wednesday...VFR. Winds mainly west around 5 knots except
potential for seabreeze to affect KACY in the afternoon with
winds shifting to south.

Outlook...

Wednesday night through Thursday night...VFR with mostly clear
skies. No significant weather expected.

Friday through Friday night...Sub-VFR conditions possible with a
chance of thunderstorms during the afternoon and evening.

Saturday through Sunday...VFR with mostly clear skies. No
significant weather expected.

&&

.MARINE...
No marine headlines thru Wednesday. Winds generally below 10
kts. Seas 1-2 ft. An isolated thunderstorm possible, mainly this
afternoon.

Outlook...

Wednesday night...No marine headlines expected. Winds around 10 kt
and seas 2 feet or less.

Thursday through Friday night...SCA conditions possible Thursday
into Friday due to winds gusting up to 20-25 kt and seas of 3-5
feet. Fair weather expected through Thursday night with a chance of
thunderstorms on Friday and Friday night.

Saturday through Sunday...No marine headlines expected. Winds up to
10-15 kt with seas around 2-3 feet. Fair weather.

Rip Currents...

A Low risk for the formation of dangerous rip currents continues
through Thursday. Southerly winds will only have a small
component onshore for most of the coast. Additionally, expecting
more short period, wind driven waves.

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

&&

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

&&

$$

SYNOPSIS...DeSilva
NEAR TERM...Fitzsimmons/RCM
SHORT TERM...DeSilva/Staarmann
LONG TERM...DeSilva/Staarmann
AVIATION...DeSilva/Fitzsimmons
MARINE...DeSilva/Fitzsimmons/Johnson