522 
FXUS61 KPHI 050751
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
351 AM EDT Thu Aug 5 2021

.SYNOPSIS...
A dissipating stationary front just offshore will give way to a 
building area of high pressure across the eastern U.S. through 
Saturday. A wave of low pressure will push across the Southeast, 
moving just offshore Saturday night into Sunday. Another area of 
high pressure looks to build back across the region through the 
first half of next week with cold front possibly affecting the 
region by late next week. 

&&

.NEAR TERM /THROUGH TONIGHT/...
There have not been too many changes for the forecast today. A front 
remain offshore and a weak wave of low pressure will travel along it 
this morning. This will keep some clouds along the shore areas and 
some showers just offshore early today. Other areas will have mostly 
sunny conditions. Tonight, the wave will have pushed away and fair 
conditions are expected everywhere tonight. 

The return of the sunshine (compared to that past few days) will 
bring afternoon temperatures hack to near normal levels with highs 
expected to reach the low/mid 80s in mot spots with some upper 70s 
for the normally cooler areas of the Southern Poconos. Winds will be 
mostly 5 to 10 mph today favoring the N/NW directions early and W/SW 
this afternoon. 

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A quiet day Friday and for most of Saturday as the pesky stationary 
front that has been offshore dissipates and nudges eastward into the 
open Atlantic. As a weak mid-level ridge builds across the Mid-
Atlantic Friday, expect mostly clear skies and warming temperatures 
as southwesterly flow overtakes the region. Across the region, we 
are forecasting highs in the upper 80s to near 90 for the urban 
corridor. 

As this ridge pushes offshore, a transient shortwave perturbation 
now looks to push across the Southeast and towards the southern Mid-
Atlantic by Saturday into Sunday. Medium-range guidance has really 
only started coming into agreement with this solution, but timing 
discrepancies still exist on how quickly showers push into the 
region and how far northwest they will reach. Tended to favor a 
slightly later approach with rain holding off most of Saturday 
afternoon given the strength of the ridge across the region and how 
stubborn the pattern has been as of late. Just don't see things 
turning ultra-progressive all of the sudden, especially when next 
week looks to return to a blocking pattern once again. Given the 
increasing cloud cover Saturday, highs will remain suppressed a few 
degrees into the mid to upper 80s, staying mostly shy of the 90-
degree mark, save maybe the Philadelphia Metro. 

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Summer lovers rejoice as a return to summer-like heat and afternoon 
thunderstorms commences into next week. 

As previously mentioned, models disagreement exists in how quickly 
the weak coastal surface low pulls off to the north and east Sunday, 
so kept chance PoPs across the region much of Sunday to account for 
this. Given the unhasty movement of the current stationary front and 
waves of low pressure, I am not expecting much change in pattern 
behavior. Otherwise, continued southwesterly flow and increasing 850 
mb temps, highs will nudge upward again to around 90 across the 
region.

Heading into next week, high pressure will gradually build across 
the region with mid-level ridging taking place. The one item to 
watch will be the wave of low pressure from this weekend and how 
quickly it pushes offshore. Monday's highs look a touch cooler than 
previously forecast. Thus, the hottest days next week look to be 
Tuesday and Wednesday with highs in the low to potentially mid 90s 
for the urban corridor. With relative humidity values nudging upward 
as dew points climb back into the low 70s, Heat Advisories may be 
needed these days. 

Afternoon showers and thunderstorms will be possible each day, but 
with a lee-side trough setting up Wednesday and Thursday, coverage 
is likely to be a little better these afternoons. A potent shortwave 
trough looks to push a surface low and cold front across the Great 
Lakes towards our region by late in the week. 

&&

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

Today... VFR conditions expected with mostly high clouds expected. A 
few daytime Cu also possible. Mostly North or Northwest winds 5 to 
10 knots this morning then winds slowly backing to W this
afternoon. 

Tonight... A continuation of VFR conditions with few clouds 
expected. Winds will be light from the S or SW early then mostly 
variable overnight. 

Outlook... 

Friday and Saturday...VFR with building high clouds Saturday. 
Southerly winds from 5 to 10 knots. High confidence. 

Saturday night and Sunday...MVFR restrictions possible as rain 
showers move into the region from south to north. Some uncertainty 
in how far north these impacts will be, however. Southerly winds 
turning westerly from 5 to 10 knots. Moderate confidence. 

Monday...MVFR restrictions possible with patchy fog early in the day 
will give way to VFR in the afternoon. Southeasterly winds from 5 to 
10 knots. Moderate confidence. 

&&

.MARINE...
Seas are still mostly 5 to 6 ft at 44009 and will probably remain 
there much of today/tonight as the front and low remain offshore. 
Further north, winds and seas are mostly the same with some gusts 
around 20 knots also, so the low-end SCA conditions will continue. 
In coordination with OKX, we'll extend the end time of the SCA flag 
for later tonight. Scattered showers along the shore early today 
then fair weather this afternoon and tonight. 

Outlook...

Friday through Monday...Winds are expected to remain below advisory 
thresholds from 10 to 15 knots each afternoon and seas will remain 
from 2 to 3 feet.


Rip Currents... 

Today...We expect a MODERATE risk for rip currents today with the 
continued onshore flow this morning and some higher seas with the 
nearby front/low. 

Friday...Conditions will improve Friday with high pressure building 
across the waters. Mostly LOW/MODERATE rip risk expected. 

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for 
     ANZ450>455.

&&

$$
Synopsis...Davis
Near Term...O'Hara
Short Term...Davis
Long Term...Davis
Aviation...Davis/O'Hara
Marine...Davis/O'Hara