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Area Forecast Discussion (AFD)

Issued by Philadelphia/Mt Holly (PHI)

                            
000
FXUS61 KPHI 221324
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
924 AM EDT Sun Sep 22 2019

.SYNOPSIS...
High pressure will continue to move slowly off the Carolina coast 
through today. Low pressure will develop over the Great Lakes
tonight and move northeast through Ontario and Quebec Monday
through Tuesday dragging a cold front across the area. High 
pressure will build into the Northeast for midweek, with 
another cold front moving through the area Thursday night. 
Another broad surface high will follow to close the week and 
persist into next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 am update: Fog is quickly dissipating in the usual spots
this morning. Another warm and mostly sunny day is on tap. Made
some minor adjustments to hourly temps and dew points for the
next few hours, but no other changes were required at this time.

Previous discussion...

Heading into the day today, the ridge aloft over the area 
breaks down while high pressure at the surface moves offshore. 
This will allow for a return flow with very warm temperatures 
and increasing moisture through the day. Late day, there is a 
chance some showers may develop to our west. They are mostly 
expected to stay out of our area and remain near the surface 
trough though there will be just a slight chance of a few 
showers or storms across the Poconos late in the afternoon. 
Highs will be mainly in the middle to upper 80s except a bit 
cooler along the coast, the Delaware Bay, and the southern 
Poconos.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
High pressure continues to move eastward over the Atlantic
Sunday night while a developing low pressure system and
associated cold front moves east through the Great Lakes. This 
will keep the area in a mild S/SW flow resulting in warmer 
overnight lows compared to this morning. Skies should remain 
mainly clear to partly cloudy. Lows will be mostly in the middle
to upper 60s...warmest over the Delmarva NE along the urban 
corridor through Philly. It will be a a bit cooler in the 
southern Poconos where lows should get down into the low 60s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Monday through Wednesday...

Warmth continues Monday due to a breezy SW flow ahead of an
approaching cold front. The day will begin mostly sunny followed
by increasing clouds in the afternoon as this front approaches.
Forecast models continue to generally back off on precip amounts
for late day Monday with the front. It appears the timing for
any scattered showers/storms approaching from the west will be
towards the late afternoon into the evening by which time it
will be past peak heating. This will limit instability. Also,
the best deep layer forcing looks to stay to our north and west.
That said, we still keep the chances for some late day scattered
showers with possible storms mainly from the I-95 corridor and
points N/W. Since instability will be limited, don't think any
storms will be severe but they could produce some gusty winds
since the flow aloft will be fairly strong. Highs Monday will
generally range from the mid 80s to close to 90 across the urban
corridor but it will be a bit cooler along the coast and over
the southern Poconos. 

The cold front moves through Monday night bringing continuing
chances for some showers/storms before clearing the area by
Tuesday. Tuesday then looks to be a partly to mostly sunny day
with seasonable temperatures and low humidity with NW winds
behind the front. 

High pressure builds in Tuesday night through Wednesday bringing
mainly clear skies with continuing seasonable temperatures and
low humidity. Lows Tuesday night will be mainly in the 50s with
highs Wednesday generally in the 70s. 

Wednesday night through Saturday...

The overall pattern will continue to be dominated by large scale
ridging in the east meaning mostly dry and fair weather can be
expected through the extended. The ridging briefly breaks down
though later Wednesday night through Thursday as a cold front 
arrives by late day Thursday. However once again, most of the 
deep layer lift will remain to our north so it should be a dry 
frontal passage. Highs Thursday look to climb back into the 80s 
for much of the area ahead of the front. Ridging becomes re-
established over the area for the end of next week into next 
weekend with sunshine and seasonably warm temperatures expected 
for Friday and Saturday.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY and surrounding areas.

Today...VFR conditions expected. Light and variable winds 
early, increasing out of the southwest 5-10 knots during the 
day, with gusts up to 15 knots possible. 

Tonight...Mainly VFR with light SW winds. 

Outlook...  

Monday and Monday night...Mainly VFR expected. MVFR or lower 
possible in scattered afternoon /evening showers. Southwest 
winds around 5 to 10 knots with some gusts around 15 to 20 knots
(more likely closer to KACY). Winds will turn to the west and 
then northwest behind a cold frontal passage Monday night. 

Tuesday through Tuesday night...Mainly VFR expected. Northwest winds 
around 5 to 10 knots. 

Wednesday through Wednesday night...Mainly VFR expected. Northwest 
winds around 5 to 10 knots turning southwest late.  

Thursday...Mainly VFR expected. W/SW winds around 5 to 10 
knots.

&&

.MARINE...
Through today...Conditions expected to remain below advisory 
levels, although winds may gust around 20 knots at times in the 
afternoon.

Tonight...SW winds increase to around 15 to 20 knots with gusts
20 to 25 knots by Monday morning. Seas increase to around 4-5
feet. 

Outlook...

Monday through Monday night...Marginal SCA conditions are likely
for the coastal waters Monday into Monday night as SW winds will
be 15 to 20 with gusts up to 25 knots. Seas will be around 5
feet. 

Tuesday through Thursday...Conditions are expected to be below 
Small Craft Advisory criteria.

RIP CURRENTS...

There is a MODERATE risk for the development of dangerous rip 
currents at New Jersey and Delaware beaches for today.

&&

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

&&

$$
Synopsis...Fitzsimmons
Near Term...CMS/Fitzsimmons
Short Term...Fitzsimmons
Long Term...Fitzsimmons
Aviation...Fitzsimmons
Marine...Fitzsimmons