-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 120935
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
535 AM EDT Fri Apr 12 2024

.SYNOPSIS...
Strong low pressure moves up into southern Canada later today.
A strong cold front, attached to the low, crosses our area this
morning. High pressure will build to the south later Saturday
through Sunday, with a weak cold front that may move through
towards the end of the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Low pressure continues to move north across the Great Lakes today.
An associated cold front will cross our area later this morning.
Frequent showers and possibly a tstm will be found ahead of the
front. Once it passes, pops will decrease back to chance (N/W) and
slight chc for other areas. Clouds will remain for mos spots, but
some late morning/early afternoon sunshine is possible for NJ and
Delmarva. Once the morning rains end, most areas will remain dry
into the afternoon. Following this, showers may develop and move
across our area for the mid/late afternoon. These showers may affect
metro Philadelphia, south NJ and Delmarva.

High temperatures today will reach the low/mid 60s for most areas,
The gusty winds will make readings feel cooler. Winds will be
Southwest to West at 15 to 20 mph with gusts over 30 mph at times.
The wind advisory for the coastal areas will continue until
expiration time.


For tonight, the strong low pressure area will be across southern
Canada while its associated fronts will have passed the area. Colder
and drier air arrives overnight with the system continuing to
circulate moisture across the area. There are chance for showers
tonight for the northern/western areas with pops in the chance range
attm. Plenty of clouds will be found N/W also, closer to the
sfc/upper lows.

Low temperatures for the region tonight will range from the
mid/upper 30s for the N/W areas to the mid/upper 40s foe Delmarva,
metro Philadelphia and south NJ. Winds will remain gusty from the
W/SW at 10 to 20 mph with gusts to 30 mph at times.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
Saturday through Saturday Night while brisk should be fairly dry.
Slight chance of showers (15-25%) in the morning north of I-78 as
the area of low pressure moves away. Strong flow combined with some
cold air advection and deeper mixing will result in breezy to windy
conditions, with the stronger winds occurring during the day time
hours on Saturday when mixing is more maximized. Gusts up to 40 MPH
are possible, especially in the higher terrain locales. The winds
then diminish Saturday night with less vertical mixing. Temperatures
will be a few degrees below normal, in the mid to upper 50s and low
60s. Lows on Saturday Night will be in the low to mid 40s.

High pressure starts building in Sunday with temperatures warming
and getting into the 70s. However, a mid level wave looks to move
through late Sunday afternoon through early Monday morning and
should bring some showers and possibly a thunderstorm across the
Lehigh Valley/Poconos and northern NJ. It will stay mild through
Sunday night with overnight lows in the 50s.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Flow aloft through the early week shifts from zonal to more of
a northwest pattern as a ridge starts to build over the Great
Lakes. At the surface this will allow higher pressure to build
and temps to warm each day with, with temperatures expected to
get well above normal for most of next week. Can`t rule out some
highs in the 80s, especially for the middle of next week.
Showers and possibly a few thunderstorms likely return late
Tuesday into Wednesday along a stalled boundary that begins to
lift as a warm front. However, this system does not look overly
impactful at this time.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Overnight... Low end MVFR or high end IFR mostly at the
terminals. Occasional showers with lower VSBYS at times. Gusty
S/SE winds 15 to 20 kts with gusts close to 30 kts. LLWS thru
10Z with 50-60 kts off the surface. Rain. Scattered thunder
possible. Medium confid.

Friday...Showers and even the chance of a tstm in the morning
as the cold front moves through but conditions improving to MVFR
in the early to mid morning and then VFR in the afternoon.
Winds shifting to southwest through the morning and eventually
more westerly at 20 gusting up to 30 knots. Moderate confidence.

Outlook...

Saturday...Sub-VFR conditions possible to start the day, but
should lift to VFR by late morning. Gusty W/NW winds with gusts
30 to 35 kt possible.

Saturday Night...VFR expected.

Sunday through Sunday Night...Sub-VFR conditions possible with
periods of showers and/or thunderstorms.

Monday through Tuesday...VFR expected. No significant weather.

&&

.MARINE...
Strong low pressure across the Great Lakes early this morning
will move north up across southern Canada today. Gale winds will
continue thru dawn, but then gradually end from S to N during the
morning, Gales will be replaced by SCA flags later this morning.
Showers this morning and then scattered showers later this
afternoon/evening. Rough seas expected thru the morning most areas.

Outlook...

Saturday through Saturday Night...Small Craft Advisory conditions
expected, with gales possible (50%), mainly during the day.

Sunday...Sub-SCA conditions expected.

Sunday Night...SCA conditions possible (30-40%) as wind gusts
approach 25 kt.

Monday through Tuesday...Sub-SCA conditions expected.

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
Forecasts from the guidance has seemingly worked out fairly well for
this event with the exception being at Bowers Beach where guidance
was too high and the gage did not reach Moderate Flood Stage.
Coastal Flood Advisories along the Atlantic have been allowed to
expire this morning with the notable exception of Ocean County
NJ and Sussex DE. For both of those areas, the along and onshore
flow has trapped water in the back bays and is producing
flooding. Mantoloking did go 0.3 feet above Moderate Flood Stage
however its right at high tide there so water levels should be
starting to recede. The advisory for Ocean County was extended
to 8pm this evening mainly focused on the northern portion of
Barnegat Bay where NWM guidance suggests that even at low tide
the gage will still be above Minor Flood Stage.

Along the Delaware River, going with the blend of BC ETSS and the
lower side of PETSS worked out well with Philadelphia cresting just
above Moderate and Burlington looking to do the same staying below
Major flood. Even so, at moderate flood stage there`s still quite a
bit of water so the tidal areas impact should still monitor for road
closings.

Confidence on the Chesapeake Bay remains low to moderate overall.
There is still a huge difference in model spread. Guidance
remains slightly down, both at Tolchester Beach and Claiborne.
So in matching obs and I felt both locations will stay in minor
flood. However we certainly cannot rule out moderate flooding
though, especially at Tolchester Beach. Regardless, tidal
flooding is expected, and any residents should take preventative
actions now before flooding begins this morning within the
Eastern Shore of Maryland.

Monitor the latest total water level forecasts for future
updates.
-- End Changed Discussion --

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
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PA...Coastal Flood Warning until 9 AM EDT this morning for PAZ070-
     071-106.
NJ...Coastal Flood Warning until 9 AM EDT this morning for NJZ015-
     017>019.
     Coastal Flood Advisory until 8 PM EDT this evening for NJZ020-
     026.
DE...Coastal Flood Advisory until 10 AM EDT this morning for DEZ003-
     004.
MD...Coastal Flood Advisory from 10 AM this morning to 2 PM EDT
     this afternoon for MDZ012.
     Coastal Flood Advisory until 11 AM EDT this morning for MDZ015-
     019-020.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ430-
     431.
     Gale Warning until noon EDT today for ANZ450>455.
-- End Changed Discussion --

&&

$$

SYNOPSIS...Deal/Hoeflich/RCM
NEAR TERM...OHara
SHORT TERM...Deal/Hoeflich
LONG TERM...Deal/Hoeflich
AVIATION...OHara
MARINE...OHara
TIDES/COASTAL FLOODING...WFO PHI