Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 261829
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
229 PM EDT Tue Mar 26 2024

.SYNOPSIS...
Strong high pressure centered across the Canadian Maritimes extends
southwestward across our area through tonight. Meanwhile, low
pressure continues to meander around well offshore. A cold front is
forecast to cross our region tonight, where it will become nearly
stationary along the coast. Low pressure tracks northward along this
front Thursday and Thursday night before moving out to sea on
Friday. A weak clipper system may move through on Saturday.


&&

.NEAR TERM /THROUGH WEDNESDAY/...
The upper ridging today led to a fairly good day overall, most
places. Low clouds lingered across the shore areas and much of
southern Delaware. Temperatures reached the low to mid 50s in those
areas that didn`t have the abundant cloud cover. For tonight, the
onshore flow will resume and clouds will again (like late last
night) return to most areas. Little in the way of precip is expected
with the exception of some drizzle across the northern areas and
perhaps at the shore. Lows tonight will drop into the low/mid 40s.
Winds will remain light mostly from the East.

On Wednesday, the upper ridge will have moved away and our area will
come under the influence of a slow moving front and upper trough to
the west. Morning clouds may thin somewhat (probably less than
today), then increase for the afternoon. A batch of showers slowly
move west to east across the region during the day. Total rains of
one-tenth to one-quarter of an inch are possible. Highs for
Wednesday will reach the low/mid 50s for most areas with 40s at the
shore.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
What has changed...Most deterministic models are continuing with the
trend of the higher rain shifting east. Have reflected this in the
forecast, though held off on depicting as far east a solution as
what is being shown by some models until we see more consistency in
this trend.

For Thursday...The main story will be the axis of rain ahead of the
cold front as the low crosses off the southeastern U.S. coast. As
mentioned above, the models are trending in the right direction to
reduce our flood threat. Will keep monitoring it, but if this trend
continues, the main area to watch will be the coastal plains. There
will likely be a very sharp cutoff on the northwest side by
Thursday, so rain amounts are expected to be very light for areas
north and west of the fall line. Rain should taper off quickly
Thursday evening as the cold front moves further off shore.

The main story on Friday will be the winds behind the front. Expect
a very tight pressure gradient, which will result in northwest winds
could gust near 35 kt, especially in the higher terrain of the
southern Poconos and NW NJ.


&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Long wave ridging building across the central CONUS should result in
seasonable temperatures and relatively benign weather conditions
this weekend into Monday of next week. A quick moving shortwave
trough may impact the area Saturday with a 20-30% chance of rain and
increasing clouds, however it will not be the washout last Saturday
was and the system overall does not look very impactful. More
widespread rain and a period of unsettled weather looks likely as
early as Tuesday, as most of the deterministic guidance has an upper
level low diving down from Canada. A lot of timing and impact
discrepancies with this system but it bears watching over the next
several days.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...


Tonight... Lower CIGS expected to increase over the area this
evening and continue overnight. MVFR then IFR expected most sites
after midnight. While no VSBY issues are expected for most sites,
some fog may develop closer to the coast, so we`ve included some
KACY/KMIV with low/medium confid. Light East to Southeast winds
overnight.

Wednesday... Low confid with a decent possibility of CIGS becoming
VFR again (like today). We`ll probably offer some improvement to
MVFR after 14Z/15Z again with limited confid. Lower conditions
likely during the afternoon with rains arriving SW to NE. Light NE/E
winds expected.

Outlook...

Thursday...Periods of MVFR conditions possible in RA, especially at
KACY and KMIV.

Friday...NW winds gusting up to 35 kt.

Saturday and Sunday...Brief sub-VFR conditions possible Saturday
afternoon and night.

&&

.MARINE...
The SCA flag for the ocean will continue tonight and Wednesday. Seas
along with a powerful swell continue for the coast. Earlier this
morning, buoy 44009 had a 13ft seas with a 14sec period. Conditions
will slowly relax as the coastal storm that is well offshore moves
away and weakens. Fair weather tonight then rains developing later
Wednesday.

Outlook...

Thursday through Saturday...prolonged period of SCA conditions.
Winds could get close to gale force on Friday.

Saturday night into Sunday...winds and seas should stay below SCA
conditions.

&&

.TIDES/COASTAL FLOODING...
A low pressure system lingering well off the coast will result
in an extended duration of long period swells and rough surf
impacting the Atlantic coast through early this week.
Widespread minor flooding has occurred with the morning high
tide. Tidal surges remain around 2-3 feet above normal, though
many stations are closer to 2 feet rather than 3 feet.

Widespread MINOR flooding is forecast to occur with at least the
next two high tides through tonight and early Wednesday morning.
For the eastern shore of the Chesapeake Bay, tidal surge
anomalies will continue to rise to near 2-3 feet above normal by
Wednesday morning, which is also forecast to result in
widespread MINOR tidal flooding with the Wednesday morning high
tide. Coastal Flood Advisories were expanded to include the
tidal Delaware River and eastern shore of the Chesapeake Bay,
and are now in effect for all tidal areas in the forecast area
to cover the impacted high tides.

Tidal surge anomalies are forecast to begin receding by late
Wednesday. This combined with a lessening influence of the
offshore storm and moving further away from the full moon are
forecast to result in a cessation of coastal flood impacts.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory until 7 AM EDT Wednesday for PAZ070-071-
     106.
NJ...Coastal Flood Advisory until 4 AM EDT Wednesday for NJZ016.
     Coastal Flood Advisory until 2 AM EDT Wednesday for NJZ012>014-
     020>027.
     Coastal Flood Advisory until 7 AM EDT Wednesday for NJZ017>019.
DE...Coastal Flood Advisory until 4 AM EDT Wednesday for DEZ001.
     Coastal Flood Advisory until 2 AM EDT Wednesday for DEZ002>004.
MD...Coastal Flood Advisory from 8 AM to noon EDT Wednesday for
     MDZ012.
     Coastal Flood Advisory from 5 AM to 10 AM EDT Wednesday for
     MDZ015-019-020.
MARINE...Small Craft Advisory until 6 PM EDT Wednesday for ANZ450>455.

&&

$$

SYNOPSIS...Gorse/Hoeflich/MPS
NEAR TERM...OHara
SHORT TERM...Johnson
LONG TERM...Hoeflich/Staarmann
AVIATION...Johnson/OHara
MARINE...Johnson/OHara
TIDES/COASTAL FLOODING...Hoeflich/Staarmann


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