Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 170717
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
317 AM EDT Sun Mar 17 2024

.SYNOPSIS...
A weak cold front passes through the region today, followed by
a reinforcing cold front on Monday. Several upper level
disturbances will pass through the region this week as surface
high pressure builds to the west. Developing low pressure
approaches for the end of the week and weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Low pressure passing north of the area today will cause a cold
front to move thru the Middle Atlantic area this morning. A
developing South to Southwest wind early this morning will bring
slightly milder air to the region but very limited moisture.
After the front passes, cooler air will arrive and drier air
from the Great Lakes region arrives.

The best dynamics with the system move north of the area today
and with the limited moisture present, we will only have small
chances for showers this morning and into the afternoon. The
best chances for any rains are for the southern Poconos and
north NJ. Slight chances exist further south. Any rain that does
occur will be light. It will be mild again today with highs in
the upper 50s/low 60s for the south/east areas and mostly 50s
for the Lehigh Valley and north NJ. Gusty winds will make the
air feel cooler today compared toe Saturday.

Tonight, the front will have moved away, but a lingering upper
trough remains over the area. We`ll carry a dry forecast for
now, but a few sprinkles for the NW areas are possible. The air
will continue to be quite dry, so this will limit any precip
possibilities. Temperatures will be cooler than recent days with
upper 20s to low 30s for the N/W areas and mid/upper 30s
elsewhere. Winds will be mostly NW at 5 to 10 mph.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
A deep upper trough with strong shortwave energy will push a
reinforcing cold front through the Northeast and Mid-Atlantic
on Monday. Meanwhile surface high pressure will build over the
Southern Plains and Gulf Coast states and will remain in place
through the middle of the week.

With the passage of that front, Lake Effect snow showers will
develop upstream and some of those snow showers may make it down
into the southern Poconos. Will carry slight chance PoPs for
Monday afternoon for Carbon and Monroe counties.

Gusty west winds will develop as the pressure gradient tightens
over the area and will range from 15 to 20 mph with gusts up to
25 mph.

With the upper trough over the area, strong cold air advection
will be underway. Highs on Monday will be in the upper 40s to
low 50s, and then highs on Tuesday will be in the 40s. Continued
breezy with gusts as high as 25 to 30 mph.

Another front approaches Tuesday night, touching off isolated
snow showers in the southern Poconos once again.

Lows at night will generally be in the 30s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Upper level trough remains in place on Wednesday and gradually
moves offshore on Thursday. Weak cold front passes through
Wednesday morning, touching off some isolated snow showers in
the southern Poconos. Canadian high pressure builds down into
the Great Lakes on Wednesday and moves into eastern Canada
Thursday. Another shot of reinforcing cold and dry air builds
south into the region on Thursday. A chilly airmass remains in
place.

Towards the end of the week, low pressure develops over the
Gulf Coast states and may take a run at the mid-Atlantic. There
are several inconsistencies among the models. The 00Z/17 ECMWF
and the 00Z/CMC have high pressure over the Northeast, and this
keeps the approaching low suppressed to the south and east. The
00Z/17 GFS has the high over eastern Canada, and low pressure
rides along the coast. For now, will follow the NBM and carry
chance PoPs.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

.thru dawn...Increasing S to SW winds as a cold front
approaches. Increasing clouds. LLWS thru 09Z/10Z as SW winds
around 40 to 45 kts develop around 2000 ft. VFR expected. A
brief sprinkle far NW areas possible. High confid.

.Today...VFR conditions expected today as a cold front crosses
the area this morning. Some low clouds (040-050) and mid level
clouds will be around for the morning then decrease during the
afternoon. Winds will switch to West following the front and
increase to 10 to 15 knots with frequent gusts to 25 kts during
the daylight hours. Medium/high confid.

.Tonight...VFR continues. Decreasing winds which will settle to
mostly NW around 5 kts. High confid.

Outlook...

Monday through Thursday...In general, a VFR forecast. A few
SHSN may briefly result in sub-VFR conditions Monday morning,
then again Tuesday night and Wednesday. A prolonged period of W
flow at 10 to 20 kt with 25 to 30 kt gusts. Moderate confidence.

&&

.MARINE...
A cold front will cross the waters this morning. Increasing
winds and seas ahead of the front will bring SCA winds/seas to
the NJ coastal waters. The SCA flag in effect will continue into
the morning. After that, winds and seas will diminish and sub-
SCA conditions are expected for the afternoon and into tonight.
Fair weather is expected for the most of the time. A brief
sprinkle or shower is possible.

Outlook...

Monday through Thursday...SCA conditions from time to time
during the week with W winds 15 to 20 kt with gusts as high as
30 kt. Sub-SCA conditions likely Tuesday night.

&&

.FIRE WEATHER...
Isolated to scattered rain showers are possible across portions
of the southern Poconos today. Isolated to scattered snow
showers are then possible across portions of the southern
Poconos Monday morning, then again Tuesday night through
Wednesday morning. Aside from that, dry conditions on tap.
Although most of the area is above normal for precipitation
since March 1, it is now a week since the last significant
rainfall, and no significant rainfall is expected this week.

Min RH values this week will generally range from 25 to 30
percent, and a breezy westerly flow will develop over the area
as well with winds generally 15 to 20 mph with 25 to 30 mph
gusts.

The day of highest concern looks to be Thursday, where surface
dew points drop into the upper single digits to low teens. Min
RH values may be as low as 20 to 25 percent, and west to
northwest winds could gust as high as 30 mph. By then, it will
be almost 2 weeks since the last significant rainfall.

Depending on how fast and how efficiently fine fuels dry out
will add to concerns for the rapid spread of any fires that may
develop.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 10 AM EDT this morning for
     ANZ450>453.

&&

$$

SYNOPSIS...MPS
NEAR TERM...OHara
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...MPS/OHara
MARINE...MPS/OHara
FIRE WEATHER...MPS


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