852
FXUS61 KPHI 121453
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
953 AM EST Wed Feb 12 2025

.SYNOPSIS...
An area of low pressure will depart this morning. Another low
pressure system tracks up the Ohio Valley and eastern Great
Lakes late Wednesday into Thursday, pulling a cold front across
our area by later Thursday. High pressure briefly builds in
later Friday, then another much stronger low with its warm and
cold fronts moves through over the weekend. Canadian high
pressure then builds toward our area early next week with below
normal temperatures and dry conditions expected.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 950 AM, the radar imagery continues to show some light ocean
effect rain/snow showers across Monmouth, Ocean and portions of
Burlington and Atlantic counties as cold/moist northeast low-
level flow continues. These are not expected to amount to much.
There are also some snow showers/flurries arriving from the
west, however these look very light. There is an area of
concentrated precipitation across southern Virginia, however
this should stay south of our southern Delmarva zones this
morning with only some light mist/drizzle expected.

Otherwise, a somewhat challenging forecast remains into Thursday
as one storm continues to depart early this morning with a lull
in the main precipitation. The next storm arrives later this
afternoon and especially tonight.

High pressure centered across Ontario/Quebec Canada will wedge
its way down into our area by later today and tonight. While a
lull in the precipitation for much of the area is expected
today, an upper- level trough approaching from the west will
drive surface low pressure northeastward up the Ohio Valley
later today before crossing the eastern Great Lakes region early
Thursday. As this occurs, surface high pressure to our north
shifts eastward and the cold air damming signature gradually
weakens during tonight. Some initial overruning looks weak
however it could be enough to squeeze out some light scattered
precipitation during especially the afternoon. The residual cold
air near the surface however may be stubborn especially north
of I-78 as a weak surface low may develop on the northbound warm
front. This may halt the northward progression of the warm
front as the parent low in the eastern Great Lakes occludes. An
area of large scale forcing will result in a precipitation
shield developing late today and especially during to night. A
strengthening low-level jet will also enhance the lift for a
time tonight. Thermal profiles look to support some snow
initially for areas mainly north and west of I-95 then to a
wintry mix including some freezing rain before changing to rain
from south to north. These details will depend on the depth of
the warm layer aloft as well as the depth of the cold air closer
to the surface. Some accumulating snow/sleet especially from
I-78 northward with a coating to an inch or so (highest amounts
along the I-80 corridor). Farther to the south and east, some
sleet or snow may mix in briefly before changing to rain as
enough warming overtakes these areas. While the snow/sleet
amounts are below advisory criteria, the forecast ice accretion
of a light glaze to around 0.10 inches results in the
continuation of the Winter Weather Advisory for the southern
Poconos. We expanded the advisory to include the next tier or so
of counties given some light icing forecast. Temperatures for
the region, especially for the coastal plain, will slowly rise
overnight.

The overall total liquid precipitation is forecast to be about
0.50 inches for the region, and we will take it as it is needed
given the significant ongoing drought. Temperatures are forecast
to rise into the 40s with even some 50s across the coastal
plain Thursday ahead of the cold front. While some spotty
freezing rain may linger early Thursday in parts of mainly the
Pocono Plateau, just plain rain is expected. The cold front
itself should take the main moisture plume eastward fast enough
before the colder air rushes back in and therefore limiting any
change back to a wintry mix or snow before ending. Cannot rule
out a few snow showers though later in the day behind the cold
front into the Pocono region as the northwest flow kicks in.
Overall, it will be drying out as the day wears on Thursday as a
cold front works its way offshore.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
A break from the active weather is expected to close out the
week with seasonable and dry conditions. Strong high pressure
(~1040 mb) will build into the Ohio Valley Thursday night with
strong cold advection underway across our region. The high will
eventually shift offshore late Friday into Friday night.

Highs Friday in the 30s. Lows will be mainly in the 20s (some
teens north of I-78). Thursday night through early Friday will
be somewhat breezy with northwest winds 10-15 mph and gusts
20-30 mph possible. Winds lessen and settle light out of the
south Friday night as the high shifts offshore. The winds will
make for a chilly day Friday, but overall not bad for mid
February. Expect mainly clear/sunny skies Thursday night through
Friday, then clouds increase Friday night ahead of the weekend
system.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A strong low pressure system will impact the region over much
of the weekend, bringing potential for some light wintry precip
accumulations then widespread moderate to locally heavy
rainfall. Following the weekend system, arctic high pressure
will build into the region into next week with below normal
temperatures and dry conditions expected.

A strongly amplified synoptic pattern is expected to take shape
across the CONUS this weekend. Troughing across the Southwest
will shift to the Plains and Deep South and then offshore of the
East Coast Sunday night, with phasing polar and sub tropical
jets as the system evolves. At the surface, a Colorado low will
track across the CONUS while strengthening considerably from
Saturday through Sunday, passing across the Ohio Valley Saturday
night then just north of our area on Sunday. The low is
anticipated to drop below 990 mb as it lifts northeast into New
England late Sunday. A warm front will lift north into the area
early Sunday as the low approaches, then a strong cold front
will follow late Sunday. Following the departure of the system
Sunday night, arctic high pressure is expected to build across
the northern Plains with strong cold advection persisting across
the Northeast early next week.

As far as sensible weather goes, the weekend looks wet to put
it simply. Strong isentropic ascent will result in precipitation
spreading into the region by Saturday afternoon into Saturday
night well ahead of the main surface low. Depending on how the
thermal profiles pan out, this precipitation could be of the
wintry variety to start during the daytime Saturday, however the
timing of precip onset under a warm advection regime should
limit any significant impacts from this activity. Nevertheless,
some light snowfall or ice accretion is possible, mainly
northwest of I-95. Any wintry precip turning to mainly rain by
Saturday night through Sunday. This setup does not support an
"all day rain", but there will be many rounds of moderate to
locally heavy rainfall at times. Still a little too far out to
know exactly when and where the heaviest rain will fall. PWats
look to rise into the 1.0-1.4" range, which is quite high for
mid February. Initial indications are for a widespread 1-2" of
rainfall. Given ongoing drought conditions and lack of
significant rains recently, flooding appears unlikely. However,
we will continue to monitor this threat in the coming days.

Temperatures will be fairly seasonable on Saturday, then
turning quite mild into Sunday as the warm front lifts north.
Highs Sunday into the 50s south of I-78, even near 60 degrees
southeast of I-95. Following the cold front Sunday night,
temperatures will plummet into the 20s and teens with wind
chills in the teens to single digits. For Monday through
Wednesday, expect highs ranging from the mid 20s north to mid
30s south and lows mainly in the teens. Single digit wind chills
possible area wide Monday night. Wind chills only topping out
in the teens to 20s during the daytime periods.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...MVFR/IFR to areas of LIFR ceilings this morning may
improve slightly for a time this afternoon. Some snow showers
or flurries around especially this morning. Some lowered
visibilities will occur at times. Northeast to east-northeast
winds near 10 knots. Low confidence.

Tonight...IFR to LIFR ceilings as some rain occurs which will
lower the visibilities to IFR/MVFR. Some snow, sleet and
freezing rain for a time at KRDG to KABE to near KTTN before
changing to rain. East-northeast to east winds near 10 knots
(gusts up to 20 knots at time mainly at KACY). A period of low-
level wind shear possible overnight. Low confidence.

Thursday...Sub-VFR conditions improve to VFR by later in the
day as any lingering rain ends. Low-level wind shear possible
through the morning. Winds become south to southwest around 5
knots, then become west-northwest 10-15 knots with gusts 20-25
knots later in the afternoon. Low confidence.

Outlook...

Thursday night through Friday night...VFR. Gusty winds through
Friday. No significant weather.

Saturday through Sunday...MVFR to IFR conditions in periods of
rain. Some wintry precip possible Saturday. Gusty winds and LLWS
likely.

&&

.MARINE...
Small Craft Advisories remain in effect through Thursday, with
the advisory for Delaware Bay this afternoon and the first half
of tonight. Onshore winds will be gusty for a time before
weakening late tonight and early Thursday morning, however they
will become more southwesterly and increase again during
Thursday. This will keep seas elevated as well through Thursday.

Outlook...

Thursday night through Friday...SCA conditions. Wind gusts
25-30 kts and season 4-6 feet. Conditions improving Friday
morning.

Friday night through Saturday...No marine hazards expected.
Periods of rain developing Saturday.

Saturday night through Sunday...SCA conditions developing.
Periods of moderate to heavy rain and areas of fog likely. Gale
force winds possible Sunday night.

&&

.TIDES/COASTAL FLOODING...
The effects of the full moon today combined with a second storm
system with gusty onshore winds looks to produce a period of
low-end minor tidal flooding at many coastal areas with the
Thursday morning high tide cycle. The departures are mostly
around 0.3 feet at the most vulnerable sites. We well continue
to monitor in the event any Coastal Flood Advisories are needed.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 4 PM this afternoon to 10 AM EST
     Thursday for PAZ054-055.
     Winter Weather Advisory from 4 PM this afternoon to midnight
     EST tonight for PAZ060>062.
NJ...Winter Weather Advisory from 7 PM this evening to 9 AM EST
     Thursday for NJZ001-007-008.
DE...None.
MD...None.
MARINE...Small Craft Advisory from 1 PM this afternoon to 1 AM EST
     Thursday for ANZ430-431.
     Small Craft Advisory until 7 AM EST Friday for ANZ450>455.

&&

$$

SYNOPSIS...Gorse/Staarmann
NEAR TERM...Gorse/MJL
SHORT TERM...Staarmann
LONG TERM...Staarmann
AVIATION...Gorse/Staarmann
MARINE...Gorse/Staarmann
TIDES/COASTAL FLOODING...