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fxus61 kphi 222000 
afdphi

Area forecast discussion
National Weather Service Mount Holly New Jersey
300 PM EST Fri Nov 22 2019

Synopsis...
a cold front moves offshore by this evening, then high pressure
builds in tonight and Saturday morning before moving offshore. Low
pressure tracks near our coastal areas later Saturday night and
Sunday morning before moving offshore of New England while
strengthening through Sunday night. High pressure slides to our
south Monday and then offshore Tuesday. The next cold front arrives
Wednesday followed by high pressure later Thursday and Friday.

&&

Near term /until 6 am Saturday morning/...
the majority of the rain showers have moved offshore at this hour
and the cold front is quickly making its way toward the coast.
Northwesterly winds behind the front will diminish through the
evening as skies clear. High pressure will build through the
overnight hours allowing colder and drier air to filter into the
region. Temperatures will depend on how quickly winds drop off, but
should generally be within a few degrees of 30 in most places.

&&

Short term /6 am Saturday morning through Sunday/...
by early Saturday, high pressure across our region will quickly
dissipate as low pressure moves from the Tennessee Valley,
across the Appalachians, through the mid-Atlantic, then offshore
by Sunday morning. Clouds will increase from southwest to
northeast by late Saturday afternoon and into the evening hours.
High temperatures should peak in the mid to upper 40s for most,
but may see a few areas in the far south/East Reach 50 degrees.

A shield of light to moderate rain will accompany the low as it
moves toward and cross the region. Rain is forecast to move into the
area by the evening hours and last through much of the overnight
hours and even into Sunday morning. As the low moves offshore, it
will be located under the left exit region of its parent trough,
which will be favorable for rapid intensification. As such,
expecting the trend of northwest banding shown in the latest
guidance to continue. This would result in the continuation of
precipitation well after daybreak Sunday and I have updated the
forecast to reflect this trend.

As far as precip type GOES, there has been a slight warming trend in
the guidance over the past couple of runs. Therefore, I increased
temperatures a bit across the northwest. As a result, backed off
quite a bit on the wintry precip in the forecast, however still
expecting some light wintry precip in the form of freezing rain,
possibly mixing with sleet or snow, overnight Saturday night. Lows
Saturday night will generally be in the mid 30s to around 40 degrees
for most outside of the higher terrain of the southern Poconos and
northwest New Jersey. As the center of the low draws near by around daybreak
Sunday, temperatures should favor precip type to Switch Back to
mostly rain if not already. Could see a few snow flakes as the
precip ends across the far northern portion of the forecast area
Sunday morning.

The low pressure will move away from the forecast area through the
remainder of Sunday and skies will clear from west to east.
Northwesterly winds of 10-15 mph behind the departing system can be
expected with some gusts up to 25 mph. High temperatures will be in
the 40s to near 50 degrees.

&&

Long term /Sunday night through Thursday/...
summary...turning warmer through the first half of next week ahead
of a strong cold front then blustery for Thanksgiving day.
Precipitation chances are centered mostly on Wednesday.

Synoptic overview...a closed low will exit coastal New England and
move across the Canadian Maritimes Sunday night and Monday, then the
flow turns more zonal for early next week. A trough amplifying
eastward from the plains Tuesday will result in a building
downstream ridge and warm air advection across the east. The
aforementioned trough moves across the Great Lakes and northeast
Wednesday, pulling a strong cold front across our region as
strengthening low pressure tracks well to our north. The trough
gradually moves out Thursday as a ridge gets closer from the west,
and this results in surface high pressure building into our region
Thursday night and Friday.

For Sunday night and Monday...strong low pressure will track near
Cape Cod Sunday evening then northeastward into Monday. The flow in
its wake in the east tends to turn more zonal into Monday, with
surface high pressure sliding across the southeast (it extends into
our area on monday). This high then shifts offshore Monday night
allowing a northwesterly flow at the surface to diminish Sunday
night into Monday before turning west to southwest. It will be
chilly Sunday night and as the winds diminish temperatures could
drop off faster during the evening especially in the typically
colder locales. As the flow backs some Sunday night and especially
Monday, warm air advection starts to increase however this looks
more pronounced Monday night. This in combination with more of a
westerly flow aloft may result in some high level clouds starting to
arrive. Overall, chilly Sunday night and then milder Monday
afternoon compared to Sunday.

For Tuesday and Wednesday...as an upper-level trough amplifies
eastward from the plains Tuesday, a downstream ridge strengthens
surface high pressure off the East Coast. This will result in a
southerly flow across the region with an uptick in the low-level
warm air advection. This will translate to high temperatures both
days well into the 50's for much of the area with some places
topping 60 degrees especially Wednesday. Some increase in the clouds
takes place especially Tuesday night and Wednesday, and despite the
warm air advection the bulk of the lift should remain to our
northwest. A surface low will track across the Great Lakes Tuesday
night and then continue northeastward Wednesday, pulling a strong
cold front across our region during Wednesday. The main forcing may
remain just to our west and north though, with much of the guidance
showing not much with the cold frontal passage in our area. Given
the depth of the incoming upper-level trough, maintained chance pops
mainly for Wednesday as the cold front moves through. The southerly
flow ahead of the front may get a little gusty especially in the
coastal plain, then gusty northwesterly winds in its wake Wednesday
night.

For Thursday and Friday...as the Wednesday systems exits New
England, ridging slides eastward from the Great Lakes to the Gulf
Coast. This will result in high pressure building eastward and
arriving over our area during Friday. There looks to be a tightened
pressure gradient in place as low pressure gradually moves into the
Canadian Maritimes, therefore much of this time frame will feature
gusty winds (blustery for Thanksgiving day). It looks to be dry
though with much drier air advecting across the region.

&&

Aviation /20z Friday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

Tonight...VFR conditions are likely through the overnight hours.
Northwesterly winds of 10 to 15 kt will gradually diminish overnight
and veer to westerly. Medium confidence.

Saturday...VFR conditions are likely through the day time hours. Mid
level clouds are expected to advect in late in the day, but at this
point it looks like MVFR or even IFR ceilings should hold off until
after sunset. Westerly winds becoming southwesterly through the day,
with speeds less than 10 kt.

Outlook...
Sunday night and Monday...VFR. West-northwest winds diminishing to
10 knots or less, becoming west to southwest Monday. Moderate
confidence.

Tuesday...VFR. Light and variable winds becoming south-southwest
around 5 knots. Moderate confidence.

Wednesday...a period of sub-VFR conditions and some showers are
possible. Southwest winds 10-15 knots with gusts to 20 knots,
becoming west to northwest late with gusts to 25 knots. Low
confidence with the timing of any sub-VFR conditions and wind
shift.

&&

Marine...
in the wake of this afternoon's cold front, northwesterly winds
gusting near or above 25 kt are expected on all waters, with the
exception of the northern Delaware Bay where gusts may fall just
short of Small Craft Advisory criteria.

Winds and seas should gradually diminish late tonight. By Saturday,
winds and seas are expected to be below Small Craft Advisory criteria on all
waters.

Outlook...
Sunday night...northwesterly winds diminish below Small Craft
Advisory criteria.

Monday and Tuesday...the conditions are anticipated to be below
Small Craft Advisory criteria. Southerly winds start to increase
Tuesday night.

Wednesday...a Small Craft Advisory is probable. Southerly winds
becoming west to northwest with the passage of a cold front.

&&

Phi watches/warnings/advisories...
PA...none.
New Jersey...none.
Delaware...none.
Maryland...none.
Marine...Small Craft Advisory until 6 am EST Saturday for anz450>455.
Small Craft Advisory until 10 PM EST this evening for anz431.

&&

$$
Synopsis...gorse
near term...staarmann

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