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FXUS61 KPHI 230756
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
256 AM EST Thu Nov 23 2017

.SYNOPSIS...
High pressure will build build across the east coast today
through early Friday, before shifting offshore later on Friday.
A cold front is forecast to move across the area during the day
Saturday. High pressure builds across the region Monday, then
offshore and to our south Monday night into Tuesday. A cold
front is expected later Tuesday into Wednesday, though
precipitation may dry out before reaching the east coast.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Center of the surface high will settle in just south of our
region. In the mid and upper levels, a weak short wave trough
will approach from the west. However, thanks to a very dry
boundary layer, this will have little impact aside from
increasing clouds late in the day.

Stayed very close to the previous forecast with highs ranging
from the upper 30s to upper 40s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
The surface high will remain in place, leading to continued
light winds. Thus, despite some mid and high clouds through the
evening, expect efficient radiational cooling conditions.
Therefore, for low temperatures went on the lower side of
guidance, with lows ranging from the lower 20s to lower 30s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Fairly quiet weather is continues for most of the extended
period through next Wednesday, with a chance of isolated showers
this weekend.

High pressure will be in place early Friday, before shifting
offshore through the day. Dry weather is expected to continue
across the region Friday and Friday night. Temperatures are
forecast to warm back to near or slightly above normal Friday.

A cold front is expected to move across the area during the day
Saturday. Models do not have a significant amount of
precipitation forecast with this frontal passage. But PW values
do approach one inch, and there is some enhanced low-mid level
moisture forecast as the short wave/vorticity impulse and cold
front move across the area. So we will keep a slight chance of
showers in the forecast during the day Saturday.

Northwest flow develops across the area behind the front
overnight For Saturday night into Sunday. It is possible that
some isolated lake effect showers/flurries could make their way
across our area Saturday night into early Sunday morning in the
northwest flow. As usual, the Poconos have the better chance of
any showers. However, the flow from the Great Lakes gets cut off
during the day Sunday, so any showers are expected to end
during the morning.

Temperatures remain above normal Saturday before the front
moves through the area, but falls back to near normal or
slightly below for Sunday.

By Sunday night, high pressure begins to approach from the west
then fully builds across the area Monday. The front then pushes
offshore and to our south Monday night into Tuesday. This will
bring dry weather back to the area early next week. Temperatures
are expected to be warm back to above normal Monday through
Tuesday as return flow develops.

A cold front is forecast to move across the area Tuesday night
into Wednesday. Moisture associated with this front is expected
to dissipate as it approaches our area and the frontal passage
may end up being precipitation free. Even with the frontal
passage, temperatures are forecast to be above normal into
Wednesday.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR conditions expected with increasing mid an upper
level clouds after 18Z. Northwesterly winds will slowly back to
westerly. However, wind speeds are generally expected to be 10
KT or less. High confidence on all aspects of the forecast.

Tonight...VFR conditions expected with only some mid to upper
level clouds. Winds will generally be westerly at 5 KT or less,
but could become light and variable. High confidence on all
aspects of the forecast.

OUTLOOK...

Friday-Friday night...VFR expected. Westerly winds Thursday-
early Friday. Becoming southwest later Friday into Friday night.
High confidence.

Saturday-Sunday...Generally VFR. Isolated showers possible
which may occasionally lower conditions. Southwest winds early
Saturday, becoming west to northwest and gusting 20-25 knots
Saturday night into Sunday. Moderate confidence on showers and
sub-VFR conditions, high confidence on winds.

Sunday night-Monday...VFR expected. High confidence.

&&

.MARINE...
On the Delaware Bay...winds and waves should stay below small
craft advisory criteria today and tonight.

On the New Jersey and Delaware Atlantic coastal waters: winds
and seas should continue to gradually diminish through the early
morning hours. Once conditions drop below SCA criteria later
this morning, sub-SCA conditions are expected for the rest of
today and tonight.

OUTLOOK...

Friday-Saturday...Sub Small Craft Advisory conditions expected,
although seas may be around 4 feet at times Friday night into
Saturday.

Saturday night-Sunday night...Small Craft Advisory conditions
likely behind cold frontal passage.

Monday...Conditions falling below Small Craft Advisory levels.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 AM EST early this morning for
ANZ450>455.

&&

$$

Synopsis...Robertson
Near Term...Johnson
Short Term...Johnson
Long Term...Robertson
Aviation...Johnson/Robertson
Marine...Johnson/Robertson
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