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Area forecast discussion
National Weather Service Wakefield Virginia
649 am EST Tue Nov 12 2019

Synopsis...
low pressure intensifies while moving off the New England coast
today and drags a strong cold front across the local area
during the afternoon. High pressure and much below average
temperatures build in from the west through midweek. This area
of high pressure moves offshore later in the week as low
pressure tracks northeast off the Carolina coast.

&&

Near term /until 6 PM this evening/...
as of 400 am EST Tuesday...

Current WV imagery depicts a strong trough digging into
the Great Lakes region. At the surface, low pressure is tracking
across ern PA and into NJ, with a cold front trailing to the SW
through the Shenandoah Valley. Meanwhile, 1042mb high pressure is
centered over the Central Plains. Partly to mostly cloudy and mild
early this morning across the area with temperatures ranging through
the 50s (these values will likely be calender day Max temps for
11/12). The cold front will steadily push through the region this
morning into early aftn. This front will become anafrontal as it
moves through the region with shallow colder air undercutting SW
flow aloft. Temperatures initially drop into the low/mid 40s behind
the front, with rain developing from W-E. Drier air will quickly
arrive into the northwest Piedmont and pcpn should end by midday. Pcpn will
continue longer (into mid-late aftn) from central to southeast VA, the ern
shore, and NE NC. Colder air will arrive aloft, and most data
supports at least a mix of rain and snow by aftn from central Virginia to
the ern shore. Surface temperatures will be an issue as a shallow
well mixed later will likely keep temperatures in the mid/upper 30s
by aftn for these locations. Pcpn could briefly change to all snow
in higher intensity bands, but will still have difficulty
accumulating on relatively warm ground. The arrival of drier air
from the northwest should bring a quick end to any pcpn by later in the
aftn from NW-se. Quantitative precipitation forecast averages 0.3-0.6" across the area.

&&

Short term /6 PM this evening through Thursday night/...
as of 400 am EST Tuesday...

High pressure builds in from the northwest tonight and settles over the
region Wednesday. The airmass will modify substantially from
what it is now over the plains. However, temperatures will still
be well below seasonal averages. Lows tonight range from the
upper teens/around 20f NW, to the low 30s southeast. Highs Wednesday
range from the upper 30s to around 40f, with lows Wednesday
night dropping into upper teens low 20s for much of the area,
with mid 20s to around 30f southeast. See the climate section below for
records. A Bay streamer is likely to develop tonight into
Wednesday morning, and this could produce some light snow showers
over portions of the Tidewater later tonight into Wednesday
morning. The freeze watch will be maintained at this time. High
pressure slides offshore Thursday into Thursday night.
Temperatures moderate, but remain below seasonal averages, with
highs Thursday in the mid 40s to low 50s, and lows Thursday night
in the upper 20s northwest to low/mid 40s southeast. Increasing clouds,
especially Thursday aftn into Thursday night.

&&

Long term /Friday through Monday/...
as of 400 am EST Tuesday...

The 00z/12 European model (ecmwf) and 00z/11 GFS have come closer together in
the extended period, but at this time, will lean toward the
European model (ecmwf) for Fri night through Mon. The center of high pressure
will build from the nrn Great Lakes eastward to east of the
Canadian Maritimes Fri night into Sun night. Meanwhile, low
pressure will sit just off the southeast coast Fri night into sun, then
lifts north-northeast off the mid Atlc coast Sun night through Mon. This
scenario will result in dry wx for most of the County Warning Area Fri night
into Sun morning, then at least slight chc/chc for rain for all
areas later sun through Mon.

As for temps, highs will range from the low 40s to lower 50s
Sat, in the upper 40s to upper 50s sun, and ranging through the
50s to near 60 Mon. Lows will range from near 30/lower 30s WNW,
to the lower 40s southeast Fri night, in the upper 20s/lower 30s WNW,
to the lower to mid 40s southeast Sat night, and mainly ranging from
the upper 30s WNW, to the upper 40s southeast Virginia/NE NC Sun night.

&&

Aviation /12z Tuesday through Saturday/...
as of 700 am EST Tuesday...

Low pressure is centered over New England as of 12z, with a
cold front trailing to the SW through the Blue Ridge. VFR
conditions still prevail ahead of the front, although cigs will
gradually fall to 5-10kft prior to the arrival of the front
along with some intermittent light rain. The cold front will
sweep across the region from 14-18z today. The wind will shift
to north-northwest behind the front with with gusts to 20-25kt (potentially
up to 30kt at the coast). Cigs are expected to drop quickly
behind the front, with IFR/MVFR conditions expected for a 3-6hr
period behind the front. Rain will develop behind the front,
with vsby potentially falling to 2-4sm. A brief changeover to
snow or a rain/snow mix is possible between 18-22z, before pcpn
ends, with the best potential at ric/sby. Clouds clear quickly
tonight at most sites. However, a Bay streamer could result in
clouds persisting at orf, with cigs of 3-4kft. Sct clouds of
3-4kft could also reach ecg later tonight.

VFR conditions return Wednesday into Thursday. Low pressure
pushes off the southeast coast Friday/Saturday bringing the
potential for rain and degraded flight conditions.

&&

Marine...
as of 345 am EST Tuesday...

A strong cold front approaches from the west early this morning
then will pass over the waters from late morning into the early
afternoon. Southwest to west winds 10-20 kt will continue ahead
of the front, before quickly shifting to the northwest and north and
increasing Post-frontal as strong cold advection ensues late
this morning into this afternoon. Post-frontal northwest to north winds are
expected to reach 15 to 25 knots with gusts up to 30 knots for
the eastern Virginia rivers and most of the Chesapeake Bay from late
this morning into tonight/Wednesday morning. Speeds will reach
25 to 30 knots with gusts between 35 and 40 kt for the mouth of
the Chesapeake Bay, the Currituck Sound and all of the local
coastal waters during the same time. Have adjusted headlines to
go with a Gale Warning for all of our coastal waters, the
Currituck Sound and the mouth of the Bay through 7 am Wed. Scas
will remain in effect for the remainder of the local waters.
Waves will reach 3-5 feet on the ches Bay by late today/tonight
with seas building to 5 to 9 feet by tonight (highest south). A
high surf advisory remains in effect from Virginia Beach southward
from 7 PM this evening through early Wednesday afternoon with
breaking waves of 6 to 9 feet expected.



High pressure builds in rather quickly by Wednesday afternoon with
improving conditions. A period of scas will be needed for areas
currently under a Gale Warning once they expire (from later Wed
morning into the afternoon as winds/seas diminish/subside). High
pressure moves offshore Thursday. The end off the week into the
weekend looks to be unsettled as low pressure nearshore and high
pressure over the northeast lead to an extended period of enhanced
northeasterly flow over the region. In fact, a coastal system is
likely to bring another round of gale conditions to the local waters
Friday night through Sunday morning.

&&

Climate...
a strong cold front will cross the region today, with the
coldest air of the season spreading across the area tonight
through Thursday. Record low and low Max temperatures for
Wednesday 11/13 are below:

Record
location low (11/13) year
------- -------- ------
Richmond 20 1941
Norfolk 27 1934
Salisbury 19 2001

Record
low Max
location (11/13) year
-------- ------ ----
Richmond 37 1911
Norfolk 42 1920
Salisbury 42 1977

&&

Akq watches/warnings/advisories...
Maryland...none.
NC...freeze watch from late tonight through Wednesday morning for
ncz017-102.
High surf advisory from 7 PM this evening to 1 PM EST
Wednesday for ncz102.
Virginia...freeze watch from late tonight through Wednesday morning for
vaz095-098-100-524-525.
High surf advisory from 7 PM this evening to 1 PM EST
Wednesday for vaz098.
Marine...Small Craft Advisory until 1 am EST Wednesday for anz635>637.
Gale Warning until 7 am EST Wednesday for anz633-634-650-652-
654-656-658.
Small Craft Advisory until 7 am EST Wednesday for anz630>632-
638.

&&

$$
Synopsis...ajz/mam
near term...ajz

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