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Area forecast discussion
National Weather Service Wakefield Virginia
1012 PM EDT Thu Jun 21 2018

Synopsis...
a cold front stalls along the North Carolina border tonight
into Friday. This front lifts back north as a warm front Friday
night into Saturday morning.

&&

Near term /through Friday/...
as of 1010 PM EDT Thursday...

Latest wx analysis features quasi-stationary frontal boundary
extending from along the NC/Virginia border back into S WV and the
lower Ohio Valley. Current upper air analysis shows a trough
over New England, with an upper low situated over the upper
Midwest, and a weak ridge stretching from the mid-Atlantic south
into Florida.

The boundary and residual convective outflows have served as
the focus for numerous showers and thunderstorms. Convection has
gradually waned this evening, but another round of showers have
developed to the west which will cross the region into the
overnight hours.

Cams have generally been a bit too aggressive (again) with pop
tonight, so have stayed in high chc to low end likely range for
sct to numerous showers through the overnight, focused along and
north of US-460 overnight. Thunder wording slowly drops to
slight to chc with waning instability and meager shear/dynamics.
Remaining warm and muggy tonight with lows from the upr 60s north
to the mid 70s southeast.

&&

Short term /Friday night through Sunday/...
as of 340 PM EDT Thursday...

On Friday, the front will remain stalled along the NC border as
the Midwest upper low pushes eastward into the Ohio Valley
late. Highest pops (50-70%) will transition inland nearest the
front, where some embedded tstms are possible (mainly pm). Pops
40-50% across the north for sct showers in onshore flow. Highs
from the mid 70s north to the mid/upr 80s south. A few places on
the Eastern Shore, including oxb, may struggle to reach the low
70s. The meandering frontal boundary lifts back north as a warm
front Friday night into Saturday morning. There area some
indications that a sfc low tracks along the front as it crosses
southern and central Virginia Fri evening/night. Given good divergence
aloft and increasing instability along/south of the advancing
warm front, would not be surprised to see a couple of strong
tstms develop. At this point, a low-end svr threat appears
possible with heavy rain being an added threat. Will continue to
monitor the evolution of this sfc feature into Friday. Have
highest pops 50-70% before 06z Friday night west of the ches Bay
(highest west of I-95), then lowering pops, especially south,
after 06z as the front lifts further north. By Saturday,
expecting temperatures to warm up again. A shortwave trough is
progged to cross the region in the afternoon/eve that could
touch of a line of mainly diurnally driven tstms. Highs in the
80s to low 90s, after morning lows in the upr 60s to mid 70s.
The next cold front crosses the area late Saturday night/Sunday
morning, with an upper trough elongating along the eastern
Seaboard. Have maintained low end pops (20-30%) with the trough
overhead possibly kicking off isolated to widely sct
showers/tstms. Highs in the upr 80s to low 90s.

&&

Long term /Sunday night through Thursday/...
as of 340 PM EDT Thursday...

A potent shortwave (coupled with an area of surface low pressure) is
still projected to dive southeastward from Canada to the
northeastern US on late Sunday into Monday. This system will bring a
chance for showers/T-storms to the region as a cold front moves
through the County Warning Area late Sunday into Monday. Both the latest 21/12z GFS
and European model (ecmwf) move the frontal boundary south of the County Warning Area by Monday
afternoon. Scattered showers/thunderstorms will overspread much of
the region (with the greatest coverage south/east of the Richmond
metro) Sunday night-Monday am. GFS shows some re-development across
southeast Virginia/NE NC Monday afternoon/evening. The European model (ecmwf) and CMC are
forecasting dry weather for the entire County Warning Area on Monday. Decided to
maintain chance pops Sunday night-Monday due to the scattered nature
of the T-storms. Behind the cold front, high pressure builds in
north of the area on Tuesday and moves offshore on Wednesday. This
will bring drier and cooler conditions to the region Monday night
through Wednesday. Moisture returns to the region as an area of
surface low pressure tracks to our north late next week, leading
to shower/T-storm chances on Thursday and Friday.

Forecast highs are in the mid-upper 80s on Monday with low-mid 80s
expected on Tuesday. Expect a slow warming trend from Wednesday
through the end of next week (highs back to around 90 by thursday)
after the area of high pressure moves offshore. Expect morning lows
between 70-75 on Monday cooling into the low-mid 60s for
Tuesday/Wednesday. Lows warming to between 66-72 on Thursday.

&&

Aviation /02z Friday through Tuesday/...
as of 800 PM EDT Thursday...

A broken line of thunderstorms stretches from Dinwiddie County
southeastward to NE NC as of 800 PM this evening. There is a
chance that these T-storms (with brief IFR visibilities in +ra)
will impact phf/orf/ecg between now and 04z tonight, so
accounted for this tempo groups. Showers with light to moderate
rain situated north of this line will impact ric through ~02z
tonight. Visibilities will likely remain MVFR/VFR at ric as
these showers move through. Am expecting ceilings/visibilities to
remain MVFR/VFR at the terminals for the majority of the time
between now and 06z. There will be a break in the showers after
09z at ric/phf/orf/ecg. Sby will likely remain dry until 06-09z
tonight before widespread showers move in.

IFR ceilings are possible starting late tonight due to stratus
(most likely at ric/sby/phf), with MVFR ceilings at orf/ecg. We
could have IFR ceilings through the morning at ric/sby, slowly
improving into the afternoon. Scattered showers/T-storms are
again possible Friday afternoon. The potential for aftn/evening
showers/T-storms will continue Saturday and Sunday. Drier
conditions potentially arrive early next week.

&&

Marine...
as of 300 PM EDT Thursday...

A weak cold front will continue to sag south over the waters this
evening before stalling to the south of the region overnight into
early Friday. This front will slowly lift back north as a warm front
late Friday into Saturday. Winds remain generally light this
afternoon, north 5 to 10 knots. Seas range from 1 to 2 feet while
waves are around 1 foot. Winds shift to the northeast this evening
and then to the east overnight into Friday. East winds will range
from 10 to 20 knots with the strongest winds mainly over the
northern Chesapeake Bay and northern ocean zones. As a result,
issued a Small Craft Advisory for the northern most Bay zone Friday
morning through Friday evening. Small Craft Advisory also remains in
effect for the northern ocean zones due to increasing seas of 4 to 6
feet. Southerly flow returns Saturday as the warm front lifts north
of the waters. A Small Craft Advisory may once again be needed
Saturday afternoon into Sunday due to a strong south-southwest push and elevated
seas.

&&

Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...Small Craft Advisory from 10 am Friday to 4 am EDT Saturday
for anz650-652.
Small Craft Advisory from 7 am to 10 PM EDT Friday for anz630.

&&

$$
Synopsis...jdm

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