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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 200248 CCA
AFDAKQ

Area Forecast Discussion
National Weather Service Wakefield VA
1046 PM EDT Sun Aug 19 2018

.SYNOPSIS...
A cold front will slowly drop across the area through Monday
morning. The front will stall over North Carolina Monday into
Monday night, before lifting back north as a warm front Tuesday.
A cold front crosses the area Wednesday.

&&

.NEAR TERM /UNTIL 8 AM MONDAY MORNING/...
As of 1045 PM EDT Sunday...

Scattered convection continues to develop across the region this
evening, mainly south of Interstate 64. This is due to the the
shortwave trough that is over Ohio. The air mass remains
moist across southern VA and NE NC so the scattered convection
should continue into the overnight hours, but expect the number
of showers to continue to diminish. These showers could produce
brief heavy rain. The remainder off the area, including the
northern neck and the Delmarva Peninsula should remain dry
overnight.

The location of the sfc boundary is difficult to find as the
wind shift seems to have moved through a line from LKU- RIC-
ECG. However, there seems to be little change in the surface
airmass as most areas still show dewpoints in the low to mid
70s. The convection seems to be a little more robust south of
the boundary but that appears to be the only difference. So have
modified pops to be higher south of the boundary and diminish
them moving north away from the boundary.

Prev Discussion...
An upper low is located over the lower Great Lakes this
aftn, with WSW flow aloft over the Mid-Atlantic ahead of this
feature. A subtle shortwave trough is tracking across the mountains
and is triggering showers/tstms over the higher terrain and the
Piedmont. Additionally, a narrow line of showers/tstms has developed
in vicinity of the VA/NC border along what is likely a residual
outflow or cold pool boundary from last nights convection. There is
also some sea-breeze convection over the MD Ern Shore. The main cold
front, though rather diffuse, appears to be located over nrn VA/NE
MD/DE. Temperatures this aftn are primarily in the low/mid 80s with
dewpoints around 70F N to the mid 70s S. The cold front will
gradually push swd through the region this evening and overnight.
This boundary combined with shortwave energy aloft should allow some
convection to linger into the evening and early overnight hours,
which has the potential to produce some localized heavy rain given
rich moisture and some lift. PoPs will be highest (30-50%) along and
S of the I-64 corridor, with 60% for NE NC, and aob 20% NE of I-64.
Low temperatures tonight will generally be around 70F N to the
low/mid 70s SE. Stratus is expected to develop along and N of the
front later tonight into early Monday morning.

&&

.SHORT TERM /8 AM MONDAY MORNING THROUGH WEDNESDAY/...
As of 400 PM EDT Sunday...

The cold front is expected to stall over nrn NC Monday. PoPs
will for showers/tstms will be highest over NE NC in closer
proximity to the front (40-50%), with 30-40% for central/srn VA,
and aob 20% for the Ern Shore. The surface wind will be NE or E
for much of the region, which combined with cloud cover will
limit the rise in temperature for much of the area. Forecast
highs range from upper 70s for the Atlantic coast of the Ern
Shore, around 80F for the far NW Piedmont, to the mid 80s S.

The front will lift back nwd and across the region as a warm
front Monday night and Tuesday. This will occur as stronger
surface low pressure organizes in the upper Midwest, and moves
NE across the Great Lakes by Tuesday evening. Chances for
showers/tstms will increase again over the entire region late
Monday night through Tuesday. Lows Monday night range from
70-75F, and highs Tuesday in the mid/upper 80s.

A cold front approaches from the NW Tuesday night and tracks
across the area Wednesday. The primary moisture plume will be
pushed offshore and PoPs will be lower (20-30%) with the frontal
passage Wednesday. Lows Tuesday night will be in the low/mid
70s followed by highs Wednesday in the mid/upper 80s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 400 PM EDT Sunday...

Drier and much cooler weather settles in Thursday, with only
slight chance PoPs remaining across NC through mid-morning. 1024
mb high moves east over the Mid-Atlantic Thu PM thru Mon. 850mb
temps in the +9 to +11 degC range spell out quite the cool
down, with surface temps staying in the low 80s Thu, low-mid 80s
Fri, and warming into the mid-upper 80s through the weekend.
The only portion of our area with marginal rain chances Fri-Sat
will be in NE NC, where ridging will be slightly weaker. 12z GFS
wants to break down high pressure quicker, allowing for a few
showers over NC/SE VA on Sunday...consider that solution TBD.

Otherwise, dew points will be lower late week into the weekend,
helping to make sensible weather more pleasant. Outdoor plans should
fare well for the most part late week through the weekend, and into
the start of next week.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
As of 800 PM EDT Sunday...

Unsettled conditions continue this evening with an upper trough
over the region, and a weak frontal boundary draped across the
region just south of Petersburg. Scattered showers and tstms
continue to develop especially along the Virginia/North Carolina
border producing very heavy rain, lots of lightning, and
MVFR/IFR conditions. With the frontal boundary in place and lots
of moisture, scattered showers and the chance of tstms will be
possible through the night over the region, although not much
affect to TAF sites is likely. Confidence of a direct impact on
a given terminal is low at this time. Stratus potentially
develops late tonight into early Monday morning N of the front,
mainly at RIC/SBY, and potentially PHF.

The front lingers in vicinity of the VA/NC border Monday, then
lifts back through the area as a warm front Tuesday, with a
stronger cold front moving across the area Wednesday. Therefore,
unsettled conditions will continue with daily chcs of
showers/tstms. High pressure builds into the area later in the
week.

&&

.MARINE...
As of 230 PM EDT Sunday...

Rather tranquil on the marine area again this afternoon, despite
frontal boundary being in the area. Front will gradually move
into NC overnight, then stall, before coming back northward as a
warm front on Tuesday. Winds turn NE behind the front, with some
uncertainty regarding how strong. Appears strongest winds,
mainly in the 12-18 kt range, will be across the northern and
central portions of the Bay, and the northern half of the
coastal waters. However, winds/waves/seas should remain below
SCA criteria.

Winds drop off for a time Monday night/early Tuesday as warm
front lifts northward, then increase significantly from the
south Tuesday afternoon/night ahead of stronger cold front
approaching the area from the west. If models remain consistent,
SCA will likely be needed in the 00Z Tuesday to at least 12Z
Tuesday time frame. Cold front moves through on Wednesday. Model
cold advection suggest winds are underdone in the models, and
would anticipate a period of SCA winds on the Bay in the
Wednesday night/Thursday time frame.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.

&&

$$
SYNOPSIS...AJZ/TMG
NEAR TERM...AJZ/ESS
SHORT TERM...AJZ/TMG
LONG TERM...BMS
AVIATION...AJZ/JEF
MARINE...WRS