-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 210111
AFDAKQ

Area Forecast Discussion
National Weather Service Wakefield VA
911 PM EDT Sat May 20 2017

.SYNOPSIS...
A cold front will stall over the Carolinas tonight into Sunday.
This front will lift back north as a warm front Sunday night.
Another cold front is expected to cross the Mid Atlantic region
Monday into Monday night, with low pressure tracking along the
boundary Tuesday into Tuesday night.

&&

.NEAR TERM /THROUGH SUNDAY/...
Quick update to reflect latest Radar/Sat trends. Some isolated
showers possible the next few hours over far SW zones mainly SW
of Farmville (W Prince Edward/Mecklenburg/Lunenburg Counties).
Rain chances drop off even out in these areas by 02-04z and
through the overnight as front slips farther south and drier air
drops across the area. Becoming partly to mostly cloudy
overnight with lows in the upper 50s to low 60s.

Previous Valid Discussion...

The current surface analysis depicts the leading edge of a
backdoor cold front situated from the SW VA piedmont to Ern NC.
The wind has shifted to NE across the local area. However,
temperatures remain in the low/mid 80s with dewpoints in the
upper 60s/low 70s across the SW corner of the area. 0-1km MLCAPE
values are 1000-1500 J/kg across the SW piedmont counties and
interior NE NC. A few showers/tstms could develop through early
evening across these locations as drier air pushes in from the
NE but confidence is diminishing. High pressure prevails
overnight. Partial clearing is possible this evening, with
increasing clouds across the W late. Lows range from the low/mid
50s N to around 60 S.

High pressure remains situated NE of the area Sunday as the
front remains stalled across the Carolinas. Moisture continues
to increase in the 950-850mb layer and this should result in
mostly cloudy to overcast conditions across much of the region,
although the MD Ern Shore could remain partly sunny through
midday. High temperatures will be cool ranging from the mid 60s
to around 70 across much of the area, with low 70s across far SE
VA/NE NC.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
The aforementioned front lifts N as a warm front Sunday night.
Moisture and lift aloft are limited Sunday evening, with PoPs
aob 20% across the E, and increasing to 20-40% over the
Piedmont. Moisture advection and lift increase overnight with
PoPs rising to high chc/likely along and NW of an AVC-RIC-XSA
line with 20-40% farther E. Lows range from the 50s NE to the
60s elsewhere under a mostly cloudy to overcast sky.

Monday continues to look unsettled with a cold front crossing
the area during the day, then slowing down and stalling over SE
VA/NE NC Monday night. There is a decent upper jet over the Ern
Great Lakes and shortwave energy supporting a 60-70% PoP, mainly
across the Piedmont I-95 corridor through midday, and then
shifting toward the coast during the aftn and early evening.
Instability is limited (250- 1000 J/kg of 0-1km MLCAPE) and
0-6km bulk shear is generally less than 25kt, so any threat of
severe tstms is very minimal. However, locally heavy rain is
possible with the combination of decent forcing and pw values of
+1-2 st dev. High temperatures range from the mid 70s W to
lower 80s SE. The front lingers near the coast Monday night with
some drying aloft behind it. However, the NAM/GFS each show
some lift lingering overnight. Likely pops E through midnight,
with chc pops west during the evening. PoPs of 20% N and W to
40% SE overnight with some lingering lift. Lows range from the
mid 50s NW to the Mid 60s SE.

The flow aloft remains SW Tuesday, with another wave lifting
newd across the Carolinas during the aftn, with deep layer
moisture returning. PoPs range from 20% across the far N to
30-50% S through midday, with 30-50% N to 60-70% S during the
aftn. High temperatures Tuesday have been trended downward
especially from the Piedmont the the Ern Shore due to the
combination of NE flow, cloud cover, and an increasing chc of
rain. The current high temperature forecast shows generally
low/mid 70s from the Piedmont to the Ern Shore, with mid/upper
70s for SE VA/NE NC. However, there is a potential that highs
could hold in the 60s from the Piedmont to the Ern Shore with
clouds/pcpn.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Long term period starts off wet with near to slightly below normal
temps. Forecast remains complicated mid to late week by a an upr-
level trough across the eastern CONUS...with transient shortwave
troughs and sfc lows passing up the Eastern Seaboard. Pattern
therefore favors frequent chances for rain, with much uncertainty
over the timing. For now...will forecast 50-60% PoPs Tue Night and
Wed, dropping to 40-50% Wed night and Thu. Lower chance into Fri as
the upper-level trough starts pulling off to the east. As for temps,
highs will be in the mid/upr 70s Wed through Fri, with low temps in
the mid 50s to mid 60s.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
High pressure to the north and northeast of the area with a ridge
extending south into inland Virginia will influence the weather over
the TAF sites during the 00Z TAF period. A cold front over North
Carolina will move to the northeast through the TAF sites as a warm
front late Sunday.

A moist northeast to east flow will continue through Sunday. Stratus
was present over southeast portions of the area and is expected to
slowly spread to Richmond overnight and continue Sunday. Current
trends keep IFR ceilings going at ECG and maintained that condition
through 14Z Sunday. There is some degree of drying advecting from
the northeast and this should keep ORF and PHF from going IFR. SBY
is expected to remain VFR. SREF probabilities for MVFR or lower
visibilities are quite low and kept them at 7 miles. Most of the
gusts from the northeast and east should drop out of the METARs this
evening but sustained winds at around 10 knots are expected Sunday.

OUTLOOK...A cold front approaches from the west Sunday night and
moves through the Mid Atlantic States Monday. This will bring a
chance for showers Sunday night with showers and thunderstorms
likely by Monday afternoon. MVFR/IFR conditions are indicated for
Sunday night through mid morning Monday and during heavier
precipitation during the rest of Monday into Monday night. Unsettled
weather is expected to continue Tuesday through Thursday with a
series of frontal passages and low pressure systems affecting the
Mid Atlantic region. Periods of deteriorating conditions are
possible.
-- End Changed Discussion --

&&

.MARINE...
Latest sfc analysis shows a cold front dropping south of the wtrs
with NE flow behind the front. SCA conditions will continue tonight
with 15-20 kt winds over the Bay/Sound/Lwr James and 4-6 ft seas
over coastal wtrs. Winds decrease then into Sun as the pres gradient
relaxes and high pres builds along the New England coast. Seas
however will remain aoa 5 ft into the aftn due to prolonged onshore
flow. Winds become S then SW on Mon ahead of the next frontal system
approaching from the west. The front crosses the area Mon night into
Tue morning. Not much change in airmass behind this front so expect
winds to remain below SCA levels early next week. Another front
affects the region mid week.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 4 AM EDT Sunday for ANZ632-634.
     Small Craft Advisory until 1 AM EDT Sunday for ANZ630-631-633-
     638.
     Small Craft Advisory until 7 PM EDT Sunday for ANZ650-652-654-
     656-658.

&&

$$
SYNOPSIS...AJZ/LKB
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...MAS
AVIATION...LSA
MARINE...MAS