Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 281816
AFDAKQ

Area Forecast Discussion
National Weather Service WAKEFIELD VA
216 PM EDT Tue Mar 28 2017

.SYNOPSIS...
A cold front approaches from the west today and crosses the
region late this afternoon and tonight. High pressure builds in
from the north on Wednesday. The high retreats to the northeast
on Thursday as the next system approaches from the west. A
strong system is expected to impact the region on Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Area of showers with embedded tstms now pivoting NE through the
Peninsula/Middle Peninsula/northern neck and approaching the
mid-upper Bay. Elsewhere, SPC mesoanalysis and lightning trends
suggest there will not be any tstms through at least noon so
have taken mention of storms out of the forecast for the rest of
the morning (though likely PoPs remain for awhile most zones).

Expect diminishing PoPs to 20-40% most areas from late morning
through early-mid aftn, then as the upper level trough
continues to push into the area, will eventually see some
redevelopment of showers/tstms with likely PoPs most areas
again after about 18-19Z. SPC continues to highlight a marginal
risk for most of the CWA (except over the far NE). The current
showers are likely to have a negative effect on the severe
threat later today, due to only a small window of opportunity
for the atmosphere to recover after this morning pcpn exits.
Thinking best chance for any strong storms will be from about
19Z through 01Z over the far southeast portions of VA/and
northeast NC where the atmosphere may not be as worked over as
other areas. Shear is also expected to be greatest in this
region (effective shear to 30-35 KT), while areas farther NW
generally have <30 KT of effective shear since they will be more
displaced from the track of shortwave aloft. It will remain
mild today despite plenty of clouds. Highs in the low to mid
70s, except cooler 60s at the ern shore beaches.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
Will limit chance PoPs to areas along/east of I-95 by late this
evening as the Piedmont dries out, then drying out all the way
to the coast after midnight with lows mainly 50-55 F (except upr
40s ern shore). Becoming partly/mostly sunny Wed after some
early clouds (especially south) as drier air moves in from the
N. Somewhat cooler but still a little above avg with highs
60-65F near the coast and in the upper 60s to lower 70s well
inland. Upper ridge axis quickly moves back into the region by
Thu, allowing return of mid/high clouds during the day. With
fairly low mixing and overrunning clouds, expect a cooler day
with highs mainly ranging from the mid 50s to around 60. Kept it
dry through the day despite the increase in clouds ahead of the
next system.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A complex low pressure system approaches from the west late Thu
night and early Fri before slowly crossing the region
Friday/Friday night. Guidance in good agreement with respect to
potential for widespread showers/tstms and potential for heavy
rain during Fri. Will limit pops to 20-30% along west of I-95
prior to 12z Fri before increasing to 60-80% all areas during
Fri (highest west). Will keep similar pops Fri night with a slow
exit of pcpn expected. Dry wx and high pressure returns for Sat
aftn thru Sun night. Yet another system may approach fm the
west late Mon.

Highs in the upper 50s to upper 60s Fri, in the 60s to near 70
Sat, in the mid 60s to lower 70s Sun, and in the 60s to near 70
Mon. Lows in the 40s Thu night, in the upper 40s to mid 50s Fri
night, in the 40s Sat night, and in the mid 40s to near 50 Sun
night.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
This morning began with widely scattered showers with isolated
thunder, and showers are still occurring east of Interstate 95
as of 28/1800Z this afternoon. Clearing can be seen in satellite
imagery over central and western VA, and additional upper level
support from a decent shortwave (and subsequent cold pool aloft)
will aid in the redevelopment of showers and thunderstorms the
rest of this afternoon into this evening. The presence of a dry
slot in water vapor imagery (currently over far SE VA/NE NC)
indicates that these areas will need to be closely monitored as
convection moves closer to the coast. Isolated strong wind gusts
will be the primary threat with thunderstorms today, however
hail could pose a lesser threat. Cigs/VIS expected to briefly
drop to MVFR flight conditions under stronger storm cores. Kept
VCTS in forecast at all TAF sites through this afternoon/evening
until more definitive storms develop. Predominantly southwest
winds 10-15kt rest of today gusting up to around 20kt; stronger
and more erratic in vicinity of thunderstorms.

Once the surface cold front clears the coast after midnight,
winds shift to the north with speeds averaging 5-10kt. Low
stratus is expected to develop late tonight as the atmosphere
saturates from the recent rainfall. Cigs should average
500-1500ft AGL. Fog not anticipated to be an issue with the
winds above 5kt. Skies will scatter out and lift from north to
south on Wednesday as high pressure slowly builds into the
region from the north. Dry with VFR conditions through Thursday.
However, clouds should increase in coverage on Thursday in a
light onshore/northeast wind regime with shortwave energy/moisture
dropping through the region from the northwest. Clouds then
thicken and lower Thursday night as the next low pressure system
approaches the area. This system should bring widespread showers
and thunderstorms to the area Friday/Friday night as it crosses
the Mid Atlantic States.

&&

.MARINE...
Latest obs reflect SSW flow across the waters. Surface high
pressure continues to linger along and just offshore of the Mid
Atlantic and Southeast coast this morning, as a cold front
approaches from the Ohio and Tennessee River Valleys. Pressure
gradient will gradually tighten today, allowing gradual increase
in winds this afternoon and tonight...before the front crosses
the waters late this evening and overnight. SSW winds become NNW
post frontal late tonight and continue through Wed, as high
pressure starts to build in fm the N. While experimental wind
probs are indicating a small chance for a few gusts to low end
SCA in the Ches Bay Wednesday morning through midday, still do
not expect predominate SCA conditions to be met thru Wed.
However, winds will be marginal for much of the morning and
early afternoon in the lower Chesapeake Bay and Currituck Sound,
and will need to watch marginal SCA gusts during that time. Will
also need to watch encroaching SSE swell on Wednesday, owing to
developing system crossing south of Bermuda this morning. NWPS
and WaveWatch in general agreement in depiction 5 ft seas mainly
south of hatteras and offshore of the Mid- Atlantic waters, and
thinking at this time is much of this energy stays well
offshore. Thus, will hold Significant wave heights at 3 to 4 ft,
just below SCA thresholds. Waves 1-2 ft today...building to
2-3 ft on Wed.

Otherwise, cool high pressure will continue to build in from the
north Wed night into Thu morning, before it slides out to sea Thu
aftn and night. NNE winds 10-15 kt Wed night and early Thursday,
become NE 5 to 10 kt by Thu aftn. E-NE winds 5 to 10 kt Thu night
become SE 10-15 kt by Friday morning, and southerly by afternoon
as a warm front lifts across the waters. Seas subside during
this period of diminishing winds Wed-Thu, but increase again
Friday afternoon and evening ahead of next cold front, which
crosses the waters Saturday morning. Seas build back to 4-5 ft,
highest toward outer waters in pre-frontal south flow. A brief
period of SCA headlines is possible over the coastal zones,
mainly for seas. Seas subside back into the 2-4ft range over the
weekend in NNW flow aob 15kt as surface high pressure rebuilds
over the waters.

&&

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

&&

$$
SYNOPSIS...JDM
NEAR TERM...JDM/LKB
SHORT TERM...JDM/LKB
LONG TERM...TMG
AVIATION...BMD
MARINE...MAM



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