Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 290836
Area Forecast Discussion
National Weather Service Wakefield VA
336 AM EST Tue Nov 29 2016
A complex weather system approaches the region from the west for
midweek...bringing an increased chance of rain to the region. A
cold front will push through the area early Thursday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Deep upper level trough is located over the Plains states
attm...w/ strong SW flow across the ern CONUS. Initial area of
shras approaching from the W...though there has been a decreasing
trend. Initial impulse will be crossing the local area through
today. Dynamics rather weak as S low level flow continues to bring
increasing moisture. Will have the highest PoPs (50-80%) across
the NW 1/2 of the FA through this afternoon/early evening...tapering
to 15-30% in far SE VA-NE NC. S winds will be gusty through the
day...to 20-30 kt. Temperatures have risen overnight...into the
50s for most areas. Highs today from the m60s NW to the l70s SE.
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
Mid-upper level moisture largely departs early tonight...leaving
lo levels moist. Winds to lower...and potential exists for lo
cigs/vsbys developing...esp inland. Otherwise...PoPs to be 20-30%
w/ lows in the u50s-l60s.
A second s/w will be tracking NE in SW flow aloft...initially
invof TN/OH Valleys by late tonight...then to the local area by
Wed afternoon. Modest instability at best ahead of that system by
Wed afternoon...mainly E of I 95. Developing area of shras
expected over the higher terrain to the W Wed morning...which
spreads to the E by late Wed. Potential for moderate/heavy RA and
isold T the farther E the systems gets. Highest PoPs W and
central locations Wed...then shifts E by late Wed evening.
Otherwise...mostly cloudy inland (highs Wed in the u60s-around
70F)...VRB clouds at the coast (highs Wed in the l-m70s).
After shras/possible isold T in the evening (highest PoPs E of I
95)...clearing out W-E after midnight Wed night. Lows in the u40s
W to u50s at the coast.
Cooler/dry wx expected Thu w/ WNW winds. Sunny to partly cloudy w/
highs in the m-u50s...except l60s in far SE VA-NE NC.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The extended period is expected to begin with cool high pressure
gradually building across the Southeast Conus. This will result in
dry conditions, with temperatures slightly below seasonal
averages, but within -1 st dev. Sky cover is expected to be mostly
clear, however, increasing high clouds are possible Saturday.
Forecast lows Friday morning range from the mid 30s to around 40,
followed by highs Friday in the low/mid 50s. Slightly cooler
Friday night and Saturday with lows ranging from the low 30s
inland to the mid/upper 30s along the coast, and highs around 50.
There is the potential for highs to remain in the 40s Saturday if
thicker high clouds arrive earlier. GFS/ECMWF diverge Saturday
night through Sunday night, with the GFS depicting a progressive
nrn stream wave tracking across the region, while the ECMWF shows
a phased system lifting ne through the Ohio Valley. At this time
forecast PoPs are ~30%, which is slightly above climo. Model
differences continue into Monday, but the consensus is for a drier
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
Starting w/ VFR conditions as cigs lowering to 3-6kft across the
FA the next few hours. Area of shras approaching from the W as sfc
winds increase. Low level jet in place w/ strongest winds
generally from 1-2kft...have continued LLWS for RIC until
11-13Z/29. Expect cigs to fall to MVFR by daybreak into central
VA...but still not anticipating IFR conditions at the TAF sites due
to mixing. Light shras become likely KRIC and KSBY early Tuesday
morning. Light shras to persist through Tue morning...w/ the best
probs RIC nwd. Lower confidence to the SE. MVFR ceilings anticipated
to persist, with MVFR visibilities at times. Showers taper
NW to SE during the late afternoon/evening. Breezy...w/ S gusts
of 20 knots inland and 25 to 30 knots near the coast. Lo prob for
LIFR/IFR conditions by late tonight as winds subside and mid-upper
level moisture clears out. Periodic sub-VFR conditions are
expected into Wed night with another (better) chance of RA by Wed
afternoon/evening. Clearing out/VFR conditions return Thu-Fri.
-- Changed Discussion --A trough pushing through the Ohio Valley will cause an increase
in wind speeds across the marine area today, reaching 15-25kt with
gusts up to 30 kt over the ocean. Waves in the Bay build to 3-4ft,
with 5-7ft seas in the ocean (highest n). The trough lifts newd
through New England tonight with the wind becoming sw to w and
diminishing to 10-15kt. Waves in the Bay subside to 2-3ft.
However, seas remain 4-6ft. SCAs for the Bay/Rivers/Sound come
down by 7 pm.
A cold front is expected to push through the Ohio Valley Wednesday
and then push off the Mid-Atlantic Coast late Wednesday night. The
wind should shift to the south Wednesday into Wednesday evening
and increase to 15-25kt. It is likely that another round of SCAs
will be necessary for the Bay/Sound/rivers, while seas may not
drop below 5ft (especially n) between the two events. Therefore,
have extended SCAs for the ocean into Wed night. The wind becomes
westerly at 10-15kt (minimal CAA) behind the front late Wednesday
night into Thursday as the front shifts offshore. A nw wind of
10-15kt should prevail Friday into Saturday as high pressure
builds across the Southeast Conus. Seas subside from 3-4ft to
2-3ft, with ~2ft waves in the Bay.
-- End Changed Discussion --
MARINE...Small Craft Advisory until 4 PM EST this afternoon for
Small Craft Advisory until 7 PM EST this evening for
Small Craft Advisory until 6 AM EST Thursday for ANZ650-652-