Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
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FXUS61 KAKQ 210629
Area Forecast Discussion
National Weather Service WAKEFIELD VA
229 AM EDT Tue Mar 21 2017
An upper level disturbance passes across the north tonight and
possibly interacts with a warm front lifting into the region.
The warm front stalls along or south of the Virginia-North
Carolina border Tuesday. A dry cold front drops into the region
Wednesday...followed by Canadian high pressure Thursday. A
gradual warming trend begins Friday into the first part of the
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Forecast updated to adjust timing/coverage of pcpn across the
area tngt based off latest radar trends and hiRES guidance. Have
Pops up to 60-70% across much of the region, lower near the
MCS over srn IN not dissipating as quickly as would normally be
expected during the daytime hours. This is keeping ongoing
showers/storms across wrn KY into srn WV/far sw VA early this
aftn. This main area of precip is expected to stay well west of
the local FA with a slight ewd drift as sfc high pressure breaks
down over the Mid Atlantic Region the rest of today. Any remnant
moisture on the NE quadrant of the MCS will generally stream
across the Nrn Neck/Delmarva tonight and become enhanced by a
weak shortwave, which is responsible for convection re-firing
across nrn IL/IN late this morning and currently moving across
ncntrl/cntrl IN early this aftn. Weak isentropic lift is also
associated with the incoming shortwave and lends more credence
to increasing rain chances overnight to 70-80%...especially for
inland VA and the MD Lower Eastern Shore. While theta-e gradient
placement overnight would be conducive for mention of thunder,
overall instability will be lacking and will maintain rain
shower wording. Lows tonight generally in the mid 40s (lower 40s
beaches and MD/VA Eastern Shore) due to mostly cloudy to cloudy
skies in showers.
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
Rain exits the coast around daybreak as a warm front stalls
along/south of the VA/NC border the rest of Tue. Showers may
redevelop invof this boundary during the aftn, however they
could be hard- pressed given overall stable conditions, mostly
cloudy skies, and nw winds present north of the front;
maintained slight chance for showers. Cooled high temps by a few
degrees: mid 50s to lower 60s NE to lower 70s SW.
A cold front approaches from the NW Tue night. Shortwave energy
out ahead of it will a) push the warm front to the SE and b)
allow another round of rain showers to develop essentially
along/south of Interstate 64. Latest 12Z model guidance has
shunted best shower chances farther south and the rain may
actually set up along/south of Hwy 460 where the best
temperature and pressure gradients are located. Have trended
precip forecast in this direction without drying out the north
too fast (40-60% south/20-30% north). Colder air doesn`t arrive
until Wed, therefore expect overnight lows in the 40s (upper 30s
possible far nrn counties). Dry cold front dips across
nrn VA/Delmarva on Wed with skies quickly clearing from north to
south in the morning and north winds becoming gusty up to
30-35 mph along the immediate coast (up to 25 mph inland). High
temperature forecast could be tricky but only anticipate a
5-10 degree warm-up despite mostly sunny skies and breezy
conditions. Highs in the upper 40s to lower 50s NE to low-mid 50s
SW. Meanwhile, strong Canadian sfc high builds across the Upper
Great Lakes Wed, into the ern Great Lakes Wed night, and finally
dropping across the Mid Atlantic Region on Thu. Cold Wed night
under mostly clear skies. Lows in the 20s most inland areas
(around 30F far SE VA/NE NC coastal areas). This is about
10 degrees (or roughly 1.5 std dev) below normal. Cooler and dry
on Thu with highs largely in the 40s areawide. Highs will also
run on the high side of 1.5 std dev (or 10-15 degrees) below
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Ridge axis over the region allows for a cold night Thursday
night. Lows in the upr 20s-lwr 30s. The high moves off the Mid
Atlantic coast Friday through Saturday allowing temps to quickly
warm. Highs Friday in the mid 50s-lwr 60s. Lows 45-50. Highs
Saturday in the mid-upr 60s along the coast, upr 60s-lwr 70s
west of the Ches Bay.
Moisture starts to increase ahead of an approaching frontal boundary
Saturday night and Sunday. Low chc pops Sat night. Lows in the upr
40s-lwr 50s. Frontal boundary progged across the region Sunday and
Sunday night. Mild with chc pops (slght chc thunder across the
south). Highs upr 50s-lwr 60s Eastern Shore areas, mid-upr 60s
west of the Bay. Lows in the upr 40s-lwr 50s. Lingering
moisture keep chc pops going into Monday. Highs in the 60s.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --Weakening low pressure and an associated cold front push into
the region early this morning. Sct -shra accompany this system
along with 6-8kft cigs. RIC has the best probability of
receiving a shower, so a tempo group for -shra has been included
through 08z. Elsewhere, confidence was not high enough to
include any -shra. The cold front drops through the region
roughly between 15-21z today producing a wind shift from SW-NNW.
Bkn VFR cigs ~6-8kft are expected to prevail today, but could
become sct at SBY by aftn. The cold front stalls across the
Carolinas tonight with low pressure tracking along the boundary.
Current trends are to shift this system swd, so there is only a
30-40% chc of -ra across far SE VA/NE NC mainly between 06-12z
tonight/Wednesday morning. A stronger cold front pushes through
early Wednesday as low pressure pushes offshore. A N wind will
increase to 15-20kt with gusts up to 25-30kt Wednesday. High
pressure builds in from the NW Wednesday aftn and settles over
the area Thursday. The high then slides offshore Friday and
settles off the Southeast coast by Saturday.
-- End Changed Discussion --
7 PM UPDATE...
Looking at buoy data...wavewatch is significantly undercutting
the easterly swell that is occuring and extended the SCA in all
the coastal waters to 1 AM. Seas through Midnight are forecast
to be 4 to 7 ft north of Chincoteague...4 to 6 ft Chincoteague
to Parramore Island...4 to 5 ft from Parramore Island to the
VA/NC border and 5 to 7 ft south of the VA/NC border. The
ending times for the SCA may be adjusted once again at 10 PM as
additional data arrives.
Seas are slow to subside so will continue the SCA`s along the
coast. Expect seas to slowly subside from north to south through
the evening hours. Otw, weak low pressure moves across the area
tonight with winds progged aob 15 kts. SW winds become north
behind the system after midnight.
A cold front drops into the region Tuesday afternoon, slowly pushing
south of the waters Tuesday evening. Models continue to produce a
decent CAA surge after 09Z Wed through 12Z Thursday as strong
gradient winds and height rises overspread the waters. Speeds
increase to 15-25 knots with gusts to 30 knots. GFS guidance
continues to hint for low end gales Wednesday morning with the
initial surge but will cap gusts to 32 kts for now given low
confidence. Strong high pressure builds over the Great Lakes
Wednesday afternoon, spilling over the central Appalachians late
afternoon. Cold air advection wanes Wednesday night, but with the
high remaining northwest of the waters, expect SCA conditions to
persist into Wednesday night. Seas build to 3-6 feet Wednesday and
waves 2-4 feet. Will hold off on issuing a 4th/5th period
headline with this package.
Improving conditions expected by Thursday as high pressure builds
across the waters. Return flow expected Friday as high pressure
slides offshore. The next front pushes across the waters late this
-- Changed Discussion --Radar KDOX remains inoperable due to a bad spectrum filter.
Part is on order and estimated (though possibly unstable) return
to service is Wednesday, March 22nd.
-- End Changed Discussion --
-- Changed Discussion --MD...None.
MARINE...Small Craft Advisory until 10 AM EDT this morning for ANZ656-
-- End Changed Discussion --