Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 052018
Area Forecast Discussion
National Weather Service Wakefield VA
318 PM EST Mon Dec 5 2016
High pressure moves into New England tonight. A complex area of low
pressure crosses the region Tuesday, then moves offshore Tuesday
night. A strong cold front crosses the area Thursday. Cold high
pressure builds into the area late in the week.
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Latest MSAS has this mornings low well offshore with high pressure
over srn Ohio. Meanwhile, low pressure and associated fronts remain
over the deep south.
Models quickly move this high over PA this evening then into New
England late. This retreating high will allow moisture from the
south to quickly overspread the fa after midnight. Will first see
clouds increase this evening with overrunning pcpn breaking out
after 06Z first across the SW to near the Ches Bay by 12Z. Eastern
shore will likely stay dry. This timing is generally a model blend
given how the models generally underestimate just how fast pcpn can
break out. Pops will quickly ramp up late tonight (likely/cat)
across the SW...chc pops further east. Like yesterday, although
there may be a few sleet pellets mixed in at the start across the
NW, this will be insignificant and will not be mentioned in the
grids. Lows in the mid-upr 30s north to lwr 40s sern zones.
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
Tuesday appears to be a washout with widespread rainfall across the
fa. The initial low tracks NE to a position over the KY/Ohio valley
Tuesday afternoon while a secondary low develops along the stalled
coastal front. This coastal low progged to become the dominant low
as it tracks NE across eastern NC then the northern Outer Banks
Tuesday afternoon to a position east of VA Beach by 00Z Wed.
Abundant GOM / Atlantic moisture becomes entrained allowing for a
widespread mdt rainfall across the region. Given the progged
forcing, some of the rainfall could be heavy at times. Kept pcpn
type stratiformed for now but some convective elements are possible
after 18Z across the extreme SE. Any thunder progged to remain
offshore ivof Gulf stream. Added areas of fog to the grids as well.
Temps always a challenge given an insitu-wedge across the piedmont
and coastal front approaching from the SE. Little if any temp rise
expected across NWRN most zones where highs will be hard pressed to
reach 40. Temps stay in the 40s along and west of the I95 corridor,
50-55 coastal areas ranging to the upr50s-lwr 60s across the nrn
Outer Banks ivof the low.
Rainfall continues into Tuesday evening across the fa with the pcpn
quickly tapering off then ending SW-NE after midnight as the low and
best lift pull away from the region. Skies remain cldy with lows
from the mid 30s NW to upr 40s SE. Total QPF expected between 1 to
High pressure builds into the area from the west Wed and Wed night.
Dry with near seasonal conditions. Highs in the mid-upr 50s under pt
cldy skies. Lows in the mid 30s-lwr 40s.
Much advertised cold crosses the region Thursday. Initial band of
moisture progged to weaken as it crosses the mts given a downsloping
wind flow. However, enough moisture seen to carry low chc pops with
the fropa (30 pop north, 20 pop south). CAA not expected to kick in
until the moisture passes to the east so expect any pcpn to remain
in liquid form. Highs in the upr 40s-mid 50s but falling dp temps
in the afternoon.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Upper trough tracks into the Northeast states Thursday, with an
associated cold front quickly pushing across the local area
Thursday. Medium range guidance now in better agreement with the
frontal timing and evolution of the upper wave. Moisture will be
limited along the front as the best dynamics lag behind. As a
result, have maintained only a slight chance to low end chance POP
Thursday morning for the Piedmont into central Virginia, and then
pushing toward the coast Thursday afternoon. Highs Thursday in the
mid/upper 40s northwest to the mid 50`s southeast. Better chances
expected in the north/northeast forecast area nearest the deepest
moisture. Front and moisture quickly push offshore late Thursday as
a cold and dry arctic air mass surges into the region. Lows drop
into the 20`s Thursday night. Cool, breezy, and dry Friday as
surface high pressure builds in from the west. Latest GEFS still
indicates 850mb temperatures of -10 to -12C (-2 standard
deviations). Highs are expected to warm only into the upper 30`s to
low 40`s. Add in a breezy northwest wind and wind chills will
struggle to reach the mid 30`s. High pressure centers over the area
Friday night as temperatures drop into upper teens to low 20`s
inland to mid/upper 20`s near the coast. 850Mb temperatures progged
to moderate slightly Saturday (-6 to -8C) as cold high pressure
centers over the region. Less mixing will result in another cool
day, with highs back around 40 under a mostly sunny sky. High
pressure slides offshore Sunday as return flow and quasi zonal flow
aloft results in moderating temperatures. Highs Sunday forecast in
the mid to upper 40`s to low 50`s southeast.
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Stubborn IFR Stratus hanging on a bit longer than expected today,
however the sat trends are noting this quickly burning off allowing
the IFR ST to dissipate with vfr conditions over the next 1-2 hours.
High level moisture will begin to increase after 00Z as the moisture
from the approaching storm from the south moves NE. Rain will quickly
overspread the region around 12Z Monday with lowering cigs and vsbys.
IFR conditions along with areas of fog and MDT pcpn expected just
before the end of the forecast period.
Outlook: IFR conditions continue into Tuesday night as the storm
slowly pulls away to the NE. Improving conditions to VFR behind
the system on Wednesday. A strong cold front crosses the area
Thursday with sct shwrs.
High pressure located just offshore this morning, with an area of
weak low pressure along the Southeast coast. Observations indicate a
light south to southeast wind over the waters, generally at or below
10 knots. Waves 1-2 feet and seas 2-3 feet. The low lifts off the
Outer Banks early to mid morning as high pressure builds in from the
northwest. Winds in the southern waters become north to northwest 10-
15 knots early morning, then northwest 10-18 knots all waters by
late morning. With a brief period of increasing onshore flow in the
southern waters, seas will build to 3-4 feet, possibly reaching 5
feet briefly out 20nm. High pressure builds into the region this
afternoon as the low slowly pushes offshore. A northwest wind around
15 knots in the coastal waters expected to keep seas in the 2-4 ft
range. High pressure centers over the Northeast tonight through
Tuesday as another area of low pressure lifts along the Southeast
coast. Flow becomes onshore late tonight and Tuesday. Pressure
gradient strengthens as height falls spread northward over the
coastal waters. Seas expected to build to 4-5 feet in the southern
waters, then 4-6 ft all waters Tuesday afternoon as east winds
increase to 15 to 25 knots. Waves 2-3 feet in the north and 3-4 feet
in the lower Bay. SCA headlines have been issued for the Bay,
Atlantic waters, and Sound. The low lifts northeast away from the
coast Tuesday evening with flow becoming northerly. Speeds remain 10
to 20 knots and seas 4-6 feet. SCA headlines for the Atlantic waters
run through 4th period. The low pushes farther offshore Wednesday
with northwest winds decreasing to 10-15 knots in the afternoon.
Seas subside to 3-4 feet late. A strong cold front pushes across the
waters Thursday, with strong SCA conditions (or low end Gale
conditions) possible Thursday night. SCA conditions expected to
linger into the weekend.
MARINE...Small Craft Advisory from 1 PM Tuesday to 1 AM EST Wednesday
Small Craft Advisory from 10 AM Tuesday to 7 AM EST Wednesday
Gale Watch from Tuesday afternoon through Wednesday morning
Small Craft Advisory from 10 AM to 4 PM EST Tuesday for ANZ650-
Small Craft Advisory from 4 AM to 4 PM EST Tuesday for ANZ656-