Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 122336
Area Forecast Discussion
National Weather Service Wakefield VA
636 PM EST Thu Jan 12 2017
A backdoor cold front drops through the area late tonight into
Friday morning as high pressure builds over New England. Periods
of unsettled weather are expected late Friday night through the
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 200 PM this aftn, it appears that all climate records
(with the exception of Norfolk) will either tie or break high
temperature records for today, Jan 12. See climate section below
A trough of low pressure will straddle a cold front that extends
from wrn Quebec, along the Eastern Great Lakes, across the Ohio
Valley and into nrn TX. The trough/front will approach the area
through this evening and allow sw wind gusts of 20-30 mph to
persist during this time. Winds should diminish shortly after
sunset but remain breezy overnight; minimizing any fog
potential. Clouds should clear briefly late this aftn into early
evening and then thicken/lower late this evening and overnight
as the front passes through most of the area from nw to se after
midnight tonight. Only a small dip in diurnal temps expected
tonight with lows in the lower 50s (possibly upper 40s MD Lower
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
The cold front pushes se of the Mid Atlantic Region by mid-late
morning with no precipitation anticipated. Dewpoints will
plummet immediately behind the front as winds veer to the north,
however temperatures will be more slow to respond as colder 850mb
air does not arrive until early Fri evening. Therefore, high
temps may not be as warm as Thu but will be around 5-10 degrees
above normal. Low-mid 50s north and upper 50s to lower 60s
south. Sfc high pressure (around 1045 mb) builds north of the
area through Sat and wedges into the area...becoming reinforced
by another sfc high (about 1035 mb) Sat night/Sun. Meanwhile, a
strong upper level ridge (590 dam) sits over the Southeast/Gulf
of Mexico Fri through Sun. The placement of these two features
will create a squeeze play of moisture/shortwave energy that
will stream unimpeded across the region late Fri night into Sun.
Models continue to vary in overall shortwave strength and
periodicity during this timeframe, however they all agree with
bringing periods of precipitation over the cold air wedge/lee
trough after midnight Fri night (which is 3-6 hours slower than
previous 12z model runs) into Sat and again on Sun. Precip
should begin as all rain until temperatures can cool to or below
freezing across far nrn counties along/above a Fluvanna/Louisa
to Accomack VA line (staying just north of Richmond) thus
creating precip-type challenges. Still anticipating a primarily
sleet event with pockets of light freezing rain mixed in. A
brief period of snow within the wintry mix may even be possible
early Sat morning across the MD Lower Eastern Shore. Remaining
srn areas will see all rain. Lows Fri night in the lower 30s
north and in the mid- upper 30s south (around 40F coastal NE NC).
Limited warming on the order of 5 degrees or less anticipated
for Sat as the area remains wedged in cold air and under cloudy
skies with light onshore winds. Highs Sat in the upper 30s far
north; otherwise lower 40s elsewhere. Wintry mix should hold
steadfast across the north throughout the morning...gradually
changing to all rain from south to north as temps slowly warm
above 35F. Otherwise, all rain south. If any ice/sleet/snow
accumulation occurs, amounts should easily be a few hundredths
of an inch at best. Overall liquid precip totals should average
0.10 inches or less (possibly up to 0.15 inches across nrn
Models in generally good agreement with having a brief break in
precip Sat evening and overnight...returning again for Sun as
another batch of moisture/energy overrides the cold air wedge in
place across the region. Overall precip-type should be all rain
Sat night into Sun. One exception will be the MD Lower Eastern
Shore where pockets of light freezing rain could linger into Sun
morning before transitioning to all rain on Sun. Warming on Sun
will be limited once again by the cold air wedge in place under
continued cloudy skies and light onshore winds. Highs generally
in the 40s.
Wintry precip potential Fri night into Sun will continue to be
highlighted within the Hazardous Weather Outlook.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Frontal boundary remains south of the fa Sun night before
lifting north as a warm front Mon. Will continue to carry low
end pops for light rain/drizzle in cool wedged airmass Sunday
night into Monday morning. Could see some light freezing
rain/drizzle across the lower Maryland eastern shore early
Monday morning as temps drop to near 32. Otw, just liquid
expected as reading stay above freezing but remain in the 30s.
Highs Mon from the mid 40s N to lwr 50s S.
The warm front lifts north of the region Mon night as strong low
pressure tracks from the midwest (where an ice storm is
expected) NE into the upr Gt Lakes region by mid week. This slow
movement keeps AKQ fa in warm sector for most of next week
thanks to high pressure off the sern coast. Models differ on
timing of the trailing cold front across the area (GFS faster)
but are coming together for a rather strong fropa with a
possible triple point low tracking just north of the area late
Thurs/Thurs night. Pcpn becomes more scattered and showery in
nature due to being in the warm sector. Kept thunder out of
forecast with the late week fropa for now.
Highs Tues lwr 50s ern shore to lwr 60s SW. Lows Tue night in
the 40s. Highs Wed from the mid 50s to lwr 60s south. Lows Wed
night mid 40s to mid 50s. Highs Thurs mid 50s to mid 60s.
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --VFR conditions continue this evening with breezy SW flow.
Increasing clouds are expected during the overnight with mid and
high cloud ceilings lowering to MVFR/IFR ceilings by early
morning as a cold front approaches and moves through the region.
As the backdoor cold front drops through the area, winds shift
back to the N/NE as strong high pressure builds north of the
region on Fri (doing so from 12-15Z (except again a little
earlier at SBY). Will probably have a brief period of gusts to
~20 Kt all sites with the front, but overall winds on Fri will
avg 10 Kt inland and ~15 Kt near the coast at ORF. MVFR to
potentially IFR conditions may prevail for a few hrs Fri morning
before conditions improve in the aftn.
There is a higher potential for more significant flight
restrictions on Sat, with some mixed precipitation possible by
Sat morning over the N and mainly a chance for rain elsewhere.
MVFR/IFR flight restrictions likely to persist into at least
Sunday (and perhaps into Mon) as a frontal boundary lingers
across the Carolinas and a NE low level flow prevails. Still a
lot of clouds and unsettled Mon night/tue but should see a
gradual improvement as flow shifts more to the S.
-- End Changed Discussion --
SCA`s continue through the early evening for the gusty SW winds.
Winds expected to go just below criteria tonight. Backdoor front
drops south across the waters Fri morning. High res data in
better agreement that a minimal SCA is possible over the Ches
Bay from late Fri morning through the afternoon with the surge
reaching the Currituck sound by late afternoon into Fri evening.
Thus, will go ahead and hoist the headlines for Friday with this
forecast package. Decided to hold off on any headline over the
coastal waters given low confidence in wind gusts to 25 kts
and/or 5 foot seas. Conditions may eventually get to criteria
over the coastal waters due to the persistent NNE flow over the
Latest storm surge guidance continues to indicate below normal
tides into Fri ahead of the cold front. Tidal locations along
the Atlantic coast...lower Ches Bay/James River can expect
departures of -1.0 to -2.0 MLLW. Have extended the low water
advisory for another tide cycle tonight.
Well above normal temperatures have occurred across the region
today. Record maximum temperatures may be challenged... just a
few days after setting several record lows.
Records Max Temps for today, Jan 12:
* Richmond: 71 (2005) *already 70F at 200 PM
* Norfolk: 75 (1890) *already 72F at 300 PM
* Salisbury, MD: 65 (1913) *already 67F at 300 PM
* Elizabeth City, NC: 70 (2005) *already 72F at 300 PM
* Wallops Island: 65 (1980) *already 70F at 200 PM
MARINE...Small Craft Advisory until 7 PM EST this evening for
Low Water Advisory until 4 AM EST Friday for ANZ632-634-638-
Small Craft Advisory from 10 AM Friday to 3 AM EST Saturday
Small Craft Advisory from 10 AM to 7 PM EST Friday for
Small Craft Advisory from 4 PM Friday to 3 AM EST Saturday for
Small Craft Advisory until 5 AM EST Friday for ANZ650-652.