Area Forecast Discussion
Issued by NWS Wakefield, VA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 211448
Area Forecast Discussion
National Weather Service Wakefield VA
948 AM EST Sat Jan 21 2017
High pressure over the area this morning will weaken and slide
offshore later today as a frontal boundary stays just off to
the south. Low pressure over the nations mid section will
intensify as it slowly tracks east across the Mid Atlantic
region Sunday and Monday. The intense low will move off the New
England coast Tuesday.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --Fog continues to be widespread across the fa this morning with
vsbys avgg 1/2 to 2SM and only sct areas of less than 1/2SM.
SPS extended thru 16Z for this with slowly improving vsbys over
the next few hrs. Left max temps alone for now but did adjust
hrly grids to current readings. Thinking is that temps jump
into the 50s once the fog burns off. Otw, remaining cldy.
Latest sfc analysis shows 1014 mb hi pres directly over the
Mid Atlc with a stationary front stretched across the Carolinas.
With light winds and plentiful low-level moisture, low stratus
is widespread across the region with areas of fog as well. This
is expected to continue through mid to late morning without any
mechanism to scour out the moisture. Dry wx this morning, with
approaching WAA and shortwave energy aloft leading to showers
psbl over SW areas late in the daytime period, with most other
locations expected to stay dry. Hi temps in the mid- upr 50s.
Best timing for the approaching slug of moisture and forcing
will be this eveng across the area, and have increase PoPs to
likely-categorical southern half of area, with chance PoPs
remainder of area. With a break in the pcpn overnight and light
winds, could see another round of patchy DZ/FG so added this to
the forecast as well, through mid morning Sunday. Lows tonight
range from the mid 40s NE to lwr 50s SW.
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.SHORT TERM /SUNDAY THROUGH MONDAY/...
Tricky forecast continues for the short term period. Following
any morning DZ/FG Sun, PoPs quickly ramp up through the day Sun
as strong sfc low pressure and shortwave energy aloft approach
from the west. Increasing PW`s will result in moderate to
locally heavy rainfall. Likely-categorical PoPs. Warm frontal
boundary progged to drift north to near the NC-VA border so will
have chc thunder across southern half of fa during the
afternoon with decent shear as well. High temps upr 50s north to
mid 60s south, but temps could easily end up higher or lower.
Models continue to have trouble with the stacked upr-level low
progged to slowly cross the region late Sunday night and Monday.
Categorical pops for shwrs Sunday night. Lows upr 40s/mid 50s.
At some point in time, a triple point low is forecasted to cross
Virginia. Current timing is Monday afternoon which will
continue to produce widespread shwrs across the north with a dry
slot potentially cutting off pcpn across parts of the area
Monday afternoon. However, enough instability is noted to keep
thunder mentioned across the SE in the warm sector. Highs mid
50s to lwr 60s. QPF through Monday should average one to two
inches with locally higher amounts possible.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Upper low pressure lifts northeastward away from the region Monday
night and Tuesday, with precipitation chances winding down by
Tuesday morning. High pressure is expected to return Tuesday night
into Wednesday. A cold front associated with an upper low lifting
over eastern Canada is progged to push across the region late
Wednesday night and Thursday. Will hold onto slight chc to low chc
pops (20-30%) during this time. High pressure returns again next
Friday with temperatures falling back below normal for this first
time in awhile. Highs Tuesday mostly in the 50s. Highs Wednesday
from the mid 50s Eastern Shore to the low 60s inland. Thursday`s
highs back in the 50s, then cooling into the 40s next Friday.
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Widespread sub-VFR conditions to start off the 12Z TAF period.
With a weak warm front in the vicinity, light/calm winds, and
abundant low-level moisture, low-stratus is prevalent with
pockets of low vsbys as well. Expect mainly IFR/LIFR conditions
through early/mid-morning, with slightly improving cigs not
until late in the morng/aftn as winds become southerly and the
next low pres systm approaches from the sw. Some areas,
especially inland like KRIC, may remain IFR for the duration of
the TAF period. There will be a good chance for showers tonight
as aviation conditions again deteriorate due to low cigs and
OUTLOOK...Periods of rain, moderate to heavy at times, Sunday
through Monday, will be accompanied by IFR conditions. As low
pressure moves off to the northeast...dry weather and a clearing
sky is indicated for Tuesday and Wednesday.
Weak high pressure right over the marine area early this
morning, will slide out into the Atlc by early this evening. NNE
winds around 5 kt or less, will become SE or S 5 to 10 kt this
aftn. One weak area of low pressure will move acrs NC and SE VA
later tngt thru Sun. This will turn winds to the E or SE acrs
most of the waters, except SW or S ovr the NC waters during this
time with speeds 5 to 15 kt. Waves 1 to 2 ft and seas 2 to 4 ft.
Then Sun night into Tue morning, stronger low pressure will move
fm ern TN/wrn NC and SC east-northeast acrs the CWA to just off
the srn New England coast. This will result in stronger E, SE
and S winds over the waters (10-20 kt with gusts to around 30
kt) Sun night thru most of Mon, with the strongest ESE winds
affecting the two nrn coastal waters. SCA conditions will be
likely there esply late Sun night thru Mon. SCA may be needed
acrs the remainder of the coastal waters as seas could reach at
least 5 ft out toward 20 NM. Seas may build to 6 to 9 ft ovr the
two nrn coastal waters. Winds become NW all waters on Tue with
SCA conditions probable, esply for the coastal waters. Seas 4-6
-- Changed Discussion --MD...None.
MARINE...Dense Fog Advisory until noon EST today for ANZ630>638-650-652-
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