Area Forecast Discussion
Issued by NWS Wakefield, VA
FXUS61 KAKQ 101107
Area Forecast Discussion
National Weather Service Wakefield VA
607 AM EST Sat Dec 10 2016
High pressure builds over the area today and tonight, then slides
offshore Sunday. Low pressure tracks east across the Great Lakes
region early next week. The associated warm front lifts north of the
region Sunday night with a trailing cold front crossing the area
late Monday. Another strong cold front impacts the region during the
middle of next week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Sfc high pressure (1034 mb) builds over the area today. Sct high
level clouds possible but overall expect a sunny and cold day.
H85 temps only support highs btwn 39-45.
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
Ridge axis shifts towards the coast tonight with mstly clear
skies during the evening hours. This allows for good radiational
cooling conditions. A northern stream trough dives into the Great
Lakes region, which allows for increasing high clouds after
midnight, especially across the north. Lows in the upr teens-
lwr20s except 25-30 along the beaches.
The sfc high moves off the Delmarva coast Sunday with the initial
wave shearing out and pushing north of the region as a more potent
wave dives into the upper Midwest. Return S-SE flow allows for a
slight rise in H85 temps. Highs in the low-mid 40s, with upr 40s
to near50 sern zones.
The northern stream wave dives through the Great Lakes Sunday night
and a southern stream wave precede it and pushes through the
Tennessee Valley. This allows a warm front to lift through the Mid-
Atlantic. Lows Sunday night will likely occur during the evening,
then remain steady or rise a bit. Lows from the mid 30s nw to the
low/mid 40s se. Clouds thicken and lower during the evening, with
light rain breaking out along the coast initially as some semblance
of a coastal trough pushes newd ahead of the approaching system and
interacts with the warm front. Pcpn remains all liquid as temps are
expected to remain above freezing even across the NW zones.
The srn stream wave tracks across the region through midday Monday,
with the nrn stream wave moving toward the Saint Lawrence Valley by
aftn, which will push the associated cold front into the area.
Given the 00Z data, went ahead and increased pops to likely across
the west during the morning and likely pops across the east during
the afternoon Forecast PoPs are highest from morning through mid-
aftn. Deep-layered w-sw flow will limit QPF, which at this time is
forecast to be btwn 1/4 to 1/3 inch. Milder with highs ranging from
the lwr 50s across the NW to mid 60s across the SE.
The cold front pushes offshore Monday night. Pcpn (liquid) lingers
through the evening then remaining pt cldy NW to mstly cldy SE.
Lowsin the mid 30s NW to mid 40s SE.
.LONG TERM /TUESDAY THROUGH FRIDAY/...
High pressure briefly builds into the area Tuesday pushing any
pcpn south of the Albemarle sound. Light N-NE winds keeps a good
deal of clouds around. Highs upr 40s north to mid 50s south.
Both the GFS/ECMWF slower in returning pcpn back north Tuesday
night. Thus, went ahead and pushed back pops until after 06Z and
limited slight chc (light rain) to swrn half of fa. Lows in the mid
to upr 30sexcept near 40 se.
Decent slug of moisture progged ahead of next strong cold front for
Wed. Went with high chc pops for now, highest sern half of fa. Highs
mid 40s north to mid 50s south.
Interesting forecast Wednesday night in whether the cold air will
come in before pcpn ends. GFS ends pcpn faster than ECMWF but both
models do show enuf cold air for several hours to allow for some
pcpn type issues. Thus, went ahead and introduced a mixture of
rain/sleet possibly ending as light snow after midnight. Exception
will be the extreme sern coastal zones where pcpn remains liquid.
Lows from the mid 20s NW to mid 30s SE.
Cold and dry Thursday and Friday as the next Canadian high pressure
builds into the area. Highs Thursday in the upr 30s north to mid 40s
south. Lows in the upr teens-lwr 20s except 25-30 at the beaches.
Increasing cloudiness and cold Friday as the next system approaches
from the west. Highs 35-40. Both the GFS/ECMWF have snow or mix
overspreading the region Friday night with a mix / change over to
rain next Saturday. Stay tuned.
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions with only a few high clouds thru the fcst prd as
as high pressure tracks across the area. Winds W-NW below 10 kts.
OUTLOOK...Chances for rain come Monday and Wednesday as a series
of cold fronts cross the area.
Sfc high pressure builds into the area from the west today. Have
allowed the sca over the ocean to expire with seas dropping below 5
ft. Will hold onto the sca over the Bay until 7 am with gusts there
still up to 20-25 kt attm. Winds then drop below 10 kt by tonight
with high pressure directly over the Mid Atlc. The high then slides
offshore Sun with winds becoming sly at 10-15 kt during the aftn. S
winds strengthen Sun night ahead of the next cold front, with
another round of marginal sca conditions psbl Mon. The cold front
crosses the area Mon night, with sub-sca conditions expected for Tue
with weak high pressure in the vicinity. A low pressure system/cold
front then move offshore Wed, with sca conditions expected into Thu.
MARINE...Small Craft Advisory until 7 AM EST this morning for