Scientific Forecaster Discussion
fxus61 kakq 091829
Area forecast discussion
National Weather Service Wakefield Virginia
129 PM EST Mon Dec 9 2019
strong low pressure tracks across the Great Lakes later today
and into eastern Canada on Tuesday. The trailing strong cold
front crosses the area Tuesday night. High pressure returns late
Wednesday and Thursday.
Near term /through tonight/...
as of 1045 am EST Monday...
Late morning weather analysis shows upper troughing extending
from the nrn plains to the SW Continental U.S.. WV satellite imagery was
showing mid-level moisture streaming from the tropical Pacific
to our local area in west-southwest-SW flow aloft. Additionally, there are
several mid-level impulses embedded in the west-southwest-SW flow aloft.
At the surface, a weak coastal trough/frontal boundary was
draped across southeast Virginia. North and west of the boundary,
temperatures are still in the 40s (while it has warmed to the
mid-upper 50s across coastal southeast Virginia/NE nc). Fog from earlier is
dissipating (vsbys are now above 1 mile in most locations), so
will not issue another Special Weather Statement. Rain has largely ended across
coastal portions of the cwa, while another area of rain was
tracking northeastward across the Virginia Piedmont (as one of the
aforementioned mid-level impulses is crossing the region). The
steady rain should continue across the Piedmont (and perhaps
clipping part of the lower Maryland ern shore) through the early-mid
aftn hours before becoming more spotty in nature. Mainly dry W/
just a few showers possible in areas S of I-64/east of I-95 through
the day today.
Temperatures will slowly warm through the day today, but will
struggle to get out of the 40s in the northwest Piedmont before the
late aftn. Temperatures will warm into the mid 50s-near 60f from
the I-95 corridor to the lower Maryland ern shore by 21z, with 60s
across coastal southeast Virginia/NE NC. Overcast skies prevail today, with a
few breaks in the clouds likely across southeast zones.
Little if any temperature drop tonight due to the SW flow and
warm air advection in place ahead of the cold front approaching the mountains.
There is little support for pcpn tonight, but enough lingering
moisture exists for a few showers across the north. Looks like a
cloudy and mild night with more stratus than fog. Lows in the
50s in most areas/near 60f across southeast Virginia/NE NC.
Short term /Tuesday through Wednesday/...
as of 335 am EST Monday...
Tues to the the "in btwn" day with not much occuring until the
moisture ahead of the apprchg cold front enters the fa during
the aftrn. It starts off cloudy and mild with little support for
any pcpn thru 18z. Clouds break up a bit across the se while
shwrs spread east of the mts by late aftrn. Unseasonably warm
along with a breezy SW wind. Tuff call on whether the nwrn most
zones erode The Wedge completely so for now will hold temps in
the low-mid 60s there. Otw, temps rise to arnd 70 east of i95
with mid 70s across the se. See cli section below for record
The cold front crosses the area tues night with likely/categorical
pops through 12z. Models now showing the potential for a pcpn type
issue arnd 12z Wed across the nrn most zones. While the thicknesses
crash as the colder air rapidly follows the fropa, sfc and wet bulb
temps remain above freezing. Much like the mid Nov event, pcpn
intensity will likely determine whether and how much wet snow can
mix in with the rain. Thus, adjusted the grids a bit to reflect a
svrl hr prd (09z-15z) Wed for a rain/wet snow mix. For now, think
this occurs btwn 09z-12z across Louisa/Fluvanna then btwn 12z-15z
from Louisa NE to nrn Carolina to Dorchester. No accumls expected
attm. Lows Tue nite mid 30s nrn zones to low-mid 40s srn zones.
Likely pops Wed morning with decreasing pops west to east Wed aftrn
as the cold front moves offshore. In fact, wrn zones will likely
become ot sunny late. Not much rise in temps given the clouds and
cold air advection. Highs in 40s.
Long term /Wednesday night through Sunday/...
as of 355 PM EST Sunday...
Strong high pressure over the upper Midwest will build into the
region Wednesday night. Strong cold advection on northwesterly winds
will lead to overnight low temperatures in the low to mid 20s NW,
mid to upper 20s for the I-95 corridor, and upper 20s and low
30s for southeast Virginia and NE NC. The aforementioned surface high will
become centered over/just north of the local area on Thursday
with decreasing clouds and winds. Daytime high temperatures will
only make it into the upper 30s and low 40s on Thursday. Models
have come into much better agreement and all now keep the area
dry on Thursday and Thursday night. Chilly overnight lows range
from the low 20s northwest to upper 30s southeast.
Surface high pressure continues its eastward migration on Friday but
will still extend ridging to the SW along and east of the higher
terrain. GFS/European model (ecmwf) solutions diverge regarding timing for the
expected wet period late week into the weekend with the GFS around
12 hours faster than the European model (ecmwf). Will increase pops slowly from the
south/southwest during the day on Friday but the bulk of the precip
is expected to fall Friday night into Saturday as low pressure lifts
northward across the region. Given the slower timing, high pressure
will have moved well away from the favored area to supply cold/dry
air to the region and concerns for mixed precipitation have
decreased. High temps on Friday range from the low 40s NW, close to
50 degrees for the Richmond Metro, and low to mid 50s for areas east
of I-95. Not looking particularly cold behind the weekend system
either, highs in the 50s Saturday and Sunday with lows in the upper
30s and low 40s.
Aviation /18z Monday through Saturday/...
as of 100 PM EST Monday...
While vsbys have improved some since this morning, IFR/LIFR cigs
still prevail across the Virginia/Maryland terminals early this aftn.
Conditions at ecg have improved to VFR. Expect conditions to
improve to MVFR/VFR by late this aftn at orf/phf, but will
likely take until 21-00z for cigs/vsbys to rise at ric/sby. In
addition, a large area of rain situated from the Virginia Piedmont to
Maryland will impact ric/sby during the next few hours before the rain
becomes more spotty in nature (although a few showers could
linger invof sby through the first part of tonight). Vsbys in
the rain will be 1-4sm at ric/sby.
Otherwise, the area will be largely rain free tonight into Tue
morning. However, MVFR cigs will be possible (especially at
ric/sby/phf) due to low stratus. Fog is not expected to be an
issue tonight, due to SW winds increasing to 10-15 kt. Rain
chances increase across the area from west to east Tue aftn as a cold
front approaches the region. The cold front crosses the area
late Tue-Tue night, but a large area of Post-frontal light-
moderate rain will track across the area Tue night before ending
from west to east during the day on Wed. Flight restrictions are
likely during this timeframe. There is a chc that pcpn changes
over to pl/snow Wed am before ending at sby, with a slightly
lesser chc of pl/snow at ric. Not expecting much in the way of
impacts from wintry pcpn. Pcpn should stay in the form of rain at
the sern terminals. High pressure builds into the area for
Wednesday/Thursday, allowing VFR/dry conditions to return.
as of 335 am EST Monday...
Latest analysis shows a warm front that extends northward and
parallels the coastal waters. Winds across the coastal waters have
already turned S/southeast 15-20 kts, while winds across the Bay on the
other side of the front are still northerly 10-15 kts. Seas are 3-6
ft in the southern coastal waters and 3-4 ft in the northern coastal
waters. Waves in the Bay are 1-2 ft. The front will continue to
advance north and a bit further inland today. Winds over the Bay
should become southerly this morning as a result. The increasing
S/SW flow should bring winds in the Bay and southern James up to 15-
20 kts by late Monday night. Winds over the coastal waters will
remain S/SW 15-20 kts with gusts around 25 kts. Waves in the Bay
will build to 2-3 ft by Monday night with around 4 ft at the mouth
of the Bay. Seas will continue to build and by late Monday night
will be 5-8 ft. Small Craft Advisory is now in effect for the coastal waters, and Small Craft Advisory
will be issued for the Bay, lower James, and Currituck Sound for
later tonight through about 18z Tuesday. Confidence is lower for Small Craft Advisory
on the rivers outside of the lower James, so will leave them out for
With very warm conditions Tuesday during the day ahead of an
approaching cold front, winds over the cold waters will likely
diminish a bit (though seas on the coast will remain at or above 5
ft). Small Craft Advisory conditions likely for all zones Tue night/Wed am as colder
air moves in from the north. Potential for stronger winds Wednesday
night into Thursday as a secondary cold surge arrives with strong
high pressure building in from the north while low pressure lingers
over the southeast Continental U.S.. seas will also remain elevated through this
record highs for 12/10:
Ric...79 in 2007
orf...78 in 2007
sby...73 in 1966
ecg...78 in 2007
Marine...Small Craft Advisory until 4 PM EST Tuesday for anz634.
Small Craft Advisory from 7 PM this evening to 1 PM EST
Tuesday for anz630>633-638.
Small Craft Advisory until 6 PM EST Tuesday for anz650-652-654-