Scientific Forecaster Discussion
fxus61 kakq 221041
Area forecast discussion
National Weather Service Wakefield Virginia
641 am EDT sun Oct 22 2017
high pressure over the mid Atlantic region will bring warm and
dry conditions through Sunday. A cold front will approach from
the west on Monday...then slowly push through the local area on
Tuesday. High pressure builds across the Gulf of Mexico
Wednesday and Thursday...as low pressure lingers from the Great
Lakes to New England.
Near term /until 6 PM this evening/...
near 1028 mb sfc hi pres centered invof srn New Jersey attm W/ upper
level ridge axis aligned north-S invof ern Seaboard. A fair amount
of cirrus now streaming into the region from the west-southwest...and
conditions overall are mild and near calm. Will once again have
patchy fog early this morning...coverage may end up a little more
than the past couple of mornings. After that...another
dry/seasonably warm day. Issue of partly sunny vs mostly sunny
dependent on coverage of clouds (mainly ci)...W/ highs in the
M-u70s...l70s at the immediate coast.
Short term /6 PM this evening through Tuesday/...
mostly clear to partly cloudy tonight with lows mainly in the
50s. During Mon...low pres deepens over the deep south/lower MS
valley while a strong upper ridge remains in place just off the
East Coast. Still warm/mainly dry through Mon...increasing pops
limited to (well) west of I 95 toward evening. Highs in the u70s
east to the l-m70s west (where clouds begin to thicken in the
Latest 00z/22 GFS/NAM/ECMWF have trended a bit slower W/ the
overall timing of the next cold front...now depicting the best
lift/forcing for likely to categorical pops (60-80%) from about
09z/Tue through 19z/Tue. Strong low level jet and sfc dew pts in
the 60s...won't rule out isolated tstms late Mon night/Tue
morning...mainly for southeast Virginia/NE NC. Partial clearing expected Tue
by late morning west and by late aftn east...and have continued W/
lowering pop trend W-E. Still mild through Tue W/ lows Mon night
in the 60s...then highs tues in the 70s as cold air lags well
behind off to the northwest of the local area.
Long term /Tuesday night through Saturday/...
cold front reaches the coast early Tue night and is expected
to exit the coast by daybreak Wed morning. Any rain tapers
off/ends near the coast early Tue evening. Temperatures falling
from the 60s in the evening to 45-50f inland and 50-55f closer
to the coast by Wed morning. Dewpoints also fall from the lower
50s northwest to lower 60s southeast in the evening to 40-45f inland and 45f
to around 50f by morning. Conditions generally dry thereafter
(wed- sat) as sfc high pressure builds back into the region Wed
night through Thu night. Sfc high slides off the mid Atlantic
coast Fri and then up off the New England coast Fri night.
Temperatures at to slightly below normal for Wed/Wed night
with highs in the 60s areawide and lows in the 40s. Temps slow
to rebound on Thu as upper trough swings through and more
stable northwest flow aloft develops over the area. Highs 60-64f. High
pressure slides overhead Thu night and then temperatures slowly
moderate. Lows Thu night in the 40s (around 50f beaches).
Seasonal normal highs Fri in the upper 60s to around 70f. Lows
Fri night in the upper 40s inland to 50-56f immediate coast.
Highs Sat in the lower 70s.
Aviation /12z Sunday through Thursday/...
sfc hi pres is situated immediately off the mid-Atlantic coast
attm. Winds remain light/vrb while broken-overcast cirrus spreads over the
region from the WSW. Another round of fog early this
morning...W/ a potential for IFR/LIFR conditions...mainly at
sby/phf/ecg. Otherwise...VFR conditions through the 12z taf
forecast period...though W/ continue broken-overcast cirrus...and a light
southeast wind of 4-8kt as hi pres remains off the mid- Atlantic coast.
Additional fog possible late tonight/early Mon morning. A cold
front is forecast to track through the region Mon night through
Tue morning. This will bring the potential for MVFR/IFR
conditions in rain and low cigs. Mainly VFR Tue aftn/eve through
a large area of surface high pressure over the region will allow for
generally benign conditions over the waters today. Winds generally
are 5 knots or less over all of the coastal waters this morning.
Winds become east-southeast by this afternoon and increase to 5 to 10 knots.
Seas are expected to range from 1 foot or less in the Bay and rivers
(1 to 2 feet at the mouth of the bay) and 2 to 3 feet over the
The next chance for significant weather over the waters does not
come later Monday through Tuesday as a strong cold front approaches
from the west crosses the waters. The pressure gradient will lead to
increasing southerly flow ahead of the front later Monday into
Tuesday, shifting to the west-northwest behind the front Tuesday night into
Wednesday. Small craft advisories will likely be needed for most or
all of the area Mon night/Tue as the pressure gradient should be
strong enough for winds of 15-25 kt with higher gusts. Coastal seas
build to 5-9 ft with waves of 3-4 ft in the Bay likely. A fair
amount of uncertainty remains Tue night/Wed regarding how strong the
pressure gradient will be as the models tend to keep the cold air
and strong winds off to our northwest over the Great Lakes until