Scientific Forecaster Discussion
fxus61 kakq 190028
Area forecast discussion
National Weather Service Wakefield Virginia
828 PM EDT Wed Sep 18 2019
surface high pressure builds into the region from the north
tonight through Thursday, and then settles over the region
Friday. Meanwhile, Hurricane Humberto is forecast to track well
east of the Carolina coast tonight and Thursday.
Near term /until 6 am Thursday morning/...
as of 830 PM EDT Wednesday...
High pressue over New England extends down the eastern Seaboard
this eve. Skies across the Piedmont have mostly cleared while
scattered-broken SC remain ivof the water. Thus, expect a mstly clr to pt
cldy and cool nite ahead. Lows in the 50s to near 60 se. Would
not be surprised to see a few upr 40s over the Piedmont by sunrise.
Short term /6 am Thursday morning through Friday night/...
as of 150 PM EDT Wednesday...
Surface high pressure continues to build swd along the coast
tonight into Thursday, and builds overhead into Friday. Continued
breezy Thursday although the wind should not be quite as high
as Wednesday, as gradient slackens with Humberto farther
offshore. Partly cloudy again along the coast with scattered late
morning and aftn cu, and mostly sunny inland. Pleasant with high
temperatures generally 70-75f, with upper 60s for the Maryland
Atlantic coast. Clear sky, light wind will bring the coolest
night of the period Thursday night. Did nudge inherited minima
down a degree or two per latest guidance, but no major changes
necessary. Early morning lows Fri morning in the u40s/l50s
inland...M/u 50s along the coast.
High pressure will be over the southeast coastal plain on Friday,
bringing a modest warm-up. But still dry/pleasant. Highs in the
mid to upper 70s, low to mid 70s along the coast.
Long term /Saturday through Wednesday/...
as of 135 PM EDT Wednesday...
Temperatures will moderate back near to above normal over the
weekend into early next week, as sfc high pressure slides
offshore. Aloft, the region will remain on the periphery of an
upper level ridge of high pressure, which will rebuild over the
region from the southwest during the upcoming weekend.
Above average temperatures likely prevail through this period
with highs in the mid/upper 80s to around 90 degrees with early
morning lows generally in the 60s area wide.
Rain chances remain essentially nil through the first half of
the period, and don't go much higher even with the next front
early next week. Aforementioned upper ridge holds strong over
the southeast, and keeps moisture from next (weak) front...and
any remnant moisture from tc Imelda...well north of the local
area late Monday and Tuesday. Pops are no better than slight
chance over far northern County Warning Area Mon night and Tue...and silent
(<14%) central and south through the period. Temperatures look
to remain at or above climo normal next week.
Aviation /01z Thursday through Monday/...
as of 730 PM EDT Wednesday...
VFR conditions continue at all taf locations tonight. Scattered cumulus
continues to erode across the eastern part of the County Warning Area and expect
mostly clear skies tonight. NE winds continue 10-15kts with
occasional gusts around 20kts at orf/phf/ecg. Scattered cumulus will
develop again tomorrow beginning late morning through the
afternoon...although ceilings should remain VFR. Winds will
remain out of the NE until Friday when high pressure centers
itself over the mid Atlantic and as a result winds will become
westerly and below 10kts.
Outlook: high pressure remains in control through Monday. Dry
conditions will prevail and expect mainly VFR conditions during
as of 430 PM EDT Wednesday...
Hurricane Humberto was continues to move east-northeast several hundred
miles off the SC coast, while ~1028 mb high pressure was
centered over far nrn New England/srn Quebec. Humberto is
forecast to slowly transition into an extratropical cyclone
during the next couple of days as it interacts with a frontal
system. The pressure gradient between Humberto and the high is
leading to NE winds of 20-25 kt with gusts to 30 kt. Waves are
~2 ft across the Northern Bay and 3-5 ft across the south. Seas
have increased to 10-11 ft in the Atlantic waters off the Outer
Banks, with seas 6-9 ft north of the Virginia/NC border to the Maryland/Delaware
High pressure has build south-southwest toward central Virginia/NC today as
Humberto continues to track to the east-northeast. Even though Humberto
will continue to slowly move away from the Atlantic coast, the
pressure gradient between Humberto and the aforementioned high
will increase. Therefore, expect a slight uptick in winds before
peaking during the 00z-06z (thu) timeframe. Sustained winds
will increase to 20-25 kt on the ches Bay/23-27 kt on the ocean
through 08z Thursday, with gusts 30-35 kt through 00z Thursday.
Occasional gusts to 15-20 kt are likely on the upper rivers
through 06z Thu.
On Thursday, the high is expected to build south-southwest toward the area, and
Humberto will be far enough offshore to allow the pressure gradient
to relax some. As a result, NE winds slowly diminish from early Thu
am through the day on Thu. The current forecast has wind gusts
dropping below Small Craft Advisory thresholds by early Thu afternoon (seas/waves
will remain above Small Craft Advisory thresholds). The high is expected to
settle into the region from Fri- Sat before moving to the southeast of
the area by sun. Winds turn to the north then northwest on Fri before
becoming SW by early Sat am. Sustained winds will remain aob 12
kt from Fri through the weekend. However, seas (and waves near
the mouth of the bay) will be slow to diminish.
Seas/waves will be slow to come down, therefore the Small Craft Advisory was
extended through 12z Saturday for the ocean zones and 15z for
the southern Chesapeake Bay. The Small Craft Advisory may need to extended for
the mouth of the Bay for high waves.
as of 400 PM EDT Wednesday...
Tidal anomalies have risen to 1-1.5 ft above normal in areas
adjacent to the ches Bay/rivers. Nuisance to minor tidal
flooding is expected in areas from the lower Maryland ern shore to the
srn shore of the ches Bay/upper James River during the late
night/early Thu high tide. Therefore, coastal flood
statements/advisories have been extended into early Thu morning.
With the persistent NE wind, tidal anomalies will remain
elevated/slowly rise through Thursday. As a result, additional
statements/advisories will be needed for the late day/evening
Thursday high tide cycles. At this time, it looks like any tidal
flooding from today-Thu will mainly be minor. However, water
levels may come approach moderate flood thresholds at bishop's
head, Lewisetta, and Jamestown during the high tide cycle Thu
aftn, and will need to be monitored closely. Tidal anomalies
slowly fall from Thu night- Fri as winds continue to diminish.
However, lingering nuisance to (low- end) minor tidal flooding
is possible through Fri.
The current forecast keeps water levels just below minor flood
thresholds along the Atlantic coast of MD, VA, and NC. However,
there is a very slight chc that water levels exceed minor flood
thresholds on the Oceanside of the Virginia ern shore/NC during the
higher astronomical tides Thu.
A high rip current risk is forecast for Thursday, as swell from
Humberto propagates toward the coast.
NC...high surf advisory until 7 PM EDT Thursday for ncz102.
Virginia...coastal flood advisory until 8 am EDT Thursday for vaz075-077-
Coastal flood advisory until 6 am EDT Thursday for vaz095-097-
High surf advisory until 7 PM EDT Thursday for vaz098.
Marine...Small Craft Advisory until 8 am EDT Saturday for anz650-652-
Small Craft Advisory until 7 am EDT Thursday for anz630-631-
Small Craft Advisory until 1 am EDT Thursday for anz636.
Small Craft Advisory until noon EDT Thursday for anz632-634.