Scientific Forecaster Discussion
fxus61 kakq 240939
Area forecast discussion
National Weather Service Wakefield Virginia
539 am EDT sun Sep 24 2017
high pressure will prevail across the mid Atlantic today
through Monday. Meanwhile, Hurricane Maria will gradually track
north over the Atlantic between the southeast coast and Bermuda.
Maria is forecast to approach the Outer Banks Tuesday into
Wednesday, before pushing farther offshore Thursday ahead of an
approaching cold front.
Near term /through tonight/...
current WV imagery shows a broad mid/upper high extending from
the mid-Mississippi Valley across the Great Lakes and into the
northeast conus, with surface high pressure co-located with the
upper anticyclone. Hurricane Maria is gradually pushing nwd north of
the Bahamas and well east of the Florida coast. Additionally, an upper
low is near the nrn Gulf Coast. Locally, the sky is mostly clear
early this morning under the influence of high pressure. There
is some patchy shallow ground fog. Temperatures generally range
through the 60s, with some upper 50s over the northwest Piedmont. The
high will remain nearly stationary today and tonight as Maria
slowly moves nwd. Mostly sunny and unseasonably warm (+1-1.5 St
dev) this afternoon, with high temperatures in the upper 80s
inland, with low/mid 80s at the coast. The srn fringe of the
high will begin to break down late tonight as Maria continues to
move nwd resulting in some increasing clouds across southeast Virginia/NE
NC. Elsewhere, patchy fog is possible where the sky remains
mostly clear. Low temperatures are forecast to be in the 60s.
Short term /Monday through Tuesday/...
Maria continues to trundle nwd Monday with the deep layer high
remaining anchored north of the region. Some outer bands of the
tropical cyclone will result in partly to mostly cloudy
conditions along the coast, with partly to mostly sunny
conditions farther inland. Deep layer moisture remains limited
with only a slight chc pop for coastal NE NC. A modest
tightening of the pressure gradient will result in a ~15 mph NE
wind across coastal southeast Virginia/NE NC with gusts to ~20 mph. High
temperatures will remain above normal ranging from the upper 70s
to around 80f at the coast to the mid/upper 80s farther inland.
There is decent model agreement showing Maria reaching about
200mi southeast of Cape Hatteras by 12z Tuesday. Maria continues to
push north Tuesday, and perhaps slightly west of due north as the upper low
drops sewd across Florida. Increasing moisture and some outer banded
features will result in 20-40% pops along and east of I-95
Tuesday, with 40-50% for coastal southeast Virginia/NE NC. Quantitative precipitation forecast will be
minimal for most areas, but there could be some localized
0.25-0.5" amounts for coastal southeast Virginia/NE NC. Lows will generally
be in the mid 60s to low 70s Tuesday night, with highs in the
upper 70s to low 80s Tuesday under a mostly cloudy sky. Becoming
breezy along the coast with a NE wind increasing to 15-20 mph
along the coast Tuesday, with gusts up to 25-30 mph possible.
Long term /Tuesday night through Saturday/...
first part of the extended, Tuesday night through Thursday,
will be predicated on future track of Hurricane Maria. Latest
NHC track is a bit further west than 24 hours ago, which
increases the potential for some rainfall near the Bay/ocean,
somewhat stronger winds, higher seas, and some coastal
flooding. Have utilized superblend for tangible weather during
this period, given potential uncertainty in the track.
Models quite consistent after the daytime hours Thursday in
taking Maria fairly quickly northeastward away from the area. In
advance of upper trof dropping southeastward from Canada. This
trof and associated cold front move into the region next
Saturday /day 7/.
Above normal temperatures continue through Thursday, with highs
from the upper 70s to mid 80s. Temperatures cool into the 70s
Friday/Saturday in the wake of Hurricane Maria. Lows Tuesday
night through Wednesday night range from the mid 60s to around
70f, then mid 50s northwest to mid 60s southeast Thursday night, and in the
50s Friday night.
Aviation /10z Sunday through Thursday/...
high pressure remains situated over the ern Great Lakes early
this morning, with Hurricane Maria tracking nwd north of the
Bahamas. Mostly clear early this morning with some bands of thin
cirrus. Shallow ground fog is possible through 12z (primarily
sby/phf) with weak flow and decent radiational cooling. Any fog
will dissipate quickly after 12z with sunny conditions expected
today with a NE wind of 5-10kt. High pressure remains anchored
north of the region tonight as Maria continues to track nwd. Mostly
clear this evening, with increasing clouds later tonight across
southeast Virginia/NE NC with some MVFR cigs possible. Otherwise, patchy fog
is possible where the sky remains mostly clear overnight.
Partly sunny to mostly cloudy Monday with a 10-15kt NE wind.
Increasing moisture and some distant banding from Maria will
result in a 40-50% chc of showers for orf/ecg and 20-40% for
ric/sby/phf. Conditions Tuesday night/Wednesday/Wednesday night
will largely be dictated by how close Maria gets to the Outer
Banks. A closer approach will result in breezy to windy
conditions, especially at orf/ecg along with an increased chc of
rain and degraded flight conditions. A cold front approaches
from the northwest Thursday and pushes Maria farther offshore.
long period swell continues to propagate toward the coast with
seas generally 4-6 ft and the current small craft for hazardous
seas will continue in effect through Mon night (after that
winds will increase and the headlines will likely be converted
to the more usual small craft advsy). Overall, expect seas of
4-6 ft to persist today/tonight, then build more significantly
Mon-Wed, as east-southeast swell and increasing NE winds arrive from slow
moving Maria. The bulk of the forecast guidance (as well as the
official NHC forecast) still keeps Maria offshore of the
Carolinas Tue into Thu, before it gets kicked quickly east-northeast out to
sea Thu night into Fri night. Based on the latest guidance,
have maintained increased winds and seas fcst for Tue-Thu, with
at least Small Craft Advisory conditions expected all areas and the potential
for gales over the Lower Bay/coastal waters (or tropical
headlines). Either way, seas over the coastal waters should
easily reach 10 ft or greater from Tue-Thu. Monitor the NHC
forecast for the official forecast track of Maria.
tidal departures early this morning avg 1.0 to 1.5 ft across
the entire area. Minor flooding continues mainly across the
Upper Bay from Lewisetta to Bishops Head through early this
morning. Water levels will tend to remain elevated today-Mon,
but overall most places should remain below any minor flood
thresholds. Will need to watch for additional flooding next
week, especially by later Tue and Wed (and perhaps thu). This
will depend on the exact track of Maria, but the potential for
significant tidal flooding exists (especially over locations
adjacent to the Lower Bay and southern Virginia/NE NC waters). High
surf advisories likely will be needed by Mon night or Tue as
High risk for rip currents for all beaches adjacent to coastal
waters continues through today, as 3-5 ft nearshore waves and
13-15 second swell persists.
Maryland...coastal flood advisory until 9 am EDT this morning for
Virginia...coastal flood advisory until 7 am EDT this morning for vaz075-
Marine...Small Craft Advisory for hazardous seas until 6 am EDT Tuesday