Scientific Forecaster Discussion
fxus61 kakq 180539
Area forecast discussion
National Weather Service Wakefield Virginia
139 am EDT Fri Oct 18 2019
surface high pressure will build in from the west through
Friday. The high will build right over the area by Friday
evening into early Saturday morning, then slides off the coast
during Saturday. Low pressure is forecast to track out of the
Gulf of Mexico and northeast just inland of the southeast coast
Saturday into Sunday morning. That low will then continue east
northeast and off the mid Atlantic coast Sunday into Monday
Near term /until 6 am this morning/...
as of 115 am EDT Friday...
Only minor tweaks to the near term forecast. Adjusted low temps
down a couple degrees across the northwest.
Sfc high pressure over the Midwest will move closer to the
area overnight. Under a clear or mostly clear sky, lows will
range from the upper 30s to mid 40s over much of the area.
Short term /6 am this morning through Sunday/...
as of 355 PM EDT Thursday...
High pressure will build into and over the region for Fri into
Sat morning, then slides off the coast Sat aftn. Dry wx expected
Fri and Sat, with seasonably cool temps. Sunny or mostly sunny
on Fri with highs in the lower to mid 60s once again. Clear an
cold Fri night with lows in the upper 30s to lower 40s over much
of the region. A few locations in the inland/Piedmont could drop
into the mid 30s. Winds will be nearly calm and with a clear
sky, would not be surprised to see some reports of patchy frost
Sat will start out sunny or mostly sunny, with increasing clouds
later in the day from the SW well in advance of low pressure
moving out of the Gulf into srn Georgia. Highs on Sat in the mid to
That low pressure area is then forecast to track NE just inland
of the southeast coast Sat aftn into Sun morning, then continues east-northeast
and off the mid Atlc coast sun into Mon morning. At this time,
expecting increasing pops (40-60%) for showers/rain quickly
from SW to NE Sat evening/Sat night. Then, have 50-60% pops for
sun. Lows Sat night will range from the upper 40s to upper 50s.
Highs on sun in the mid 60s to around 70.
Long term /Sunday night through Thursday/...
as of 430 PM EDT Thursday...
Low pressure system will be moving off the mid-Atlantic coast
Sunday night, leaving the area mostly dry. Weak sfc high
pressure will build south east of the mountains on Monday.
Temperatures will be seasonal for Monday with morning
temperatures in the upper 40s west of I-95 and 50s east, and
highs in the low 70s inland and upper 60s near the coast.
A closed low will be moving NE across the upper plains with a
cold front extending south to the Gulf of Mexico Monday night.
The low pressure system will continue to move north towards the
Hudson Bay as a cold front approaches the area. Second sfc low
pressure system developing in the region at the same time,
bringing the next chance of widespread rainfall for VA, MD, and
NC. Timing of the frontal passage will be overnight Tuesday.
European model (ecmwf) is slower than the GFS but both models moves all the rain
off the coast by sunrise on Wednesday, with dry condition
expected during the day Wednesday through the end of the work
Since the main area of low pressure will be moving north into
central Canada, we will not see strong cold air advection as sfc
high pressure system builds into the area behind the front,
although temperatures will be cooler. Low temperatures will be
in the 40s inland and low 50s near the immediate coast. Coldest
morning for the week will be Thursday morning as the center of
the sfc high will be over southeast Virginia/NE NC, with lows in the mid 40s
(near 50 along the immediate coast).
Aviation /06z Friday through Tuesday/...
as of 130 am EDT Friday...
VFR conditions through the taf period. Northwest winds are 10kts or
less at all sites except ksby where they are gusting 15-20kts
tonight. Skies are clear across the region. High pressure
currently centered over the Ohio Valley will drift overhead by
late Friday into early Saturday. This will result in light winds
5kts or less and outside of some scattered cumulus over the eastern
portion of the area Friday afternoon skies should remain mostly
Next chance for flight restrictions will be with a storm system
currently in the western Gulf. This storm is forecast to track
NE and up the southeast coast this weekend, bringing rain to our area
as of 1005 PM EDT Thursday...
Have replaced gales for the Upper Bay and coastal waters north
of Cape Charles with scas late this evening as winds have begun
to diminish. Scas expected to continue for all waters thru late
Fri morning, except thru early afternoon for the Chesapeake
Bay. Given latest trends in wind speeds, may be able to even
cancel scas sooner.
Sub-Small Craft Advisory conditions return Fri aftn, as high pressure settles
over the waters. Low pressure (now known as potential tc 16)
tracks newd across the Gulf of Mexico before reaching the Florida
Panhandle by ~12z Sat. Latest 12z GFS/European model (ecmwf) models have trended
into better agreement are forecasting the low to track into southeast
NC by 12z sun before pushing off the Virginia/NC coast by Sunday
night. Went with a model consensus and increased sustained winds
(out of the ne) to 17- 20 kt over the Bay/20-25 kt over the
ocean with seas building to 6-7 ft by late Sunday/waves to ~4 ft
at the mouth of the Bay. Another round of scas (starting as
early as 09-12z sun) looks likely now for most of the marine
area. There is some potential for gales on Sunday across the srn
coastal waters (local wind probabilities show a ~20% chc of
gale gusts at Duck pier). Winds turn to the north-north-northeast and fall below
Small Craft Advisory thresholds by 12z Mon (although seas may remain elevated
through at least mon). Winds remain below Small Craft Advisory thresholds through
Tue am before another cold front crosses the waters late Tue-
as of 400 PM EDT Thursday...
No coastal flooding is expected through Saturday night. However,
water levels are expected to rise as low pressure tracks from southeast NC
to offshore of the Virginia/NC coast from sun-Sun night. Guidance
continues to show the potential for minor coastal flooding across
parts of the area by high tide on Sunday (best chances are in areas
adjacent to the lower ches Bay/James river).
Marine...Small Craft Advisory until 10 am EDT this morning for anz633-
Small Craft Advisory until 1 PM EDT this afternoon for