Scientific Forecaster Discussion
fxus61 kakq 180834
Area forecast discussion
National Weather Service Wakefield Virginia
334 am EST Mon Nov 18 2019
low pressure well off the Carolina coast will lift northeast
while remaining well offshore today. Weak low pressure crosses
the local area tonight, with high pressure gradually building
in from the west by midweek.
Near term /through tonight/...
as of 315 am EST Monday...
Latest analysis reveals ~995 mb sfc low pressure well off the
NC coast. Sfc high pressure is retreating to the east/NE from
northern New England to Atlantic Canada, but still continues to
ridge south-southwest into the local area, providing an ongoing cool air
wedge and low stratus well inland to the Appalachians. Meanwhile,
occasional light rain or drizzle continues along the coast, as
the offshore sfc low gets a nudge NE from next upper trough,
currently digging southeast across the mid MS and lower Ohio Valley. For
today, will gradually see some modest drying as the low level
winds continue to shift a bit more to the NW, though low clouds
and areas of light rain/drizzle will linger along the coast
through most of the morning. While it remains dry inland, think
the clouds will hang around even as the ceiling heights lift by late
morning/aftn. The models have really latched on to about a 3-6
hr period of strong lift and just enough deep layer moisture
late this aftn and this evening for a significant increase in
pops during that timeframe. This is in response to that digging
upper trough becoming closed off as an upper low into the Ohio
Valley by 18z, and then moving east across WV and Virginia by this
evening. Quantitative precipitation forecast amounts will generally only be about 0.10" to
0.20", but have raised pops to likely for much of the County Warning Area from
about 22z through 03z. Expect another day of cloudy to mostly
cloudy skies (there may be a few hrs from 18-22z with a few
breaks in the overcast well inland). Highs today will range
mostly from the upper 40s to lower 50s, but expect temperatures
in south central Virginia to fall about 5-7f with the arrival of
showers late. Will shift the highest pops this evening east of
I-95, and then off to the coast after 03z. Lows tonight will
range from the mid 30s west of I-95 to the lower 40s near the coast
in southeast Virginia/NE NC. Without any strong downsloping, low clouds and
some patchy fog will be possible into early Tue am.
Short term /Tuesday through Wednesday night/...
as of 315 am EST Monday...
On Tue, a secondary trough aloft crosses the region bringing
variable clouds/partly cloudy conditions...however dry low
levels and less vertical motion mean very low prob for shras.
Highs Tue will be a bit warmer, mostly in the mid to upper 50s.
Finally by Wed...northwest flow aloft and sfc high pressure building
in from the west/SW will allow for a mostly sunny day (partly sunny
ne). Lows Tue night in the low-mid 30s west to the low 40s at the
immediate coast in southeast Virginia- NE NC. Highs Wed again in the M-u50s.
Mainly clear Wed night with lows 30-35f well inland and 35-40f
closer to the coast.
Long term /Thursday through Sunday/...
as of 205 PM EST Sunday...
Dry/milder wx expected Wed night through Thu night/Fri morning.
By Fri...a cold front approaches from the northwest increasing clouds
and pops - shras by late in the day/night (w/ the front off the
coast sat). A trailing system may affect the region by
sun...though there are rather significant differences in the
extended guidance (12z GFS keeps that system S tracking through
the Carolinas...while the European model (ecmwf) is farther north and slower - though
the GFS ensembles agree more W/ the European model (ecmwf) solution). Will use a
blend of the guidance for now which results in increasing
clouds/pops Sat night...then remaining unsettled sun. Lows Wed
night in the l30s west to the u30s-l40s at the coast. Highs Thu in
the u50s to around 60f north to the l60s S. Lows Thu night ranging
through the 40s. Highs Fri mainly in the l-m60s. Lows Fri night
in the l-m30s north and west to around 40f at the coast in southeast Virginia-NE NC.
Highs Sat in the l-m50s. Highs sun from the l50s north to around
60f far southeast.
Aviation /08z Monday through Friday/...
as of 100 am EST Monday...
Conditions have deteriorated early this morning with main
terminals now mostly reporting IFR cigs from 500-700 ft, though
kric is still barely MVFR (~1000 ft). Some drizzle and reduced
vsbys are also observed closer to the coast. Expect primarily
IFR conditions through 12-15z east of I-95 to affect main
terminals. At kric have the ceiling dropping to IFR by 09z. Gusty
mainly north winds to remain...to 20-30 kt...at orf/ecg...10-15 kt
elsewhere. Slow improvement later this morning into the aftn,
with improvement to VFR conditions by ~18z at kric, and to MVFR
at the other taf sites. An upper level system to move into the
region late aftn through the evening will bring scattered to
numerous light rain showers, followed by a return to
IFR/possibly LIFR conditions overnight into early Tue am (winds
will be rather light).
Mainly VFR conditions will then prevail after Tue morning and
last into the late week period.
as of 245 am EST Monday...
Gales for the ocean have been replaced with scas this morning
and continue through 6 PM Tuesday. Scas have ended for the
upper James, York and Rappahannock rivers this morning and will
end over the lower James by 7 am. Scas for the Upper Bay will
end at 10 am and for the Lower Bay (minus the mouth) by 4 PM.
Small Craft Advisory for the mouth of the Bay doesn't end until 1 am tues due to
lingering waves aoa 4 ft.
Low pressure will continue to track quickly north-northeast today,
reaching the waters off srn New England by this evening. Winds
slowly decrease (and turn more to the nw) this morning into the
afternoon as the low exits to the NE and the pressure gradient
finally starts to relax over the area. Therefore, anticipate
that winds fall below Small Craft Advisory criteria by late this morning on the
Bay and this aftn over the ocean. Winds then remain sub-Small Craft Advisory
through at least Tue evening.
Seas are currently running 10-15 ft offshore with waves in the
ches Bay in the 3-6 ft range (up to 8 ft at the mouth) and will
be slow to subside early this week. Seas likely remain above 5
ft through late Tuesday. In addition, waves near the mouth of
the Bay will most likely remain above 4 ft through late tonight.
Extended the high surf advisory until 21z Mon for all area
beaches (although seas may remain aoa 8 ft nearshore S of the
Virginia-NC border through the first part of tonight).
as of 245 am EST Monday...
Widespread minor tidal flooding is expected during today's high
tide cycle (as it is the higher of the two astronomical tides).
Coastal flood advisories will remain in effect through this
afternoon/evening to cover this.
The threat for coastal flooding will likely end for most
locations by Tuesday. However, additional minor tidal flooding
may occur for areas adjacent to the mid/upper ches Bay during
tuesday's high tide. Will extend coastal flood advisories as
Maryland...coastal flood advisory until 4 PM EST this afternoon for
High surf advisory until 4 PM EST this afternoon for mdz025.
Coastal flood advisory from 1 PM this afternoon to 10 PM EST
this evening for mdz021>023.
NC...coastal flood advisory until 4 PM EST this afternoon for
High surf advisory until 4 PM EST this afternoon for ncz102.
Virginia...coastal flood advisory until 7 PM EST this evening for vaz084-
Coastal flood advisory until 4 PM EST this afternoon for
High surf advisory until 4 PM EST this afternoon for
Coastal flood advisory until 10 PM EST this evening for vaz075-
Marine...Small Craft Advisory until 6 PM EST Tuesday for anz650-652-654-
Small Craft Advisory until 10 am EST this morning for anz630-
Small Craft Advisory until 1 am EST Tuesday for anz634.
Small Craft Advisory until 4 PM EST this afternoon for anz632.
Small Craft Advisory until 7 am EST this morning for anz638.