Scientific Forecaster Discussion
fxus61 kakq 231124
Area forecast discussion
National Weather Service Wakefield Virginia
624 am EST Thu Nov 23 2017
high pressure will remain over the region through Friday. Low
pressure will linger off the southeast coast Friday through
Saturday morning. Another cold front will cross the area late
Saturday into Saturday night, with high pressure building back
in from the northwest Sunday and Monday.
Near term /through tonight/...
latest wx analysis indicating a broad area of sfc high pressure
extending east-northeast from Texas to the Ohio Valley and mid-Atlc states.
Aloft, a trough axis is in place from the Tennessee Valley south to the
Gulf of Mexico and high clouds are streaming into the local area
in the west-southwest flow aloft. Overall a dry/cold airmass has settled
across the cwa, still some mixing near the coast so temperatures
there are mainly in the upper 30s/lower 40s, while northwest portions
of the County Warning Area have dropped into the lower- mid 20s. Temperatures to
fall a few more degrees through sunrise. For today/tonight, sfc
high pressure will remain in control, keeping moisture
associated with low pressure over Florida shunted to our south.
Mostly sunny skies will prevail today, though the high clouds
will continue and may dim the sunshine a bit, particularly
across southeast Virginia/NE NC later today. Rather shallow mixing underneath
sfc high pressure and latest model guidance appears to have
finally latched onto this by trending cooler for highs which
will be mainly in the upper 40s (around 50 f to lower 50s for
extreme southeast Virginia and NE nc). Light winds this aftn through tonight
along with dew pts mainly in the 20s will allow for a rapid drop
in temperatures after sunset. Lows tonight will avg in the mid
20s to around 30 f most areas (locally a few degrees warmer southeast
Short term /Friday through Sunday/...
latest GFS/NAM/ECMWF remain in good agreement with the pattern
through the weekend, with enough northern stream trough energy
passing by to our NE Fri morning to keep sfc low pressure and
associated moisture off the southeast coast and south of the local
area. Sfc high pressure more or less to stay entrenched over the
region Fri, gradually shifting off the mid-Atlc coast by Fri
aftn/evening. BUFKIT soundings again depict fairly
limited/shallow mixing for Fri so even with significant rises
in 850 mb temperatures Fri, actual high temperatures at the sfc
will not warm all that much, mainly into the mid 50s. Mostly
sunny, except for some increasing clouds over the far southeast. Next
upper trough moves into and through the Great Lakes Fri night/Sat.
Still looks like bulk of moisture from low pressure off the southeast
and mid Atlc coasts stays over the Gulf Stream, as it lifts
north-northeast. Not quite as cold Fri night with lows in the mid 30s to
lower 40s. Sfc cold front approaches from the west Fri night
into midday Sat, then crosses the area late Sat into Sat night.
A somewhat breezy south-southwest flow to develop and will see a milder day
with highs to around 60 f north to the mid 60s southeast. Clouds will
increase during the aftn and become mostly cloudy across the northwest.
Sfc cold front and a lagging shortwave trough aloft to cross the
region Sat evening and push offshore Sat night. System remains
moisture starved, but will carry 20% pops over the north/NE, GFS
is stronger with the forcing than the European model (ecmwf). Lows in the mid 30s
northwest to the lower 40s southeast. Becoming mostly sunny and turning cooler
sun as sfc high pressure returns from the west. Highs mainly 50-55
Long term /Sunday night through Wednesday/...
dry weather and increasing temps on tap for the long term period.
Sfc high pressure builds in from the west early next week as an
upper-level trough pulls offshore, leading to mostly sunny/clear
skies Sun night and into Mon with high temps averaging in the
low/mid 50s. Warmer then for Tue and Wed as the high slides
offshore allowing for S/SW flow over the mid Atlc...highs in the
upper 50s to mid 60s.
Aviation /12z Thursday through Monday/...
VFR/dry today with just some scattered-broken high clouds
today/tonight.North winds to 10 kt this morning will become
light/variable by this aftn and tonight. Sfc high pres will
maintain VFR conditions into Sat, winds will strengthen from the
south-southwest Sat ahead of a cold front and turn to the northwest Sunday. Skies
may become mostly cloudy Sat aftn/evenings with isolated showers
possible, but VFR conditions will prevail.
high pressure has begun to build into the region from the west this
morning which has allowed winds to diminish. As of 6 am, scas
for the coastal waters north of Cape Charles have been cancelled
as seas have subsided below 5 ft. Seas are expected to drop
below 5 ft south of Cape Charles by 10 am when the last of the
scas will expire.
With high pressure over the waters, sub-Small Craft Advisory conditions are expected
the rest of today into Friday. The next cold front crosses the
region Saturday night bringing the potential for gusty northwest
winds/Small Craft Advisory conditions for Sunday.
Marine...Small Craft Advisory until 10 am EST this morning for anz656-