Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Wakefield Virginia
1031 PM EST Thu Jan 17 2019
low pressure tracks through the Ohio Valley tonight then onto
New England by Friday. An Arctic cold front crosses the area
Sunday, followed by dry and much colder weather Sunday night
Near term /until 6 am Friday morning/...
as of 1030 PM EST Thursday...
Radar continues to indicate showers have largely pushed through
the area, and have left low pop for some lingering sprinkles/flurries
into the overnight period. Otherwise, look for partial clearing
and perhaps some patchy fog late tonight out in the Piedmont,
with lingering clouds through much of the night along the coast.
Low temperatures will bottom out in the low to mid 30s across
the north with upper 30s and low 40s farther south.
Short term /6 am Friday morning through Sunday/...
as of 330 PM EST Thursday...
Precip will end from west to east early Friday with decreasing
clouds as high pressure builds into the region. Not a terrible mid
Atlantic January day on tap for Friday with clearing skies and
temperatures in the upper 40s north to nearly 60 degrees S.
The upper level pattern amplifies sharply as the next storm
system takes shape across the mid south on Saturday with
increasing clouds and chances for rain from west-to-east by the
afternoon. Increasing southerly winds on Saturday will allow
temperatures to remain warm despite increasing clouds. Rain
chances increase into the likely range Saturday night and early
Sunday as low pressure approaches from the west. The low will
cross the region Sunday morning with a sharp cold front in its
wake. Rapidly falling temperatures and strong northwesterly
winds Sunday afternoon will introduce the chance for some snow
on the back side of the precip along with concerns for flash
freezing of any remaining liquid on roads and vehicles left over
from morning rains. High temperatures for Sunday will certainly
occur early in the morning with most areas near or below
freezing by sunset.
Long term /Sunday night through Thursday/...
as of 400 PM EST Thursday...
Northwest winds behind exiting low pressure and associated cold front
will usher a much colder/Arctic airmass into the region Sun
night into Mon night. There may be a few flurries or snow
showers along the coastal counties early Sun night, otherwise
clearing sky and very cold with lows ranging thru the teens into
the lower 20s. Wind chills will be in the single digits and
Dry, brisk and cold on Mon, as a large area of high pressure
builds in FM the west-northwest. Highs on Mon will only range FM the mid
20s to lower 30s, with wind chills ranging FM the single digits
to around 20. Clear and cold Mon night with lows mainly in the
mid teens to around 20. High pressure will provide a partly to
mostly sunny sky and a slight moderation in temps on Tue. Highs
on Tue will range FM the mid 30s to lower 40s.
High pressure will slide off the coast Tue night into Wed, as
another low pressure area and associated frontal boundary will
approach FM the west. There could be isolated rain or snow
showers by early Wed morning. Then, another good chance for more
rain Wed aftn thru Wed night, as the system crosses the region.
There is a lingering chance for rain showers, possibly rain
and/or snow showers over northwest or nrn counties at least the first
part of Thu, as the system exits out to sea.
Lows Tue night in the lower to mid 30s. Highs on Wed will range
thru the 50s to near 60. Lows Wed night mainly in the mid 30s to
lower 40s. Highs on Thu will range thru the 40s to around 50.
Aviation /04z Friday through Tuesday/...
as of 800 PM EST Thursday...
VFR ceilings across area terminals early this evening will
gradually lower to MVFR range after midnight (05z) tonight at
ric and ~07z at sby late tonight...with low end VFR (with short
lived MVFR possible) at orf/phf between 09-13z Fri morning.
Weak low pressure, with a very light rain/snow mix possible ivof
ksby with generally light rain expected to skirt just the
south (vcsh at ecg). Ceilings slowly lift to VFR at inland
terminals after 10z Friday morning, reaching the coast by 14-15z
as high pressure builds in. East and southeast winds tonight
will become south and southwest early Friday.
Outlook: a stronger cold front crosses the region Sat night and
sun (accompanied by widespread rain possibly ending as snow,
and flight restrictions due to cigs/vsbys).
as of 330 PM EST Thursday...
High pressure is located over nrn New England this aftn,
with a broad area of low pressure moving ewd through the Ohio
Valley. The wind is east 5-10kt with 2-3ft seas and 1-2ft waves in the
mouth of the Bay. This area low pressure will track across the area
tonight, with the wind becoming southeast then south-southwest with speeds of 5-10kt.
The wind shifts to northwest Friday behind the low, and then turns NE
Friday night with speeds aob 10kt. A strong low pressure system
approaches from the SW Saturday and tracks immediately north of the area
Saturday night. Strong pressure falls combined with a strong
gradient could result in a brief period where a south-southeast wind increases
to 20-30kt, especially north. Strong cold air advection and pressure rises then follow
this boundary Sunday aftn/night into Monday with gales likely for at
least the Bay and ocean (gusts to 40 kt), and no less than strong
scas for the remaining zones in a northwest wind. Seas build to 5-8ft
Sunday into Sunday night, with 3-5ft waves in the Bay. An Arctic
blast of cold air will follow the strong cold front Sunday night
with low temps dropping into the low-mid 20s over water. This
coupled with gale force wind will most likely pose a threat of
freezing spray. Conditions slowly improve Monday night into Tuesday
as high pressure builds into the region. Another low pressure system
potentially impacts the region by Wednesday.