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Area forecast discussion 
National Weather Service Blacksburg Virginia
355 PM EDT Wednesday Apr 1 2015

Synopsis...
high pressure will pass overhead tonight providing clear skies
and light winds. A warm front will push north through the Ohio
Valley Thursday...supporting spotty shower mainly west of the
mountains. A strong cold front will pass across the area Friday
night...producing showers and thunderstorms...followed by
breezy but dry conditions for the weekend.

&&

Near term /through Thursday/...
as of 330 PM EDT Wednesday...

1022 mb surface high pressure was centered overhead. This feature
will promote clear skies tonight with near calm winds. A light
southeast breeze may develop along the ridgetops toward daybreak
Thursday...but valleys should remain decoupled with potential
for patchy frost...lows in the 30s.

The high should be centered near the Atlantic coast to start the
day Thursday. Clockwise flow around the high resulting in
increasing southerly winds and dewpoints. Moisture will begin to
return to the area as a warm front lifts north through the Tennessee/Ohio
valleys on Thursday...promoting increasing cloudiness and the
threat for a few sprinkles west of the Blue Ridge. Pending
cloud cover...temperatures should warm well into the 60s...
potentially testing 70 degrees across the Piedmont.

&&

Short term /Thursday night through Saturday night/...
as of 345 PM EDT Wednesday...

Our area will be in a warm sector squeeze play for the latter
portion of the week with high pressure moving off to our east and a
slow moving cold front approaching from the west. This warm our
temperatures in the 60s and 70s on Friday and keep US in a chance of
showers until late Friday night when showers are likely as the front
moves through. While the best dynamics with the front will slide by
to our northwest the amount of shear across the area Friday
afternoon into Friday night is not trivial and the low level wind
field has a good amount of brisk early Spring energy. The big
limiting factor for convection is the lack of significant
instability with convective available potential energy at or below 500j/kg late Friday afternoon.
Will continue the forecast for showers/chance of thunder and agree
with Storm Prediction Center day three severe outlook which places the far western
portion of the area in a marginal risk for a wind threat.

Significantly colder air moves in behind the front late Friday night
and Saturday on blustery northwest winds. The far western slopes
will see some upslope snow showers develop before daybreak Saturday
and a minimal slushy coating of snow is possible...especially for
western Greenbrier County...before the precipitation dissipates as
we go through Saturday morning. Currently expect winds behind the
front to remain below advisory criteria but conditions will
certainly be quite gusty.

&&

Long term /Sunday through Wednesday/...
as of 345 PM EDT Wednesday...

Evolving upper pattern will remain progressive and feature some flat
ridging through the extended period and looks to keep our area in
the mild air at least through midweek. High pressure will build in
with quiet weather and the start of a warming trend on Sunday to
close out the weekend. The first part of next week will see a series
of weak upper level short waves move through as the airmass over the
eastern US becomes warmer and more moist thanks to persistent
southwesterly winds. This should set US up for bouts of diurnal
convection with a chance of showers and thunderstorms just about
each afternoon...becoming more likely across western portions of
the area. As we go out in time model guidance starts to differ on
timing of weather systems but it appears the next cold front
approaching from the west will not affect our region until late
Wednesday at the earliest.

&&

Aviation /20z Wednesday through Monday/...
as of 330 PM EDT Wednesday...

VFR conditions expected through the taf valid period as high
pressure drifts across the region. The air mass over the area will
remain dry through tonight. Moisture will begin to advect into the
area from the south and southwest on Thursday...associated with a
warm front moving north through the Ohio/Tennessee valleys. In spite of the
increasing moisture...conditions are expected to remain VFR.

Winds tonight will be light and variable...becoming southerly and
increasing on Thursday...and potentially gusty Thursday afternoon
as a 40-50kt southerly low level jet...3-5kft above ground level...develops over
the region.

Extended aviation forecast... a strong cold front will cross the
region Friday night. Scattered showers are expected to develop
ahead of the front Friday...becoming numerous Friday evening...
in addition to thunderstorms. Sub VFR conditions are anticipated from
Friday evening through Friday night...with gusty southwest winds
ahead of the front...followed by gusty northwest winds behind the
front.

Improving conditions appear likely Saturday as the front moves
east of the area...pressure rises resulting in a continuation of
gusty northwest winds. The winds are expected to subside by Sunday
as high pressure builds back across the region supporting VFR
conditions.

&&

Fire weather...
high pressure will pass overhead early tonight resulting
in clear skies and near calm winds. As the high moves to
along the Atlantic coast...a southeast wind will develop
along the ridge tops...but remaining nearly calm in the
valleys.

Southerly wind speeds and cloud cover will increase on
Thursday as a cold front moves across the Midwest states.
Little or no precipitation is expected Thursday.

By Friday...the front will be close enough to produce
scattered showers...and by Friday night showers will become
likely with the opportunity for thunderstorms. This is expected
to be a strong frontal passage with gusty southwest winds ahead
of the front...followed by gusty northwest winds behind the
front from Saturday into Sunday morning.

&&

Rnk watches/warnings/advisories...
Virginia...none.
NC...none.
WV...none.

&&

$$
Synopsis...PM
near term...PM
short term...mbs
long term...mbs
aviation...PM
fire weather...PM

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