Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 222302

Area Forecast Discussion
National Weather Service Blacksburg VA
702 PM EDT Wed Mar 22 2017

A large area of high pressure over the Great lakes will settle
across the Mid-Atlantic Region for tonight and Thursday.
The high center will slide off the coast Thursday night and
push out into the Atlantic ocean Friday. A warmer southerly flow
will develop Friday into the weekend ahead of a slow moving
cold front that will approach the region Sunday.


As of 702 PM EDT Wednesday...I`ve made essentially noise-level
changes to winds and dewpoints with this update. Ridging
continued to extend southeastward from a strong anticyclone
centered near Cleveland as of 22z. North- northwesterly gradient
flow still continues around 6-13 kts, and have tried to better
account for this in the grids through 10 pm. However wind speeds
do steadily slacken starting around mid/late evening along with
a veer to a northeasterly direction. Expect rapid hourly
temperature falls given the dry air mass with sunset and
particularly after midnight as winds decouple. Though dewpoints
are quite low, only little recovery anticipated as air mass
further north is nearly as dry, so I did lower these into the

Previous near-term discussion issued at 220 PM follows...

A strong area of high pressure will track from the Great Lakes
tonight and be centered over Virginia tomorrow morning. This high
will keep the area cool and dry with very little in the way of cloud
cover. Winds will subside this evening and under clear skies,
overnight lows will radiate down into the 20s. Cool northeast flow
will keep the areas east of the Blue Ridge just as cool as the
mountains. high temperatures Thursday will range from the mid 40s to
lower 50s.


As of 300 PM EDT Wednesday...

High pressure will drift east and off the Mid-Atlantic coast
Thursday night into Friday. Southerly wind flow will develop
on the back side of the high with increasing moisture aloft
resulting in mid/upper level cloudiness Friday into Saturday.
The boundary layer is forecast to remain dry, thus little or no
precipitation threat anticipated through Saturday, although
can`t rule out some virga or a sprinkle west of the Blue Ridge.

By Saturday night, enough moistening may take place for
measurable rainfall after midnight, but again threat will be
mainly along and west of the Blue Ridge with amounts less than a
tenth of an inch.

Temperatures through the weekend will gradually moderate with
lows in the 30s Friday morning, then into the 40s by Saturday
morning. Daytime highs will also inch upward with highs in the
50s to around 60 Friday then into the 60s to lower 70s by Sat.


As of 315 PM EDT Wednesday...

The models have come into fairly good agreement that a series of
upper level low pressure systems will track across the country
from the west coast this weekend and into next week. The first
in this series of upper lows is slated to track through the
central plains this weekend, then lift towards the northeast and
weaken as an open wave as it crosses the Ohio Valley Sunday. A
second low will take a similar track Monday into Tuesday, but
may offer a slightly different solution with respect to a shot
of colder air for mid week as it phases with a short wave moving
east along the U.S./Canadian Border. Both systems suggest an
unsettled but mild weather pattern for Sunday through Tuesday
with a potential brief intrusion of cooler weather Wednesday
before entertaining another round of unsettled weather toward
the end of the week. Due to the weakening nature of these
systems, the potential for thunderstorms and severe weather for
our CWA appears to be low.

For Sunday, the surface cold front, from the first area of low
pressure is forecast to enter the western CWA early, with clouds
and showers potentially entering the forecast area before
daybreak. Forecast consensus is for about a tenth to a quarter
of an inch of rain Sunday. The actual front is of pacific
origin, so anticipate little or no temperature change. If
anything, an increase in dewpoints may actually make it feel
warmer during the day, and will definitely be warmer at night
due to the higher dewpoints maintaining elevated temperatures
at night.

For Monday into Tuesday, the next upper low will track into the
Ohio Valley, resulting in another round of showers, favoring
Tuesday more so than Monday with respect to pops/qpf.


As of 702 PM EDT Wednesday...

VFR under strong high pressure. Expect SKC until about 22z
Thursday with an increase in high clouds. Change groups
essentially reflect wind speed/direction changes. Trend will be
for initially northerly winds 5-10 kts becoming light and
variable overnight, then veer to east/southeast 3-6 kts during
the day Thursday as ridge axis shifts east into eastern

Extended Aviation Discussion...

Good flying weather is expected to linger into Friday before
moisture starts to increase over the weekend ahead of a cold front
approaching from the west. However, precipitation is not expected
until Sunday when sub-VFR conditions become more of a possibility.
Otherwise looking at overall VFR to start the weekend with most
lower cigs remaining west of the area until later Sunday at this




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