Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 232012

Area Forecast Discussion
National Weather Service Blacksburg VA
412 PM EDT Thu Mar 23 2017

High pressure will slide off the coast tonight into Friday. A
warmer southerly flow will develop Friday into the weekend ahead
of a slow moving cold front that will approach the region
Sunday. A series of upper-level low pressure areas will track
across the central and southern U.S. through next week keeping
an unsettled weather pattern in place.


As of 214 PM EDT Thursday...

Dome of high pressure along the east coast is going move offshore
tonight  into Friday allowing for the area to move into warm
advection. Expect temperatures to drop again tonight to the upper
20s to lower 30s in the east and mountain valleys, except mid to
upper 30s across the higher terrain in the west with southerly winds
picking up more.

Late tonight through Friday, models are showing increasing moisture
in the mid and upper levels tracking from KY/TN into the mid-
Atlantic with some light precip being generated north of our
forecast area. Anticipate some increase in clouds late tonight into
Friday  mainly over the west and north, but still looking at more
sun than clouds Friday as temperature warm into the 60s, except some
50s along the Blue Ridge.


As of 345 PM EDT Thursday...

A pattern transition will be underway this weekend as
predominate northwest flow aloft comes to an end, replaced by
unsettled split flow with series of southern stream storm
systems of Pacific origin to parade across the CONUS. First in
this series of storm systems will arrive Sunday. Until its
arrival, the first half of the weekend will be dry, Saturday
certainly a great day to be outdoors with temperatures in the

Late Saturday, moisture will be on the increase west of the
Appalachians per the approach of an upper low to lifting out of
the Southern Plains. Showers/thunderstorms associated with this
system will be advancing east across the Tennessee Valley into
far southwest VA or southern WV Saturday night. The upper low
will then take a more northward track into the Ohio Valley and
weaken as it encounters the upper ridge along the eastern
seaboard. This will result in a weakening of the thunderstorm
activity as it crosses the mountains, but still sufficient
forcing, instability, to promote high probability of showers
areawide for Sunday. Temperatures Sunday will be just a tad
lower thanks to cloud cover and precipitation, but with
increasing dewpoints, overnight lows will be warmer.

With regard to QPF, models are in fairly good agreement,
advertising 1/2 to 3/4 inch of rain along and west of the Blue
Ridge Sunday, and 1/4 to 1/2 inch east of the Blue Ridge.
Severe weather is not expected for our CWA for this first


As of 400 PM EDT Thursday...

Next in a series of upper-level low pressure areas will move
from the Southern Plains into the Tennessee Valley/Central
Appalachians late Monday into Tuesday. While this system will
again be weakening as it moves toward the western Atlantic upper
ridge, it will have somewhat better dynamics and instability to
work with than the Sunday system. Therefore, a chance of
thunderstorms anticipated areawide for Tuesday afternoon. This
still does not look like a widespread severe weather maker for
our CWA, but slightly better potential for at least some
stronger storms with small hail per warmer temperatures, higher
surface dewpoints and slightly better instability compared to
the Sunday system. Rainfall amounts again appear to be in the
1/4 to 3/4 inch range over all with this event.

A quieter midweek period appears in order as another upper-
level system deepens but slows as it moves into Texas and an
upper ridge amplifies across the eastern U.S. A weak area of
high pressure from the Great Lakes filters into the area for
midweek. By Friday, this aforementioned system will move into
the Mid-Atlantic region as yet another upper-level low pressure
area moves from the southwest U.S. into Texas.

Temperatures will remain mild through the upcoming week with no
significant intrusions of Canadian air. A slight cooling will
be noted midweek, but temperatures will favor the warm side of
normal with highs in the 60s/70s and lows mainly in the 40s to
lower 50s.


As of 110 PM EDT Thursday...

Do not see any aviation issues this period with high pressure
exiting to our east. Will see some increase in clouds at the AC
to CS level overnight through Friday morning, with southerly to
southwesterly winds increasing some over the mountains.

Extended Aviation Discussion...

Good flying weather is expected to linger into Friday night before
moisture starts to increase over the weekend ahead of an upper-
level low pressure area moving northeast from the Southern
Plains. 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 point.
Periods of unsettled weather will continue into the first half
of next week as a series of upper-level lows track from west to
east across the U.S.




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