Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS61 KRNK 212305

Area Forecast Discussion
National Weather Service Blacksburg VA
705 PM EDT SAT MAY 21 2016

Low pressure off the North Carolina/Virginia coast will deepen
and move northeast through Sunday as a weaker low over the Ohio
Valley tracks southeast and dissipates. High pressure over the
central United States will move east Monday and Tuesday, then off
the East Coast on Wednesday.

AS OF 247 PM EDT Saturday...

Have showers and some thunderstorms across the area this afternoon.
Best instability lies across the mountains from Southern WV into the
NC foothills...but with more sunshine in the southeast expect some
stronger storms over the Piedmont of VA/NC mid to late afternoon.
Still seeing upper trough moving across the Ohio Valley this
afternoon. Overall, models favor a cutoff low developing across the
Mid Atlantic by overnight and will see this system impact us
tomorrow with more showers and isolated storms. Coverage will be
shotgun but based on upper level forcing, looks like more coverage
will be from the Alleghany Highlands, southeast to the Piedmont of
VA/NC. With cool pool aloft, any stronger cell could produce some
graupel/small hail

Looking at coverage this evening and overnight to subside but do not
foresee any completely ending, so keeping at least chance pops in
from the SW Virginia mountains north and east to the Shenandoah
Valley and Lynchburg with less coverage after late evening from the
NC foothills east. Areas of fog possible overnight though cloud
cover will impede good coverage. Lows tonight to range from the upper
40s west to mid 50s southeast.

Sunday will see a decent enough gradient with surface low off the
coast to provide a breezy day. Sunshine looks more likely across
Southern WV to the NC mountains with less from the Alleghanys to
Lynchburg and Charlotte Courthouse. Highs will still about 10
degrees below normal ranging from the lower 60s mountains, to near
70 NC foothills to Southside Virginia.


As of 320 pm Saturday...

A closed low is forecasted to move over the coastal piedmont of
Virginia and North Carolina Sunday night, then off Cape Hatteras
Monday evening. This low is then forecasted to track north to New
England on Tuesday. Since this low will remain inland, there is a
good chance for showers Sunday night into Monday, especially east of
the Blue Ridge. Also with a cold pool pivoting over the piedmont
Sunday evening into Monday afternoon, can not rule out an isolated
strong to severe storm with hail being the primary threat and wind a
secondary threat. Bulk of the stronger storms and heavy rain will
remain with the low and points east.

The chance for showers will remain in the area Monday night,
however, strong storm threat will decrease as the low jogs to the
east. As this low continues to move east, showers will taper off
from west to east with rain leaving the piedmont early Tuesday
morning. With the slower movement of this low and the track
remaining inland, PoPs have been increased and durations has been
stretched into Monday night, mainly across the piedmont.

While this low is in the vicinity, temperatures will remain cooler
than normal Monday with highs in the upper 60s to lower 70s. The sun
and warmer temperatures return Tuesday with high in the 70s.


As of 330 PM EDT Saturday...

The upper level low tracks northeast of the area and off the New
England coast Tuesday night. Behind this system high pressure and
upper level ridge will bring drier and warm weather to the region
starting Wednesday. Temperatures will warm and stay above normal
through Saturday. With the warmer weather comes a better chance for
showers and thunderstorms each afternoon and evening. Storms do not
look organized but pulse-like, tracking slowly from the southwest to
the northeast.


As of 645 PM EDT Saturday...

Bands/clusters of shra/tsra continue across much of the region
early this evening and expect most sites to have at least a shower
in the vicinity over the next couple of hours. Thus will keep
either a MVFR prevailing or tempo group in, or just a VCSH/VCTS
pending release coverage at this point and amend into the evening.

Some showers may linger until around midnight despite weakening
instability per latest HRRR. Appears low clouds and/or fog may
set up at times across most of the area espcly east of the Blue
Ridge where the wedge may flop back a bit. Expect these lower
conditions to linger overnight until a better pressure gradient
kicks in Sunday as low deepens off the east coast. Therefore
keeping in MVFR to IFR cigs most spots after the showers fade with
a variable range in VSBYS, but overall MVFR at times in fog

Persistent upper low will drop south over the area Sunday with the
next round of shortwave energy producing the best coverage of
showers across the north and east during the day. Expecting a
faster improvement in conditions early Sunday as increasing
northwest winds kick in and low cigs/vsbys rise. However once
heating develops will see cigs fill back in with VFR cloud bases,
except likely MVFR at KBLF per upslope nw flow, and where any
afternoon showers redevelop under the upper cold pool.

Isolated to scattered showers will also occur, espcly across the
east Sunday into Sunday evening making for MVFR vsbys or worse at
times. Isolated thunder will also be possible along with patchy
sub-VFR vsbys overnight in fog where earlier rainfall occurred.

Surface gusts of 20 to 30 kts can be expected across the
mountains Sunday, with 10-20 kts possible east of the Blue Ridge.
850 mb winds are progged to increase to 25 to 35 kts, and gradually
veer northwest to north.

Extended discussion...

On Monday, winds will start to decrease as the center of the
upper low continues to exit the region. Isolated showers and with
periodic sub-VFR conditions will still be possible, especially in
the east, related to this feature.

Monday night through Wednesday, expect mainly VFR conditions as
high pressure settles offshore with southwest flow in place.

By Thursday we should start to see some potential for shower and
thunderstorms to pop during the heating of the day mainly in the
mountains. Fog may start to become an issue by the mornings
midweek, in the typical areas like KLWB and KBCB.




AVIATION...AMS/JH/WP is the U.S. government's official web portal to all federal, state and local government web resources and services.