Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KRNK 220553
Area Forecast Discussion
National Weather Service Blacksburg VA
153 AM EDT SUN MAY 22 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.
.NEAR TERM /THROUGH TODAY/...
As of 905 PM EDT Saturday...
Shallow convection continues to linger this evening along a
residual surface trough axis extending north from low pressure
over the Carolinas and ahead of shortwave energy rotating around
the upper low to the north. These showers also supported by
lingering surface based cape of 500-1k J/KG as seen off the latest
SPC analysis and 00z RNK raob. Most guidance still supports this
convection slowly winding down through midnight per loss of
heating and then diminishing further overnight under some brief
drying aloft between spokes of energy rotating through. Thus
keeping low likely pops going nw third for another couple of hours
and over the southeast where still have bands/clusters that the
HRRR hangs onto until just before midnight. Otherwise appears
coverage should decrease enough to lower pops to mainly slight
chances north/east, and low pops nw where will continue to have
upslope driven spotty coverage overnight.
Expect fog to be mostly patchy early on before winds pick up late
helping scour things out by daybreak mountains but perhaps lingering
east a bit longer where likely more widespread. Little change to
going temps with lows mostly 50s, except a few 40s west where the
onset of deeper cool advection will begin after midnight.
Previous discussion 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
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.
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
As of 320 PM EDT 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.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
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
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 150 AM EDT Sunday...
Mainly MVFR flight conditions expected at most terminal forecast
points overnight as gradually increasing upsloping winds maintain
clouds over the mountains. Further east, weakness in the pressure
gradient and influence of weak moist cool wedge should help to
keep low level clouds trapped, where some flight restrictions
into the ifr range are likely - most notably at/near Lynchburg
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 from late morning into the early
evening. Expecting a faster improvement in conditions early
Sunday as increasing northwest winds kick in and lower ceilings
and visibilities rise. However, once daytime heating
develops, will likely see ceilings fill back in with MVFR cloud
bases - especially in upslope areas such as KBLF, and where any
afternoon showers redevelop under the upper cold pool.
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 40 kts, and
gradually veer northwest to north.
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.