Area Forecast Discussion
Issued by NWS Blacksburg, VA
FXUS61 KRNK 240452
Area Forecast Discussion
National Weather Service Blacksburg VA
1252 AM EDT Sun Jul 24 2016
Strong high pressure aloft to the west will continue to bring
increasing heat and humidity into Monday. A series of weak
surface cold fronts approaching from the northwest should
gradually bring an increasing threat for showers and storms early
.NEAR TERM /THROUGH TODAY/...
As of 1125 PM EDT Saturday...
Been a quiet evening weather wise and should stay that way
overnight. Remaining very muggy and temperatures at 11 pm were
still running in the 70s most places. Some fog will form late over
the rivers, with skies staying mostly clear.
Previous valid discussion...
Strong upper level ridge will continue to expand eastward
tomorrow with heights increasing over the Mid Atlantic.
Temperatures at 850 mb will increase a couple of degrees (+22C to
+24C) over the next 24 hours resulting in another day of warmer
than normal temperatures across the region. Sunday`s temperatures
across the mountains will range from the lower 80s along ridge
tops to near 90 in the valleys. Combining these warmer than normal
temperatures with dew points in the 60s, heat indices values will
run around 5F warmer than the actual temperature. Temperatures
east of the Blue Ridge Sunday will run 5F-10F warmer than normal
with mid to upper 90s. The piedmont counties of south- central
Virginia and northwest North Carolina may flirt with triple digit
heat by the end of the day. Heat indices across the piedmont may
top out close to 103F for a few hours in the afternoon.
With a ridge, warm temperatures, and little support aloft, only
expecting isolated thunderstorms tomorrow afternoon, mainly across
the mountains. With less than ideal conditions for convection, any
afternoon or evening showers or thunderstorms that develops will
be short-lived, lasting about 30 minutes to maybe an hour.
However, with modest instabilities and abundant low level
moisture, we can not rule out a strong pulse thunderstorm or two
during the late afternoon and early evening.
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
As of 310PM EDT Saturday...
Overall more troffing at 500MB Tuesday and Wednesday over the
northeast United States as the axis of highest heights drifts
south. Weak surface boundary gets close enough to the forecast
area by Tuesday to result in a better probability of showers and
thunderstorms, especially in the mountains. Do not expect much
push south or any change in air mass. Weak winds and pooling of
moisture with precipitable water values close to two inches ahead
of the front will mean any of the stronger thunderstorms will have
very heavy rain Tuesday.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 315 PM EDT Saturday...
Little change in the overall pattern will mean a persistent chance
each day of afternoon and evening showers and thunderstorms.
Northern stream upper trof will bring some lift into the region
Friday. Temperatures will be close to normal through the period.
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 1245 AM EDT Sunday...
VFR conditions expected to continue for most of the period with
high pressure aloft in place. Exception would be patchy
fog/stratus, especially valleys (KLWB/KBCB) overnight, where
could see a period of IFR/LIFR and some at KLYH.
Any fog/stratus should quickly fade early Sunday morning with
mainly scattered cu during the afternoon. Showers and storms
Sunday afternoon will again be isolated so leaving out any mention
in the terminal forecast.
Rather similar scenario likely Sunday night with any evening
convection quickly giving way to mainly clear skies and patchy
valley fog overnight into early Monday.
Extended aviation discussion...
Strong high pressure aloft looks to remain in place on Monday
with continued VFR outside of additional mainly mountain
convection Monday afternoon/evening. Ridge will weaken through mid
week as an initial cold front sinks toward the area from the
northwest. This should bring about an increase in daily convective
coverage Tuesday into Wednesday with periodic MVFR/IFR possible.
Late night and early morning fog will likely occur at the usual
valley locations, and those chances increase across the entire
region if any rain occurs during the afternoon or evening at any