Severe Thunderstorm Warning 114, NWS Blacksburg, VA

Area Forecast Discussion
National Weather Service Blacksburg VA
324 PM EDT Wed Jul 25 2018

.SYNOPSIS...
An upper trough of low pressure across the eastern U.S. will
lift into the Northeastern states tonight. Quieter weather with
high pressure building into the region for Thursday. A cold
frontal passage will then progress eastward Friday bringing a
renewed chance at showers and thunderstorms. The outlook for
early next week looks unsettled with the potential for several
opportunities for rain.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 323 PM EDT Wednesday...

Upper level low continues to deamplify and is expected to progress
northeast through tonight. Modest heating this afternoon in
conjunction with an environment of nil convective inhibition has
resulted in scattered to numerous showers and thunderstorms.
Showers/storms have been most concentrated along the Blue Ridge, and
have largely produced heavy downpours given high moisture-content
air in place. However, earlier this afternoon a 33-kt gust was
reported at the Roanoke Airport from a thunderstorm. Showers and
thunderstorms will be capable of torrential rain through mid-
evening, as guidance indicates rain should shift eastward by that
point. Will keep heavy rain wording in the grids through early
evening, though don't see a need for any flood headlines with short-
fused flood products best handling what may be an isolated flood
threat. Still, will need to keep close monitor on any slow-moving
cells that may affect the upper Piedmont of North Carolina into
Southside, as these areas saw heavy rains and notable flooding
Tuesday night. As we saw near Roanoke, a few instances of gusty
winds may be possible from collapsing water-loaded downdrafts as
well, but the more common threat should be heavy rain today.

As the upper low exits late tonight, it will leave behind an area of
light to calm winds. The ground should be rather damp from recent
rain, and model guidance shows area of high near-surface RH and
favorable hydrolapse profiles for fog. Though sometimes overdone,
the NAM-3km visibility products really sock in a large part of the
Piedmont and Blue Ridge area with low visbilities after midnight
tonight. Think fog will be more widespread than simply in the river
valleys and have included patchy fog pretty much everywhere for the
overnight. It's possible a short-fused fog SPS or even a dense fog
advisory may be needed later if it becomes more clear that dense fog
is more imminent, but confidence wasn't high enough for one at this
point. Lows tonight in the mid to upper 60s.

Should have some leftover fog, as well as some lower stratus along
the western flanks of the central Appalachians early Thursday.
However, it's expected by mid-morning that both should begin to thin
out as shallow inversion is mixed out from dry advection and
heating. Should see the first largely dry day in some time for most
as well, with high pressure building in and PWATs beginning to
decrease some. If there is an area where a limited threat of showers
or a garden variety thunderstorm may pop up, it's toward the
afternoon mainly along and east of Route 29. Not looking like a
washout though, and will keep PoPs around slight chance range for
this general area. Thermal profiles are pretty similar to today with
850 mb temps around +14 to +16C, but more sunshine than today should
boost temperatures back into the upper 70s to mid/upper 80s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 323 PM EDT Wednesday...

Pattern dries somewhat this period as upper flow goes toward a
westerly fetch, but still seeing troughiness from the Great Lakes
south into the Ohio/Tennessee Valleys. Piece of shortwave energy
moves across Friday with a frontal boundary. Main convergence
situates over the mountains with west flow keeping pops lower in the
east. Should be a warmer day with highs in the lower 90s in the
piedmont to 80s elsewhere, except a few 70s in the highest
elevations.

Front kicks east Friday night, but could see some development in the
piedmont around dusk before activity shifts east.

Saturday, weak high shifts over the Ohio Valley, but still some
residual low level convergence may lead to scattered showers and
storms mainly over the piedmont of VA to the NC foothills Sat
afternoon.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 323 PM EDT Wednesday...

Not much change in the forecast as it looks active Sunday-Wednesday
as upper trough digs into the midwest/mid MS valley bring a
southwest to south flow as we head into midweek. Warm frontal
boundary lifts north across us Sunday night into Monday while the
cold frontal boundary stay situated west of the Appalachians. As
such expect periods of moderate to heavy showers and storms, and
flooding could become an issue once again. Temperatures staying
close to or below normal for highs but above normal for lows.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
As of 141 PM EDT Wednesday...

Overall, less than ideal flying conditions through the next
12-18 hrs with scattered to numerous showers/thunderstorms
through mid- evening, then becoming patchy fog and low stratus
overnight.

VFR/MVFR ceilings persist but with showers/thunderstorm coverage
on the increase as upper low begins its northeastward migration.
Indicated VCTS at most TAFs generally between 18-01z and will
TEMPO in any imminent shower/thunder mention. Thunderstorms
today would be capable of torrential rainfall (brief IFR/lower
visby), lightning and perhaps sub-severe wind gusts leading to
localized mechanical turbulence. Showers/storms should drift
eastward at a rather slow clip into the Piedmont by late this
afternoon before exiting into eastern VA/NC by around 02z. See
TAFs for timing. Outside of thunderstorms, winds should be
rather light northwesterly west of the Blue Ridge, and tend more
light southerly into the Piedmont.

Later tonight, upper low lifts to the northeast and leads a
period of light to calm surface winds in its wake. Models depict
rather high RH in a very shallow layer near the ground trapped
beneath shallow inversion. Given recent rainfall and damp
ground, think this is an environment conducive to patchy fog
even outside of the river valleys. Have indicated MVFR/TEMPO IFR
visby fog in most areas, though confidence is low on dense fog.
Have hit Lewisburg the hardest with VLIFR dense fog where
confidence is a little higher on dense fog there. Looks like fog
should burn off around 12-13z. May also see some lower stratus
along the western flanks of the central Appalachians as well.
Winds generally light to calm.

After areas of fog burn off, expect largely VFR conditions the
remainder of the TAF period with winds northwest 4-6 kts.

Extended Aviation:

Drier air should push in from the west Thursday resulting in
an overall return to widespread VFR from later Thursday morning
through much of Friday. Moisture will return ahead of another
cold front by this weekend with added rounds of at least
scattered showers, and storms from Friday evening into Sunday
with the best coverage likely later Sunday as a disturbance
swings in along the front. This may result in periods of sub-VFR
mainly during the afternoon/evening hours with overall VFR
prevailing outside of late night/early morning fog/stratus
through the weekend.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

SYNOPSIS...AL
NEAR TERM...AL
SHORT TERM...WP
LONG TERM...WP
AVIATION...AL/RAB

Hazardous Weather Outlook
National Weather Service Blacksburg VA
307 PM EDT Wed Jul 25 2018

VAZ019-020-023-024-035-WVZ507-261915-
Alleghany VA-Bath-Botetourt-Rockbridge-Amherst-Eastern Greenbrier-
307 PM EDT Wed Jul 25 2018

This Hazardous Weather Outlook is for central Virginia, west
central Virginia and southeast West Virginia.

.DAY ONE...This afternoon and tonight.

Scattered to numerous showers and thunderstorms are expected
through mid-evening. Locally heavy rainfall capable of instances of
flooding is possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

There is a marginal risk for severe thunderstorms Friday afternoon
and evening as a cold front moves southward through the area.

Otherwise, the probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ001>006-018>020-VAZ007-009>018-022-032>034-043>047-058-059-
WVZ042>044-508-261915-
Ashe-Alleghany NC-Surry-Stokes-Rockingham-Caswell-Watauga-Wilkes-
Yadkin-Tazewell-Smyth-Bland-Giles-Wythe-Pulaski-Montgomery-Grayson-
Carroll-Floyd-Craig-Roanoke-Patrick-Franklin-Bedford-Henry-
Pittsylvania-Campbell-Appomattox-Buckingham-Halifax-Charlotte-Mercer-
Summers-Monroe-Western Greenbrier-
307 PM EDT Wed Jul 25 2018

This Hazardous Weather Outlook is for north central North Carolina,
northwest North Carolina, central Virginia, south central Virginia,
southwest Virginia, west central Virginia and southeast West
Virginia.

.DAY ONE...This afternoon and tonight.

Scattered to numerous showers and thunderstorms are expected through
mid-evening. Locally heavy rainfall capable of instances of flooding
is possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

There is a marginal risk for severe thunderstorms Friday afternoon
and evening as a cold front moves southward through the area.

Otherwise, the probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>