Severe Thunderstorm Warning 196, NWS Blacksburg, VA

Area Forecast Discussion
National Weather Service Blacksburg VA
532 PM EDT Sat Aug 26 2023

.SYNOPSIS...
Rounds of showers and thunderstorms continue through the
weekend and beginning of the work week as a cold front settles
into the Mid- Atlantic. Another stronger cold front will arrive
next week, bringing cooler temperatures.

&&

.NEAR TERM /THROUGH SUNDAY/...
As 532 PM EDT Saturday...

Adjusted pops with the latest radar trends for this afternoon.
Modified temperatures with the latest surface obs, their trends
and blended in NBM. In general, warmed temperatures this
afternoon into this evening especially in Piedmont. more changes
late this evening.

Previous Discussion:
As of 145 PM EDT Saturday...

Key Message:

1. Marginal Risk of severe weather today, west of I-77.
2. Marginal Risk of severe weather Sunday, south of VA/NC
border.
3. Main threat is damaging winds.

The potential for showers and thunderstorms increases from this
afternoon through late tonight/early tomorrow as a front slowly
works its way south through the Mid Atlantic. The front is still
over the northern part of the CWA, around I-64, and extends westward
into the Ohio Valley, where the low pressure center is in southern
Illinois, also where most of the convection is ongoing currently.
There are some showers popping up in central West Virginia, where
the front is closer to the low, and that may continue to push into
the area. There is a Marginal Risk of severe weather associated
with that activity for locations west of I-77 today. For Sunday, showers
and storms will likely develop along the front as it pushes
farther south, with a marginal risk for severe weather
highlighting locations along and south of the VA/NC border. With
plenty of ambient heat and moisture over the central
Appalachians, greater bulk shear near the front, confidence is
higher in greater coverage of showers and storms, but still not
a sure bet.

High temperatures tomorrow will be cooler than today, with highs
in the upper 70s in the west and low to mid 80s in the east. For
the overnight, lows will be in the mid 60s in the west and low
70s in the east.

Forecast confidence is low to average.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 100 PM EDT Saturday...

Key Message:

1. Locally heavy rain possible in northwest NC/southwest VA Sunday
night into Tuesday

Unsettled weather is expected during the short term period of the
forecast as PWAT values during the entire period remain 100-150% of
normal, with the highest anomalies across northern NC into southwest
Virginia.

An upper level disturbance, noted on water vapor satellite imagery
across NW MO early this afternoon, will weaken as it enters our area
Sunday night. Still, with an increase in UVM combined with
abnormally high moisture, expect to see a prolonged period of off
and on showers and storms Sunday night, Monday, Monday night and
into early Tuesday. The NBM is focusing the eastern slopes of the
Blue Ridge from northwest NC to southwest VA as the area for highest
precipitation totals with a modest 30-50% chance that this area will
experience 72 hour precipitation amounts 3" or higher. The ECMWF
Extreme Forecast Index highlights Monday as the period when the
highest rainfall falls with forecast values on the very high end
of the amounts seen for this time of year over a 20 year period,
Will highlight this threat in the HWO.

Otherwise, with abundant cloud cover, temperatures will be below
normal, but there is a larger than normal spread in the ensemble
members for highs, indicating confidence is lower than normal.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 1215 PM EDT Saturday...

Key Message:

1. Track of tropical disturbance over the northwest Caribbean will
need to be monitored in the coming days.
2. Below normal temperatures expected for Thursday and Friday.

Confidence in the long range forecast is lower than average, due to
the uncertainty about the track of a tropical disturbance currently
in the northwestern Caribbean Sea. The most likely scenario is that
this feature, and its associated rainfall, remains south our area as
most, but not all, of the deterministic models predict. The 06Z
individual GEFS ensembles also paints a low probability of this
feature impacting our area. Still, with the 12Z GFS continuing to
show this feature entering our forecast area on Thursday, kept small
POPs mainly in the southern portion of the forecast area.

Otherwise, the deterministic long range models are
in good agreement that a secondary surge of drier air rushes into
our area on Wednesday. The GEFS produces a small chance (10-30%)
of CAPES in excess of 250 j/kg across the VA southside and
northern Piedmont of NC, so kept a risk of thunder in for this
area.

With a wedge of high pressure building into our area Thursday and
Friday, temps will are expected to be below normal, but the NBM
shows a large range in forecast highs during this period, so there
is some uncertainty with just how cool high temperatures will be.
The amount of cloud cover will highly influence low temperatures,
but if enough clearing can occur, the GEFS suggests there is a
chance (30-50%) for temperatures in the Greenbrier Valley to fall
below 50 degrees.

Temperatures should warm closer to normal values on Saturday as
upper level ridging builds.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
As of 130 PM EDT Saturday...

Cloud cover has increased over the area, but flight conditions
are VFR across the area. Cloud cover will continue to increase
through the TAF period as a front pushes southward through the
Mid Atlantic. Showers and thunderstorms are possible from this
front, mainly west of I-77 this evening and could linger into
the overnight hours. For sunday, the chances for showers and
thunderstorms, as well as coverage, increases from east to west
by the end of the TAF period.

Periods of rain and storms will reduce visibilities and lower
ceilings, so times of sub-VFR conditions are possible.

Winds will be mostly from the northwest through the remainder of
the day and into the evening, turning more northeasterly by
Sunday midday, around 5 to 10 knots.

Patchy fog may develop in the early morning hours of Sunday in
the typical river and mountains valleys, but the increase in
cloud cover overnight will be a limiting factor. At this time,
have only included fog for KLWB, KBLF, and KBCB.

Forecast confidence is average.

EXTENDED AVIATION OUTLOOK...

Weather pattern remains unchanged for through Tuesday with
additional chances for showers and thunderstorms and the
associated MVFR conditions, though VFR expected most of the
time. Isolated showers are possible on Wednesday.

&&

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

&&

SYNOPSIS...NF
NEAR TERM...KK/AS
SHORT TERM...PH
LONG TERM...PH
AVIATION...VFJ/AS

<!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>

Special Weather Statement
National Weather Service BLACKSBURG VA
409 PM EDT Sat Aug 26 2023

VAZ007-009-262100-
Tazewell-Smyth-
409 PM EDT Sat Aug 26 2023

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT
NORTHWESTERN SMYTH AND SOUTHWESTERN TAZEWELL COUNTIES...

At 409 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Claypool Hill to near Allison Gap to
near Saltville. Movement was southeast at 15 mph.

Winds in excess of 40 mph are possible with these storms. Brief
heavy rainfall and occasional cloud-to-ground lightning can also be
expected with this activity.

Locations impacted include...
Saltville...
Chilhowie...
Adwolf...
Hungry Mother State Park...
Broadford...
Quarry...
and Allison Gap.

Locally heavy rain will quickly reduce visibility and result in
ponding of water on roadways, standing water in low lying areas, and
minor flooding of creeks, streams, and areas of poor drainage.
Drivers are urged to slow down and use extra caution to avoid
hydroplaning.

LAT...LON 3700 8151 3686 8152 3676 8162 3678 8169
      3692 8183 3693 8183 3695 8182 3696 8178
      3703 8181 3708 8186
TIME...MOT...LOC 2009Z 303DEG 14KT 3701 8183 3693 8177 3687 8182

RAB

<!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>

Special Weather Statement
National Weather Service BLACKSBURG VA
555 PM EDT Sat Aug 26 2023

NCZ002-003-VAZ015-016-262230-
Surry NC-Alleghany NC-Grayson VA-Carroll VA-
555 PM EDT Sat Aug 26 2023

...STRONG THUNDERSTORMS WILL IMPACT
NORTHEASTERN ALLEGHANY AND NORTHWESTERN SURRY COUNTIES IN
NORTHWESTERN NORTH CAROLINA...SOUTHWESTERN CARROLL AND SOUTHEASTERN
GRAYSON COUNTIES IN SOUTHWESTERN VIRGINIA AND THE CITY OF GALAX
THROUGH 630 PM EDT...

At 555 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from Spring Valley to near Baywood to near Sparta.
Movement was east at 25 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Galax...
Independence...
Fries...
Ennice...
Baywood...
Lambsburg...
and Cumberland Knob.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Locally heavy rain will quickly reduce visibility and result in
ponding of water on roadways, standing water in low lying areas, and
minor flooding of creeks, streams, and areas of poor drainage.
Drivers are urged to slow down and use extra caution to avoid
hydroplaning.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3674 8078 3663 8073 3650 8075 3655 8120
      3662 8118 3672 8121
TIME...MOT...LOC 2155Z 263DEG 22KT 3672 8108 3663 8105 3654 8111

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

RAB