Severe Thunderstorm Warning 236, NWS Blacksburg, VA

Area Forecast Discussion
National Weather Service Blacksburg VA
311 PM EDT Wed Aug 21 2019

.SYNOPSIS...
Weak high pressure will remain over the region tonight resulting in
a continuation of the muggy weather. A cold front approaches by the
end of the week bringing increasing chances of showers and
thunderstorms Thursday and Friday. This front should finally work
southeast through the area Saturday with less humid weather possible
Sunday.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 311 PM EDT Wednesday...

The hot and humid weather continues today with scattered showers and
thunderstorms this afternoon into tonight. The combination of
shortwaves, instability, orographic lift and surface boundaries will
generate scattered showers and thunderstorms. Some of the storms can
be strong to severe as highlighted in SPC Day one convective outlook
marginal risk. The main threats are damaging winds, hail, and heavy
rains.

SPC Mesoscale 18z analysis showed capes from 1500 to 2500 j/kg and
SB LI from minus one to minus four. Deep moisture convergence
showing up along the higher terrain in the west. Convection has
developed along the exiting shortwave in eastern Virginia and
with the shortwave to our north across northern West Virginia
and northern Virginia. Our local KFCX radar showed showers and
thunderstorms forming along the southern Blue Ridge Mountains this
afternoon. Cloud cover from this morning has delay the timing
of storms a little this afternoon across the region. With PWATS
around 1.5 inch and weak mean flow, locally heavy rains are
possible with higher rates and training of storms.

Convection will diminish or dissipate this evening with the loss of
solar heating. Then,partly to mostly cloudy and warm conditions
expected tonight. Light winds and low level moisture will
create areas of low clouds and fog late tonight into Thursday
morning. Low temperatures will range from around 60 degrees in
the mountains to around 70 degrees in the piedmont.

The cold front will approach from the north Thursday. Scattered
showers and thunderstorms will develop especially during the
afternoon and evening hours. Better forcing remains to our north and
west, though we should still have enough convergence and instability
along the Blue Ridge and Alleghany Mountains for storms to start in
the high terrain and then travel east into the Piedmont. There
remains the potential for scattered pulse severe storms with
the strong instability. The SPC Day 2 highlights the chance for
severe thunderstorms with a marginal risk on Thursday. High
temperatures on Thursday will vary from the upper 70s in the
mountains to the lower 90s in the piedmont.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 307 PM EDT Wednesday...

A cold front is expected to stall across the southern Ohio River
Valley Thursday night. A surface reflection will then track along
this boundary, moving to central/northern Virginia on Friday. With
the front close to the area, scattered mountains (isolated east of
the Blue Ridge) showers are possible Thursday night into Friday
morning. Friday afternoon, this surface reflection will move east of
the area and with strong heating (highs in the upper 80s), there is
a marginal risk for severe storms Friday afternoon and evening east
of the Blue Ridge. Morning clouds and rain should keep the
heating/instabilities low across the mountains. The primary threat
will be gusty winds. Torrential downpours are also possible but the
threat will mostly be localized/isolated.

As convection exits the area Friday evening, the cold front will
slide south into the Carolinas into the day Saturday. As the front
was slow to enter the region, it will also be slow to exit. Light
rain and thick clouds may linger along and south of the VA/NC border
through the day Saturday. Drier air will work into the region from
the north Saturday night. High temperatures Saturday will range in
the 70s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 300 PM EDT Wednesday...

If the front sinks south into the Carolinas Saturday, cool northeast
winds will keep the area dry into Monday (ECM). The latest GFS has
an upper level trough moving northeastward across the Ohio Valley
with overrunning warm moist air moving over a wedge of cooler air.
We think the GFS is overdone on measurable precipitation, but think
it has the right idea with increasing cloud cover. The wedge is
expected to hang over the region into Tuesday morning then erode
with the passing of a weak front.

Temperatures will run 10F or cooler than normal Sunday and Monday.
Temperature return to normal Wednesday.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
As of 203 PM EDT Wednesday...

VFR conditions with scattered MVFR showers and thunderstorms
expected this afternoon into tonight. A shortwave crossing into
western Pennsylvania will result in showers and thunderstorms
this afternoon and evening which includes MVFR visibility due to
heavy rain and erratic gusty winds with the slow moving storms.
The combination of heating,instability, orographic lift and low
level boundaries will result in scattered showers and
thunderstorms.

Any convection will diminish with the loss of solar heating this
evening. Partly cloudy conditions will return to most location
tonight. With light winds and low level moisture, areas of low
cloud and fog will develop late tonight into Thursday morning.
KLWB has the best chance for IFR/LIFR fog overnight. Any
location which receives heavy rains for thunderstorms Wednesday
afternoon has the better potential for fog.

The hot and humid weather continues Thursday with scattered
MVFR showers and thunderstorms.

Confidence in average for ceilings,visibilities and winds during
the taf period.

.Extended Aviation Discussion...

Weather pattern will continue to promote scattered showers and
thunderstorms. A cold front will approach from the northwest
late in the week, resulting in scattered to numerous
thunderstorm with potential for organized clusters of
thunderstorms to track across the Ohio Valley into the Mid-
Atlantic region.

Improving conditions with more in the way of VFR will be
possible for the late weekend, pending just how far south of
the Mid Atlantic area the front progresses. Some MVFR showers
are possible in the southwest portion of the forecast area
on Monday.

&&

.CLIMATE...
As of 245 AM EDT Wednesday...

Record Daily Maximum Temps:

August 21:
ROA: 105/1983
BLF: 94/1936
DAN: 104/1983
LYH: 101/1983
BCB: 98/1983

&&

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

&&

SYNOPSIS...AMS/KK
NEAR TERM...KK
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AMS/KK
CLIMATE...AMS

Hazardous Weather Outlook
National Weather Service Blacksburg VA
318 PM EDT Wed Aug 21 2019

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>044-507-508-221930-
Ashe-Alleghany NC-Surry-Stokes-Rockingham-Caswell-Watauga-Wilkes-
Yadkin-Tazewell-Smyth-Bland-Giles-Wythe-Pulaski-Montgomery-Grayson-
Carroll-Floyd-Craig-Alleghany VA-Bath-Roanoke-Botetourt-Rockbridge-
Patrick-Franklin-Bedford-Amherst-Henry-Pittsylvania-Campbell-
Appomattox-Buckingham-Halifax-Charlotte-Mercer-Summers-Monroe-
Eastern Greenbrier-Western Greenbrier-
318 PM EDT Wed Aug 21 2019

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.

Strong to severe thunderstorms are possible this afternoon into
tonight. The primary threats is damaging wind and hail.

Locally heavy rain is also likely in any of the strong, slow moving
storms. This may result in flooding.

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

There is a marginal risk for severe thunderstorms on Thursday and Friday
with the main threat being damaging wind.

Thursday through Friday locally heavy rain is possible, which may
result in flooding.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
429 PM EDT WED AUG 21 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0405 PM     TSTM WND DMG     4 SE ARARAT             36.56N 80.48W
08/21/2019                   PATRICK            VA   911 CALL CENTER

            TREE DOWN ON CAR ALONG CLAUDVILLE HWY/103.
            NO INJURIES.

&&

WP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
431 PM EDT WED AUG 21 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0412 PM     TSTM WND DMG     1 E STUART              36.63N 80.27W
08/21/2019                   PATRICK            VA   911 CALL CENTER

            TREE DOWN NEAR HARDEES.

&&

WP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
436 PM EDT WED AUG 21 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0402 PM     TSTM WND DMG     2 SE ARARAT             36.58N 80.49W
08/21/2019                   PATRICK            VA   911 CALL CENTER

            A FEW TREES DOWN ALONG HOME PLACE ROAD.

&&

WP

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