Severe Thunderstorm Warning 75, NWS Blacksburg, VA

Area Forecast Discussion
National Weather Service Blacksburg VA
808 PM EDT Wed Jul 1 2020

.SYNOPSIS...
Low Pressure over New England will move offshore tonight.
Meanwhile, high pressure over the Plains will also shift east
and move over the Midwest. As high pressure edges into the
region through the weekend, warm and muggy conditions will
continue with temperatures near or just above normal. Coverage
of thunderstorms will gradually increase from isolated Thursday
and Friday to scattered over the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 800 PM EDT Wednesday...

A couple of changes for the evening update. Temperatures are
running a bit warmer than expected this hour, with still some
readings in the mid 80s, so delayed cooling during the evening
some. Dewpoints are lower in most areas than 24 hours ago, so we
should be able to achieve the advertised low temperatures.

Second change was to update the pops. Held onto some slight
chance pops in the southwest and some chance pops in the east.
Earlier strong to severe convection in eastern/coastal VA sent
an outflow boundary into our eastern CWA. Convection has
redeveloped along this and a weak backdoor front evident across
northern VA in the LYH area. This activity could persist for the
next few hours and drift or redevelop back to ROA with time. Do
not expect it to make it a whole lot further west, but will
account for the next 2-3 hours at least. Pops trend toward zero
by Thursday morning.

As of 125 PM EDT Wednesday...

An upper level low over New England will move offshore tonight,
ushering in some drier air. But before it does that, weak
pieces of energy will rotate around the base of the low,
bringing scattered showers and thunderstorms to the VA/NC
piedmont. Some storms could be strong to severe east of Route
29. Elsewhere, the combination of afternoon heating and low
level moisture could produce isolated storms this afternoon.
Showers will fade this evening with loss of heating and energy
moving off the coast.

The region will be in between the low moving off the New
England coast and an upper level ridge entering the Midwest.
Models showing some weak low level convergence along the Blue
Ridge Thursday, but does not appear instabilities are strong
enough to produce any showers.

Low tonight will range in the 60s. high tomorrow will be in the
80s and close to normal.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 135 PM EDT Wednesday...

On Friday, upper level ridging from the Midwest edges into the
region. With increasing heights aloft, surface temperatures will
warm above normal. Highs Friday will range in the 80s across
the mountains to lower 90s east.

A lee trough or low level convergence along with diurnal
heating along the Blue Ridge Saturday may generate a few natural
fireworks for the area. With loss of heating in the evening,
showers will fade. Similar temperatures Saturday as compared to
Friday, but with a slight uptick in humidity.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 130 PM EDT Wednesday...

The large scale flow pattern will remain generally the same
from the weekend into Midweek. The trough axis along the
Northeast coast will slide east, as the upper ridge builds
eastward across our region. The weak flow aloft and some mid to
upper level disturbances combined with heating and orographic
lift will generate diurnal convection with the best opportunity
across the higher terrain especially the southwest mountains.
Isolated to scattered afternoon and evening showers and
thunderstorms are expected. Near normal temperatures are
anticipated with readings generally from the upper 70s in the
mountains to the lower 90s east of the Blue Ridge.

A surface low pressure center does form in Florida Sunday night
and lifts northeast off the Carolina coast Tuesday into
Wednesday. Then, the low pressure center heads out into the
Atlantic ocean Wednesday into Thursday. There remains some
differences in the timing and strength of the low center on the
GFS and ECMWF.

Medium confidence in long term forecast.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 800 PM EDT Wednesday

Another weak short wave in the base of the upper trough located
across the northeast U.S. triggered another round of afternoon
convection. This time the focus was on the northeast part of the
CWA and southeastward into the coastal plain region and eastern
VA. Outflow boundaries from this activity and a weak backdoor
front in northeast GA, which helped to organize this activity
initially, are allowing for convection to redevelop this evening
in the LYH to FVX area. This may continue for a while and could
even drift/redevelop back toward ROA late this evening. For now,
will include VCTS at LYH for a couple of hours, but not anywhere
else.

Generally a VFR forecast. However, the big question is whether
or not there will be any fog late tonight/early Thursday.
Dewpoints have dropped on average about five degrees from
yesterday, so confidence in widespread dense fog such as we saw
at several TAF sites this morning, is low. Backed off the
intensity of the fog a bit, but still kept TEMPO periods of fog
late tonight/early Thursday and attendant IFR-LIFR conditions
for 3-4 hours at LWB, BCB, LYH, and DAN. Rain at LYH in the
next couple of hours could lead to IFR-LIFR for several hours in
BR/FG there early in the morning. Otherwise, look for VFR
visibilities and ceilings after 14Z and throughout most of this
evening as well. Thunderstorms should remain well south and west
of the CWA Thursday with a more stable, drier air mass in place
from the northeast.

Winds will become northeast 5-8kts after 14Z Thursday.

/Confidence in Forecast Parameters/
Ceilings - Moderate to High,
Visibilities - Moderate to High,
Winds - High,
Thunderstorm Threat - Low.

Extended Aviation Discussion...

Low level moisture and afternoon heating may develop a few
showers mainly Friday afternoon. Any showers will not last long
into the evening. The threat for scattered afternoon and
evening pulse thunderstorms increases this weekend as moisture
and warm temperatures become more widespread.

&&

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

&&

SYNOPSIS...RCS
NEAR TERM...RAB/RCS
SHORT TERM...RCS
LONG TERM...KK
AVIATION...RAB/RCS

Hazardous Weather Outlook
National Weather Service Blacksburg VA
447 AM EDT Wed Jul 1 2020

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>044-507-508-020900-
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-
447 AM EDT Wed Jul 1 2020

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...Today and tonight.

The probability for widespread hazardous weather is low.

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

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service BLACKSBURG VA
259 PM EDT Wed Jul 1 2020

NCZ005-011945-
Rockingham-
259 PM EDT Wed Jul 1 2020

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN ROCKINGHAM
COUNTY...

At 258 PM EDT, a strong thunderstorm was developing over Stoneville,
moving southeast at 15 mph.

Winds in excess of 40 mph and small hail are possible with this
storm.

Locations impacted include...
Reidsville...
Wentworth...
Mayodan...
Madison...
Stoneville...
Intelligence...
and Bethany.

LAT...LON 3625 7992 3645 8001 3652 7991 3633 7962
      3625 7976
TIME...MOT...LOC 1858Z 322DEG 12KT 3645 7994

MBS

Special Weather Statement
National Weather Service BLACKSBURG VA
758 PM EDT Wed Jul 1 2020

VAZ035-045-046-020030-
Amherst-Campbell-Appomattox-
758 PM EDT Wed Jul 1 2020

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN APPOMATTOX...
NORTHEASTERN CAMPBELL...AND SOUTHEASTERN AMHERST COUNTIES AND THE
CITY OF LYNCHBURG...

At 757 PM EDT, a strong thunderstorm was located near Madison
Heights, or near Lynchburg, moving south at 20 mph.

Winds in excess of 40 mph are possible with this storm. Heavy
rainfall is also occurring with this storm, and may cause localized
flooding of poor drainage areas.

Locations impacted include...
Lynchburg...
Concord...
Rustburg...
Madison Heights...
Stonewall...
Bocock...
and Spout Spring.

LAT...LON 3722 7920 3738 7925 3739 7923 3740 7925
      3742 7925 3743 7926 3745 7927 3745 7925
      3747 7921 3747 7918 3748 7920 3753 7900
      3727 7888
TIME...MOT...LOC 2357Z 350DEG 18KT 3745 7909

MBS