Severe Thunderstorm Warning 171, NWS Raleigh, NC

Area Forecast Discussion
National Weather Service Raleigh NC
918 PM EDT Tue Aug 7 2018

.SYNOPSIS...
A surface trough will linger across central NC until a weak cold
front approaches from the west late Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 918 PM Tuesday...

Thunderstorms have been driven by outflows from earlier storms
moving SE across the northern Piedmont. MLCapes, even at 900 PM
local time ranged in the 1500 J/KG to 2000 J/KG along the
intersection of the surface trough and outflow boundary. This
boundary extended from SW to NE across the Piedmont, moving very
slowly SE. There is developing CINH over the SW and W Piedmont and
Foothills where the nighttime cooling stabilization has begun.

Interestingly, the IR satellite data indicated a rapid expansion of
68-70 below zero (very cold cloud tops) over Yadkin/Surry/Stokes
Counties and over Vance County recently. We should have an
additional hour or two of marginally severe thunderstorms before
they weaken just before midnight or so. Some additional development
is possible, especially in the Triad region as there was still some
surface moisture convergence of high PW's in the 1.7 to 1.8 range
directed into the surface trough and outflows.

Only isolated storms expected around Laurinburg and Raeford through
midnight, otherwise a minimum of POP in the south and east. Partly
cloudy in general expected overnight with lows in the 70s.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 310 PM Tuesday...

Copy and paste today's forecast in for Wednesday. The piedmont
trough will remain in place over the area. Primarily diurnal
convection with coverage similar to today, mainly along differential
heating boundaries. Pwats in the 1.5-2.0 range will also persist.
The upper level trough will start to push the ridge south late
Wednesday into Wednesday night, with increasing warm, moist
advection into central NC. With the majority of convection holding
off until later in the evening, expect highs to reach the low to mid
90s, resulting in heat indices in the 100-103 range along and east
of I-85. Overnight lows also similar to to night, low to mid 70s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 215 PM TUESDAY...

Longer range forecast remains on track with a steady rise in diurnal
convection coverage, along with a gradual decrease in daytime
heating potential through the period.

A surface lee-side trough will remain across the area through the
end of the workweek before finally becoming washed out by a
shortwave likely to stall a front across region by Friday morning.
In the upper-levels, an amplifying trough over the Great Lakes and
Northeast will become more prominent late in the period before
transitioning into more of a cutoff upper low early next work-week.
Most of Thursday looks to be relatively dry ahead of the front which
is likely to enter and stall across central NC primarily after
sunset. Can't rule out an airmass thunderstorm and/or pre-frontal
trough-initiated storm, but signals remain relatively sparse thanks
to an utter lack of forcing. Some residual showers/storms will
likely spill east of the Appalachians with the front after sunset,
absorbing what's left of the instability before dying out near the
Triangle overnight Thursday/pre-dawn Friday. Southerly/southwesterly
flow becomes better established over the weekend, giving the
potential for more widespread shower/storm development, especially
in the Saturday through Monday time frame. Guidance suggests drier
air moving into the region on Tuesday.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 830 PM Tuesday...

24 Hour TAF Period:  Expect mostly VFR conditions through the TAF
period with short wave ridging over the area helping to limit the
usual afternoon/evening tstm activity over central NC through the 24
hour TAF period. However, lingering isolated to scattered showers
and storms may affect KRDU and possibly KINT/KGSO through around 04Z
or so this evening. Isolated to scattered late day/evening showers
and storms will again be possible Wednesday as well, with the best
chance across the far NW Piedmont. Otherwise, outside of possibly
some patchy sub-VFR visbys at KRWI, VFR conditions are expected.

Outlook: A typical summer pattern is expected, featuring mainly
afternoon/evening showers and tstms each day with patchy morning fog
possible, mainly where showers/tstms occurred the day before. Right
now it appears that the coverage of shower/tstm activity will
increase over the weekend, with perhaps a more prolonged period of
sub-VFR conditions possible then.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

SYNOPSIS...PWB/CBL
NEAR TERM...Badgett/KC
SHORT TERM...KC
LONG TERM...JJM/Franklin
AVIATION...BSD/NP

Hazardous Weather Outlook
National Weather Service Raleigh NC
314 AM EDT Tue Aug 7 2018

NCZ007>011-021>028-038>043-073>078-083>086-088-089-080715-
Person-Granville-Vance-Warren-Halifax-Forsyth-Guilford-Alamance-
Orange-Durham-Franklin-Nash-Edgecombe-Davidson-Randolph-Chatham-Wake-
Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson-
Richmond-Scotland-Hoke-Cumberland-Sampson-
314 AM EDT Tue Aug 7 2018

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Today and Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service Raleigh NC
619 PM EDT TUE AUG 7 2018

NCZ083-072300-
Anson NC-
619 PM EDT TUE AUG 7 2018

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN ANSON COUNTY UNTIL
700 PM EDT...

At 618 PM EDT, Doppler radar was tracking a strong thunderstorm near
Chesterfield, or 10 miles south of Wadesboro, moving east at 10 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Heavy rain and minor flooding and deadly cloud to ground lightning
will also be possible with this storm.

Locations impacted include...
Lilesville, Morven, McFarlan and Blewett Falls Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter in a nearby building or vehicle. Wind gusts as high as
50 mph are capable of knocking down small or weakened trees and
blowing around trash cans, potted plants, lawn furniture and other
light outdoor objects.

Cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3481 8015 3489 8019 3500 7990 3497 7986
      3495 7987 3491 7985 3488 7987 3486 7988
      3486 7990 3482 7991 3481 7992
TIME...MOT...LOC 2218Z 249DEG 8KT 3481 8007

77

Special Weather Statement
National Weather Service Raleigh NC
648 PM EDT TUE AUG 7 2018

NCZ022-023-072345-
Guilford NC-Alamance NC-
648 PM EDT TUE AUG 7 2018

...A LINE OF THUNDERSTORMS WILL AFFECT CENTRAL GUILFORD AND
CENTRAL ALAMANCE COUNTIES UNTIL 745 PM EDT...

At 645 PM EDT, a line of thunderstorms extended from near PTI
Airport east to Gibsonville and Burlington, moving southeast at 15
mph.

Frequent lightning will be possible with this storm.

Wind gusts up to 40 mph will be possible with this storm.

Brief heavy rain for 20 to 30 minutes will occur, possibly producing
minor flooding in urban areas.

Locations impacted include...
Greensboro, High Point, Burlington, Graham, Mebane, McLeansville,
Elon College, Gibsonville, Pleasant Garden and Jamestown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter in a nearby building or vehicle.

&&

LAT...LON 3624 7926 3591 7926 3587 7925 3584 7928
      3584 7954 3590 7955 3591 7991 3601 8002
      3625 7936
TIME...MOT...LOC 2245Z 314DEG 14KT 3603 7988

PWB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
807 PM EDT TUE AUG 7 2018

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

0740 PM     TSTM WND DMG     1 S ALAMANCE            36.02N 79.49W
08/07/2018                   ALAMANCE           NC   911 CALL CENTER

            MULTIPLE TREES REPORTED DOWN IN ALAMANCE
            COUNTY, SOUTH OF I-40 AND 85.

&&

JFD

Special Weather Statement
National Weather Service Raleigh NC
816 PM EDT TUE AUG 7 2018

NCZ039-080100-
Randolph NC-
816 PM EDT TUE AUG 7 2018

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN RANDOLPH COUNTY
UNTIL 900 PM EDT...

At 816 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Thomasville, or 11 miles west of Asheboro, moving
east at 10 mph.

Pea size hail and wind gusts up to 50 mph will be possible with this
storm.

Heavy rain and minor flooding and deadly cloud to ground lightning
will also be possible with this storm.

Locations impacted include...
Asheboro, Randleman, North Carolina Zoo and Randleman Regional
Reservior Marina.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter in a nearby building or vehicle. Wind gusts as high as
50 mph are capable of knocking down small or weakened trees and
blowing around trash cans, potted plants, lawn furniture and other
light outdoor objects.

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

&&

LAT...LON 3582 8005 3590 7976 3564 7974 3570 8006
TIME...MOT...LOC 0016Z 266DEG 9KT 3577 8001

77

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
821 PM EDT TUE AUG 7 2018

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

0800 PM     TSTM WND DMG     1 NE HILLSBOROUGH       36.08N 79.08W
08/07/2018                   ORANGE             NC   911 CALL CENTER

            TREE DOWN BLOCKING ROAD AT ST MARYS RD AND
            MILLER RD IN HILLSBOROUGH.

&&

JFD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
824 PM EDT TUE AUG 7 2018

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

0800 PM     TSTM WND DMG     HILLSBOROUGH            36.08N 79.10W
08/07/2018                   ORANGE             NC   911 CALL CENTER

            TREE DOWN ON E KING ST AND S CAMERON ST IN
            HILLSBOROUGH. THE TREE TOOK DOWN POWER LINES
            AND CAUGHT ON FIRE.

&&

JFD