Special Weather Statement, NWS Raleigh, NC

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
346 PM EDT Fri Aug 20 2021

.SYNOPSIS...
Tropical cyclone Henri will move north just off the Atlantic coast
tonight and Saturday. A surface trough across central North Carolina
will move toward the Carolina coast on Saturday. A series of upper
level disturbances will swing across the region through Saturday.
Weak high pressure will settle across the southern Appalachians
early next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 250 PM Friday...

Latest surface analysis shows a weak surface boundary extending
northeast to southwest across the the eastern Carolinas. Surface dew
points near and east of the boundary are in the lower to mid 70s with
a light northerly wind on the backside of the boundary across the
Piedmont where dew points were in the upper 60s to lower 70s.
Further aloft, a series of disturbances rotating around the upper
trough will advance across the mid-Atlantic and Carolinas through
tonight. Given a moist airmass across the area with precipitable
water values ranging from 1.75 inches in the Triad increasing toward
the east and exceeding 2 inches near and east of U.S. route 1 with
the forcing for ascent from the waves in the upper trough, scattered
showers and thunderstorms have developed across central NC early
this afternoon.

Expect the convection to expand in coverage and intensity as the
disturbances push east into a more moist and unstable airmass with
numerous showers and thunderstorms expected across the eastern
Piedmont and Coastal Plain. While the SPC outlook doesn't highlight
a widespread severe threat, a few storms this afternoon and evening
could be severe with the primary threat of damaging winds from wet
microbursts. With the upper trough dropping south, the mid levels
have cooled a bit and with some stronger shear, some hail is also
possible. The main severe weather threat however will be from very
heavy rain producing localized flooding in low-lying and poor
drainage areas or where storms move over the same locations
repeatedly. The greatest storm coverage and intensity will move from
the eastern Piedmont and Sandhills during the mid afternoon toward
the Coastal Plain where the heaviest rain is expected late this
afternoon and early evening and where the greatest flooding threat
is expected. Convective coverage will wane from west to east this
evening with little convection expected overnight after mid night.
Lows tonight will range in the upper 60s in the Triad to the lower
70s elsewhere. -Blaes

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
As of 220 PM Friday...

The southward dropping eastern U.S. upper level trough will close
off by Saturday morning and move slowly east/southeast from WV on
Saturday morning to eastern VA by Sunday morning. The upper level
trough axis across central VA and NC on Saturday morning will shift
slowly east through most of the period. Some drier air will be
advancing east across central NC with afternoon PW values ranging
from 1.5 inches in the Triad to 1.75 inches in the Triangle and
locations south and east. Expect convective coverage to be much
reduced on Saturday vs today with convection favored across the
east, mainly east of U.S route 1 with only slight chance PoPs across
the west. High temperatures will range from the mid 80s across the
north to the upper 80s across the south. Lows on Saturday night will
range in the upper 60s northwest to lower 70s across the southeast.
-Blaes

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 345 PM Friday...

A mid/upper trough will continue to slowly push east across central
and eastern NC on Sunday. At the surface, there will be a lee trough
along with a weak cold front draped over our region. This will
result in isolated to widely scattered showers and storms Sunday
afternoon and evening, with the best coverage along and east of the
front in the Coastal Plain and Sandhills. POPs have increased there
a bit compared to yesterday as the models show a slower eastward
progression of the trough. Dry NW flow aloft will limit convective
development farther west. This mid/upper trough is also causing
Tropical Cyclone Henri to turn to the north, and it is forecast to
track a few hundred miles east of the NC coast on Saturday and into
the southern New England coast late Sunday.

As the trough finally lifts NE off the mid-Atlantic coast on Monday,
it will be replaced by a strengthening mid/upper ridge centered over
the lower Mississippi Valley and Southern Plains. A subtropical
ridge will also strengthen over the western Atlantic. While the
surface boundary will start to wash out, a lee trough will still be
in place, and central NC will be under a mid/upper trough sandwiched
between the two aforementioned ridges. Monday looks to be the
relative driest day, with rising heights and NNW flow aloft, but
some isolated showers and storms are still possible. Again the best
chance for this will be in the Coastal Plain and Sandhills near the
sea breeze and where PW values will be higher. POPs then increase to
the 40-50% range by Wednesday and Thursday as the ridge over the
Southern Plains begins to retrograde west, and the mid/upper trough
over the Southeast US strengthens. In fact, both the GFS and ECMWF
even show potential for a closed low to develop over the Southeast.
However, uncertainty on details this far out is high.

Rising heights will bring temperatures back slightly above average
on Sunday, into the upper-80s to lower-90s. Monday and Tuesday look
to be the hottest days, with highs in the lower-90s in most places,
before decreasing back into the 80s on Thursday/Friday with more
clouds and precipitation. Lows will generally be in the upper-60s to
lower-70s through the period.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
As of 210 PM Friday...

A surface trough across central NC and a series of upper level
disturbances will initiate the development of numerous showers and
thunderstorms across the area this afternoon and continuing into
this evening. Convection will initially be favored across the
southern and Western Piedmont and then shift east and become even
more widespread across the Sandhills and Coastal Plain late this
afternoon and this evening. Adverse aviation conditions with reduced
VSBYs and CIGs along with locally gusty winds are possible with the
convection. The convection will shift east and northeast later this
evening with little convection expected after midnight. Another
period of adverse aviation conditions is expected late tonight and
early Saturday morning with IFR to possibly LIFR stratus and fog
across the area, most favored across the north and northeast.
Conditions will improve on Saturday morning with VFR conditions and
light winds expected by late morning.

Outlook: Expect a chance of widely scattered mainly afternoon and
evening showers and storms across the area during the period with
the greatest coverage across the east. Some late night and daybreak
fog and stratus is also possible. -Blaes

&&

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

&&

SYNOPSIS...Blaes
NEAR TERM...Blaes
SHORT TERM...Blaes
LONG TERM...Danco
AVIATION...Blaes

Hazardous Weather Outlook
National Weather Service Raleigh NC
327 PM EDT Fri Aug 20 2021

NCZ008>011-024>028-040>043-073>078-083>086-088-089-211930-
Granville-Vance-Warren-Halifax-Orange-Durham-Franklin-Nash-Edgecombe-
Chatham-Wake-Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-
Wayne-Anson-Richmond-Scotland-Hoke-Cumberland-Sampson-
327 PM EDT Fri Aug 20 2021

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...This afternoon and tonight.

Heavy downpours and localized flooding are possible in scattered to
numerous thunderstorms through tonight. An isolated strong to severe
storm will also possible through early this evening. The main
threat is expected to be flooding in some urban or poor drainage
areas.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ007-021>023-038-039-211930-
Person-Forsyth-Guilford-Alamance-Davidson-Randolph-
327 PM EDT Fri Aug 20 2021

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...This afternoon and tonight.

Scattered thunderstorms through early this evening may produce some
heavy rain and some accumulation of water in low-lying and poor
drainage areas.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service Raleigh NC
423 PM EDT Fri Aug 20 2021

NCZ088-089-202130-
Sampson NC-Cumberland NC-
423 PM EDT Fri Aug 20 2021

...A strong thunderstorm will impact portions of west central Sampson
and southeastern Cumberland Counties through 530 PM EDT...

At 422 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Fayetteville, moving east at 15 mph.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Eastover, Roseboro, Stedman, Salemburg, Autryville, Vander, Bushy
Lake Natural Area and Cedar Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3485 7850 3485 7877 3496 7888 3508 7881
      3514 7857 3512 7838 3495 7841 3484 7849
TIME...MOT...LOC 2022Z 274DEG 11KT 3499 7880

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

22

Special Weather Statement
National Weather Service Raleigh NC
448 PM EDT Fri Aug 20 2021

NCZ042-043-078-202145-
Johnston NC-Wayne NC-Wilson NC-
448 PM EDT Fri Aug 20 2021

...A strong thunderstorm will impact portions of northeastern Wayne,
southwestern Wilson and northeastern Johnston Counties through 545 PM
EDT...

At 448 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles northeast of Smithfield, moving east at 20 mph.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Goldsboro, Smithfield, Wilson, Fremont, Micro, Selma, Pine Level,
Kenly, Princeton and Lucama.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3530 7801 3550 7843 3573 7825 3573 7819
      3574 7818 3577 7787 3551 7782
TIME...MOT...LOC 2048Z 283DEG 16KT 3561 7822

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

22

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
455 PM EDT FRI AUG 20 2021

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

0407 PM     TSTM WND DMG     3 NW FLOWERS            35.69N 78.39W
08/20/2021                   JOHNSTON           NC   911 CALL CENTER

            ONE TREE WAS REPORTED DOWN ACROSS THE
            ROADWAY NEAR THE INTERSECTION OF LOOP RD AND
            COVERED BRIDGE RD. TIME ESTIMATED BY RADAR.

&&

Special Weather Statement
National Weather Service Raleigh NC
455 PM EDT Fri Aug 20 2021

NCZ008-025-026-041-202145-
Franklin NC-Durham NC-Wake NC-Granville NC-
455 PM EDT Fri Aug 20 2021

...A strong thunderstorm will impact portions of southern Granville,
north central Wake, southeastern Durham and west central Franklin
Counties through 545 PM EDT...

At 455 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Durham. This storm was nearly stationary.

HAZARD...Winds in excess of 30 mph, and heavy rainfall.

SOURCE...Radar indicated.

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

Locations impacted include...
Durham, Creedmoor, Butner, Falls Lake, Falls Lake State Rec Area,
Falls Lake Boat Ramp, Purnell, Gorman and Rollingview Marina.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Heavy rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

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 3591 7877 3601 7892 3622 7868 3607 7844
TIME...MOT...LOC 2055Z 227DEG 4KT 3600 7879

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

CA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
501 PM EDT FRI AUG 20 2021

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

0403 PM     TSTM WND DMG     2 E CLAYTON             35.64N 78.42W
08/20/2021                   JOHNSTON           NC   NWS EMPLOYEE

            MULTIPLE TREES DOWN NEAR THE INTERSECTION OF
            NC-42 E AND GLEN LAUREL RD.

&&

Special Weather Statement
National Weather Service Raleigh NC
537 PM EDT Fri Aug 20 2021

NCZ011-027-028-202215-
Edgecombe NC-Nash NC-Halifax NC-
537 PM EDT Fri Aug 20 2021

...A cluster of strong thunderstorms will impact portions of east
central Nash, Edgecombe and south central Halifax Counties through
615 PM EDT...

At 536 PM EDT, Doppler radar was tracking a cluster of strong
thunderstorms near Rocky Mount, moving east at 5 mph.

HAZARD...Winds in excess of 30 mph, and heavy rainfall.

SOURCE...Radar indicated.

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

Locations impacted include...
Rocky Mount, Tarboro, Enfield, Princeville, Whitakers, Hobgood,
Speed, Leggett, Battleboro and Kingsboro.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Heavy rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

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.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Raleigh.

&&

LAT...LON 3580 7772 3593 7789 3618 7767 3603 7737
      3600 7741 3599 7741 3594 7736 3593 7736
TIME...MOT...LOC 2136Z 266DEG 5KT 3593 7775

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

CA