Severe Thunderstorm Warning 121, NWS Raleigh, NC

Area Forecast Discussion
National Weather Service Raleigh NC
912 AM EDT Sun Jul 9 2023

.SYNOPSIS...
A series of upper troughs will move across the Carolinas today and
Monday.  The first one will result in a line of strong thunderstorms
crossing central North Carolina today.  The second one will push a
cold front through the area on Monday.  High pressure will move into
our area for Tuesday and Wednesday.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 912 AM Sunday...

Water vapor/radar imagery this morning depicted an area of
showers/thunderstorms over the NC foothills/Blue Ridge mountains.
This activity is associated with a shortwave perturbation poised to
move across NC/VA over the next several hours. While considerable
cloud cover was evident over our area this morning, we are starting
to see some clearing out ahead of this feature. As such, as this
upper wave moves eastward, still expecting enough destablization to
aid in thunderstorm intensification with any cells that push through
our area today.

Latest high-res guidance has been pretty consistent in moving
convection into the Triad region between ~16 to 18Z, the Triangle
~19 to 21Z, and the Coastal Plain ~20 to 23Z. Given how early this
activity is expected to reach our western zones, think the severe
threat there is less so there compared to locations east of US-1.
Bulk layer shear of ~25 to 35 kts will accompany the progressing
short wave which could help to promote a few strong to severe storms
along and east of US-1. Soundings suggest uni-lateral profiles with
height which would indicate a primarily damaging wind gust threat
with any stronger cells today. Otherwise, cells should be moving
relatively fast enough to preclude a widespread flash flooding
threat. However, given the presence of high PWAT (~1.75 inches) and
somewhat north-south storm motion vectors (conducive to some
training), any stronger cells could produce heavy downpours which
could lead to isolated instances of flash flooding especially in
urban areas.

The initial band of convection should push east of our area by late
afternoon/early evening. A trailing cool front and an additional
short wave (currently over OK) will then push through our area
overnight.  Lingering MUCAPE along the boundary could promote
additional scattered rounds of showers/storms overnight, but the
overall severe threat should be limited with this activity. However,
depending on how much QPF is realized today, there could continue to
be an isolated threat for flash flooding in urban areas through
Monday morning.

Temps today will range between the lower 80s northwest to around 90
across our far southeast zones. Overnight lows in the lower 70s.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 330 AM Sunday...

The s/w trough and assoc sfc cold front moving across central NC
late tonight and early Monday morning will cross our Coastal Plain
counties during the late-morning Monday then exit to our east Monday
afternoon. Will need to keep low-end PoPs in our grids through at
least early afternoon or until the trough axis moves through.
However, with most of the models showing good subsidence and drying
behind the trough, we should see quick clearing tomorrow afternoon
from west to east. This late-day clearing will result in a somewhat
atypical geographical summertime high temperature profile, with the
warmest readings (mid-upper 80s for highs) across our Triad zones
with coolest readings east (low-mid 80s) due to prolonged cloudiness
and later clearing.

Dwpts will quickly fall behind the front Monday afternoon, reaching
the mid-upper 50s (west) to lower 60s (east) by sunset.  Lower dwpts
coupled with mainly clear and calm night will set us up for a more
comfortable night of relatively cooler readings.  Lows early Tuesday
morning will bottom out in the low-mid 60s...coolest across our
Triad and northern zones.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 330 AM Sunday...

The extended forecast begins with the first mostly dry pattern
compared to the past couple of weeks. The main synoptic cold front
will be well through central NC by Tuesday morning arcing back into
southern SC and central GA. Aloft, shortwave ridging in the the wake
of the departing deepening upper trough will lead to steady H5
height rises through Wednesday night. A weak transient surface high
pressure will progress over the area before pushing off the coast
late Wednesday along with PWAT values falling to 1-1.5 inches will
result in a mostly dry forecast. Some isolated showers can't be
completely ruled out over the Coastal Plain forced along the sea-
breeze and weak MLCAPE values (around 500 J/kg) during the afternoon
hours. However, point sounding highlight a stout 700mb subsidence
inversion and abundant dry air aloft, even along the coast, which
will both work to inhibit any deep convection fairly substantially.
Highs quickly rebound back into the low/mid 90s with lows
temperatures coolest Tuesday night into Wednesday morning with
low/mid 60s possible in the coolest spots and mid/upper 60s expected
in urban areas.

From Thursday onward, the upper level pattern remains persistent as
the sub-tropical high over the Desert Southwest shifts east and
elongates over the GOM states as the broad and deep closed-low over
northern portions of Canada sinks south into western Ontario by
Saturday. The main forecast concern will be the increasing
temperatures and the heat related effects heading into the weekend.
As the sub-tropical high begins to nose into our area due to down
stream amplification over the eastern CONUS, 500mb heights rise to
590-593dam and 850mb temps rise to 20-22C by the weekend based on
the grand-ensemble mean (combination of all GEFS, EPS, and CMCE
ensemble members). Additionally, ensemble guidance is highlighting
probabilities of greater than 95 degrees 30-40% on Friday and 40-50%
on Saturday, with probabilities of 100 degrees or higher around 5-
15% for Saturday (greatest probabilities across the Sandhills and
southern Piedmont). There are still quite a few forecast wrinkles
that need to be ironed out between now and then, but confidence is
increasing for temperatures to rise into the mid/upper 90s by next
weekend given the signals in ensemble guidance. There will also be a
threat for showers/storms each afternoon with the return of the hot
and humid airmass and perturbed westerly flow directed into the
southern Mid-Atlantic.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
As of 632 AM Sunday...

Through 12Z Monday:  Scattered patches of LIFR fog are occurring
attm across parts of central NC attm.  Look for this to continue for
a while longer, but should begin to quickly burn off after sunrise
given the very thin/shallow nature of the fog/stratus.  Later this
morning, scattered showers/tstms are expected to move from western
NC into and across central NC, first in the Triad region (KINT/KGSO)
between 16-18Z, then across the KRDU area between 18-21Z, and
finally KRWI and KFAY between 20-23Z. IFR conditions and brief gusty
sfc winds are expected in and near the tstm activity. Flt conditions
will improve after 00Z Monday, however that may be short-lived as a
secondary area of showers may begin crossing central NC around 06Z
Monday.

After 12Z Monday:  A band of showers will move across central NC
between 06-18Z Monday as the upper trough axis and sfc cold front
move across the region.  Then after the passage of the trough, drier
air will move into the area with mostly VFR conditions from mid-day
Monday through the mid-week period.

&&

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

&&

SYNOPSIS...np
NEAR TERM...Luchetti
SHORT TERM...np
LONG TERM...Swiggett
AVIATION...np

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Special Weather Statement
National Weather Service Raleigh NC
1021 AM EDT Sun Jul 9 2023

NCZ021-091445-
Forsyth NC-
1021 AM EDT Sun Jul 9 2023

...A strong thunderstorm will impact portions of Forsyth County
through 1045 AM EDT...

At 1021 AM EDT, Doppler radar was tracking a strong thunderstorm over
Enon, or near East Bend, moving east at 35 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail and heavy
         rainfall.

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...
Winston-Salem, Kernersville, Clemmons, Bermuda Run, Huntsville,
Lewisville, Walkertown, Pfafftown and Sedge Garden.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential 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 3611 8050 3612 8046 3614 8044 3621 8004
      3601 8005 3603 8014 3603 8021 3600 8022
      3600 8032 3598 8037 3598 8041 3601 8042
      3603 8045 3606 8046 3606 8047 3604 8049
      3606 8051 3609 8052
TIME...MOT...LOC 1421Z 264DEG 31KT 3612 8048

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

CA

Special Weather Statement
National Weather Service Raleigh NC
1048 AM EDT Sun Jul 9 2023

NCZ021-022-091530-
Guilford NC-Forsyth NC-
1048 AM EDT Sun Jul 9 2023

...A strong thunderstorm will impact portions of Forsyth and northern
Guilford Counties through 1130 AM EDT...

At 1048 AM EDT, Doppler radar was tracking a strong thunderstorm over
Winston-Salem, moving east at 30 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel 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...
Greensboro, Winston-Salem, Kernersville, Clemmons, Bermuda Run,
Lewisville, Summerfield, Stokesdale, Walkertown and Rural Hall.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential 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 3612 8046 3614 8044 3620 8044 3626 8030
      3625 7979 3617 7964 3602 8014 3603 8021
      3600 8022 3599 8024 3600 8032 3597 8039
      3598 8041 3601 8042 3603 8044 3611 8049
TIME...MOT...LOC 1448Z 253DEG 27KT 3613 8029

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

CA

Preliminary Local Storm Report
National Weather Service Raleigh NC
1057 AM EDT Sun Jul 9 2023

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

1020 AM     Tstm Wnd Dmg     2 SSE Donnaha           36.20N 80.41W
07/09/2023                   Forsyth            NC   911 Call Center

            Tree reported down on 8900 block of Reynolda
            Road.

&&

NTL

Special Weather Statement
National Weather Service Raleigh NC
1115 AM EDT Sun Jul 9 2023

NCZ038-091600-
Davidson NC-
1115 AM EDT Sun Jul 9 2023

...A strong thunderstorm will impact portions of northern Davidson
County through NOON EDT...

At 1115 AM EDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Mocksville, moving east at 40 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel 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...
High Point, Lexington, Thomasville, Welcome and Arcadia.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3584 8048 3583 8046 3583 8043 3585 8042
      3585 8039 3587 8039 3588 8042 3589 8041
      3589 8037 3596 8038 3597 8040 3598 8036
      3600 8022 3601 8021 3602 8012 3601 8004
      3580 8005 3579 8005 3577 8045 3583 8049
TIME...MOT...LOC 1515Z 268DEG 37KT 3587 8041

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

CA