Hail in North Carolina, May 10, 2021

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
633 PM EDT Mon May 10 2021

.SYNOPSIS...
A cold front will become stationary from the Gulf Coast to South
Carolina and remain near the area through Wednesday.  Relatively dry
high pressure builds in from the north on Thursday and lingers into
the weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 630 PM EDT: Within the western periphery of the deep shear and
waning sbcape values along and east of I-77, there remains the
chance of isolated strong storms until 01/02z.

Otherwise, tonight, the 850 mb baroclinic zone gets hung up over the
forecast area, with intermittent upglide keeping clouds in place and
producing some spotty light precipitation. Focus PoPs near the
escarpment where low level convergence should maximize. Insulation
effects of the cloud cover will offset the cooler airmass filtering
into the region with lows in the 50s to near 60.

Tuesday it appears upglide will weaken and we'll likely see breaks
in the clouds by the afternoon. Weak cold air advection and the
cloud cover should keep us a bit below normal. A secondary
disturbance may support increasing upglide and shower activity by
early Tuesday evening.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 130 PM EDT Monday...starting Tuesday evening, the 500mb
pattern becomes increasingly zonal as the frontal boundary sets up
stagnant to our south and east.  This persists until Wednesday
afternoon, when the relaxed upper flow gives way to a vort lobe
creeping out of the southern stream and leading to a peak in upper
forcing on Wednesday afternoon...especially across NE GA and the SC
Upstate. After this, we'll have a brief period of CAA, ushering in
somewhat drier air and cutting off the rain chances for a bit.  We
should see a relatively tight pressure gradient over the mountains
as we are postfrontal at this point, but it's not that impressive
and likely won't warrant an advisory.  We should continue to see
ripples of QG forcing coming out of the southern stream on Wednesday
evening, before a highly elongated trough over the Mid-Atlantic
pushes offshore and carries the better dynamics with it. Any
recovery in heights will be short-lived, as by Thursday evening a
shortwave will be approaching out of the Ozarks. So, with
competition between improving forcing and still-only-modest PWATs,
I'd anticipate a bit of a lull in PoPs early Thursday, ramping back
up in the afternoon as the shortwave rolls in and moist advection
kicks back in.  At this point, I've kept chance PoPs in the grids
through the end of the short term.

Temperature-wise, we can expect below-normal temps through the short
term.  On Wednesday, CAA combined with limited insolation should
keep temps more than 10 degrees below normal...and on Thursday,
cloud cover should continue to suppress daytime heating even as the
cessation of CAA allows temperatures to creep somewhat closer to
normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 145 PM EDT Monday...as the trough axis crosses over the CWA on
Thursday night, we should see a quick return to calm conditions
Friday afternoon as the upper pattern gives way to gently rising
heights ahead of a broad ridge pushing out of the west-central
CONUS.  For now, it's looking like the QPF response on Thursday
night will be fairly light - no more than a tenth of an inch
anywhere - with both the GFS and ECMWF depicting the brunt of even
that precip taking place in the NC mountains.  There's a fair bit of
uncertainty in the details are models are beginning to diverge at
this point, but in broad strokes, it appears that the weekend will
be dominated by ridging and the arrival of a broad Canadian surface
high, possibly continuing into the start of next week.  On Friday
night/Saturday morning, a weak embedded shortwave may spur some
showers, once again restricted to the NC mountains. Past this,
models disagree concerning PWATs, with the ECMWF keeping us dry
through to early Monday, and the GFS giving us a wetting rain late
Sunday.

Temperatures will slowly climb toward normal each day in the
extended, starting out several degrees below normal on Thursday, and
finally reaching a near-normal high in the upper 70s on Sunday.
afternoon.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Sole concern for additional deep convection
will be limited to KCLT through 01z.  Elsewhere across the FA, wind
shift to westerly then northerly is expected coincident with the
southward progression of surface cold front. Weak upglide may
reintroduce showers to the area but if this occurs it'd probably be
after 04Z. Any low cigs that do form may be slow to lift/scatter out
tomorrow as a stable airmass is maintained with N/E winds.

Outlook: A stalled frontal zone near, or just south of the area
periodic low cigs/vsbys and shra is expected to continue through
Thursday. This should be followed by gradual late week drying into
the weekend.

Confidence Table...

            22-04Z        04-10Z        10-16Z        16-18Z
KCLT       High 100%     High 100%     Med   65%     Med   63%
KGSP       High 100%     High 100%     Med   60%     High  94%
KAVL       High 100%     High  97%     Med   72%     High  97%
KHKY       High 100%     High 100%     High  95%     High  86%
KGMU       High 100%     High 100%     Med   60%     High  94%
KAND       High 100%     High 100%     Med   62%     Med   61%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

SYNOPSIS...DEO
NEAR TERM...CSH/Munroe
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...CSH/Munroe

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
627 PM EDT Mon May 10 2021

NCZ036-057-069>072-082-SCZ008-009-013-014-112230-
Iredell-Rowan-Lincoln-Gaston-Mecklenburg-Cabarrus-Union NC-Cherokee-
York-Union SC-Chester-
627 PM EDT Mon May 10 2021

This Hazardous Weather Outlook is for piedmont North Carolina and
upstate South Carolina.

.DAY ONE...Tonight.

A few thunderstorms will develop ahead of cold front into the early
evening. A few of these storms may become severe and be capable of
producing large hail and damaging winds. Cloud to ground lightning
will also be a threat.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-018-026-028-029-NCZ033-035-037-048>053-056-058-059-
062>065-068-501>510-SCZ001>007-010>012-019-112230-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-Davie-
Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-Graham-
Northern Jackson-Macon-Southern Jackson-Transylvania-Henderson-
Cleveland-Caldwell Mountains-Greater Caldwell-Burke Mountains-
Greater Burke-McDowell Mountains-Eastern McDowell-
Rutherford Mountains-Greater Rutherford-Polk Mountains-Eastern Polk-
Oconee Mountains-Pickens Mountains-Greenville Mountains-
Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg-
Anderson-Abbeville-Laurens-Greenwood-
627 PM EDT Mon May 10 2021

This Hazardous Weather Outlook is for northeast Georgia, piedmont
North Carolina, western North Carolina and upstate South Carolina.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
600 PM EDT Mon May 10 2021

NCZ069>071-102230-
Gaston NC-Lincoln NC-Mecklenburg NC-
600 PM EDT Mon May 10 2021

...A STRONG THUNDERSTORM WILL IMPACT EASTERN LINCOLN...NORTHWESTERN
MECKLENBURG AND NORTHEASTERN GASTON COUNTIES UNTIL 630 PM EDT...

At 559 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Huntersville, or near Westport, moving east at 15 mph.

Locations to be impacted include...
Huntersville, Cornelius, Davidson, Westport, Denver, Ramsey Creek
Park, Northeast Charlotte, Northwest Charlotte, Lake Norman and
Lowesville.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

Lake Norman is in the path of this storm. Cloud to ground lightning
and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3527 8083 3538 8109 3555 8104 3554 8095
      3553 8094 3553 8095 3552 8096 3550 8096
      3549 8095 3551 8091 3551 8078 3549 8079
      3545 8077
TIME...MOT...LOC 2159Z 289DEG 12KT 3545 8099

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
627 PM EDT Mon May 10 2021

NCZ069>072-102300-
Gaston NC-Lincoln NC-Cabarrus NC-Mecklenburg NC-
627 PM EDT Mon May 10 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN CABARRUS...EASTERN
LINCOLN...NORTHWESTERN MECKLENBURG AND NORTHEASTERN GASTON COUNTIES
UNTIL 700 PM EDT...

At 627 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles west of Huntersville, or near Ramsey Creek Park, moving east at
15 mph.

Locations to be impacted include...
Huntersville, Kannapolis, Northeast Charlotte, Cornelius, Davidson,
Westport, University City, Coddle Creek Reservoir, Denver and Hidden
Valley.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

Lake Norman is in the path of this storm. Cloud to ground lightning
and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3524 8074 3540 8109 3555 8111 3553 8094
      3553 8096 3551 8096 3549 8095 3551 8091
      3550 8063
TIME...MOT...LOC 2227Z 289DEG 12KT 3544 8092

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
634 PM EDT Mon May 10 2021

NCZ036-057-102300-
Rowan NC-Iredell NC-
634 PM EDT Mon May 10 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN IREDELL AND
SOUTHWESTERN ROWAN COUNTIES UNTIL 700 PM EDT...

At 633 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles south of Statesville, or near Troutman, moving east at 15 mph.

Locations to be impacted include...
Statesville, Mooresville, Enochville, Troutman, Cleveland, Lake
Norman State Park, Lake Norman, Mount Ulla, Piedmont Research Station
and Doolie.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

&&

LAT...LON 3551 8066 3551 8078 3558 8094 3559 8093
      3561 8094 3562 8092 3564 8095 3580 8086
      3572 8057
TIME...MOT...LOC 2233Z 289DEG 12KT 3566 8086

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
732 PM EDT Mon May 10 2021

NCZ036-056-110000-
Iredell NC-Catawba NC-
732 PM EDT Mon May 10 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN CATAWBA AND CENTRAL
IREDELL COUNTIES UNTIL 800 PM EDT...

At 732 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles west of Statesville, or near Catawba, moving east at 20 mph.

Locations to be impacted include...
Statesville, Troutman, Catawba, Lookout Shoals Lake, Lake Norman
State Park, Mooresville, Lake Norman, Bandys, Scotts and Sherrills
Ford.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

Lookout Shoals Lake is in the path of this storm. Cloud to ground
lightning and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3569 8077 3567 8077 3561 8076 3564 8113
      3581 8114 3580 8113 3579 8113 3578 8111
      3580 8108 3581 8108 3583 8106 3588 8078
TIME...MOT...LOC 2332Z 276DEG 18KT 3574 8104

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
801 PM EDT Mon May 10 2021

NCZ036-056-057-110030-
Rowan NC-Iredell NC-Catawba NC-
801 PM EDT Mon May 10 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CATAWBA...SOUTHERN
IREDELL AND WESTERN ROWAN COUNTIES UNTIL 830 PM EDT...

At 800 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles south of Statesville, or near Lake Norman State Park, moving
east at 20 mph.

Locations to be impacted include...
Statesville, Mooresville, Enochville, Troutman, Cleveland, Lake
Norman, Lake Norman State Park, Sherrills Ford, Mount Ulla and
Terrell.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Lake Norman is in the path of this storm. Cloud to ground lightning
and gusty winds will create dangerous boating conditions. Move to
shore immediately.

&&

LAT...LON 3551 8065 3551 8073 3556 8103 3577 8102
      3581 8063
TIME...MOT...LOC 0000Z 291DEG 16KT 3568 8094

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
835 PM EDT Mon May 10 2021

NCZ036-057-110100-
Rowan NC-Iredell NC-
835 PM EDT Mon May 10 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN IREDELL AND
SOUTHWESTERN ROWAN COUNTIES UNTIL 900 PM EDT...

At 835 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles south of Statesville, or near Mooresville, moving southeast at
15 mph.

Locations to be impacted include...
Kannapolis, Mooresville, China Grove, Landis, Enochville, Lake Norman
State Park, Lake Norman, Mount Ulla and Doolie.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

LAT...LON 3550 8063 3551 8090 3558 8095 3559 8093
      3561 8094 3562 8092 3565 8096 3572 8083
      3557 8055
TIME...MOT...LOC 0035Z 312DEG 12KT 3561 8085

RWH