What forecasters said that day
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Greenville-Spartanburg, SC wrote its last area forecast discussion before the first event at May 3, 10:24 AM EST, 1 hour 15 minutes earlier.
Area forecast discussion, May 3, 10:24 AM EST, 1 hour 15 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1124 AM EDT Mon May 3 2021
.SYNOPSIS...
An upper level disturbance will move northeast across the region
today accompanied by a humid and unstable air mass. Numerous
showers and thunderstorms...a few of them severe...will occur
today and then again on Tuesday as a cold front approaches from
the west. The front should move across the region early in the
day on Wednesday. We may dry out temporarily on Thursday as high
pressure moves past to our north.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1100 am: Broad/moist warm advection regime is resulting in
numerous/widespread coverage of showers along with scattered
thunderstorms across the region this morning. Per the SPC
Mesoanalysis, surface-based buoyancy has been surprisingly high
considering the time of day/relatively cool temps/poor lapse rates,
with 500-1000 J/kg of sbCAPE encompassing much of the forecast area.
This combined with bulk shear of around 40 kts has yielded multiple
(mostly) weakly rotating cells throughout the morning. A two-ish
hour lull in the precip across the southeast quadrant of the CWA may
allow for some modest additional destabilization in those areas over
the next couple of hours before the next round of widespread showers
and storms overspread that area early this afternoon. This may be
enough to allow for an uptick in the potential for severe storms in
those areas during early-to-mid afternoon. Additionally, with the
southern edge of this area of showers likely just skirting the
southern Upstate and Georgia Piedmont zones...and a general absence
of convection south of the forecast area, we are likely to see some
rather robust (i.e., 2000 J/kg, if not higher) sbCAPE develop this
afternoon just south of the area, potentially providing an inflow of
quite unstable air into the SC/GA Lakelands/Piedmont areas, where
shear will be more than adequate for supercells producing an
isolated tornado or two. The severe potential will diminish north of
I-85, but still can't rule out a stray severe storm anywhere in the
forecast area at this point.
The storms should bring a period of heavy rain, and while some
drainage issues are likely to develop in urban areas, the flash
flood threat appears secondary to the severe thunderstorm threat
given the dry conditions as of late. Temps may be kept down a
few degrees compared to yesterday because of the cloud cover
and relatively early precip development. The storms should move
off to the east in the early evening at the latest, and
thereafter we should have a relative lull for the overnight
hours. A chance of showers will be retained over mainly the
southwest mtns of NC because of the continued moist low level SW
flow. Low temps will once again be mild.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 330 AM EDT Monday...Another day with a severe tstm threat
looks on tap for Tuesday, as an upper trough approaches from the
west. The forecast area is expected to be in a humid, warm sector
air mass, with sfc dewpoints in the upper 60s to near 70. Enough
of a lull in precip and some breaks in the clouds should allow
temps to warm into upper 70s to lower 80s and result in sbCAPE over
2000-3000 J/kg by early aftn. Shear looks a little more marginal
than today's (Monday), but still 30-40 kts of 0-6 km bulk shear
across the mountains. The CAMs all have plenty of convection
develop to our west by 18z, then westerly steering flow brings
activity into the forecast area thru the aftn hours. There may
not be enough shear for supercells, but rather more of multicell
clusters. Interestingly, the NAMnest and HRW-NMM have another round
of storms develop near the sfc front over western TN/KY and grow
upscale to a squall line. This line pushes into the NC Mountains
Tuesday evening. For now, confidence in the details is modest at
best, but ingredients are in place for organized severe storms. The
new Day 2 SPC convective outlook has the western 2/3rd of the CWFA
in a slight risk, and a marginal risk east for all but Union County,
NC. Will continue to mention in the HWO. The other concern is any
possible excessive rainfall. While we could see some training storms
within the SWLY flow, the current soil conditions are quite dry,
and anything more than very isolated minor flooding looks unlikely.
The latest model guidance seems to be a little slower on pushing
the cold front thru the area Wednesday, with the NAM especially
slow. All but the GFS have the eastern half of the forecast area
still ahead of the front with sbCAPE of 1000-2000 J/kg and better
bulk shear than we'll have Tuesday. There is the chance though,
that if the NAMnest-like squall line blasts thru the area Tuesday
night, we may not see as much destabilization Wednesday. But in any
case, the new day 3 convective outlook has a marginal risk for the
eastern half of the forecast area, and that seems reasonable. Temps
will be above normal again Wednesday with highs in the lower 80s
east of the mountains. The front should push thru Wednesday night
and bring low temps close to normal.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 300 AM EDT Monday...The medium range starts 12z Thursday
with a digging upper trough across the Ohio Valley, carving out
a longwave trough across the eastern CONUS that persists into the
weekend. The upper flow gradually flattens out over the weekend,
with flat upper ridging returning by Sunday night. There will be
a slug of moisture with the digging trough, bringing a chance of
showers across mainly the NC mountains. Although, the 00z ECMWF has
come in a lot drier for Thu-Thu night. Will feature mainly slight
chc to low-end chc PoPs. Cool high pressure will builds in under
the trough Friday, with the sfc high center reaching the forecast
area by 12z Saturday. Temps will return to slightly below normal,
and there may be some frost concerns in the NC mountains Friday
night. The high drifts east off the Carolina Coast by Sunday and
return flow allows temps to warm back slightly above normal. The
next front looks to stay to our west thru Sunday, but a chance of
showers creeps into our western zones Sunday night.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: An active day shaping up across the
region. Showery precip has already developed in the southerly
moist warm advection upslope/upglide flow near the Blue Ridge
Escarpment. Ceilings are already a mixed bag with many locations
having an MVFR to LIFR restriction. Holes should open up in the
IFR/LIFR by mid/late morning with deep convection developing
rapidly in the increasingly unstable/sheared environment
across the region. Model guidance develops numerous showers and
thunderstorms affecting the terminals from mid-morning through
late afternoon. Have tried to shoot for the most likely 4-hr time
range with a TEMPO at the beginning of the active period. Decided
against PROB30 groups for the stragglers in the late afternoon and
early evening because the TAFs will require several amendments this
morning due to ongoing weather. Expect an improvement to VFR after
storms move off to the east in the late afternoon/early evening. By
the early morning hours on Tuesday, expect the redevelopment of
an IFR ceiling restriction before daybreak. Wind should be S to
SW through the period, and gusty before/during thunderstorms.
Outlook: A cold front will likely bring another round of SHRA/TSRA
to the area by Tue afternoon, with chances persisting into Wed.
Another lull in convection is expected for the end of the week.
Confidence Table...
15-21Z 21-03Z 03-09Z 09-12Z
KCLT High 85% High 100% High 100% Med 67%
KGSP High 81% High 88% High 91% Med 64%
KAVL High 86% High 91% Med 78% Med 69%
KHKY High 88% High 98% High 81% Med 79%
KGMU High 88% High 86% High 90% Med 69%
KAND High 91% High 91% High 95% High 89%
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...PM
NEAR TERM...JDL/PM
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PMHazardous weather outlook, May 3, 4:00 AM EST, 7 hours 39 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
500 AM EDT Mon May 3 2021
GAZ010-017-018-026-028-029-NCZ068>072-082-508-510-SCZ001>014-019-
040900-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Cleveland-Lincoln-
Gaston-Mecklenburg-Cabarrus-Union NC-Greater Rutherford-Eastern Polk-
Oconee Mountains-Pickens Mountains-Greenville Mountains-
Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg-
Cherokee-York-Anderson-Abbeville-Laurens-Union SC-Chester-Greenwood-
500 AM EDT Mon May 3 2021
This Hazardous Weather Outlook is for northeast Georgia, upstate
South Carolina, and the southern foothills and southern Piedmont of
North Carolina, including the Charlotte metro area.
.DAY ONE...Today and tonight.
Numerous thunderstorms are expected to develop across the region
later this morning and through the afternoon hours. Enough
instability and wind shear will be present for some of the storms to
become severe this afternoon, perhaps as a squall line that moves
east across the area along and southeast of Interstate 85. The
stronger storms will produce damaging wind gusts and hail the size
of quarters or larger. An isolated tornado will also be possible. The
thunderstorms should move away during the early part of the evening.
.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.
A cold front approaching from the west will be the trigger for another
round of strong to severe thunderstorms during the afternoon and
evening hours on Tuesday. The storms will increase the threat for
isolated flash flooding across areas that see storms with heavy rain
on Monday. The cold front could trigger isolated severe thunderstorms
east of the mountains again on Wednesday as it crosses the region.
.SPOTTER INFORMATION STATEMENT...
Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.
NCZ033-035>037-048>053-056>059-062>065-501>507-509-040900-
Avery-Alexander-Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-
Buncombe-Catawba-Rowan-Graham-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-Caldwell Mountains-
Greater Caldwell-Burke Mountains-Greater Burke-McDowell Mountains-
Eastern McDowell-Rutherford Mountains-Polk Mountains-
500 AM EDT Mon May 3 2021
This Hazardous Weather Outlook is for the mountains, northern
foothills, and northwest Piedmont of North Carolina.
.DAY ONE...Today and tonight.
Numerous thunderstorms are expected to develop across the region
later this morning and through the afternoon hours. Enough
instability and wind shear will be present for some of the storms to
become severe this afternoon. A few of the storms will become strong
enough to produce damaging wind gusts and hail the size of quarters
or larger. Any of the storms will have frequent cloud-to-ground
lightning and heavy downpours of rain. The thunderstorms should move
away during the late afternoon.
.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.
A cold front approaching from the west will be the trigger for
another round of strong to severe thunderstorms during the afternoon
and evening hours on Tuesday. The storms will increase the threat for
isolated flash flooding across areas that see storms with heavy rain
on Monday. The cold front should move across the mountains early on
Wednesday.
.SPOTTER INFORMATION STATEMENT...
Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.
In the hours before
Special weather statement, May 3, 7:30 AM EST, 4 hours 9 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
830 AM EDT Mon May 3 2021
NCZ037-031300-
Davie NC-
830 AM EDT Mon May 3 2021
...A STRONG THUNDERSTORM WILL IMPACT NORTHERN DAVIE COUNTY UNTIL 900
AM EDT...
At 829 AM EDT, Doppler radar was tracking a strong thunderstorm 6
miles north of Mocksville, moving northeast at 35 mph.
Locations to be impacted include...
Bermuda Run, Farmington and Sheffield.
Wind gusts up to 40 mph 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.
Doppler radar indicates weak rotation with this storm. Spin-up of a
very brief, weak tornado cannot be ruled out. Be prepared to take
immediate action if a tornado is sighted or a Tornado Warning is
issued.
&&
LAT...LON 3599 8042 3592 8066 3596 8070 3605 8067
3605 8050 3604 8049 3606 8046 3605 8046
3600 8041
TIME...MOT...LOC 1229Z 236DEG 31KT 3598 8059
KRENTZSpecial weather statement, May 3, 8:30 AM EST, 3 hours 9 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
930 AM EDT Mon May 3 2021
NCZ068-SCZ008-031400-
Cleveland NC-Cherokee SC-
930 AM EDT Mon May 3 2021
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CLEVELAND AND
NORTHEASTERN CHEROKEE COUNTIES UNTIL 1000 AM EDT...
At 930 AM EDT, Doppler radar was tracking a strong thunderstorm 6
miles southeast of Shelby, or near Patterson Springs, moving
northeast at 40 mph.
Locations to be impacted include...
Grover, Patterson Springs, Earl, Blacksburg, Kings Mountain and
Crowders Mountain State Park.
Wind gusts up to 45 mph will be possible in these areas.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.
&&
LAT...LON 3517 8133 3516 8136 3517 8137 3516 8137
3511 8157 3519 8160 3532 8141
TIME...MOT...LOC 1330Z 242DEG 35KT 3521 8148
KRENTZSpecial weather statement, May 3, 8:45 AM EST, 2 hours 54 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
945 AM EDT Mon May 3 2021
NCZ068-070-031430-
Gaston NC-Cleveland NC-
945 AM EDT Mon May 3 2021
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CLEVELAND AND
CENTRAL GASTON COUNTIES UNTIL 1030 AM EDT...
At 945 AM EDT, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Shelby, or near Kings Mountain, moving northeast
at 35 mph.
Locations to be impacted include...
Gastonia, Kings Mountain, Bessemer City, South Gastonia, Dallas,
Cramerton, Lowell, Ranlo, High Shoals and Crowders Mountain State
Park.
Wind gusts up to 45 mph will be possible in these areas.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.
&&
LAT...LON 3521 8105 3516 8134 3517 8134 3517 8145
3524 8147 3541 8125 3541 8120
TIME...MOT...LOC 1345Z 243DEG 29KT 3522 8138
KRENTZSpecial weather statement, May 3, 9:15 AM EST, 2 hours 24 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1015 AM EDT Mon May 3 2021
NCZ069>071-031445-
Gaston NC-Lincoln NC-Mecklenburg NC-
1015 AM EDT Mon May 3 2021
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN LINCOLN...
NORTHWESTERN MECKLENBURG AND GASTON COUNTIES UNTIL 1045 AM EDT...
At 1014 AM EDT, Doppler radar was tracking a strong thunderstorm near
Gastonia, moving northeast at 30 mph.
Locations to be impacted include...
Gastonia, Uptown Charlotte, Huntersville, Northeast Charlotte,
Northwest Charlotte, Cornelius, Mt Holly, Belmont, Bessemer City and
South Gastonia.
Wind gusts up to 45 mph 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 3515 8111 3516 8119 3516 8123 3529 8130
3550 8096 3549 8094 3551 8091 3551 8087
3526 8069
TIME...MOT...LOC 1414Z 241DEG 28KT 3524 8114
KRENTZSpecial weather statement, May 3, 10:58 AM EST, 41 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1158 AM EDT Mon May 3 2021
NCZ056-068>070-504-508-SCZ008-009-013-031630-
Greater Rutherford NC-Gaston NC-Cleveland NC-Lincoln NC-
Greater Burke NC-Catawba NC-York SC-Cherokee SC-Union SC-
1158 AM EDT Mon May 3 2021
...A CLUSTER OF THUNDERSTORMS WILL IMPACT SOUTHWESTERN CATAWBA...
NORTHEASTERN RUTHERFORD...WESTERN LINCOLN...CLEVELAND...WESTERN
GASTON...SOUTHEASTERN BURKE...NORTHWESTERN YORK...EASTERN CHEROKEE
AND NORTH CENTRAL UNION COUNTIES UNTIL 1230 PM EDT...
At 1158 AM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from near Forest City to 6
miles north of Gaffney to 11 miles southwest of Union, and moving
northeast at 35 mph.
Locations to be impacted include...
Shelby, Lincolnton, Union, Gastonia, Kings Mountain, Cherryville,
Bessemer City, Valdese, Icard and Blacksburg.
Wind gusts up to 45 mph 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 8121 3508 8125 3465 8174 3520 8157
3549 8182 3578 8155 3578 8147
TIME...MOT...LOC 1558Z 222DEG 29KT 3535 8186 3516 8163 3464 8180
KRENTZSpecial weather statement, May 3, 11:24 AM EST, 15 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1224 PM EDT Mon May 3 2021
NCZ035-056-068>071-502-504-SCZ008-031715-
Gaston NC-Cleveland NC-Lincoln NC-Greater Burke NC-
Greater Caldwell NC-Mecklenburg NC-Alexander NC-Catawba NC-
Cherokee SC-
1224 PM EDT Mon May 3 2021
...A CLUSTER OF THUNDERSTORMS WILL IMPACT CATAWBA...SOUTHWESTERN
ALEXANDER...LINCOLN...SOUTHEASTERN CALDWELL...NORTHWESTERN
MECKLENBURG...SOUTHEASTERN CLEVELAND...GASTON...SOUTHEASTERN BURKE
AND NORTHEASTERN CHEROKEE COUNTIES UNTIL 115 PM EDT...
At 1224 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 11 miles southwest of
Hickory to near Lincolnton to 11 miles southeast of Shelby, and
moving northeast at 30 mph.
Locations to be impacted include...
Gastonia, Hickory, Newton, Lincolnton, Taylorsville, Huntersville,
Kings Mountain, St. Stephens, Conover and Cherryville.
Wind gusts up to 45 mph 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 3594 8118 3579 8110 3578 8111 3574 8107
3553 8095 3550 8096 3550 8093 3542 8089
3516 8132 3517 8137 3511 8140 3508 8146
3543 8137 3572 8161
TIME...MOT...LOC 1624Z 223DEG 25KT 3565 8150 3549 8129 3515 8141
KRENTZ