A surface front edging south across SE Georgia combined with a passing mid level short wave trough triggered a few strong to isolated severe storms over a moist and unstable airmass.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS JAX wrote it up.
A surface front edging south across SE Georgia combined with a passing mid level short wave trough triggered a few strong to isolated severe storms over a moist and unstable airmass.
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 Jacksonville, FL wrote its last area forecast discussion before the first event at May 12, 2:27 PM EST, 48 minutes earlier.
Area Forecast Discussion
National Weather Service Jacksonville FL
327 PM EDT Wed May 12 2021
.NEAR TERM [Through Tonight]...
A slow moving cold front stretches across Srn SC and central GA
this afternoon, a little south of an arc from near Charleston, SC
to near Warner Robins. South of this front, our area remains in a
warm, humid, moderately unstable airmass. RAP analysis data shows
ML CAPE values in NE FL and coastal SE GA to be around 1000-1500
J/kg with effective bulk shear around 35-40 knots. There's a
Marginal Risk of severe storms, with the main hazards being gusty
winds and small hail. The greater risk area for more intense
storms is still along the I-95 corridor of NE FL where sea breeze
is pinned close to the coastline and easterly low level flow is
in place beneath westerly mid-level flow, leading to directional
vertical shear as well as slightly stronger speed shear (45 kts).
The cold front boundary will sink steadily south through our area
overnight tonight, but thick low level clouds and lingering rain
showers behind the front could last into Thursday morning,
resulting in moderated low temperatures tonight. Lows will be in
the low-mid 50s in SE GA, and in the 60s in NE FL.
.SHORT TERM [Thursday Through Friday Night]...
A bit of a tricky forecast for Thursday. The cold front is poised
to push just south of our forecast area by Thursday morning, but
with strong northeasterly onshore flow behind the front, we may
be stuck under a thick deck of low level clouds with light rain
showers or drizzle hanging in through much of the day. How long
we're stuck in those breezy, cloudy, drizzly conditions will
determine how much we will actually warm up on Thursday. Model
guidance has been pretty consistent with highs in the low-mid 60s
in SE GA over the last several runs, but how far south those temps
in the 60s will dig has been more up in the air. Current forecast
roughly keeps those 60s along and north of I-10, with temperatures
warming into the 70s south of I-10.
Showers should exit offshore Thursday night, with drier conditions
anticipated for Friday. As a ridge of low level high pressure
moves eastward, a cooler, drier air mass will push in. Friday
should be nice day with clearing skies and highs in the mid-upper
70s over most of the area, around 80 near Ocala and Gainesville.
Lows will be mostly in the 50s both nights, with low 60s near the
beaches.
.LONG TERM [Saturday Through Wednesday]...
Deep layer ridging forecast over the area for this weekend, with
the low level ridge centered over the TN Valley Saturday and the
upper level ridge axis over the north-central Gulf coast Saturday,
with both sliding eastward through the weekend. Under mostly sunny
skies, temperatures will gradually warm, with highs forecast to
return to the 80s across the area on Sunday afternoon and upper
80s to low 90s forecast Tuesday and Wednesday. Winds will become
more easterly next week as the ridge continues to roll eastward
and when combined with the increasing temperatures will likely
lead to the return of scattered seabreeze showers and
thunderstorms around mid-week.
&&
.AVIATION...
[Through 18Z Thursday]
VFR conditions continues through the afternoon. Widely scattered
TSRA possible near TAF sites...with best chance being in the 21z-
02z period, which is the focus of TEMPO group for TSRA and MVFR
CIGs. Cold front moves across the TAF sites this
evening...shifting surface winds to northerly. Latest guidance
suggests an MVFR CIG spreads over TAF sites after front passes.
&&
.MARINE...
A cold front lies just north of our coastal waters this afternoon
and will continue to nudge south into Georgia waters this
evening and the northeast Florida waters overnight. Ahead of the
front, showers and thunderstorms will increase over the waters
and will continue to move south through tonight. Behind the front,
shower activity may continue to linger through Thursday
afternoon. Winds will shift to the northeast and increase in speed
behind the front, allowing seas to build as well. Small Craft
Advisory conditions will develop tonight and last into Friday
night.
Rip Currents: Moderate risk of rip currents this afternoon, high
risk of rip currents tomorrow at all area beaches.
&&
.FIRE WEATHER...
Rounds of showers and thunderstorms will continue through tonight
ahead of an approaching cold front, with lingering showers
possible behind the front tomorrow. Strong northeast winds are
forecast along the coastline from Thursday through much of the
weekend, but further inland winds will be lower, and when combined
with low mixing heights, will lead to low-end daytime dispersions
(around 20-30) across inland portions of the area Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 52 64 51 75 50 / 50 40 10 0 0
SSI 59 66 59 73 61 / 70 60 10 0 0
JAX 60 67 57 75 58 / 50 50 10 10 0
SGJ 66 71 62 74 63 / 50 50 20 10 0
GNV 63 74 56 79 55 / 30 40 10 0 0
OCF 67 79 60 81 57 / 30 40 10 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory from 6 AM Thursday to 8 AM EDT Saturday for
Coastal waters from Fernandina Beach to St. Augustine FL
out 20 NM-Coastal waters from St. Augustine to Flagler
Beach FL out 20 NM-Waters from Fernandina Beach to St.
Augustine FL from 20 to 60 NM-Waters from St. Augustine to
Flagler Beach FL from 20 to 60 NM.
Small Craft Advisory until 8 AM EDT Saturday for Coastal waters
from Altamaha Sound to Fernandina Beach FL out 20 NM-Waters
from Altamaha Sound GA to Fernandina Beach FL from 20 to 60
NM.
&&Special Weather Statement
National Weather Service Jacksonville FL
302 PM EDT Wed May 12 2021
FLZ023-024-030-031-232-425-GAZ364-121945-
Baker FL-Western Clay FL-Union FL-Western Duval FL-Inland Nassau FL-
Bradford FL-Western Charlton GA-
302 PM EDT Wed May 12 2021
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN NASSAU...
NORTHEASTERN BRADFORD...SOUTHEASTERN BAKER...NORTHEASTERN UNION...
NORTHWESTERN CLAY...SOUTHWESTERN DUVAL AND SOUTH CENTRAL CHARLTON
COUNTIES UNTIL 345 PM EDT...
* At 302 PM EDT, National Weather Service meteorologists were
tracking thunderstorms centered near Glen St. Mary, or 9 miles
northeast of Raiford, moving northeast at 25 mph.
* Winds in excess of 40 mph possible with these storms.
* Locations impacted include...
Macclenny, Glen St. Mary, Cecil Field, Maxville, Sanderson, Oakleaf
Plantation, Bryceville, Bellair-Meadowbrook Terrace, Baldwin and
Ellerbee.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
To report severe weather, contact your nearest law enforcement
agency. You can also share your report with NWS Jacksonville on
Facebook and Twitter.
&&
LAT...LON 3001 8219 3028 8230 3054 8195 3038 8183
3019 8174
TIME...MOT...LOC 1902Z 234DEG 20KT 3019 8217
SHASHYSpecial Weather Statement
National Weather Service Jacksonville FL
321 PM EDT Wed May 12 2021
FLZ124-125-122000-
Coastal Nassau FL-Coastal Duval FL-
321 PM EDT Wed May 12 2021
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NASSAU AND
NORTHEASTERN DUVAL COUNTIES UNTIL 400 PM EDT...
* At 321 PM EDT, National Weather Service meteorologists were
tracking a strong thunderstorm over Yulee, or near Fernandina
Beach, moving east at 20 mph.
* Small hail and winds in excess of 45 mph possible with this storm.
* Locations impacted include...
Fernandina Beach and Yulee.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
To report severe weather, contact your nearest law enforcement
agency. You can also share your report with NWS Jacksonville on
Facebook and Twitter.
&&
LAT...LON 3052 8159 3070 8164 3072 8155 3071 8154
3072 8154 3073 8151 3073 8150 3074 8148
3073 8147 3074 8147 3075 8142 3053 8139
TIME...MOT...LOC 1921Z 260DEG 17KT 3063 8154
SHASHYSpecial Weather Statement
National Weather Service Jacksonville FL
330 PM EDT Wed May 12 2021
GAZ165-166-122000-
Inland Camden GA-Coastal Camden GA-
330 PM EDT Wed May 12 2021
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN CAMDEN COUNTY UNTIL
400 PM EDT...
* At 330 PM EDT, National Weather Service meteorologists were
tracking a strong thunderstorm 7 miles west of Jekyll Island, or 8
miles southwest of Brunswick, moving east at 30 mph.
* Winds in excess of 45 mph possible with this storm.
* Locations impacted include...
Dover Bluff, Cumberland Island and Harrietts Bluff.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
To report severe weather, contact your nearest law enforcement
agency. You can also share your report with NWS Jacksonville on
Facebook and Twitter.
&&
LAT...LON 3082 8142 3084 8172 3109 8164 3111 8156
3109 8156 3104 8146 3108 8152 3110 8152
3109 8149 3110 8150 3110 8149 3104 8143
3105 8143 3110 8147 3109 8144 3104 8142
3101 8143 3108 8137
TIME...MOT...LOC 1930Z 274DEG 28KT 3103 8154
SHASHYSpecial Weather Statement National Weather Service Jacksonville FL 342 PM EDT Wed May 12 2021 FLZ023-024-GAZ165-264-350-364-122030- Baker FL-Inland Nassau FL-Northeastern Charlton GA-Inland Camden GA- Western Charlton GA-Southern Ware GA- 342 PM EDT Wed May 12 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN NASSAU...NORTH CENTRAL BAKER...SOUTHWESTERN CAMDEN...SOUTHEASTERN WARE AND CENTRAL CHARLTON COUNTIES UNTIL 430 PM EDT... * At 342 PM EDT, National Weather Service meteorologists were tracking strong thunderstorms 11 miles south of Stephen Foster State Park, moving east at 30 mph. * Small hail and winds in excess of 45 mph possible with these storms. * Locations impacted include... Hilliard, Folkston and Kings Ferry. PRECAUTIONARY/PREPAREDNESS ACTIONS... Frequent cloud to ground lightning is occurring with this storm. If you can hear thunder, you are close enough to be struck! Seek a safe shelter inside a building or vehicle. To report severe weather, contact your nearest law enforcement agency. You can also share your report with NWS Jacksonville on Facebook and Twitter. && LAT...LON 3055 8236 3078 8231 3085 8181 3059 8180 TIME...MOT...LOC 1942Z 262DEG 26KT 3067 8227 SHASHY
Special Weather Statement National Weather Service Jacksonville FL 402 PM EDT Wed May 12 2021 FLZ033-125-132-133-232-325-122045- Eastern Clay FL-Coastal St. Johns FL-Western Clay FL- South Central Duval FL-Coastal Duval FL-Inland St. Johns FL- 402 PM EDT Wed May 12 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN ST. JOHNS...NORTHEASTERN CLAY AND SOUTHEASTERN DUVAL COUNTIES UNTIL 445 PM EDT... * At 402 PM EDT, National Weather Service meteorologists were tracking a strong thunderstorm over Green Cove Springs, moving east at 25 mph. * Winds in excess of 45 mph possible with this storm. * Locations impacted include... Green Cove Springs, Fruit Cove, World Golf Village, Palm Valley, Sawgrass, South Ponte Vedra, Nocatee, Bayard, Durbin and Switzerland. PRECAUTIONARY/PREPAREDNESS ACTIONS... To report severe weather, contact your nearest law enforcement agency. You can also share your report with NWS Jacksonville on Facebook and Twitter. && LAT...LON 2992 8173 3005 8178 3024 8134 2998 8126 TIME...MOT...LOC 2002Z 250DEG 21KT 3000 8165 SHASHY
Special Weather Statement
National Weather Service Jacksonville FL
415 PM EDT Wed May 12 2021
FLZ024-124-125-425-GAZ165-166-122115-
Western Duval FL-Inland Nassau FL-Coastal Nassau FL-Coastal Duval FL-
Inland Camden GA-Coastal Camden GA-
415 PM EDT Wed May 12 2021
...SIGNIFICANT WEATHER ADVISORY FOR NASSAU...NORTHEASTERN DUVAL AND
SOUTHERN CAMDEN COUNTIES UNTIL 515 PM EDT...
* At 415 PM EDT, National Weather Service meteorologists were
tracking a strong thunderstorm over Hilliard, moving east at 35
mph.
* Winds of 40 to 50 possible with this storm.
* Locations impacted include...
St. Marys, Kingsland, Fernandina Beach, Hilliard, Callahan, Kings
Bay Base, Jacksonville International Arpt, Yulee, Kings Ferry and
Nassau Village-Ratliff.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
To report severe weather, contact your nearest law enforcement
agency. You can also share your report with NWS Jacksonville on
Facebook and Twitter.
&&
LAT...LON 3046 8138 3047 8171 3056 8201 3058 8201
3070 8191 3086 8181 3084 8141 3077 8142
TIME...MOT...LOC 2015Z 271DEG 30KT 3069 8190
SHASHYThe Jacksonville radar (KJAX), 54 km away, was scanning. The volume nearest the first event began at 20:12 UTC.
1 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds damaged a few boat house roofs on the St. Johns River near Orangedale, a few mile north of the Shands Bridge. Patio furniture was blown into the river. The cost of damage was estimated for inclusion of the damage in Storm Data.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2021Every state in 2021This day in weather historyWarnings in Florida, May 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 952908.