Alert archive / Florida / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 149, NWS Jacksonville, FL
NWS Jacksonville, FL issued this severe thunderstorm warning at Aug 20, 2021, 10:25 PM EDT for Clay County, Saint Johns County, Florida. It was in force for 35 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 20, 2021, 10:25 PM EDT (02:25 UTC)
- Expired
- Aug 20, 2021, 11:00 PM EDT
- In force
- 35 min
- Issued by
- NWS Jacksonville, FL
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Clay County, FL, Saint Johns County, FL
The radar
The Jacksonville radar (KJAX), 47 km from the middle of the area, began a volume at 02:28 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Jacksonville, FL (KJAX), launched 00:00Z, 2.4 hours before the alert went out and 48 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 735 J/kg
- Mixed-layer CIN
- -65 J/kg
- Mixed-layer LCL
- 1521 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 45 m²/s²
- 0-3 km storm-relative helicity
- 49 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
745
WUUS52 KJAX 210225
SVRJAX
FLC019-109-210300-
/O.NEW.KJAX.SV.W.0149.210821T0225Z-210821T0300Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Jacksonville FL
1025 PM EDT Fri Aug 20 2021
The National Weather Service in Jacksonville has issued a
* Severe Thunderstorm Warning for...
Northwestern St. Johns County in northeastern Florida...
Northeastern Clay County in northeastern Florida...
* Until 1100 PM EDT.
* At 1025 PM EDT, a severe thunderstorm was located over Switzerland,
or over Fruit Cove, moving east at 15 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Locations impacted include...
Green Cove Springs, Fruit Cove and Switzerland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 2994 8152 3001 8172 3013 8168 3012 8168
3013 8163 3013 8160 3012 8157 3012 8154
3010 8154 3010 8148
TIME...MOT...LOC 0225Z 282DEG 14KT 3007 8165
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
KB2 follow-up statements
607
WWUS52 KJAX 210242
SVSJAX
Severe Weather Statement
National Weather Service Jacksonville FL
1042 PM EDT Fri Aug 20 2021
FLC019-210251-
/O.CAN.KJAX.SV.W.0149.000000T0000Z-210821T0300Z/
Clay FL-
1042 PM EDT Fri Aug 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CLAY COUNTY IS
CANCELLED...
The severe thunderstorm which prompted the warning has moved out of
the warned area. Therefore, the warning has been cancelled.
LAT...LON 2994 8152 2998 8162 3001 8168 3013 8163
3013 8160 3012 8157 3012 8154 3010 8154
3010 8148
TIME...MOT...LOC 0241Z 282DEG 14KT 3006 8158
$$
FLC109-210300-
/O.CON.KJAX.SV.W.0149.000000T0000Z-210821T0300Z/
St. Johns FL-
1042 PM EDT Fri Aug 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1100 PM EDT
FOR NORTHWESTERN ST. JOHNS COUNTY...
At 1041 PM EDT, a severe thunderstorm was located near Fruit Cove,
moving east at 15 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Fruit Cove and Switzerland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
&&
LAT...LON 2994 8152 2998 8162 3001 8168 3013 8163
3013 8160 3012 8157 3012 8154 3010 8154
3010 8148
TIME...MOT...LOC 0241Z 282DEG 14KT 3006 8158
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
KB683
WWUS52 KJAX 210256
SVSJAX
Severe Weather Statement
National Weather Service Jacksonville FL
1056 PM EDT Fri Aug 20 2021
FLC109-210306-
/O.EXP.KJAX.SV.W.0149.000000T0000Z-210821T0300Z/
St. Johns FL-
1056 PM EDT Fri Aug 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN ST. JOHNS COUNTY
WILL EXPIRE AT 1100 PM EDT...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However gusty
winds are still possible with this thunderstorm.
LAT...LON 2994 8152 2998 8162 3001 8168 3013 8163
3013 8160 3012 8157 3012 8154 3010 8154
3010 8148
TIME...MOT...LOC 0256Z 282DEG 14KT 3005 8152
$$
KBThe office that day
Everything else NWS Jacksonville, FL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 8:35 PM EDT | Special Weather Statement | JAX | Nassau | 40 min |
| Aug 20, 8:51 PM EDT | Special Marine Warning | JAX | 114 min | |
| Aug 20, 9:03 PM EDT | Special Weather Statement | JAX | Nassau | 42 min |
| Aug 20, 9:29 PM EDT | Special Weather Statement | JAX | Clay | 31 min |
| Aug 20, 9:44 PM EDT | Special Weather Statement | JAX | Nassau | 31 min |
| Aug 20, 9:56 PM EDT | Special Weather Statement | JAX | Clay | 34 min |
| Aug 20, 10:47 PM EDT | Special Marine Warning | JAX | 58 min | |
| Aug 20, 10:55 PM EDT | Special Weather Statement | JAX | Saint Johns | 35 min |
| Aug 20, 11:08 PM EDT | Special Marine Warning | JAX | 67 min | |
| Aug 20, 11:20 PM EDT | Special Marine Warning | JAX | 55 min | |
| Aug 20, 11:43 PM EDT | Special Marine Warning | JAX | 47 min |
Nearby
Severe Thunderstorm Warnings in Florida, 2021Every severe thunderstorm warning in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.