Alert archive / Georgia / Tornado Watches in 2021
Tornado Watch 40
The Storm Prediction Center issued this tornado watch at Mar 18, 2021, 11:42 AM EDT for 13 counties in Florida; 27 counties in Georgia; 13 counties in South Carolina. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 18, 2021, 11:42 AM EDT (15:42 UTC)
- Expired
- Mar 18, 2021, 6:00 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 53 counties
Alachua County, FL, Baker County, FL, Bradford County, FL, Clay County, FL, Columbia County, FL, Duval County, FL, Gilchrist County, FL, Hamilton County, FL, Nassau County, FL, Putnam County, FL, Saint Johns County, FL, Suwannee County, FL, Union County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Burke County, GA, Camden County, GA, Candler County, GA, Charlton County, GA, Chatham County, GA, Clinch County, GA, Coffee County, GA, Echols County, GA, Effingham County, GA, Evans County, GA, Glynn County, GA, Jeff Davis County, GA, Jenkins County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Pierce County, GA, Screven County, GA, Tattnall County, GA, Ware County, GA, Wayne County, GA, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Hampton County, SC, Jasper County, SC, Orangeburg County, SC
The radar
The Charleston,SC radar (KCLX), 65 km from the middle of the area, began a volume at 15:42 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 50%
- One or more EF2 to EF5 tornadoes
- 30%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 18, 1:23 PM EDT | Severe Thunderstorm Warning | JAX | Appling, Bacon, Pierce, Ware, Wayne | 30 min |
| Mar 18, 1:38 PM EDT | Tornado Warning | JAX | Appling, Pierce, Wayne | 14 min |
| Mar 18, 1:41 PM EDT | Severe Thunderstorm Warning | JAX | Columbia, Gilchrist, Suwannee | 49 min |
| Mar 18, 1:47 PM EDT | Severe Thunderstorm Warning | CHS | Bryan, Liberty, Long, Tattnall | 43 min |
| Mar 18, 2:29 PM EDT | Severe Thunderstorm Warning | JAX | Alachua, Gilchrist | 46 min |
| Mar 18, 2:40 PM EDT | Tornado Warning | JAX | Alachua, Gilchrist | 35 min |
| Mar 18, 2:55 PM EDT | Tornado Warning | CHS | Bryan, Chatham | 21 min |
| Mar 18, 2:58 PM EDT | Severe Thunderstorm Warning | JAX | Alachua, Bradford, Union | 47 min |
| Mar 18, 3:07 PM EDT | Tornado Warning | JAX | Alachua, Bradford, Union | 23 min |
| Mar 18, 3:22 PM EDT | Severe Thunderstorm Warning | JAX | Baker, Bradford, Clay, Duval, Union | 38 min |
| Mar 18, 3:57 PM EDT | Severe Thunderstorm Warning | JAX | Baker, Bradford, Clay, Duval | 36 min |
| Mar 18, 4:10 PM EDT | Tornado Warning | JAX | Clay, Duval | 11 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Charleston AFB, SC (KCHS), launched 12:00Z, 3.7 hours before the alert went out and 132 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
- 219 J/kg
- Mixed-layer CIN
- -83 J/kg
- Mixed-layer LCL
- 679 m above ground
- 0-6 km bulk shear
- 65 kt
- 0-1 km storm-relative helicity
- 170 m²/s²
- 0-3 km storm-relative helicity
- 244 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.9
The text
As transmitted.
595 WWUS20 KWNS 181540 SEL0 SPC WW 181540 FLZ000-GAZ000-SCZ000-CWZ000-182200- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 40 NWS Storm Prediction Center Norman OK 1140 AM EDT Thu Mar 18 2021 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of North Florida Eastern Georgia Southern South Carolina Coastal Waters * Effective this Thursday morning and evening from 1140 AM until 600 PM EDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A broken line of thunderstorms should spread east-northeast from south-central Georgia and the eastern Florida Panhandle. Intensification is expected with the development of a few embedded supercells this afternoon. Tornado and damaging wind are the primary hazards. The tornado watch area is approximately along and 60 statute miles east and west of a line from 20 miles east of Orangeburg SC to 50 miles southwest of Jacksonville FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 39... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 24035. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 17, 11:15 PM EDT | Mesoscale Discussion | SPC | Escambia, Okaloosa, Santa Rosa | 90 min |
| Mar 18, 12:02 AM EDT | Tornado Watch | SPC | Bay, Calhoun, Escambia, Holmes, Jackson, Okaloosa and 3 more | 9 hr |
| Mar 18, 2:52 AM EDT | Mesoscale Discussion | SPC | Escambia, Holmes, Okaloosa, Santa Rosa | 83 min |
| Mar 18, 5:28 AM EDT | Mesoscale Discussion | SPC | Bay, Calhoun, Holmes, Jackson, Walton, Washington | 92 min |
| Mar 18, 7:32 AM EDT | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 6 more | 58 min |
| Mar 18, 7:53 AM EDT | Tornado Watch | SPC | Dixie, Franklin, Gadsden, Gulf, Jefferson, Lafayette and 5 more | 5 hr |
| Mar 18, 11:05 AM EDT | Mesoscale Discussion | SPC | Columbia, Dixie, Hamilton, Jefferson, Lafayette, Madison and 2 more | 115 min |
| Mar 18, 10:34 AM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Clarke, Elbert, Franklin, Habersham and 5 more | 2 hr |
| Mar 18, 2:08 PM EDT | Tornado Watch | SPC | Elbert, Lincoln | 4 hr |
| Mar 18, 3:10 PM EDT | Mesoscale Discussion | SPC | Elbert | 3 hr |
| Mar 18, 5:57 PM EDT | Mesoscale Discussion | SPC | Chesterfield, Lancaster, Marlboro | 63 min |
Nearby
Tornado Watches in Georgia, 2021Tornado Watches in Florida, 2021Tornado Watches in South Carolina, 2021Every tornado watch 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.