Alert archive / Florida / Tornado Watches in 2021

Tornado Watch 340

July 6, 202128 counties in Florida

The Storm Prediction Center issued this tornado watch at Jul 6, 2021, 10:37 PM EDT for 28 counties in Florida. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
Jul 6, 2021, 10:37 PM EDT (02:37 UTC)
Expired
Jul 7, 2021, 8:00 AM EDT
In force
9 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 28 counties

Alachua County, FL, Charlotte County, FL, Citrus County, FL, Collier County, FL, DeSoto County, FL, Gilchrist County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Hernando County, FL, Highlands County, FL, Hillsborough County, FL, Lake County, FL, Lee County, FL, Levy County, FL, Manatee County, FL, Marion County, FL, Okeechobee County, FL, Orange County, FL, Osceola County, FL, Pasco County, FL, Pinellas County, FL, Polk County, FL, Putnam County, FL, Sarasota County, FL, Seminole County, FL, Sumter County, FL, Volusia County, FL

The radar

The Tampa radar (KTBW), 60 km from the middle of the area, began a volume at 02:37 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
30%

Warnings issued inside it

9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jul 7, 1:10 AM EDTTornado WarningTBWHernando, Pasco, Sumter20 min
Jul 7, 2:08 AM EDTTornado WarningTBWDeSoto, Manatee, Sarasota22 min
Jul 7, 3:51 AM EDTTornado WarningTBWHardee24 min
Jul 7, 4:02 AM EDTTornado WarningJAXAlachua, Marion28 min
Jul 7, 4:16 AM EDTTornado WarningMLBLake18 min
Jul 7, 4:29 AM EDTTornado WarningJAXAlachua, Marion31 min
Jul 7, 4:33 AM EDTTornado WarningJAXMarion27 min
Jul 7, 6:02 AM EDTTornado WarningJAXAlachua, Bradford, Union28 min
Jul 7, 6:40 AM EDTTornado WarningJAXAlachua, Columbia, Union35 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

Tampa Bay, FL (KTBW), launched 00:00Z, 2.6 hours before the alert went out and 60 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.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 00:00Z on 2021-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tampa Bay, FL at 00:00Z on 2021-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
46 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
1020 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
266 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

383 
WWUS20 KWNS 070231
SEL0  
SPC WW 070231
FLZ000-CWZ000-071200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 340
NWS Storm Prediction Center Norman OK
1035 PM EDT Tue Jul 6 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Central and Western Florida Peninsula
  Coastal Waters

* Effective this Tuesday night and Wednesday morning from 1035 PM
  until 800 AM EDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...Hurricane Elsa continues to track northward off the west
coast of Florida.  Shear profiles are favorable for a risk of a few
tornadoes overnight in the rainbands associated with the hurricane.

The tornado watch area is approximately along and 55 statute miles
east and west of a line from 35 miles east of Cross City FL to 30
miles south southeast of Naples 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 337...WW 338...WW 339...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 18030.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 6, 11:59 PM EDTMesoscale DiscussionSPCCharlotte, DeSoto, Hardee, Hillsborough2 hr
Jul 7, 3:03 AM EDTMesoscale DiscussionSPCCharlotte, Citrus, DeSoto, Hardee, Hernando, Hillsborough and 5 more117 min
Jul 7, 5:42 AM EDTMesoscale DiscussionSPCAlachua, Bradford, Charlotte, Citrus, Columbia, DeSoto and 19 more2 hr
Jul 7, 6:46 AM EDTTornado WatchSPCBaker, Bradford, Clay, Columbia, Duval, Hamilton and 4 more6 hr
Jul 7, 7:06 AM EDTMesoscale DiscussionSPCCharlotte, Citrus, DeSoto, Hardee, Hernando, Highlands and 10 more54 min
Jul 7, 10:30 AM EDTMesoscale DiscussionSPCBaker, Bradford, Clay, Columbia, Duval, Hamilton and 3 more2 hr
Jul 7, 12:28 PM EDTMesoscale DiscussionSPCBaker, Bradford, Clay, Columbia, Duval, Nassau and 1 more2 hr
Jul 7, 1:04 PM EDTTornado WatchSPCBaker, Bradford, Clay, Columbia, Duval, Hamilton and 3 more7 hr
Jul 7, 4:47 PM EDTMesoscale DiscussionSPCBaker, Clay, Columbia, Duval, Nassau, Saint Johns and 1 more118 min

Nearby

Tornado Watches in Florida, 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.