Alert archive / Florida / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 18, NWS Tampa Bay, FL

June 21, 2021Polk County, Florida

NWS Tampa Bay, FL issued this severe thunderstorm warning at Jun 21, 2021, 4:21 PM EDT for Polk County, Florida. It was in force for 24 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jun 21, 2021, 4:21 PM EDT (20:21 UTC)
Expired: Jun 21, 2021, 4:45 PM EDT
In force: 24 min
Issued by: NWS Tampa Bay, FL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Polk County, FL

The radar

The Melbourne radar (KMLB), 77 km from the middle of the area, began a volume at 20:21 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 was reported inside it

Time	Report	Where	Remark
Jun 21, 4:33 PM EDT	HAIL 0.75	800 Block Of Hillside,, FL	REPORTS OF PENNY SIZE HAIL IN LAKE WHALES.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 12:00Z, 8.4 hours before the alert went out and 101 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1048 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 1094 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 58 m²/s²
0-3 km storm-relative helicity: 61 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.6

Open this sounding in Storm Lab

The text

As transmitted.

641 
WUUS52 KTBW 212021
SVRTBW
FLC105-212045-
/O.NEW.KTBW.SV.W.0018.210621T2021Z-210621T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Tampa Bay Area Ruskin FL
421 PM EDT Mon Jun 21 2021

The National Weather Service in Ruskin has issued a

* Severe Thunderstorm Warning for...
  Central Polk County in central Florida...

* Until 445 PM EDT.

* At 420 PM EDT, a severe thunderstorm was located near Lake Wales,
  moving north 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...
  Poinciana, Winter Haven, Haines City, Lake Wales, Lake Alfred,
  Crooked Lake Park, Dundee, Lake Hamilton, Highland Park and Cypress
  Gardens.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 2807 8137 2804 8136 2801 8138 2804 8143
      2806 8144 2806 8146 2805 8146 2800 8142
      2800 8139 2797 8137 2783 8145 2783 8162
      2809 8174 2810 8146 2809 8145 2808 8135
      2807 8135
TIME...MOT...LOC 2020Z 178DEG 15KT 2793 8151 

HAIL...0.75IN
WIND...60MPH
 
$$

TBW

1 follow-up statement

013 
WWUS52 KTBW 212042
SVSTBW

Severe Weather Statement
National Weather Service Tampa Bay Area Ruskin FL
442 PM EDT Mon Jun 21 2021

FLC105-212051-
/O.EXP.KTBW.SV.W.0018.000000T0000Z-210621T2045Z/
Polk FL-
442 PM EDT Mon Jun 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL POLK COUNTY WILL
EXPIRE AT 445 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 2807 8137 2804 8136 2801 8138 2804 8143
      2806 8144 2806 8146 2805 8146 2800 8142
      2800 8139 2797 8137 2783 8145 2783 8162
      2809 8174 2810 8146 2809 8145 2808 8135
      2807 8135
TIME...MOT...LOC 2041Z 178DEG 15KT 2801 8151 

$$

TBW

The office that day

Everything else NWS Tampa Bay, FL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 21, 1:27 PM EDT	Special Weather Statement	TBW	Gilchrist	33 min
Jun 21, 2:35 PM EDT	Special Weather Statement	TBW	Manatee	40 min
Jun 21, 3:55 PM EDT	Special Weather Statement	TBW	Hillsborough	35 min
Jun 21, 4:09 PM EDT	Severe Thunderstorm Warning	TBW	Hillsborough, Polk	21 min
Jun 21, 4:47 PM EDT	Special Weather Statement	TBW	Polk	28 min
Jun 21, 5:56 PM EDT	Special Weather Statement	TBW	Highlands	34 min

Nearby

Severe Thunderstorm Warnings in Florida, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.