Alert archive / Florida / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS Tampa Bay, FL

April 18, 2021Levy County, Florida

NWS Tampa Bay, FL issued this severe thunderstorm warning at Apr 18, 2021, 8:51 AM EDT for Levy County, Florida. It was in force for 24 min. 2 reports 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: Apr 18, 2021, 8:51 AM EDT (12:51 UTC)
Expired: Apr 18, 2021, 9:15 AM EDT
In force: 24 min
Issued by: NWS Tampa Bay, FL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Levy County, FL

The radar

The Jacksonville radar (KJAX), 141 km from the middle of the area, began a volume at 12:52 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
Apr 18, 9:05 AM EDT	HAIL 0.7	Bronson, FL	REPORTS OF DIME SIZE HAIL.
Apr 18, 9:19 AM EDT	TSTM WND DMG	Bronson, FL	REPORTS OF TREE AND POWER LINES DOWN OFF COURT ST IN BRONSON, FL.

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

The nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 0.9 hours before the alert went out and 142 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: 7 J/kg
Mixed-layer CIN: -105 J/kg
Mixed-layer LCL: 565 m above ground
0-6 km bulk shear: 74 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

022 
WUUS52 KTBW 181251
SVRTBW
FLC075-181315-
/O.NEW.KTBW.SV.W.0011.210418T1251Z-210418T1315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Tampa Bay Area Ruskin FL
851 AM EDT Sun Apr 18 2021

The National Weather Service in Ruskin has issued a

* Severe Thunderstorm Warning for...
  Northeastern Levy County in northern Florida...

* Until 915 AM EDT.

* At 851 AM EDT, a severe thunderstorm was located near Bronson,
  moving east at 45 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Williston, Chiefland, Bronson, East Bronson and Otter Creek. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2954 8265 2954 8256 2948 8255 2948 8250
      2949 8249 2948 8241 2939 8241 2933 8280
      2951 8286 2957 8276 2957 8266
TIME...MOT...LOC 1251Z 260DEG 49KT 2943 8270 

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

TBW

1 follow-up statement

346 
WWUS52 KTBW 181311
SVSTBW

Severe Weather Statement
National Weather Service Tampa Bay Area Ruskin FL
911 AM EDT Sun Apr 18 2021

FLC075-181320-
/O.EXP.KTBW.SV.W.0011.000000T0000Z-210418T1315Z/
Levy FL-
911 AM EDT Sun Apr 18 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LEVY COUNTY WILL
EXPIRE AT 915 AM EDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 2954 8265 2954 8256 2948 8255 2948 8250
      2949 8249 2948 8241 2939 8241 2933 8280
      2951 8286 2957 8276 2957 8266
TIME...MOT...LOC 1310Z 260DEG 49KT 2947 8241 

$$

TBW

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 18, 8:33 AM EDT	Special Weather Statement	TBW	Levy	42 min
Apr 18, 11:20 AM EDT	Rip Current Statement	TBW	Charlotte, Hillsborough, Lee, Manatee, Pinellas, Sarasota	18 hr
Apr 18, 4:46 PM EDT	Special Marine Warning	TBW		59 min
Apr 18, 5:59 PM EDT	Areal Flood Advisory	TBW	Citrus, Levy	91 min
Apr 18, 6:24 PM EDT	Special Marine Warning	TBW		66 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.