Alert archive / Florida / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 9, NWS Melbourne, FL

April 11, 2021Brevard County, Indian River County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Apr 11, 2021, 1:55 PM EDT for Brevard County, Indian River County, Florida. It was in force for 36 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 11, 2021, 1:55 PM EDT (17:55 UTC)
Expired: Apr 11, 2021, 2:31 PM EDT
In force: 36 min
Issued by: NWS Melbourne, FL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Brevard County, FL, Indian River County, FL

The radar

The Melbourne radar (KMLB), 40 km from the middle of the area, began a volume at 17:57 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 11, 2:09 PM EDT	TSTM WND GST 52	Vero Beach Airport, FL	ASOS AT VERO BEACH MUNICIPAL AIRPORT MEASURED A PEAK WIND GUST OF 45 KNOTS/52 MPH FROM THE NW.
Apr 11, 2:15 PM EDT	TSTM WND GST 45	5 Sse Barefoot Bay, FL	SEBASTIAN MUNICIPAL AIRPORT X26 MEASURED A PEAK WIND GUST OF 39KT/46MPH FROM THE NNW.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 11, 8:15 AM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 5.9 hours before the alert went out and 80 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: 449 J/kg
Mixed-layer CIN: -181 J/kg
Mixed-layer LCL: 1002 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 199 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

541 
WUUS52 KMLB 111755
SVRMLB
FLC009-061-111900-
/O.NEW.KMLB.SV.W.0009.210411T1755Z-210411T1900Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Melbourne FL
155 PM EDT Sun Apr 11 2021

The National Weather Service in Melbourne has issued a

* Severe Thunderstorm Warning for...
  Indian River County in east central Florida...
  Southeastern Brevard County in east central Florida...

* Until 300 PM EDT.

* At 155 PM EDT, a severe thunderstorm was located over
  Grant-Valkaria, or near Malabar, moving southeast at 20 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Palm Bay, Sebastian, Vero Beach, Fellsmere and Indian River Shores.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2756 8068 2756 8071 2793 8085 2805 8051
      2800 8048 2764 8032
TIME...MOT...LOC 1755Z 326DEG 15KT 2794 8055 

HAIL...<.75IN
WIND...60MPH
 
$$

Smith

2 follow-up statements

997 
WWUS52 KMLB 111815
SVSMLB

Severe Weather Statement
National Weather Service Melbourne FL
215 PM EDT Sun Apr 11 2021

FLC009-061-111900-
/O.CON.KMLB.SV.W.0009.000000T0000Z-210411T1900Z/
Indian River FL-Brevard FL-
215 PM EDT Sun Apr 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR INDIAN RIVER AND SOUTHEASTERN BREVARD COUNTIES...

At 214 PM EDT, a severe thunderstorm was located over Vero Beach
South, moving southeast at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Sebastian, Vero Beach, Fellsmere, Indian River Shores and Roseland. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2756 8068 2756 8071 2785 8082 2796 8048
      2764 8032
TIME...MOT...LOC 1814Z 332DEG 38KT 2763 8041 

HAIL...<.75IN
WIND...60MPH
 
$$

Smith

980 
WWUS52 KMLB 111831
SVSMLB

Severe Weather Statement
National Weather Service Melbourne FL
231 PM EDT Sun Apr 11 2021

FLC009-061-111839-
/O.CAN.KMLB.SV.W.0009.000000T0000Z-210411T1900Z/
Indian River FL-Brevard FL-
231 PM EDT Sun Apr 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR INDIAN RIVER AND SOUTHEASTERN
BREVARD COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 400 PM EDT for
east central Florida.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Melbourne.

Remember, a Severe Thunderstorm Warning still remains in effect for
southeastern Indian River County until 315 PM!

LAT...LON 2756 8068 2756 8071 2785 8082 2796 8048
      2764 8032
TIME...MOT...LOC 1827Z 326DEG 15KT 2757 8037 

$$

Smith

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 11, 4:31 AM EDT	Special Weather Statement	MLB	Flagler	44 min
Apr 11, 7:38 AM EDT	Special Marine Warning	MLB		2 hr
Apr 11, 7:43 AM EDT	Special Weather Statement	MLB	Volusia	62 min
Apr 11, 8:45 AM EDT	Special Weather Statement	MLB	Volusia	45 min
Apr 11, 9:19 AM EDT	Special Marine Warning	MLB		26 min
Apr 11, 9:45 AM EDT	Special Weather Statement	MLB	Lake	60 min
Apr 11, 10:35 AM EDT	Severe Thunderstorm Warning	MLB	Orange, Seminole	23 min
Apr 11, 10:56 AM EDT	Severe Thunderstorm Warning	MLB	Seminole, Volusia	30 min
Apr 11, 11:01 AM EDT	Special Weather Statement	MLB	Lake	44 min
Apr 11, 11:05 AM EDT	Special Weather Statement	MLB	Seminole	10 min
Apr 11, 11:29 AM EDT	Special Marine Warning	MLB		2 hr
Apr 11, 11:31 AM EDT	Special Weather Statement	MLB	Seminole, Volusia	44 min
Apr 11, 11:39 AM EDT	Special Weather Statement	MLB	Lake, Orange	66 min
Apr 11, 11:45 AM EDT	Special Weather Statement	MLB	Volusia	60 min
Apr 11, 12:23 PM EDT	Severe Thunderstorm Warning	MLB	Lake, Orange, Osceola	52 min
Apr 11, 12:39 PM EDT	Special Weather Statement	MLB	Brevard, Osceola	66 min
Apr 11, 1:04 PM EDT	Special Weather Statement	MLB	Seminole	41 min
Apr 11, 1:08 PM EDT	Special Marine Warning	MLB		3 hr
Apr 11, 1:13 PM EDT	Special Weather Statement	MLB	Indian River, Okeechobee	62 min
Apr 11, 2:11 PM EDT	Special Weather Statement	MLB	Indian River, Martin, Okeechobee, Saint Lucie	94 min
Apr 11, 2:17 PM EDT	Severe Thunderstorm Warning	MLB	Indian River, Martin, Okeechobee, Saint Lucie	58 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.