Alert archive / Florida / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 10, NWS Melbourne, FL

April 11, 20214 counties in Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Apr 11, 2021, 2:17 PM EDT for 4 counties in Florida. It was in force for 58 min. 16 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, 2:17 PM EDT (18:17 UTC)
Expired
Apr 11, 2021, 3:15 PM EDT
In force
58 min
Issued by
NWS Melbourne, FL
Area
Storm-based polygon
Hail
0.75 in
Wind
70.0 mph

Counties Indian River County, FL, Martin County, FL, Okeechobee County, FL, Saint Lucie County, FL

The radar

The Melbourne radar (KMLB), 102 km from the middle of the area, began a volume at 18:18 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

TimeReportWhereRemark
Apr 11, 2:43 PM EDTTSTM WND GST 604 Nnw Saint Lucie Nucle, FLWEATHERFLOW SITE XSTL AT THE ST. LUCIE NPP MEASURED A PEAK WIND GUST OF 60MPH OR 52KT. A SECOND WIND GUST OF 50KT/58MPH WAS MEASURED AT 248 PM.
Apr 11, 2:45 PM EDTTSTM WND DMG1 Nw Indiantown, FLOFF-DUTY NWS METEOROLOGIST REPORTED A METAL AWNING RIPPED OFF A CLUBHOUSE NEAR INDIANWOOD GULF CLUB. OTHER MINOR DAMAGE OCCURRED TO SIGNS NEARBY.
Apr 11, 2:45 PM EDTTSTM WND GST 477 Nne Indiantown, FLSFWMD MESONET IN ALLAPATTAH FLATS MEASURED A PEAK WIND GUST OF 47 MPH.
Apr 11, 2:50 PM EDTTSTM WND GST 63Witham Field, FLTHE AWOS AT STUART WITHAM FIELD MEASURED A PEAK WIND GUST OF 55KT/63MPH FROM THE NW.
Apr 11, 2:51 PM EDTTSTM WND GST 712 Sw Hobe Sound, FLWEATHERFLOW SITE XHOB AT HOBE SOUND MEASURED A PEAK WIND GUST OF 71MPH/62KT. A SECOND PEAK GUST OF 64MPH/56KT WAS OBSERVED AT 256PM.
Apr 11, 2:52 PM EDTTSTM WND DMG5 Sse Jensen Beach, FLLOCAL BROADCAST MEDIA REPORTED A VERY LARGE TREE WAS KNOCKED DOWN ON A PROPERTY NEAR SE ST. LUCIE BLVD IN STUART, JUST SOUTH OF THE AIRPORT AND GOLF COURSE. TIME IS ESTIMATED FROM RADAR.
Apr 11, 2:52 PM EDTTSTM WND DMG5 Sse Jensen Beach, FLA TRAINED SPOTTER REPORTED NUMEROUS DOWNED BRANCHES THAT WERE 4-5 INCHES IN DIAMETER, NEAR SEWALL POINT.
Apr 11, 2:54 PM EDTTSTM WND DMG1 Se Jensen Beach, FLPUBLIC REPORTS DAMAGE IN SOUTH JENSEN BEACH, WHICH CONSISTED OF DOWNED TREE LIMBS, BACKYARD ITEMS THROWN AROUND, AND A COVERED PORCH THAT WAS LIFTED AND DROPPED A FEW FEET AWAY.
Apr 11, 2:54 PM EDTTSTM WND GST 686 Sse Jensen Beach, FLTRAINED SPOTTER MEASURED A PEAK WIND GUST OF 68MPH/59KT AT ROCKY POINT NEAR STUART. PEAK SUSTAINED WIND WAS 38MPH.
Apr 11, 2:56 PM EDTTSTM WND DMG2 Sse Hobe Sound, FLLOCAL MEDIA REPORTS A LARGE TREE WAS DOWNED ACROSS SE DUNCAN STREET AND SE FLAMINGO DRIVE IN HOBE SOUND, BLOCKING THE ROAD.
Apr 11, 2:57 PM EDTHAIL 0.72 Wsw Jensen Beach, FLTRAINED SPOTTER REPORTS DIME SIZED HAIL IN JENSEN BEACH.
Apr 11, 3:03 PM EDTHAIL 1.751 S Hobe Sound, FLLOCAL BROADCAST MEDIA REPORTS GOLF BALL SIZED HAIL IN HOBE SOUND.
Apr 11, 3:04 PM EDTTSTM WND GST 481 Nw Tequesta, FLPEAK GUST SO FAR. MESONET STATION CW8019 JUPITER.
Apr 11, 3:04 PM EDTMARINE TSTM WIND 481 Nw Tequesta, FLDELAYED REPORT. A MARINE THUNDERSTORM WIND GUST OF 48 MPH / 42 KNOTS WAS RECORDED BY MESONET STATION CW8019 JUPITER.
Apr 11, 3:06 PM EDTHAIL 12 Nw Hobe Sound, FLTRAINED SPOTTER REPORTS QUARTER SIZED HAIL IN HOBE SOUND.
Apr 11, 3:07 PM EDTHAIL 0.72 Wsw Jensen Beach, FLTRAINED SPOTTER REPORTS DIME SIZED HAIL IN JENSEN BEACH.

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.

IssuedProductOfficeLasted
Apr 11, 8:15 AM EDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 6.3 hours before the alert went out and 143 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, Cape Canaveral, FL at 12:00Z on 2021-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 449 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, Cape Canaveral, FL at 12:00Z on 2021-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 202 square meters per square second.1939587897Sfc1 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
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.

568 
WUUS52 KMLB 111817
SVRMLB
FLC061-085-093-111-111915-
/O.NEW.KMLB.SV.W.0010.210411T1817Z-210411T1915Z/

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

The National Weather Service in Melbourne has issued a

* Severe Thunderstorm Warning for...
  St. Lucie County in east central Florida...
  Okeechobee County in east central Florida...
  Southeastern Indian River County in east central Florida...
  Martin County in east central Florida...

* Until 315 PM EDT.

* At 217 PM EDT, a severe thunderstorm was located 10 miles west of
  Treasure Coast Airport, or 11 miles southwest of Indrio, moving
  southeast at 45 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Port Saint Lucie, Jupiter, Walton, Fort Pierce and Stuart. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2697 8008 2697 8014 2695 8015 2696 8061
      2711 8066 2716 8071 2721 8081 2714 8087
      2719 8091 2723 8099 2730 8100 2733 8105
      2736 8103 2738 8107 2738 8111 2742 8114
      2765 8033 2719 8013 2703 8008
TIME...MOT...LOC 1817Z 332DEG 38KT 2745 8052 

HAIL...<.75IN
WIND...70MPH
 
$$

Smith
2 follow-up statements
770 
WWUS52 KMLB 111856
SVSMLB

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

FLC061-111906-
/O.CAN.KMLB.SV.W.0010.000000T0000Z-210411T1915Z/
Indian River FL-
256 PM EDT Sun Apr 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN INDIAN RIVER
COUNTY IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area.  Therefore, the warning has been cancelled.

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

LAT...LON 2696 8061 2711 8066 2716 8071 2721 8081
      2719 8084 2714 8087 2719 8091 2723 8098
      2753 8029 2719 8013 2703 8008 2697 8008
      2697 8014 2695 8015
TIME...MOT...LOC 1856Z 332DEG 38KT 2708 8030 

$$

FLC085-093-111-111915-
/O.CON.KMLB.SV.W.0010.000000T0000Z-210411T1915Z/
St. Lucie FL-Okeechobee FL-Martin FL-
256 PM EDT Sun Apr 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 315 PM EDT
FOR ST. LUCIE...SOUTHEASTERN OKEECHOBEE AND MARTIN COUNTIES...

At 256 PM EDT, a severe thunderstorm was located near Palm City,
moving southeast at 45 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Port Saint Lucie, Jupiter, Walton, Fort Pierce and Stuart. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2696 8061 2711 8066 2716 8071 2721 8081
      2719 8084 2714 8087 2719 8091 2723 8098
      2753 8029 2719 8013 2703 8008 2697 8008
      2697 8014 2695 8015
TIME...MOT...LOC 1856Z 332DEG 38KT 2708 8030 

HAIL...1.00IN
WIND...70MPH
 
$$

Smith
252 
WWUS52 KMLB 111910
SVSMLB

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

FLC085-093-111-111919-
/O.EXP.KMLB.SV.W.0010.000000T0000Z-210411T1915Z/
St. Lucie FL-Okeechobee FL-Martin FL-
310 PM EDT Sun Apr 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR ST. LUCIE...SOUTHEASTERN
OKEECHOBEE AND MARTIN COUNTIES WILL EXPIRE AT 315 PM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds over 40 mph are still occurring 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.

LAT...LON 2696 8061 2711 8066 2716 8071 2721 8081
      2719 8084 2714 8087 2719 8091 2723 8098
      2753 8029 2719 8013 2703 8008 2697 8008
      2697 8014 2695 8015
TIME...MOT...LOC 1909Z 332DEG 38KT 2698 8024 

$$

Smith

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 11, 4:31 AM EDTSpecial Weather StatementMLBFlagler44 min
Apr 11, 7:38 AM EDTSpecial Marine WarningMLB2 hr
Apr 11, 7:43 AM EDTSpecial Weather StatementMLBVolusia62 min
Apr 11, 8:45 AM EDTSpecial Weather StatementMLBVolusia45 min
Apr 11, 9:19 AM EDTSpecial Marine WarningMLB26 min
Apr 11, 9:45 AM EDTSpecial Weather StatementMLBLake60 min
Apr 11, 10:35 AM EDTSevere Thunderstorm WarningMLBOrange, Seminole23 min
Apr 11, 10:56 AM EDTSevere Thunderstorm WarningMLBSeminole, Volusia30 min
Apr 11, 11:01 AM EDTSpecial Weather StatementMLBLake44 min
Apr 11, 11:05 AM EDTSpecial Weather StatementMLBSeminole10 min
Apr 11, 11:29 AM EDTSpecial Marine WarningMLB2 hr
Apr 11, 11:31 AM EDTSpecial Weather StatementMLBSeminole, Volusia44 min
Apr 11, 11:39 AM EDTSpecial Weather StatementMLBLake, Orange66 min
Apr 11, 11:45 AM EDTSpecial Weather StatementMLBVolusia60 min
Apr 11, 12:23 PM EDTSevere Thunderstorm WarningMLBLake, Orange, Osceola52 min
Apr 11, 12:39 PM EDTSpecial Weather StatementMLBBrevard, Osceola66 min
Apr 11, 1:04 PM EDTSpecial Weather StatementMLBSeminole41 min
Apr 11, 1:08 PM EDTSpecial Marine WarningMLB3 hr
Apr 11, 1:13 PM EDTSpecial Weather StatementMLBIndian River, Okeechobee62 min
Apr 11, 1:55 PM EDTSevere Thunderstorm WarningMLBBrevard, Indian River36 min
Apr 11, 2:11 PM EDTSpecial Weather StatementMLBIndian River, Martin, Okeechobee, Saint Lucie94 min

Nearby

Severe Thunderstorm Warnings in Florida, 2021Every 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.