Alert archive / Florida / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 87, NWS Melbourne, FL

August 21, 20124 counties in Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Aug 21, 2012, 3:25 PM EDT for 4 counties in Florida. It was in force for 31 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
Aug 21, 2012, 3:25 PM EDT (19:25 UTC)
Expired
Aug 21, 2012, 3:56 PM EDT
In force
31 min
Issued by
NWS Melbourne, FL
Area
Storm-based polygon

Counties Lake County, FL, Orange County, FL, Seminole County, FL, Volusia County, FL

The radar

The Melbourne radar (KMLB), 110 km from the middle of the area, began a volume at 19:28 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
Aug 21, 3:30 PM EDTTSTM WND DMGApopka, FLLARGE TREE DOWN. REPORT FROM WRDQ

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

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 7.4 hours before the alert went out and 99 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 2012-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 318 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 2012-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.1939Sfc1 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
318 J/kg
Mixed-layer CIN
-106 J/kg
Mixed-layer LCL
1227 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

630 
WUUS52 KMLB 211925
SVRMLB
FLC069-095-117-127-212030-
/O.NEW.KMLB.SV.W.0087.120821T1925Z-120821T2030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
325 PM EDT TUE AUG 21 2012

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEAST LAKE COUNTY IN FLORIDA
  NORTHWESTERN ORANGE COUNTY IN FLORIDA
  NORTHWESTERN SEMINOLE COUNTY IN FLORIDA
  SOUTHWEST VOLUSIA COUNTY IN FLORIDA

* UNTIL 430 PM EDT.

* AT 324 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR APOPKA...AND MOVING
  NORTHEAST AT 25 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE...BUT ARE NOT LIMITED TO...
  WEKIWA SPRINGS...ALTAMONTE SPRINGS...MOUNT PLYMOUTH... 
  LONGWOOD...LAKE MARY...CASSIA...SANFORD... AND DEBARY

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 58 MILES AN
HOUR AND OR LARGE DESTRUCTIVE HAIL. FREQUENT TO EXCESSIVE LIGHTNING
AND VERY HEAVY RAIN WILL ALSO BE POSSIBLE. IF THE STORM APPROACHES
YOU...SEEK SHELTER IN AN ENCLOSED BUILDING ON THE LOWEST FLOOR. KEEP
AWAY FROM WINDOWS.

&&

LAT...LON 2903 8142 2878 8117 2856 8151 2870 8166
TIME...MOT...LOC 1924Z 225DEG 14KT 2870 8152

$$


52
1 follow-up statement
941 
WWUS52 KMLB 211956
SVSMLB

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
356 PM EDT TUE AUG 21 2012

FLC069-095-117-127-212006-
/O.CAN.KMLB.SV.W.0087.000000T0000Z-120821T2030Z/
SEMINOLE-ORANGE-LAKE-VOLUSIA-
356 PM EDT TUE AUG 21 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL VOLUSIA...EAST
CENTRAL LAKE...NORTHWESTERN ORANGE AND NORTHWESTERN SEMINOLE COUNTIES
IS CANCELLED...

THE SEVERE STORM THAT PROMPTED THE WARNING HAD WEAKENED AND WAS NO
LONGER CAPABLE OF PRODUCING LARGE HAIL OR DAMAGING WINDS. AS A 
RESULT...THE WARNING HAS BEEN CANCELLED. HOWEVER...HEAVY 
RAIN...STRONG WIND GUSTS AND DANGEROUS LIGHTNING STRIKES WILL 
CONTINUE TO BE POSSIBLE.

LAT...LON 2903 8142 2878 8117 2856 8151 2870 8166
TIME...MOT...LOC 1956Z 225DEG 14KT 2879 8142

$$


WEITLICH

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 11:28 PM EDTSpecial Weather StatementMLBOrange47 min
Aug 21, 1:33 PM EDTSpecial Weather StatementMLBLake57 min
Aug 21, 2:39 PM EDTSpecial Marine WarningMLB66 min
Aug 21, 2:53 PM EDTSevere Thunderstorm WarningMLBBrevard37 min
Aug 21, 3:10 PM EDTSpecial Marine WarningMLB2 hr
Aug 21, 3:12 PM EDTAreal Flood AdvisoryMLBLake93 min
Aug 21, 3:15 PM EDTSevere Thunderstorm WarningMLBBrevard, Volusia45 min
Aug 21, 3:37 PM EDTSpecial Weather StatementMLBBrevard, Indian River, Lake, Martin, Okeechobee, Orange and 4 more53 min
Aug 21, 3:41 PM EDTSpecial Marine WarningMLB94 min
Aug 21, 3:54 PM EDTAreal Flood AdvisoryMLBLake, Orange, Seminole, Volusia81 min
Aug 21, 4:24 PM EDTSevere Thunderstorm WarningMLBOkeechobee45 min
Aug 21, 4:37 PM EDTSpecial Weather StatementMLBBrevard, Indian River, Martin, Okeechobee, Osceola, Saint Lucie53 min
Aug 21, 4:37 PM EDTSevere Thunderstorm WarningMLBBrevard38 min
Aug 21, 4:49 PM EDTSevere Thunderstorm WarningMLBMartin, Okeechobee, Saint Lucie34 min
Aug 21, 5:06 PM EDTSpecial Marine WarningMLB84 min
Aug 21, 5:06 PM EDTSevere Thunderstorm WarningMLBIndian River24 min
Aug 21, 5:08 PM EDTSpecial Marine WarningMLB82 min
Aug 21, 5:12 PM EDTSevere Thunderstorm WarningMLBBrevard, Osceola20 min

Nearby

Severe Thunderstorm Warnings in Florida, 2012Every severe thunderstorm warning in 2012

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.