Alert archive / Florida / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 96, NWS Melbourne, FL

July 21, 2011Lake County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Jul 21, 2011, 7:52 PM EDT for Lake County, Florida. It was in force for 22 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 21, 2011, 7:52 PM EDT (23:52 UTC)
Expired
Jul 21, 2011, 8:14 PM EDT
In force
22 min
Issued by
NWS Melbourne, FL
Area
Storm-based polygon

County Lake County, FL

The radar

The Melbourne radar (KMLB), 135 km from the middle of the area, began a volume at 23:54 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.

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 11.9 hours before the alert went out and 120 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 2011-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 382 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 2011-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
382 J/kg
Mixed-layer CIN
-81 J/kg
Mixed-layer LCL
1083 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
0 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.

657 
WUUS52 KMLB 212352
SVRMLB
FLC069-220030-
/O.NEW.KMLB.SV.W.0096.110721T2352Z-110722T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
752 PM EDT THU JUL 21 2011

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN LAKE COUNTY IN FLORIDA

* UNTIL 830 PM EDT.

* AT 752 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND   
DAMAGING WINDS IN EXCESS OF 58 MPH.  THIS STORM WAS LOCATED 10 MILES 
WEST OF CASSIA...AND MOVING NORTH AT 5 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE...BUT ARE NOT LIMITED TO...
  PAISLEY

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 2916 8152 2910 8150 2909 8149 2910 8146
      2909 8146 2906 8146 2904 8143 2883 8146
      2883 8163 2905 8166 2905 8164 2920 8165
TIME...MOT...LOC 2352Z 162DEG 3KT 2889 8156

$$
1 follow-up statement
032 
WWUS52 KMLB 220014
SVSMLB

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
814 PM EDT THU JUL 21 2011

FLC069-220024-
/O.CAN.KMLB.SV.W.0096.000000T0000Z-110722T0030Z/
LAKE-
814 PM EDT THU JUL 21 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LAKE COUNTY 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 AND 
DANGEROUS LIGHTNING STRIKES WILL CONTINUE TO BE POSSIBLE ACROSS 
NORTHEAST LAKE COUNTY.

LAT...LON 2916 8152 2910 8150 2909 8149 2910 8146
      2909 8146 2906 8146 2904 8143 2883 8146
      2883 8163 2905 8166 2905 8164 2920 8165
TIME...MOT...LOC 0014Z 162DEG 3KT 2891 8157

$$


15

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 3:21 PM EDTSpecial Weather StatementMLBIndian River39 min
Jul 21, 7:24 PM EDTSevere Thunderstorm WarningMLBOrange, Seminole41 min
Jul 21, 7:35 PM EDTSpecial Weather StatementMLBLake40 min
Jul 21, 7:36 PM EDTAreal Flood AdvisoryMLBLake, Orange, Seminole84 min

Nearby

Severe Thunderstorm Warnings in Florida, 2011Every severe thunderstorm warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.