Alert archive / Florida / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 21, NWS Melbourne, FL

April 29, 1999Okeechobee County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Apr 29, 1999, 6:34 PM EDT for Okeechobee County, Florida. It was in force for 61 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Apr 29, 1999, 6:34 PM EDT (22:34 UTC)
Expired
Apr 29, 1999, 7:35 PM EDT
In force
61 min
Issued by
NWS Melbourne, FL
Area
Whole counties

County Okeechobee County, FL

The radar

The Melbourne radar (KMLB), 84 km from the middle of the area, began a volume at 22:36 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 29, 6:44 PM EDTHail 0.75Okeechobee, FL

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 12:00Z, 10.6 hours before the alert went out and 153 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, Tampa Bay, FL at 12:00Z on 1999-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 220 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tampa Bay, FL at 12:00Z on 1999-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.193958Sfc1 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
220 J/kg
Mixed-layer CIN
-106 J/kg
Mixed-layer LCL
1233 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
75 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.

999 
WUUS01 KMLB 292233 RRA
SVRMLB
FLC093-292335-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
634 PM EDT THU APR 29 1999

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     OKEECHOBEE COUNTY IN EAST CENTRAL FLORIDA

* UNTIL 735 PM EDT

* AT AT 635 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM NEAR OKEECHOBEE CITY.  MOVEMENT WAS EAST
  AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
    THIS STORM WILL AFFECT EAST OKEECHOBEE COUNTY WITH LARGE HAIL.

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 29, 5:27 PM EDTSevere Thunderstorm WarningMLBLake48 min
Apr 29, 6:07 PM EDTSevere Thunderstorm WarningMLBOrange, Seminole63 min
Apr 29, 7:31 PM EDTSevere Thunderstorm WarningMLBIndian River59 min
Apr 29, 7:42 PM EDTSevere Thunderstorm WarningMLBBrevard63 min

Nearby

Severe Thunderstorm Warnings in Florida, 1999Every severe thunderstorm warning in 1999

Sources

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