Alert archive / Florida / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 30, NWS Melbourne, FL

May 6, 1999Osceola County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at May 6, 1999, 9:06 PM EDT for Osceola County, Florida. It was in force for 24 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
May 6, 1999, 9:06 PM EDT (01:06 UTC)
Expired
May 6, 1999, 9:30 PM EDT
In force
24 min
Issued by
NWS Melbourne, FL
Area
Whole counties

County Osceola County, FL

The radar

The Melbourne radar (KMLB), 49 km from the middle of the area, began a volume at 01:10 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
May 6, 9:10 PM EDTHail 2Kissimmee, 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 00:00Z, 1.1 hours before the alert went out and 129 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 00:00Z on 1999-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 961 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 00:00Z on 1999-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 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
961 J/kg
Mixed-layer CIN
-68 J/kg
Mixed-layer LCL
1537 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
70 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 070104 RRA
SVRMLB
FLC097-070140-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
906 PM EDT THU MAY 6 1999

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     WESTERN OSCEOLA COUNTY IN EAST CENTRAL FLORIDA

* UNTIL 930 PM EDT

* AT 905 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER KISSIMMEE.  MOVEMENT WAS NORTH AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
    WILL MOVE NORTH INTO ORANGE COUNTY BY 920 PM.


SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 58
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN.
MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STRONG BUILDING.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Melbourne, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at May 6, 8:40 PM EDT, 26 minutes earlier.

Area forecast discussion, May 6, 8:40 PM EDT, 26 minutes before
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
840 PM EDT THU MAY 6 1999

WEST COAST SEA BREEZE INITIATED CONVECTION EARLY THIS EVENING...AND
EVENTUAL INTERACTION WITH EAST COAST BREEZE YIELDED SEVERAL LOCALLY
SEVERE HAILSTORMS. ACTIVITY BEGINNING TO WEAKEN AT THIS TIME AND
WILL REMOVE POPS FROM INLAND AND VOLUSIA COUNTIES LATER THIS
EVENING. SKIES CLEARING BY LATE EVENING. MINS OK.

MARINE...NO SIGNIFICANT CHANGES ANTICIPATED.

.MLB...NONE.

SPRATT/KELLY

The office that day

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

IssuedProductOfficeCountiesLasted
May 6, 8:05 PM EDTSevere Thunderstorm WarningMLBVolusia65 min
May 6, 8:58 PM EDTSevere Thunderstorm WarningMLBOrange47 min
May 6, 9:49 PM EDTSevere Thunderstorm WarningMLBOrange31 min
May 6, 9:54 PM EDTSevere Thunderstorm WarningMLBSeminole46 min
May 6, 9:58 PM EDTSevere Thunderstorm WarningMLBVolusia47 min
May 7, 2:40 PM EDTSevere Thunderstorm WarningMLBLake50 min
May 7, 3:15 PM EDTSevere Thunderstorm WarningMLBVolusia50 min
May 7, 3:33 PM EDTSevere Thunderstorm WarningMLBLake62 min
May 7, 4:05 PM EDTSevere Thunderstorm WarningMLBVolusia60 min
May 7, 4:14 PM EDTSevere Thunderstorm WarningMLBOrange31 min
May 7, 4:37 PM EDTSevere Thunderstorm WarningMLBLake48 min
May 7, 4:43 PM EDTSevere Thunderstorm WarningMLBOrange32 min
May 7, 5:11 PM EDTSevere Thunderstorm WarningMLBSeminole34 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.