Alert archive / Florida / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 19, NWS Melbourne, FL

April 29, 1999Lake County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Apr 29, 1999, 5:27 PM EDT for Lake County, Florida. It was in force for 48 min. 2 reports 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, 5:27 PM EDT (21:27 UTC)
Expired
Apr 29, 1999, 6:15 PM EDT
In force
48 min
Issued by
NWS Melbourne, FL
Area
Whole counties

County Lake County, FL

The radar

The Melbourne radar (KMLB), 126 km from the middle of the area, began a volume at 21:31 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, 5:45 PM EDTThunderstorm Wind 60Umatilla, FLThunderstorm winds blew down trees and power lines, destroyed a barn and damaged the roof of a mobile home in Umatilla. One mobile home was damaged by a falling tree.
Apr 29, 5:45 PM EDTHail 1.75Umatilla, 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, 9.5 hours before the alert went out and 136 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 292125 RRA
SVRMLB
FLC069-292215-

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

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

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

* UNTIL 615 PM EDT

* AT 525 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM ABOUT OT ENTER LAKE COUNTY NEAR EMERALDA.
  MOVEMENT WAS SOUTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
    UMATILLA BY 540 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.

CRISTALDI

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 Apr 29, 3:45 PM EDT, 1 hour 42 minutes earlier.

Area forecast discussion, Apr 29, 3:45 PM EDT, 1 hour 42 minutes before
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
134 PM EDT THU APR 29 1999

CURRENTLY...INFLUENCE OF DEVELOPING ATLC LOW INCREASING ACROSS CWA.
METARS SHOW INCREASING N COMPONENT TO SFC WINDS...ACTUALLY BECOMING
NE ALONG THE N COASTAL AREAS. LOW CLOUDS ALSO DEVELOPING ACROSS
NORTH FL BEHIND THE "BACK DOOR" FRONT...WHICH WILL CONTINUE TO SAG
SOUTH TOWARDS NORTHERN CWA.

TONIGHT...RESIDUAL CONVECTION WILL EXIT OFFSHORE FAIRLY RAPIDLY AS
FRONT BEGINS TO PUSHES THROUGH AREA. AS LOW LEVEL MOISTURE INTERACTS
WITH SOME WEAK COOL ADVECTION AND INCREASIN 500MB PVA...THERE
SHOULD BE DEVELOPMENT OF A LOW SC OR ST DECK OVER THE CWA WITH SOME
LIGHT RAIN DEVELOPING...NOT QUITE AS MUCH AS IMPLIED BY THE ETA/NGM.

FRI...MODELS FAIRLY SIMILAR AT 500MB...ALTHOUGH I'VE FOLLOWED THE
ETA/AVN EARLY ON WITH RESPECT TO INTENSITY OF THE ATLC SURFACE LOW.
N-NW WINDS TO INCREASE BY AFTERNOON AS LOW GRADUALLY INTENSIFIES
OFFSHORE. WITH 500MB LOW ONLY DROPPING SLOWLY SOUTH...LOW WILL GO
ABSOLUTELY NOWHERE FOR A WHILE. TEMPS LOOK TO BE IN THE L-M70S AT
BEST AREA-WIDE WITH BKN-OVC LOW CLOUDS AND SOME PERIODS OF LIGHT RAIN
SOCKING IN AS SECOND VORT LOBE ROTATES AROUND 500MB. FAIRLY HEFTY
MODEL POPS SEEM JUSTIFIED...AND COVERAGE MAY ACTUALLY BE HIGHER THAN
WHAT MOS IS SAYING.

LONG TERM...OMEGA PATTERN WILL INCH ACROSS THE E HALF OF U.S.
THROUGH EXTENDED FCST PD.  DUE TO THE STAGNENT FORWARD MOTION...THE
DEVELOPING SW ATLC LOW WILL HAVE THE OPPORTUNITY TO BE ENHANCED BY
SEVERAL JET CORES FROM THE NRN H25 JET STREAM THROUGH 12Z SUN.  AS THE
LOW SQUEEZES WITH THE EWD MOVING OMEGA SYSTEM...PRESSURE GRADIENT
WILL BECOME QUITE PACKED.  H50 VORT LOBES SHOULD BE CLEAR OF FL PEN
BY 00Z SUN AS DRY AIR OVER THE MIDWEST IS PULLED SE INTO THE GULF
REGION.  CLOUDY SKIES SHOULD BREAK UP 00Z-12Z SUN...BUT WINDY
CONDITIONS WILL CONTINUE THROUGH SUN AS THE LOW PULLS AWAY.  DRY WX
TO RETURN FOR THE FIRST PART OF THE WEEK.

MARINE...ALL MODELS INDICATING ONSHORE WINDS NEAR GALE FORCE OVER
NRN COASTAL WATERS ON SAT.  ADD A NORTHEAST SWELL AND A FULL MOON
FRI NIGHT...AND THE COASTAL SITUATION LOOKS BLEAK FOR THE WEEKEND.
AFTER EXTENSIVE COOR WITH KJAX AND KMIA WILL GO WITH HIGHEST SEAS
AND WINDS OVER NRN WATERS...SOMEWHAT LESS OVER SRN WATERS.  WILL
HOLD OFF CFW FOR NOW...BUT SOMETHING TO KEEP IN MIND SHOULD THE
LATEST MODEL RUNS VERIFY.

PRELIMINARY NUMBERS...

DAB RE 063/072 062/072 061 81386
MCO RE 064/073 061/074 060 81386
MLB RE 064/076 065/075 062 81386=

.MLB...NONE

CRISTALDI/BRAGAW

In the hours before

Special weather statement, Apr 29, 11:45 AM EDT, 5 hours 42 minutes before
FLZ041-044>047-053-054-058-059-064-292100-

EAST CENTRAL FLORIDA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MELBOURNE FL
1145 AM EDT THU APR 29 1999

...A FEW SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

CONDITIONS REMAIN FAVORABLE FOR THE FORMATION OF SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF EAST CENTRAL FLORIDA TODAY. RAINFALL
COVERAGE IS NOT EXPECTED TO BE QUITE AS HIGH AS ON WEDNESDAY...
HOWEVER MANY AREAS WILL STILL EXPERIENCE MUCH NEEDED RAINFALL. THE
GREATEST CHANCE FOR RAIN WILL OCCUR NORTH OF A LINE FROM LAKELAND TO
CAPE CANAVERAL...IN ADVANCE OF A COLD FRONT WHICH WILL MOVE INTO
NORTH FLORIDA THIS AFTERNOON.

INITIAL STORM DEVELOPMENT IS EXPECTED TO OCCUR AROUND MID DAY NEAR
THE FLORIDA WEST COAST AND NEAR SOME OF THE LARGER INLAND LAKES.
A LATE AFTERNOON SEA BREEZE IS ALSO EXPECTED TO FORM ALONG THE
IMMEDIATE EAST COASTAL AREAS. STORMS ALONG THE WEST COAST BREEZE
WILL MOVE SOUTHEAST AT 20 MPH ACROSS THE PENINSULA AND SHOULD
INTERACT WITH THE EAST COAST SEA BREEZE VERY LATE THIS AFTERNOON

DRIER AND COOLER AIR AT MID LEVELS OF THE ATMOSPHERE WILL INCREASE
THE LIKELIHOOD FOR A FEW STORMS TO BECOME SEVERE. THE GREATEST
THREAT FOR SEVERE WEATHER WILL BE DAMAGING HAIL AND WIND GUSTS.
FREQUENT CLOUD TO GROUND LIGHTNING...AND LOCALLY HEAVY RAIN WILL
ALSO OCCUR WITH THE STRONGER STORMS. RAINFALL MAY TOTAL AN INCH OR
MORE IN A FEW SPOTS.

MARINE OUTLOOK...SCATTERED THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS
THE INTRACOASTAL WATERWAYS AND INTO THE COASTAL WATERS THIS
AFTERNOON AND EVENING. A FEW OF THE STORMS MAY PRODUCE SQUALLS WITH
LARGE HAIL...FREQUENT LIGHTNING AND WATERSPOUTS. STORM MOTION WILL
BE FASTER TODAY THAN RECENT DAYS. WIND AND SEAS WILL INCREASE FRIDAY
AND FRIDAY NIGHT...POSSIBLY TO GALE FORCE...AS LOW PRESSURE FORMS
OFFSHORE.

SKYWARN ACTIVATION MAY BE REQUIRED TODAY. HAM RADIO OPERATORS ARE
ASKED TO SELF ACTIVATE WEATHER NETWORKS IF SEVERE WEATHER BECOMES
IMMINENT.

CRISTALDI
Special weather statement, Apr 29, 11:45 AM EDT, 5 hours 42 minutes before
FLZ041-044>047-053-054-058-059-064-292100-

EAST CENTRAL FLORIDA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MELBOURNE FL
1145 AM EDT THU APR 29 1999

...A FEW SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

CONDITIONS REMAIN FAVORABLE FOR THE FORMATION OF SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF EAST CENTRAL FLORIDA TODAY. RAINFALL
COVERAGE IS NOT EXPECTED TO BE QUITE AS HIGH AS ON WEDNESDAY...
HOWEVER MANY AREAS WILL STILL EXPERIENCE MUCH NEEDED RAINFALL. THE
GREATEST CHANCE FOR RAIN WILL OCCUR NORTH OF A LINE FROM LAKELAND TO
CAPE CANAVERAL...IN ADVANCE OF A COLD FRONT WHICH WILL MOVE INTO
NORTH FLORIDA THIS AFTERNOON.

INITIAL STORM DEVELOPMENT IS EXPECTED TO OCCUR AROUND MID DAY NEAR
THE FLORIDA WEST COAST AND NEAR SOME OF THE LARGER INLAND LAKES.
A LATE AFTERNOON SEA BREEZE IS ALSO EXPECTED TO FORM ALONG THE
IMMEDIATE EAST COASTAL AREAS. STORMS ALONG THE WEST COAST BREEZE
WILL MOVE SOUTHEAST AT 20 MPH ACROSS THE PENINSULA AND SHOULD
INTERACT WITH THE EAST COAST SEA BREEZE VERY LATE THIS AFTERNOON

DRIER AND COOLER AIR AT MID LEVELS OF THE ATMOSPHERE WILL INCREASE
THE LIKELIHOOD FOR A FEW STORMS TO BECOME SEVERE. THE GREATEST
THREAT FOR SEVERE WEATHER WILL BE DAMAGING HAIL AND WIND GUSTS.
FREQUENT CLOUD TO GROUND LIGHTNING...AND LOCALLY HEAVY RAIN WILL
ALSO OCCUR WITH THE STRONGER STORMS. RAINFALL MAY TOTAL AN INCH OR
MORE IN A FEW SPOTS.

MARINE OUTLOOK...SCATTERED THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS
THE INTRACOASTAL WATERWAYS AND INTO THE COASTAL WATERS THIS
AFTERNOON AND EVENING. A FEW OF THE STORMS MAY PRODUCE SQUALLS WITH
LARGE HAIL...FREQUENT LIGHTNING AND WATERSPOUTS. STORM MOTION WILL
BE FASTER TODAY THAN RECENT DAYS. WIND AND SEAS WILL INCREASE FRIDAY
AND FRIDAY NIGHT...POSSIBLY TO GALE FORCE...AS LOW PRESSURE FORMS
OFFSHORE.

SKYWARN ACTIVATION MAY BE REQUIRED TODAY. HAM RADIO OPERATORS ARE
ASKED TO SELF ACTIVATE WEATHER NETWORKS IF SEVERE WEATHER BECOMES
IMMINENT.

CRISTALDI

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 29, 6:07 PM EDTSevere Thunderstorm WarningMLBOrange, Seminole63 min
Apr 29, 6:34 PM EDTSevere Thunderstorm WarningMLBOkeechobee61 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.