Alert archive / Florida / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 72, NWS Melbourne, FL

May 20, 1999Martin County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at May 20, 1999, 1:45 PM EDT for Martin County, Florida. It was in force for 60 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 20, 1999, 1:45 PM EDT (17:45 UTC)
Expired: May 20, 1999, 2:45 PM EDT
In force: 60 min
Issued by: NWS Melbourne, FL
Area: Whole counties

County Martin County, FL

The radar

The Melbourne radar (KMLB), 117 km from the middle of the area, began a volume at 17:48 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

Miami, FL (KMFL), launched 12:00Z, 5.8 hours before the alert went out and 141 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 946 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 1066 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 32 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.

000 
TTAA00 KMLB 201745 RRA
SVRMLB
FLC085-201845-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
145 PM EDT THU MAY 20 1999

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     NORTH CENTRAL MARTIN COUNTY IN EAST CENTRAL FLORIDA

* UNTIL 245 PM EDT

* AT 140 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 15 MILES WEST OF PALM CITY.  MOVEMENT WAS
  STATIONARY.

* THE SEVERE THUNDERSTORM WILL REMAIN NEAR...
    THE I-95 AND ROUTE 714 INTERSECTION THROUGH 230 PM.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 58
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN.
MTOVE 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 20, 10:43 AM EDT, 3 hours 2 minutes earlier.

Area forecast discussion, May 20, 10:43 AM EDT, 3 hours 2 minutes before

EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
945 AM EDT THU MAY 20 1999

FORECAST OF LOW POPS LOOKS GOOD ATTM...ANY CHANGES WOULD BE
INSIGNIFICANT.   MORNING SOUNDINGS ACROSS FL PEN ARE UNIMPRESSIVE.
WEAK LAPSE RATES ABV H85...WEAK TO MARGINAL INSTABILITY
PARAMETERS...AND MODERATE PW/RH VALUES.  MODELS SHOW DECENT H70
OMEGA OVER CWA DUE TO SEA BREEZE EFFECTS...BUT H50 VORT MAX IS
ALREADY TO THE SE OF THE CAPE.  BEST POPS OVER SRN CWA WITH HIGHEST
MOISTURE VALUES AND PVA.

MARINE...MINOR CHANGE TO WIND DIRECTION.

.MLB...NONE.

BRAGAW/BLOTTMAN

Nearby

Severe Thunderstorm Warnings in Florida, 1999 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.