Alert archive / Florida / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 91, NWS Melbourne, FL

June 10, 1999Indian River County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Jun 10, 1999, 5:25 PM EDT for Indian River County, Florida. It was in force for 45 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: Jun 10, 1999, 5:25 PM EDT (21:25 UTC)
Expired: Jun 10, 1999, 6:10 PM EDT
In force: 45 min
Issued by: NWS Melbourne, FL
Area: Whole counties

County Indian River County, FL

The radar

The Melbourne radar (KMLB), 47 km from the middle of the area, began a volume at 21:27 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

Tampa Bay, FL (KTBW), launched 12:00Z, 9.4 hours before the alert went out and 180 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: 646 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 900 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 43 m²/s²
0-3 km storm-relative helicity: 66 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.

990 
WUUS01 KMLB 102126 RRA
SVRMLB
FLC061-102210-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
525 PM EDT THU JUN 10 1999

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     INDIAN RIVER COUNTY IN EAST CENTRAL FLORIDA

* UNTIL 610 PM EDT

* AT 525 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 10 MILES SOUTH OF FELLSMERE...JUST WEST OF
  INTERSTATE 95. THIS STORM HAS A HISTORY OF PRODUCING LARGE HAIL.
  MOVEMENT WAS SOUTH AT 5 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
    HIGHWAY 60 THROUGH 545 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 Jun 10, 2:33 PM EDT, 2 hours 52 minutes earlier.

Area forecast discussion, Jun 10, 2:33 PM EDT, 2 hours 52 minutes before

EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
233 PM EDT THU JUN 10 1999

TONIGHT...WATER VAPOR SHOWING MOISTURE DISCONTINUITY OVER NORTHERN
SECTIONS WHERE MOST ACTIVE CONVECTION WAS OCCURRING.  REST OF EAST
COAST SEA BREEZE HAD SCATTERED SHOWERS/TSTMS ON IT AND LOW LEVEL
FLOW WAS KEEPING IT RATHER CLOSE TO THE COAST.  EXPECT THAT
BOUNDARIES WILL KICK INLAND THE REST OF THIS AFTERNOON INTO
EVENING.  CONVECTION ALONG WEST COAST WILL PUSH BOUNDARIES INLAND SO
EVENTUALLY THERE SHOULD BE SOME GOOD BOUNDARY INTERACTIONS OVER THE
INTERIOR...ESPECIALLY FROM ORLANDO NORTH.  THEREFORE WILL GO WITH
THE HIGHEST EVENING POPS THERE (40 PERCENT).

FRI...UPPER CYCLONIC SHEAR AXIS WILL PULL NORTH OF THE AREA WITH
WEAK UPPER RIDGING NUDGING NORTH FOR THE CARIBBEAN.  WATER VAPOR
LOOP INDICATES THAT THERE IS NO MAJOR SUBSIDENCE ASSOCIATED WITH
THIS RIDGE AT THE PRESENT TIME SO DO NOT EXPECT THAT DEEP MOISTURE
WILL DECREASE.  THEREFORE CONTINUED CHANCE/GOOD CHANCE POPS.
COVERAGE SHOULD BE HIGHEST INLAND AS STEERING FLOW WEAKENS AND LOW
LEVEL FLOW BECOMES MOSTLY EASTERLY.

SAT...MODELS DIFFER SOMEWHAT WITH RESPECT TO ADVECTION OF DEEP LAYER
DRY AIR ASSOCIATED WITH DIGGING UPPER LOW OFF THE MID ATLANTIC COAST.
ETA WAS MORE RESOLVED IN SWEEPING THE DRYING ACROSS WHILE AVN/NGM DO
NOT SHOW MUCH OF A DECREASE IN PRECIPITABLE WATER.  WITH SLIGHT
RETROGRESSION OF WEAK UPPER RIDGE...WOULD EXPECT THE DRIER AIR TO BE
FURTHER WEST THAN THE AVN SHOWS...SO WILL CUT POPS ABOUT 10 PERCENT
FROM FRIDAY.  LOW LEVEL EASTERLY WINDS SHOULD SHIFT MAIN FOCUS
INLAND ONCE AGAIN.

SUN THROUGH TUE...WITH A TROUGH TO OUR NORTH...EXPECT WESTERLY
STEERING FLOW AND SCATTERED AFTERNOON POPS ON THE EAST SIDE OF THE
PENINSULA.

MARINE...WEAK BACKDOOR FRONT MOVING DOWN EASTERN SEABOARD WILL KEEP
SURFACE RIDGE OVER THE OFFSHORE WATERS WEAK SO EXPECT GRADIENT TO
KEEP WINDS AROUND 10 KT TONIGHT. REINFORCING HIGH PRESSURE MAY PICK
UP GRADIENT ON FRIDAY BUT FOR NOT WILL KEEP WITH A 10 KT FORECAST.

PRELIMINARY NUMBERS...
DAB BB 072/087 073/086 073 2423
MCO TB 071/089 072/089 072 4534
MLB BB 072/087 073/086 073 2423

.MLB...NONE.

LASCODY

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 10, 4:19 PM EDT	Severe Thunderstorm Warning	MLB	Indian River	51 min

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.