Alert archive / Florida / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 76, NWS Melbourne, FL

May 28, 1999Seminole County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at May 28, 1999, 4:29 PM EDT for Seminole County, Florida. It was in force for 46 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: May 28, 1999, 4:29 PM EDT (20:29 UTC)
Expired: May 28, 1999, 5:15 PM EDT
In force: 46 min
Issued by: NWS Melbourne, FL
Area: Whole counties

County Seminole County, FL

The radar

The Melbourne radar (KMLB), 88 km from the middle of the area, began a volume at 20:32 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

Time	Report	Where	Remark
May 28, 5:00 PM EDT	Hail 1	Geneva, FL
May 28, 5:10 PM EDT	Thunderstorm Wind 50	Geneva, FL	Thunderstorm winds blew down a few trees south of Geneva.

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, 8.5 hours before the alert went out and 160 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: 45 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 911 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 55 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 282032 RRA
SVRMLB
FLC117-282115-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
429 PM EDT FRI MAY 28 1999

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

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

* UNTIL 515 PM EDT

* AT 430 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER LAKE JESSUP.  MOVEMENT WAS SOUTH AT 15
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
    GENEVA BY 445 PM

THIS IS A DANGEROUS STORM. BE PREPARED FOR DAMAGING WIND IN EXCESS
OF 58 MPH...LARGE HAIL AND DEADLY LIGHTNING. PEOPLE OUTSIDE OR IN
MOBILE HOMES SHOULD MOVE INSIDE A STRONG BUILDING AND STAY AWAY FROM
WINDOWS.

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 28, 2:30 PM EDT, 1 hour 59 minutes earlier.

Area forecast discussion, May 28, 2:30 PM EDT, 1 hour 59 minutes before

EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
230 PM EDT FRI MAY 28 1999

AS OF MID AFTERNOON...LOW LEVEL CONVERGENCE ASSOCIATED WITH EAST
COAST SEA BREEZE LEADING TO WIDELY SCATTERED SHOWERS AND A FEW
LIGHTNING STORMS OVER THE COASTAL COUNTIES. MINIMUM OF CU FORMATION
ON SATELLITE LOOPS OVER SOUTHERN/WESTERN PORTION OF THE STATE
INDICATE LESSER EXTENT OF MOISTURE. SURFACE OBSERVATIONS CONFIRM THIS AS
DEWPOINTS HAVE FALLEN INTO LOWER/MID 60S...DUE TO VERTICAL MIXING OF
DRY AIRMASS. HOWEVER...SOME ADDITIONAL STORM FORMATION LIKELY AS THE
WEST COAST BOUNDARY INTERACTS WITH LAKE BREEZES AND OTHER OUTFLOWS
OVER THE CENTRAL FL INTERIOR. WESTERLY FLOW ALOFT WILL ADVECT THE
BRUNT OF ACTIVITY TOWARDS THE EAST SIDE OF BY EARLY EVENING. EXPECT
SOME LINGERING CONVECTION EARLY TONIGHT ALONG THE EAST COAST. SKIES
WILL BECOME PARTLY/MOSTLY CLEAR OVERNIGHT WITH MINS NEAR CLIMO.

SATURDAY AND SUNDAY...BROAD MID/UPPER TROUGH SHOWS AMPLIFICATION
ALONG THE EAST COAST. ASSOCIATED DEEP LAYER DRYING FORECAST TO MOVE
SOUTHWEST OVER THE ATLANTIC BUT REMAIN EAST OF THE AREA.  SURFACE
HIGH SHOWN BY ALL MODELS TO STRENGTHEN WITH DEPTH OF ONSHORE FLOW
INCREASING. WOULD THEREFORE EXPECT COVERAGE OF SHOWERS AND STORMS TO
CONTINUE TO BE AT LEAST SCATTERED.  ACTIVITY SHOULD START TO FAVOR
THE EARLY PART OF THE DAY ALONG THE EAST COAST BY SUNDAY AS ONSHORE
FLOW DEEPENS TO AROUND 700 MB.

MEMORIAL DAY THROUGH WEDNESDAY...MID/UPPER RIDGE PUSHING EAST INTO
THE ATLANTIC SHOULD ALLOW WEAK UPSTREAM TROUGH TO PUSH TOWARDS
EASTERN SEABOARD.  00Z MRF WAS SUGGESTING SOME DEEP LAYER DRYING
MOVING IN FROM THE EAST ON MEMORIAL DAY...BUT 12Z AVN BRINGS
MOISTURE ASSOCIATED WITH TROUGH ACROSS THE PENINSULA...SO IT LOOKS
LIKE CONTINUATION OF MOIST EASTERLY FLOW REGIME.

MARINE...BUOYS STILL SHOWING ONLY 10 KT AND LATEST RUC CONTINUES
THIS INTO THE EVENING.  OTHER MODELS SHOWS SOME 15 KT WINDS LATER
TONIGHT BUT THE ACTUAL PRESSURE GRADIENT STILL LOOKS LIKE IT
SUPPORTS AROUND 10 KT.  ALL INDICATE THAT GRADIENT WILL INCREASE
SATURDAY AND WILL SHOW TREND TO 10 TO 15 KT IN SECOND PERIOD.

PRELIMINARY
DAB BB 070/083 071/083 072 2423
MCO BB 070/086 071/086 071 2423
MLB BB 072/085 073/084 074 2323

.MLB...NONE.

SPRATT/LASCODY

The office that day

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

Issued	Product	Office	Counties	Lasted
May 28, 4:06 PM EDT	Tornado Warning	MLB	Indian River	49 min
May 28, 5:47 PM EDT	Severe Thunderstorm Warning	MLB	Lake	58 min
May 28, 6:42 PM EDT	Tornado Warning	MLB	Lake	33 min
May 28, 6:47 PM EDT	Tornado Warning	MLB	Orange	48 min
May 28, 7:14 PM EDT	Tornado Warning	MLB	Osceola	56 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.