Alert archive / Florida / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 64, NWS Miami, FL
NWS Miami, FL issued this severe thunderstorm warning at May 20, 1999, 2:20 PM EDT for Palm Beach County, Florida. It was in force for 65 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 20, 1999, 2:20 PM EDT (18:20 UTC)
- Expired
- May 20, 1999, 3:25 PM EDT
- In force
- 65 min
- Issued by
- NWS Miami, FL
- Area
- Whole counties
County Palm Beach County, FL
The radar
The Miami radar (KAMX), 115 km from the middle of the area, began a volume at 18:21 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 20, 2:32 PM EDT | Hail 0.75 | West Palm Beach, 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
Miami, FL (KMFL), launched 12:00Z, 6.3 hours before the alert went out and 93 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.
- 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
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KMIA 201822 RRA SVRMIA FLC099-201925- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MIAMI FL 220 PM EDT THU MAY 20 1999 THE NATIONAL WEATHER SERVICE IN MIAMI HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... NORTHEASTERN PALM BEACH COUNTY IN SOUTHEASTERN FLORIDA * UNTIL 325 PM EDT * AT 217 PM EDT...MIAMI NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM OVER THE SOUTH END OF LOXAHATCHEE SLOUGH WEST OF RIVIERA BEACH DRIFTING SOUTH VERY SLOWLY. LARGE HAIL IS LIKELY WITH THIS SEVERE THUNDERSTORM. * SOME LOCATIONS AFFECTED... ROYAL PALM BEACH...LOXAHATCHEE...20 MILE BEND...WELLINGTON... HAVERHILL SEVERE THUNDERSTORMS PRODUC E DAMAGING WIND IN EXCESS OF 55 MPH... LARGE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. SEEK SHELTER IN A STRONG BUILDING. STAY AWAY FROM WINDOWS. DO NOT USE TELEPHONES OR ELECTRICAL APPLIANCES.
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.
In the hours before
Local storm report, May 20, 9:01 AM EDT, 5 hours 19 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MIAMI FL
901 AM EDT THU MAY 20 1999
TIME(EDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
1250 PM HOLLYWOOD FL .88 INCH HAIL
05/19/99 BROWARD HOLLYWOOD BOULEVARD AND 62
AVE NICKEL SIZE HAIL AND
WIND GUST 45 TO 55 MPH.
0125 PM DAVIE FL .75 INCH HAIL
05/19/99 BROWARD WEATHER SERVICE FAMILY
MEMBER REPORTED DIME SIZE
HAIL AT GRIFFIN RD AND
UNIVERSITY IN DAVIE
0138 PM HIALEAH FL .75 INCH HAIL
05/19/99 DADE SPOTTER REPORTED 3/4 INCH
HAIL AND WIND GUSTS TO 50
MPH AT LEJEUNE RD AND SW
41ST ST
0150 PM MIAMI FL .75 INCH HAIL
05/19/99 DADE MIAMI SPRINGS DIME SIZE
HAIL REPORTED
0205 PM MIAMI FL .5 INCH HAIL
05/19/99 DADE PUBLIC REPORTED PEA SIZE
HAIL AND WIND GUSTS TO 45
MPH AT SW 8TH ST AND 67TH
AVENUE
0230 PM PERRINE FL .75 INCH HAIL
05/19/99 DADE DIME SIZE HAIL COVERED
GROUNDSpecial weather statement, May 20, 9:32 AM EDT, 4 hours 48 minutes before
FLZ063-066>075-202300- SOUTH FLORIDA HAZARDOUS WEATHER OUTLOOK...UPDATE... NATIONAL WEATHER SERVICE MIAMI FL 932 AM EDT THU MAY 20 1999 SCATTERED SHOWERS AND THUNDERSTORMS ARE AGAIN EXPECTED ON THE SOUTH FLORIDA MAINLAND TODAY. THUNDERSTORMS WILL FORM ALONG THE SEA BREEZE FRONTS AND MOVE SLOWLY TO THE EAST SOUTHEAST. CONDITIONS ARE AGAIN CONDUCIVE FOR HAIL DEVELOPMENT...GUSTY WINDS ...AND FREQUENT LIGHTNING. ADDED TODAY WILL BE THE SLOW MOVEMENT OF THE THUNDERSTORMS THAT WILL ALLOW HEAVY RAINFALL TO OCCUR THAT MAY LEAD TO LOCAL PONDING OF WATER ON ROADWAYS AND LOCAL FLOODING IN FLOOD PRONE AREAS. MARINERS...ESPECIALLY OFF OF THE DADE COUNTY COAST OUT TO 50 NM ...SHOULD BE ALERT FOR POSSIBLE WATERSPOUTS DEVELOPING THIS MORNING IN A LINE OF CLOUDS EXTENDING FROM NORTHEAST DADE COUNTY SOUTHEAST TOWARDS ANDROS ISLAND.
The office that day
Everything else NWS Miami, FL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 3:35 PM EDT | Severe Thunderstorm Warning | MFL | Broward | 60 min |
| May 20, 6:24 PM EDT | Severe Thunderstorm Warning | MFL | Collier | 31 min |
| May 20, 6:56 PM EDT | Severe Thunderstorm Warning | MFL | Hendry | 44 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.