Alert archive / Florida / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 67, NWS Miami, FL

July 4, 1998Monroe County, Florida

NWS Miami, FL issued this severe thunderstorm warning at Jul 4, 1998, 4:58 PM EDT for Monroe County, Florida. It was in force for 47 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
Jul 4, 1998, 4:58 PM EDT (20:58 UTC)
Expired
Jul 4, 1998, 5:45 PM EDT
In force
47 min
Issued by
NWS Miami, FL
Area
Whole counties

County Monroe County, FL

The radar

The Miami radar (KAMX), 51 km from the middle of the area, began a volume at 20:57 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
Jul 4, 5:20 PM EDTThunderstorm Wind 65Marathon, FLASOS at Marathon Airport recorded 50 knots at 1620 EDT. The C-MAN at Sombrero Key recorded 59 knots. A storm spotter estimated wind gusts of 65 knots. Signs and trees were downed throughout the Marathon area. Several boats were swamped. Five people were knocke

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, 9.0 hours before the alert went out and 69 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, Miami, FL at 12:00Z on 1998-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1054 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, Miami, FL at 12:00Z on 1998-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 square meters per square second.1939Sfc1 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
1054 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
1476 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
56 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 KMIA 042058 RRA
SVRMIA
FLC087-042145-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MIAMI FL
458 PM EDT SAT JUL 4 1998

THE NATIONAL WEATHER SERVICE IN MIAMI HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MONROE MIDDLE KEYS IN SOUTHERN FLORIDA
  MONROE LOWER KEYS IN SOUTHERN FLORIDA

* UNTIL 545 PM EDT

* AT 455 PM A SEVERE THUNDERSTORM WAS INDICATED OVER FLORIDA BAY 10
  MILES NORTH OF MARATHON IN THE MIDDLE KEYS. THE STORM IS MOVING
  SOUTH AT 15 TO 20 MPH. DAMAGING WIND GUSTS IN EXCESS OF 60 MPH
  AND LARGE HAIL ARE LIKELY WITH THIS STORM. TAKE COVER IMMEDIATELY!!

* SOME LOCATIONS AFFECTED INCLUDE MARATHON TO DUCK KEY BETWEEN 505
  AND 510 PM AND BAHIA HONDA KEY BY 515 PM.

SEVERE THUNDERSTORMS PRODUCE 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.

IF YOU ARE CAUGHT OUTSIDE...SEEK REFUGE FROM THE WEATHER IN A
STRONG BUILDING. DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...
AND DEADLY LIGHTNING ARE ALL POSSIBLE IN A SEVERE THUNDERSTORM.
STAY INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 4, 3:00 PM EDTSevere Thunderstorm WarningMFLCollier65 min
Jul 4, 3:18 PM EDTSevere Thunderstorm WarningMFLMiami-Dade57 min
Jul 4, 6:18 PM EDTSevere Thunderstorm WarningMFLMiami-Dade47 min

Nearby

Severe Thunderstorm Warnings in Florida, 1998Every severe thunderstorm warning in 1998

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.