Alert archive / Florida / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 68, NWS Tallahassee, FL

August 18, 1990Calhoun County, Florida

NWS Tallahassee, FL issued this severe thunderstorm warning at Aug 18, 1990, 5:21 PM CDT for Calhoun County, Florida. It was in force for 39 min.

The area

The counties it named.

The facts

Issued
Aug 18, 1990, 5:21 PM CDT (22:21 UTC)
Expired
Aug 18, 1990, 6:00 PM CDT
In force
39 min
Issued by
NWS Tallahassee, FL
Area
Whole counties

County Calhoun County, FL

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Apalachicola Mun, FL (KAQQ), launched 12:00Z, 10.4 hours before the alert went out and 78 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, Apalachicola Mun, FL at 12:00Z on 1990-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2311 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, Apalachicola Mun, FL at 12:00Z on 1990-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 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
2311 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
821 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
24 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 KTLH 182222
SVRTLH
FLC013-182300-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TALLAHASSEE FL
621 PM EDT (521 PM CDT) SAT AUG 18 1990
 
THE NATIONAL WEATHER SERVICE IN TALLAHASSEE HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  700 PM EDT (600 PM CDT)
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTH FLORIDA
 
   ...SOUTHWESTERN CALHOUN COUNTY
 
NATIONAL WEATHER SERVICE RADAR INDICATED A SEVERE THUNDERSTORM 5 MILES
SOUTHEAST OF YOUNGSTOWN MOVING TOWARD THE SOUTH SOUTHWEST AT 10 MILES
AN HOUR.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECT[ION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

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

Special weather statement, Aug 18, 3:29 PM CDT, 1 hour 52 minutes before
FLZ005-182130-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
426 PM EDT SAT AUG 18 1990

AT 425 PM EDT NATIONAL WEATHER SERVICE RADAR INDICATED A STRONG
THUNDERSTORM 10 MILES NORTHEAST OF TALLAHASSEE OVER NORTHERN LEON
COUNTY. THIS THUNDERSTORM IS CAPABLE OF PRODUCING VERY HEAVY
RAINFALL...FREQUENT CLOUD TO GROUND LIGHTNING...STRONG GUSTY
WINDS...AND POSSIBLE SMALL HAIL.

MOVEMENT WAS TOWARD THE SOUTH SOUTHWEST AT 10 MILES AN HOUR AND THIS
THUNDERSTORM SHOULD MOVE ACROSS THE EASTERN HALF OF LEON COUNTY OF
NORTH FLORIDA DURING THE NEXT HOUR.

JGM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 4:19 PM CDTSevere Thunderstorm WarningTAEJackson26 min
Aug 18, 5:02 PM CDTSevere Thunderstorm WarningTAEBay58 min
Aug 18, 5:05 PM CDTSevere Thunderstorm WarningTAEGadsden, Liberty40 min

Nearby

Severe Thunderstorm Warnings in Florida, 1990Every severe thunderstorm warning in 1990

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.