Alert archive / Florida / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 21, NWS Jacksonville, FL

March 8, 1991Saint Johns County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Mar 8, 1991, 5:10 PM EST for Saint Johns County, Florida. It was in force for 60 min.

The area

The counties it named.

The facts

Issued: Mar 8, 1991, 5:10 PM EST (22:10 UTC)
Expired: Mar 8, 1991, 6:10 PM EST
In force: 60 min
Issued by: NWS Jacksonville, FL
Area: Whole counties

County Saint Johns County, FL

The nearest sounding before it

Jacksonville, FL (KAYS), launched 12:00Z, 10.2 hours before the alert went out and 71 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: 100 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 569 m above ground
0-6 km bulk shear: 81 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 245 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 KJAX 082213
SVRJAX
FLC109-082310-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING...CORRECTED
NATIONAL WEATHER SERVICE JACKSONVILLE FL
510 PM EST FRI MAR 8 1991

THE NATIONAL WEATHER SERVICE IN JACKSONVILLE FL   HAS ISSUED A
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING
EFFECTIVE UNTIL 610 PM EST


IN NORTHEAST FLORIDA

   ...ST JOHNS COUNTY

  AND

  ...COASTAL WATERS OFFSHORE ST AUGUSTINE TO MARINELAND...

AT 510 PM EST WEATHER RADAR INDICATED A CLUSTER OF THUNDERSTORMS NEARING
WESTERN ST JOHNS COUNTY NEAR HASTINGS. IT IS MOVING EAST TO SOUTHEAST
AT UP TO 40 MPH. AS THESE THUNDERSTORMS MOVE INTO THE ST AUGUSTINE AREA
THEY WILL LIKELY CONTAIN STRONG GUSTY WINDS...DANGEROUS LIGHTNING STRIKES
...AND LOCALLY HEAVY RAINFALL.

MARINE INTERESTS OPERATING IN THE COASTAL WATERS OFF ST JOHNS COUNTY
BE PREPARED TO SEEK SAFE HARBOR.

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, Mar 8, 4:11 PM EST, 59 minutes before

FLZ008-007-009-082300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSONVILLE FL
415 PM EST FRI MAR 8 1991

AN AREA OF SHOWERS AND THUNDERSTORMS IS MOVING THROUGH NORTHEST FLORIDA.
OF PARTICULAR INTEREST IS A CLUSTER OF THUNDERSTORMS MOVING OVER LAKE BUTLER
IN UNION COUNTY FLORIDA. RADAR INDICATES THAT MODERATE TO HEAVY RAINS
ARE ASSOCIATED WITH THE CLUSTER OF THUNDERSTORMS THAT IS MOVING EAST AT
SPEEDS OF UP TO 40 MPH.

AS THESE THUNDERSTORMS MOVE EAST AT 40 MPH THEY WILL BE MOVING INTO
THE STARKE..LAWTEY AREA IN BRADFORD COUNTY WITHIN THE HOUR ACCOMPANIED
BY PERIODS OF BRIEF GUSTY WINDS..HEAVY RAINS AND DANGEROUS LIGHTNING
STRIKES. OTHER THUNDERSTORMS ARE DEVELOPING RAPIDLY JUST SOUTHWEST
OF JACKSONVILLE...AND IN NORTH JACKSONVILLE.

MOST EXPERTS AGREE THAT THE SINGLE MOST IMPORTANT THING YOU CAN DO
DURING A THUNDERSTORM IS TO GET INDOORS..STAY AWAY FROM ELECTRICAL
FIXTURES SUCH AS TELEPHONES..HAIR DRYERS ETC.

Nearby

Severe Thunderstorm Warnings in Florida, 1991 Every severe thunderstorm warning in 1991

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.