Alert archive / Florida / Tornado Watches in 1998

Tornado Watch 829

September 25, 199815 counties in Florida

The Storm Prediction Center issued this tornado watch at Sep 25, 1998, 6:15 AM EDT for 15 counties in Florida. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Sep 25, 1998, 6:15 AM EDT (10:15 UTC)
Expired: Sep 25, 1998, 1:00 PM EDT
In force: 7 hr
Issued by: the Storm Prediction Center

Counties Broward County, FL, Charlotte County, FL, Collier County, FL, DeSoto County, FL, Glades County, FL, Hendry County, FL, Highlands County, FL, Lee County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Okeechobee County, FL, Palm Beach County, FL, Saint Lucie County, FL, Sarasota County, FL

The radar

The Miami radar (KAMX), 101 km from the middle of the area, began a volume at 10:17 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.

Warnings issued inside it

5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Sep 25, 6:43 AM EDT	Tornado Warning	MLB	Saint Lucie	62 min
Sep 25, 7:23 AM EDT	Tornado Warning	MLB	Okeechobee	62 min
Sep 25, 7:29 AM EDT	Tornado Warning	MLB	Martin	61 min
Sep 25, 8:05 AM EDT	Flash Flood Warning	MLB	Martin, Saint Lucie	115 min
Sep 25, 10:08 AM EDT	Tornado Warning	MLB	Saint Lucie	67 min

The nearest sounding before it

Miami, FL (KMFL), launched 00:00Z, 10.3 hours before the alert went out and 89 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: 1419 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 969 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 83 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.

177 
WWUS9 KMKC 250951
SEL9  
MKC WW 250951
FLZ000-251700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 829
STORM PREDICTION CENTER NORMAN OK
551 AM EDT FRI SEP 25 1998

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   SOUTHERN FLORIDA                            
   AND ADJACENT COASTAL WATERS

EFFECTIVE THIS FRIDAY MORNING AND AFTERNOON FROM 615 AM UNTIL 100
PM EDT.

TORNADOES...HAIL TO 1 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 85 STATUTE MILES EAST AND WEST
OF A LINE FROM 65 MILES NORTH NORTHEAST OF FORT MEYERS FLORIDA TO
70 MILES SOUTH SOUTHWEST OF MIAMI FLORIDA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.


DISCUSSION...CONVECTION DEVELOPING AROUND HURRICANE GEORGES
INCREASING AS IT APPROACHES SOUTHEASTERN FLORIDA COASTAL AREAS.
STRONG LOW LEVEL WIND SHEAR DETECTED ON AREA RADARS INDICATING
POTENTIAL FOR A FEW BRIEF TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. 
MEAN STORM MOTION VECTOR 13050.

...ROGASH

272,0800 245,0792 245,0820 272,0825

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 25, 11:00 AM EDT	Tornado Watch	SPC	Brevard, Broward, Charlotte, Citrus, Collier, DeSoto and 23 more	12 hr

Nearby

Tornado Watches in Florida, 1998 Every tornado watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.