Alert archive / Florida / Tornado Warnings in 1998

Tornado Warning 31, NWS Tampa Bay, FL

February 20, 1998Hillsborough County, Florida

NWS Tampa Bay, FL issued this tornado warning at Feb 20, 1998, 2:20 AM EST for Hillsborough County, Florida. It was in force for 30 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
Feb 20, 1998, 2:20 AM EST (07:20 UTC)
Expired
Feb 20, 1998, 2:50 AM EST
In force
30 min
Issued by
NWS Tampa Bay, FL
Area
Whole counties

County Hillsborough County, FL

The radar

The Tampa radar (KTBW), 23 km from the middle of the area, began a volume at 07:20 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
Feb 20, 2:20 AM ESTThunderstorm WindRuskin, FLThunderstorm winds downed numerous trees and power lines across the southern portion of Hillsborough County.

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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Feb 19, 9:00 PM ESTTornado WatchSPC6 hr

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 00:00Z, 7.3 hours before the alert went out and 23 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, Tampa Bay, FL at 00:00Z on 1998-02-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 762 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, Tampa Bay, FL at 00:00Z on 1998-02-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 267 square meters per square second.1939587897Sfc1 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
762 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
786 m above ground
0-6 km bulk shear
78 kt
0-1 km storm-relative helicity
267 m²/s²
0-3 km storm-relative helicity
289 m²/s²
Significant tornado parameter
1.6
Supercell composite
7.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

044 
WFUS1 KTBW 200719 RRA
TORTBW
FLC057-200750-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
220 AM EST FRI FEB 20 1998

THE NATIONAL WEATHER SERVICE HAS ISSUED A...TORNADO WARNING
EFFECTIVE UNTIL 250 AM EST FOR

...POLK COUNTY

AT 218 AM EST... NATIONAL WEATHER SERVICE DOPPLER RADAR IN RUSKIN
INDICATED A SEVERE THUNDERSTORM WITH A DEVELOPING TORNADO JUST SOUTH OF
PLANT CITY NEAR HIGHWAYS 39 AND 60. THIS STORM WILL MOVING TOWARD THE
SOUTH LAKELAND AND WINTER HAVEN AREA.

A DOPPLER RADAR DETECTED TORNADO MEANS THAT THERE IS STRONG
ROTATION WITHIN A STORM. THE STORM MAY NOT BE PRODUCING A TORNADO AT
THE MOMENT...BUT WILL LIKELY DURING THE WARNING PERIOD. THE STORM MAY
ALSO INCLUDE HAIL AND DAMAGING STRAIGHT LINE WIND. THOSE IN THE PATH
OF THE STORM ARE ADVISED TO TAKE COVER IMMEDIATELY.

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Tampa Bay, FL wrote its last area forecast discussion before this tornado warning went out at Feb 19, 7:15 PM EST, 7 hours 5 minutes earlier.

Area forecast discussion, Feb 19, 7:15 PM EST, 7 hours 5 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY-RUSKIN, FL
715 PM EST THU FEB 19 1998

CONVECTION OVR CNTRL/NRN FA ASSOCIATED WITH MESOSCALE/SYNOPTIC SCALE
BNDRYS COMBINED WITH UPR JET AND UPR DIVERGENCE. ADDITIONAL ACTIVITY
OFFSHORE IN ADVANCE OF SFC FNT. NHC PLOTS SFC BNDRY ACRS SRN FL WHICH
MAY TRIGGER ACTIVITY OVR THE SRN FA. EXPECT SHOWERS AND THUNDERSTORMS
TO CONTINUE OVR THE FA OVERNIGHT AS THE FNT APPROACHES THE FA AND THE
UPR DYNAMICS REMAIN SOMEWHAT. CONVECTION WL END NW TO SE AFTER FROPA
FRI. CURRENT FCST REASONABLE.

11

In the hours before

Special weather statement, Feb 19, 11:11 PM EST, 3 hours 9 minutes before
FLZ043-048-049-200440-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
1111 PM EST THU FEB 19 1998

...THE TORNADO WATCH FOR THE COUNTIES OF HERNANDO...PASCO AND
   SUMTER HAS BEEN CANCELLED...

...THE TORNADO WATCH REMAINS FOR THE COUNTIES OF PINELLAS...
   HILLSBOROUGH... MANATEE... SARASOTA... CHARLOTTE... POLK...
   HIGHLANDS... DESOTO ... AND HARDEE...

AT 1110 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THAT STRONG TO SEVERE THUNDERSTORMS HAVE MOVED OUT OF THE FOREGOING
COUNTIES. HOWEVER...RESIDENTS SHOULD REMAIN ALERT FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TONIGHT.

COLLINS

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 19, 8:22 PM ESTTornado WarningTBWHillsborough, Pasco48 min
Feb 19, 9:44 PM ESTSevere Thunderstorm WarningTBWPinellas51 min
Feb 19, 9:53 PM ESTSevere Thunderstorm WarningTBWHillsborough, Manatee47 min
Feb 19, 10:48 PM ESTSevere Thunderstorm WarningTBWManatee47 min
Feb 19, 10:54 PM ESTSevere Thunderstorm WarningTBWPolk46 min
Feb 20, 12:14 AM ESTSevere Thunderstorm WarningTBWHillsborough66 min
Feb 20, 1:25 AM ESTFlash Flood WarningTBWHillsborough, Pinellas4 hr
Feb 20, 2:10 AM ESTSevere Thunderstorm WarningTBWHillsborough, Manatee30 min

Nearby

Tornado Warnings in Florida, 1998Every tornado warning in 1998Tornadoes 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.