Alert archive / Florida / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 59, NWS Tampa Bay, FL

August 18, 2002Polk County, Florida

NWS Tampa Bay, FL issued this severe thunderstorm warning at Aug 18, 2002, 7:28 PM EDT for Polk County, Florida. It was in force for 32 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 18, 2002, 7:28 PM EDT (23:28 UTC)
Expired
Aug 18, 2002, 8:00 PM EDT
In force
32 min
Issued by
NWS Tampa Bay, FL
Area
Counties, with a storm outline in the text

County Polk County, FL

The radar

The Tampa radar (KTBW), 56 km from the middle of the area, began a volume at 23:30 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
Aug 18, 7:35 PM EDTThunderstorm WindLakeland, FLEmergency Management reported numerous trees down in the Lakeland Heights subdivision.

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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 12:00Z, 11.5 hours before the alert went out and 56 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 12:00Z on 2002-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1203 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 12:00Z on 2002-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 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
1203 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
814 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
43 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.

469 
WUUS52 KTBW 182328
SVRTBW
FLC105-190000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
727 PM EDT SUN AUG 18 2002

THE NATIONAL WEATHER SERVICE IN RUSKIN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN POLK COUNTY IN FLORIDA.

* UNTIL 800 PM EDT

* AT 727 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM WITH LARGE HAIL AND DAMAGING WINDS...10 MILES
  SOUTHWEST OF LAKELAND...MOVING WEST AT 5 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT AREAS WEST OF...
  LAKELAND HIGHLANDS.
  WINSTON.

MOVE INSIDE A STURDY BUILDING. DAMAGING WIND...LARGE HAIL...
TORRENTIAL RAIN...AND DEADLY LIGHTNING ARE EXPECTED. STAY INSIDE AWAY
FROM WINDOWS UNTIL THE STORM HAS PASSED.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE
INDOORS IMMEDIATELY. DO NOT USE ELECTRICAL APPLIANCES OR TELEPHONES.

&&

LAT...LON 2804 8204 2787 8196 2796 8179 2817 8191

$$

23

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.

NWS Tampa Bay, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 18, 2:35 PM EDT, 4 hours 53 minutes earlier.

Area forecast discussion, Aug 18, 2:35 PM EDT, 4 hours 53 minutes before
WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
235 PM EDT SUN AUG 18 2002

CURRENTLY...VISIBLE SATELLITE IMAGERY AND 88D RETURNS DEPICT
DEVELOPING CONVECTION ALONG BOTH EAST AND WEST COAST SEA BREEZE
BOUNDARIES EARLY THIS AFTERNOON. LAPS SOUNDING DATA DEPICTS A VERY
MOIST AND UNSTABLE AIR MASS COVERING THE FA...SO AS THE AFTERNOON
CONTINUES EXPECT TO SEE ADDITIONAL CONVECTIVE DEVELOPMENT TO OCCUR AS
MESO-SCALE BOUNDARY INTERACTION TAKE PLACE. OVERALL STEERING FLOW IS
WEAK BUT STILL FROM A SE-SLY DIRECTION...SO WILL AGAIN KEEP HIGHEST
POPS (30%) ALONG MY COASTAL ZONES FOR THE EVENING HOURS.

SHORT TERM(TON-WED)...MODEL TREND CONTINUE TO BE QUITE SIMILAR TO
PREVIOUS RUNS...ALTHOUGH MODELS CONTINUE TO DIFFER EVER SO SLIGHTLY
WITH RESPECT TO PWS AND THE EXACT POSITION OF SFC RIDGE AXIS OVER
THE NEXT FEW DAYS. IN DEALING WITH THE PWS THE MODELS CONTINUE TO
INSIST ON SLIGHTLY LOWER VALUES OVER THE NEXT SEVERAL DAYS (PWS
DROPPING TO BETWEEN 1.5 AND 1.6) WHICH IN TURN ARE REFLECTED IN THE
BELOW CLIMO POPS ADVERTISED BY GUIDANCE. SEEING THAT THE TREND FOR
LOWER PWS HAS YET TO REALLY MATERIALIZE...AND I DONT SEE WHERE IT
WILL COME ON THE CURRENT WV LOOP...WILL OPT TO KEEP POPS NEAR CLIMO
LEVEL (50%) COASTAL ZONES...AND 40% INTERIOR THROUGH THE PERIOD WITH
THE MAIN TRIGGER FOR CONVECTION BEING THE AFTERNOON SEA/LAKE BREEZE
BOUNDARY INTERACTIONS. GUIDANCE TEMPERATURES CONTINUE TO BE VERY
SIMILAR...SO WILL USE A BLEND.

EXTENDED(THURS-SUN)...LATEST AVN SOLUTION CONTINUES TO DEPICT A
SPRAWLING UPPER RIDGE TO DOMINATE MUCH OF THE SERN U.S. AND FL DURING
THIS TIME FRAME WITH A RENEWED SFC HIGH CENTER BUILDING IN ALONG THE
MID ATLANTIC. LITTLE CHANGE IN MOISTURE PROFILES AND AN EASTERLY FLOW
AROUND THE HIGH TO THE NORTH WILL CONTINUE TO SUPPORT SCATTERED
SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE PERIOD...MAINLY DURING
THE AFTERNOON AND EARLY EVENING HOURS. NO TEMPERATURE CHANGES WITH
READINGS CONTINUING AROUND OR SLIGHTLY ABOVE CLIMO-LEVELS.

MARINE...SURFACE RIDGE AXIS SETTING UP JUST NORTH OF THE LAKE WILL
PROVIDE TRANQUIL BOATING CONDITIONS ACROSS THE MARINE WATERS FOR MUCH
OF THE UPCOMING WORK WEEK. EXPECT LIGHT SE-SLY WINDS IN THE 5-10 KNOT
RANGE WITH SLIGHT SEAS AND A DAILY SEA BREEZE COMPONENT DEVELOPING
NEAR SHORE EACH AFTERNOON. NO HIGHLIGHTS EXPECTED.

FIRE WEATHER...NO CONCERNS.

PRELIMINARY #S
BKV 071/092 071/091 3535
TPA 075/092 075/090 3535
GIF 074/093 074/093 2424
SRQ 074/090 074/090 3535
FMY 074/092 074/092 3535

.TBW...NONE.

MCMICHAEL

Nearby

Severe Thunderstorm Warnings in Florida, 2002Every severe thunderstorm warning in 2002

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.