Alert archive / Florida / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 41, NWS Tampa Bay, FL

July 21, 2000Polk County, Florida

NWS Tampa Bay, FL issued this severe thunderstorm warning at Jul 21, 2000, 2:38 PM EDT for Polk County, Florida. It was in force for 37 min. 2 reports 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
Jul 21, 2000, 2:38 PM EDT (18:38 UTC)
Expired
Jul 21, 2000, 3:15 PM EDT
In force
37 min
Issued by
NWS Tampa Bay, FL
Area
Whole counties

County Polk County, FL

What was reported inside it

TimeReportWhereRemark
Jul 21, 2:40 PM EDTHail 0.88Lake Alfred, FLThe public reported, through WTVT-TV of Tampa, nickel sized hail near the intersection of U.S. Highways 92 and 17 in Lake Alfred of northern Polk county.
Jul 21, 2:50 PM EDTThunderstorm WindLake Alfred, FLPolk County Emergency Management reported that thunderstorm winds downed several large trees and a few power poles along County Road 557 in Lake Alfred to State Road 60 in Bartow.

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 nearest sounding before it

Tampa Bay, FL (KTBW), launched 12:00Z, 6.6 hours before the alert went out and 74 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 2000-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3275 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 2000-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 47 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
3275 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
643 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
47 m²/s²
0-3 km storm-relative helicity
33 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.

863 
WUUS52 KTBW 211839
SVRTBW
FLC105-211915-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
238 PM EDT FRI JUL 21 2000

THE NATIONAL WEATHER SERVICE IN RUSKIN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN POLK COUNTY.

* UNTIL 315 PM EDT.

* AT 238 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM WITH LARGE HAIL AND DAMAGING WINDS...OVER     
  AUBURNDALE...MOVING NORTH AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT...
  LAKE ALFRED.

SEVERE THUNDERSTORMS CONTAIN WIND GUSTS OF 60 MPH OR HIGHER...AND
HAIL THE SIZE OF DIMES OR LARGER. MOVE TO A PLACE OF SAFETY.

$$

LAT...LON 2809 8182 2811 8164 2826 8163 2832 8180

88
NNNN

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 Jul 21, 1:37 PM EDT, 1 hour 1 minute earlier.

Area forecast discussion, Jul 21, 1:37 PM EDT, 1 hour 1 minute before
WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
137 PM EDT FRI JUL 21 2000

ACTION FIRING QUICKLY AS EXPECTED...AND MORE WIDESPREAD ACTIVITY BY
MID AFTERNOON...SO WILL KEEP THIS BRIEF.

UNSETTLED IS THE WATCHWORD FOR THE WEEKEND.  FALLING HEIGHTS FROM
THE MIDWEST THROUGH THE CENTRAL GULF WILL ALLOW PERSISTENT SHORT
WAVE(S) AND/OR SHEAR AXIS TO REMAIN ACROSS THE PENINSULA RIGHT
THROUGH THE WEEKEND.  IRONICALLY...ALL MODELS ARE CONSISTENT ON
THIS BIG PICTURE...WHICH (HOPEFULLY) WILL MAKE THIS A GOOD FORECAST
PACKAGE.

IN A NUTSHELL...PLENTY OF CLOUDS...SCT TO NUMEROUS SHOWERS AND
TSTMS...AND CONTINUED MUGGY (BUT WITH LOWER HEAT INDICES GIVEN MORE
CLOUD COVER).  POPS NOT REALLY A FACTOR...RANGING FROM THE HIGH CHC
(SCT) RANGE TO THE LOW LIKELY RANGE.  ULTIMATELY...AN MCS (OR TWO)
IS POSSIBLE...BUT IT'S FAR TOO EARLY TO SPECULATE ON WHEN AND WHERE.

THE FCST:  TONIGHT...ALL MODELS LEAVE SHEAR AXIS AND ABUNDANT MEAN
RH ACROSS THE CWFA.  THE TREND IS TO DRIFT THE BEST LIFT/RH INTO
THE GULF OVERNIGHT.  FOR THIS REASON...AND GIVEN CONTINUED SW LOW
LVL FLOW...WILL NOT TIME PCPN HERE.  FOR INLAND AREAS...MOST ACTION
WILL BE THIS EVENING...BUT COULD WELL LAST TOWARD MIDNIGHT.

SAT...THE MEAN GUIDANCE NUMBERS GIVE 60 POP INTERIOR...AND 50 POP
COAST.  WITH SHEAR AXIS IN PLACE...OLD BOUNDARIES...AND A HINT OF
BETTER SEA BREEZE COLLISION AS LOW LVL FLOW BECOMES A SHADE MORE
SOUTHERLY...LIKELY POPS OVER INTERIOR PORTIONS IS PLAUSIBLE.
CERTAINLY...THIS COULD BE THE CASE EVERYWHERE BUT WILL DEFER TO THE
NEXT SHIFT TO MAKE FINAL DETERMINATION.

SAT NIGHT...SHEAR AXIS GETS "ACTIVATED" BY UPSTREAM ACTIVITY...
WHICH FURTHER DEEPENS THE TROUGH.  IN ADDITION...SW FLOW MAY
STRENGTHEN A TAD.  WILL CONTINUE 50 POP (NO TIMING) ON THE COAST...
MAINLY EVENING INLAND.

SUN...ONCE AGAIN...STRAIGHT MODEL SOLNS ARGUE FOR LIKELY POPS
EVERYWHERE.  BUT...MODEL SOLNS ARE ALWAYS APT TO CHANGE.  WILL FCST
CLIMO (50) EVERYWHERE.

FOR CLOUDS...VRBL CLOUDS CERTAINLY A GOOD BET WITH THIS PATTERN...
PERHAPS A BIT LESS OVER INTERIOR PORTIONS OVERNIGHT.  FOR TEMPS...
CLIMO DURING THE DAY...A SMIDGE WARMER (MU 70S) AT NIGHT.

MARINE:  NOTHING DIFFICULT HERE.  AVG WINDS GENERALLY 5 TO 10
KNOTS...HIGHER IN TSTMS.  DIRECTION SW...PERHAPS A BIT MORE S BY
SUN NIGHT.

FIRE WX:  COMBINATION OF SHOWERS AND HIGH RH MEANS NO RED FLAG
CONDITIONS.

PRELIM NUMBERS:
TPA TT 077/091/077/091 5555
FMY TT 076/091/076/091 4545 88

.TBW...NONE.

GOLDSMITH

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 5:07 PM EDTSevere Thunderstorm WarningTBWHillsborough23 min
Jul 21, 5:08 PM EDTSevere Thunderstorm WarningTBWHillsborough37 min

Nearby

Severe Thunderstorm Warnings in Florida, 2000Every severe thunderstorm warning in 2000

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.