Alert archive / Florida / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 39, NWS Tampa Bay, FL

July 20, 2000Polk County, Florida

NWS Tampa Bay, FL issued this severe thunderstorm warning at Jul 20, 2000, 7:13 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 counties it named, with what was reported inside it.

The facts

Issued
Jul 20, 2000, 7:13 PM EDT (23:13 UTC)
Expired
Jul 20, 2000, 7:45 PM EDT
In force
32 min
Issued by
NWS Tampa Bay, FL
Area
Whole counties

County Polk County, FL

What was reported inside it

TimeReportWhereRemark
Jul 20, 7:25 PM EDTHail 0.75Loughman, FLThe public reported dime sized hail in Loughman along U.S. Highway 92 near the Polk-Osceola county line.

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, 11.2 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 2000-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3636 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tampa Bay, FL at 12:00Z on 2000-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
3636 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
608 m above ground
0-6 km bulk shear
2 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
54 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 
WUUS52 KTBW 202314
SVRTBW
FLC105-202345-
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
713 PM EDT THU JUL 20 2000

THE NATIONAL WEATHER SERVICE IN RUSKIN HAS ISSUED A

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

* UNTIL 745 PM EDT.

* AT 713 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM WITH LARGE HAIL AND DAMAGING WINDS...OVER
  EASTERN POLK COUNTY...MOVING NORTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT...
  RURAL EASTERN POLK COUNTY.

THIS IS A DANGEROUS STORM! DESTRUCTIVE WIND GUSTS TO 60 MPH WILL 
CAUSE LOCALLY MAJOR STRUCTURAL DAMAGE. MOBILE HOMES ARE NOT SAFE! 
TAKE COVER NOW.

QUARTER SIZE HAIL IS LIKELY. MOVE INDOORS IMMEDIATELY.

$$

LAT...LON 2804 8160 2793 8145 2823 8110 2839 8131

RK
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 20, 2:17 PM EDT, 4 hours 56 minutes earlier.

Area forecast discussion, Jul 20, 2:17 PM EDT, 4 hours 56 minutes before
WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
217 PM EDT THU JUL 20 2000

LOW LVL SW FLOW WILL CONTINUE TO DOMINATE THIS PACKAGE...AND
PROBABLY BEYOND.  WITH NO SIG CHANGE TO THE UPPER PATN ACROSS NOAM
(STRONG WESTERN U.S. RIDGE...CONTINUED TROFFINESS ACROSS THE E)...
THE STATUS QUO IS THE BEST BET.

UNFORTUNATELY...COMBINING THIS TYPE OF PATTERN WITH A VERY HUMID LOW
LVL AIR MASS MEANS IT'S NEXT TO IMPOSSIBLE TO TIME CONVECTIVE
ACTIVITY.  IN FACT...THE BEST FORECAST MAY BE A COMBINATION OF
PERSISTENCE AND CLIMATOLOGY BLENDED WITH CURRENT OR EXPECTED SHORT
TERM CONDITIONS.

THE ONE THING WE CAN COUNT ON IS MORE HEAT AND HUMIDITY.  HOWEVER...
WE REMAIN ON THE CRUX OF TRUE HEAT ADZY CONDITIONS.  FOR THE NEXT
24H...EXPECT A VIRTUAL REPEAT OF THE PAST REGARDING AMBIENT AND
"FEELS LIKE" TEMPS.  SINCE THE ONLY LOCATIONS WHICH MEET THE LOW TEMP
CRITERIA ARE ON THE IMMEDIATE COAST AND URBAN CENTERS (ASSUMING NO
TSTMS TO KNOCK VALUES DOWN)...WE PREFER TO KEEP HEADLINING AFTN
VALUES IN LIEU OF ADZY.  THIS ALSO JIBES WITH JAX/MLB/TLH.

THE FCST:  TONIGHT...STARTING FROM THE COAST...EXPECT ACTIVITY TO
CONTINUE TO FIRE NOW (MID AFTN)...BUT DIE BEFORE SUNSET.  WILL
PROBABLY CARRY A RMDR AFTN/EVE PERIOD...LEAVING THE OVERNIGHT FAIR.
THE ONLY EXCEPTION IS THE SW CORNER (SARASOTA CO/S)...WHERE WE'VE
SEEN REPEATED SHOTS OF PCPN OVERNIGHT.  WILL CARRY AN EVENING POP
INTERIOR COS...THEN FAIR.  TEMPS GENERALLY 75 TO 80...HIGHEST NEAR
THE COAST.

FRI...THE BEST GUESS HERE IS THAT LOW LVL SW FLOW WILL PUSH BEST
COVERAGE INTO INTERIOR ZONES BY MID AFTN.  FORCING REMAINS IN THE
FORM OF A SHEAR AXIS...BUT AREA STILL UNDER INFLUENCE OF UPPER
RIDGE.  FOR NOW...WILL CALL IT CHC POPS CENTRAL/N COAST...SCT PCPN
SW THROUGH NE (AS TODAY).

FRI NIGHT...ALL MODELS ARE SHOWING SLOW HEIGHT FALLS FROM H50-H85...
WITH SW WINDS DEEPENING FROM THE SFC-H85 LAYER.  THIS WOULD TEND
TO INCREASE NOCTURNAL ACTIVITY...SO WILL PLAY IT SAFE WITH A
PTCLDY/30 POP (NO TIMING) ALONG THE COAST...AND SCT RESIDUAL EVE
ACTIVITY INLAND.

SAT...NO SENSE IN GETTING CUTE HERE.  ETA IS MOST PRONOUNCED WITH
PENINSULAR MEAN RH...BUT TREND APPEARS TO BE FOR A TEMPORARY
WEAKENING OF SW FLOW WHICH WOULD FAVOR AN OVERALL INCREASE IN
COVERAGE.  WILL GO MIDDLING POPS EVERYWHERE.

EXTENDED...MRF SHOWS A CONTINUED TREND FOR DEEPENING SW FLOW IN
RESPONSE TO DEVELOPING TROF ACROSS THE LOWER MIDWEST/MS VALLEY
REGION.  OF COURSE...WE SAW THIS ABOUT A WEEK AGO...AND IT DIDN'T
PAN OUT QUITE AS EXPECTED.  WILL MODIFY TO GENERIC "CURRENT"
PATTERN.

MARINE:  LOTSA S/SW FLOW...ALL FAIRLY LIGHT (OUTSIDE OF CONVECTION).

FIRE WX:  HIGH HUMIDITY AND SCT CONVECTION MEANS NO FLAG PROBLEMS.
LEVY CO MAY TOUCH 40 PERCENT DUE TO HIGH TEMPS FRI (MU 90S)...BUT
THAT'S ABOUT IT.

PRELIM NUMBERS...
TPA 080/091/078/091 1335
FMY 078/091/077/092 3435 88

.TBW...NONE.

GOLDSMITH

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 7:56 PM EDTSevere Thunderstorm WarningTBWPolk24 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.