Alert archive / Florida / Tornado Watches in 2005

Tornado Watch 803

September 20, 20056 counties in Florida

The Storm Prediction Center issued this tornado watch at Sep 20, 2005, 4:40 AM EDT for 6 counties in Florida. It was in force for 12 hr.

The area

The outline as issued.

The facts

Issued
Sep 20, 2005, 4:40 AM EDT (08:40 UTC)
Expired
Sep 20, 2005, 4:27 PM EDT
In force
12 hr
Issued by
the Storm Prediction Center

Counties Broward County, FL, Collier County, FL, Hendry County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 75 km from the middle of the area, began a volume at 08:39 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

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

IssuedProductOfficeCountiesLasted
Sep 20, 2:13 PM EDTTornado WarningMFLBroward35 min
Sep 20, 2:54 PM EDTTornado WarningMFLMiami-Dade36 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Miami, FL (KMFL), launched 00:00Z, 8.7 hours before the alert went out and 82 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, Miami, FL at 00:00Z on 2005-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2313 joules per kilogram.LCLEL10008507005003002001001 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, Miami, FL at 00:00Z on 2005-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 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
2313 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
690 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
65 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 
WWUS20 KWNS 200839
SEL3  
SPC WW 200839
FLZ000-CWZ000-202100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 803
NWS STORM PREDICTION CENTER NORMAN OK
440 AM EDT TUE SEP 20 2005

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

       SOUTH FLORIDA AND THE FLORIDA KEYS
       COASTAL WATERS

EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 440 AM UNTIL 500
PM EDT.

TORNADOES...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS
LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE MILES
EAST AND WEST OF A LINE FROM 25 MILES WEST NORTHWEST OF WEST PALM
BEACH FLORIDA TO 15 MILES EAST SOUTHEAST OF KEY WEST FLORIDA.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU3).

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...TROPICAL STORM RITA IS EXPECTED TO BECOME A HURRICANE
TODAY WHILE MOVING WWD ACROSS THE FL STRAITS.  LOW-LEVEL SHEAR AND
WINDS SHOULD CONTINUE TO INCREASE OVER S FL AND THE KEYS
TODAY...SUPPORTING A THREAT FOR A FEW MINI SUPERCELLS AND A COUPLE
OF TORNADOES WITH THE OUTER NRN BANDS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH EXTREME
TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI
WITH MAXIMUM TOPS TO 550. MEAN STORM MOTION VECTOR 09040.


...THOMPSON

264,0792 242,0803 242,0823 264,0812

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 20, 2:42 PM EDTMesoscale DiscussionSPCBroward, Collier, Hendry, Miami-Dade, Monroe, Palm Beach2 hr
Sep 20, 4:30 PM EDTTornado WatchSPCBroward, Collier, Miami-Dade, Monroe9 hr

Nearby

Tornado Watches in Florida, 2005Every tornado watch in 2005

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.