Alert archive / Florida / Tornado Watches in 2011
Tornado Watch 833
The Storm Prediction Center issued this tornado watch at Sep 4, 2011, 11:41 AM CDT for 5 counties in Alabama; 17 counties in Florida; 14 counties in Georgia. It was in force for 10 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 4, 2011, 11:41 AM CDT (16:41 UTC)
- Expired
- Sep 4, 2011, 10:00 PM CDT
- In force
- 10 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 36 counties
Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Brooks County, GA, Calhoun County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Miller County, GA, Mitchell County, GA, Seminole County, GA, Thomas County, GA
The radar
The Tallahassee radar (KTLH), 76 km from the middle of the area, began a volume at 16:45 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 SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 50%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 4, 4:03 PM CDT | Tornado Warning | TAE | Taylor | 27 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
Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 4.7 hours before the alert went out and 77 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.
- Mixed-layer CAPE
- 1223 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 468 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 95 m²/s²
- 0-3 km storm-relative helicity
- 179 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.3
The text
As transmitted, in the capitals the NWS used until 2016.
840
WWUS20 KWNS 041640
SEL3
SPC WW 041640
ALZ000-FLZ000-GAZ000-CWZ000-050300-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 833
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM EDT SUN SEP 4 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
EXTREME SOUTHEAST ALABAMA
FLORIDA PANHANDLE
SOUTHWEST GEORGIA
COASTAL WATERS
EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1240 PM UNTIL
1100 PM EDT.
TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHWEST OF ALBANY
GEORGIA TO 25 MILES EAST SOUTHEAST OF APALACHICOLA 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.
OTHER WATCH INFORMATION...CONTINUE...WW 832...
DISCUSSION...BANDS OF TSTMS HAVE CONTINUED TO EVOLVE WELL-DOWNSTREAM
OF THE CENTER OF TS LEE WITHIN A SECONDARY SLY LLJ MAX AND AMIDST
MODEST DIABATIC HEATING. TLH PROFILER AND DIAGNOSTIC DATA INDICATE
THAT LLVL SHEAR PROFILES WILL CONTINUE TO INCREASE THROUGH THE
AFTN/EVE WITH POTENTIAL FOR SHALLOW SUPERCELLS AND ATTENDANT BRIEF
TORNADO RISK. ACTIVITY WILL SPREAD NWD INTO SWRN GA WITH TIME AS
LEE BECOMES ELONGATED AND WIND FIELDS EXPAND FARTHER DOWNSTREAM.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 17025.
...RACYSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 3, 9:43 PM CDT | Tornado Watch | SPC | Baldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more | 9 hr |
| Sep 3, 11:35 PM CDT | Mesoscale Discussion | SPC | Baldwin, Escambia, Mobile, Washington | 115 min |
| Sep 4, 4:30 AM CDT | Mesoscale Discussion | SPC | Baldwin, Clarke, Conecuh, Escambia, Mobile, Monroe and 1 more | 60 min |
| Sep 4, 5:05 AM CDT | Tornado Watch | SPC | Baldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 8 more | 11 hr |
| Sep 4, 9:50 AM CDT | Mesoscale Discussion | SPC | Baldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 12 more | 85 min |
| Sep 4, 2:47 PM CDT | Mesoscale Discussion | SPC | Autauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 26 more | 88 min |
| Sep 4, 3:47 PM CDT | Tornado Watch | SPC | Autauga, Baldwin, Butler, Choctaw, Clarke, Conecuh and 13 more | 6 hr |
| Sep 4, 6:29 PM CDT | Mesoscale Discussion | SPC | Autauga, Baldwin, Barbour, Bullock, Butler, Choctaw and 22 more | 2 hr |
| Sep 4, 11:27 AM CDT | Mesoscale Discussion | SPC | Calhoun, Gadsden, Jackson, Jefferson, Leon, Liberty and 2 more | 33 min |
Nearby
Tornado Watches in Florida, 2011Tornado Watches in Georgia, 2011Tornado Watches in Alabama, 2011Every tornado watch in 2011
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.