Alert archive / Florida / Tornado Watches in 2009
Tornado Watch 790
The Storm Prediction Center issued this tornado watch at Dec 2, 2009, 2:46 PM EST for 20 counties in Florida; 11 counties in Georgia. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 2, 2009, 2:46 PM EST (19:46 UTC)
- Expired
- Dec 2, 2009, 10:00 PM EST
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 31 counties
Alachua County, FL, Baker County, FL, Bradford County, FL, Citrus County, FL, Clay County, FL, Columbia County, FL, Duval County, FL, Flagler County, FL, Gilchrist County, FL, Hamilton County, FL, Hernando County, FL, Levy County, FL, Marion County, FL, Nassau County, FL, Pasco County, FL, Putnam County, FL, Saint Johns County, FL, Sumter County, FL, Suwannee County, FL, Union County, FL, Appling County, GA, Bacon County, GA, Brantley County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Echols County, GA, Glynn County, GA, Pierce County, GA, Ware County, GA, Wayne County, GA
The radar
The Jacksonville radar (KJAX), 46 km from the middle of the area, began a volume at 19:47 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
- 30%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 2, 2:56 PM EST | Tornado Warning | JAX | Appling, Bacon, Pierce | 49 min |
| Dec 2, 3:19 PM EST | Severe Thunderstorm Warning | JAX | Appling, Bacon, Wayne | 41 min |
| Dec 2, 3:40 PM EST | Severe Thunderstorm Warning | JAX | Brantley, Pierce, Wayne | 65 min |
| Dec 2, 4:09 PM EST | Tornado Warning | JAX | Baker, Columbia | 24 min |
| Dec 2, 4:38 PM EST | Severe Thunderstorm Warning | JAX | Appling, Wayne | 21 min |
| Dec 2, 4:56 PM EST | Severe Thunderstorm Warning | JAX | Brantley, Charlton, Ware | 11 min |
| Dec 2, 5:40 PM EST | Severe Thunderstorm Warning | JAX | Duval, Nassau | 65 min |
| Dec 2, 7:50 PM EST | Severe Thunderstorm Warning | JAX | Alachua, Bradford, Clay, Marion, Putnam | 40 min |
| Dec 2, 8:01 PM EST | Severe Thunderstorm Warning | TBW | Citrus, Hernando, Pasco, Pinellas | 29 min |
| Dec 2, 8:13 PM EST | Severe Thunderstorm Warning | JAX | Clay, Duval, Putnam, Saint Johns | 47 min |
| Dec 2, 8:23 PM EST | Severe Thunderstorm Warning | JAX | Clay, Duval, Nassau | 39 min |
| Dec 2, 8:32 PM EST | Severe Thunderstorm Warning | TBW | Hernando, Hillsborough, Pasco, Pinellas, Sumter | 28 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
Jacksonville, FL (KJAX), launched 12:00Z, 7.8 hours before the alert went out and 47 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
- 157 J/kg
- Mixed-layer CIN
- -28 J/kg
- Mixed-layer LCL
- 602 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 283 m²/s²
- 0-3 km storm-relative helicity
- 304 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 2, 12:10 AM EST | Mesoscale Discussion | SPC | Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 8 more | 2 hr |
| Dec 2, 4:11 AM EST | Tornado Watch | SPC | Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 9 more | 6 hr |
| Dec 2, 6:02 AM EST | Mesoscale Discussion | SPC | Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 9 more | 58 min |
| Dec 2, 9:52 AM EST | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Columbia, Dixie, Gilchrist and 9 more | 83 min |
| Dec 2, 10:32 AM EST | Tornado Watch | SPC | Columbia, Dixie, Franklin, Gadsden, Gilchrist, Hamilton and 8 more | 6 hr |
| Dec 2, 12:48 PM EST | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Columbia, Dixie, Gilchrist and 9 more | 117 min |
| Dec 2, 6:39 PM EST | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Citrus, Clay, Columbia and 12 more | 96 min |
| Dec 2, 1:31 PM EST | Mesoscale Discussion | SPC | Baldwin, Bleckley, Bryan, Bulloch, Burke, Candler and 23 more | 89 min |
| Dec 2, 2:08 PM EST | Tornado Watch | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Columbia and 11 more | 8 hr |
| Dec 2, 5:44 PM EST | Mesoscale Discussion | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Columbia and 11 more | 91 min |
Nearby
Tornado Watches in Florida, 2009Tornado Watches in Georgia, 2009Every tornado watch in 2009
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.