Alert archive / Georgia / Tornado Watches in 2018

Tornado Watch 406

October 10, 201819 counties in Florida; 24 counties in Georgia

The Storm Prediction Center issued this tornado watch at Oct 10, 2018, 4:46 AM CDT for 19 counties in Florida; 24 counties in Georgia. It was in force for 11 hr.

The area

The outline as issued.

The facts

Issued
Oct 10, 2018, 4:46 AM CDT (09:46 UTC)
Expired
Oct 10, 2018, 4:00 PM CDT
In force
11 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 43 counties

Bay County, FL, Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gilchrist County, FL, Gulf County, FL, Hamilton County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Levy County, FL, Liberty County, FL, Madison County, FL, Suwannee County, FL, Taylor County, FL, Wakulla County, FL, Washington County, FL, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Echols County, GA, Grady County, GA, Irwin County, GA, Lanier County, GA, Lee County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Worth County, GA

The radar

The Tallahassee radar (KTLH), 38 km from the middle of the area, began a volume at 09:50 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
60%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
5%
One or more gusts of 65 knots or more
5%
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
20%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Oct 10, 9:47 AM CDTTornado WarningTBWLevy28 min
Oct 10, 2:55 PM CDTFlash Flood WarningTAEBay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 6 more6 hr

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 00:00Z, 9.8 hours before the alert went out and 40 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, Tallahassee Rgnl, FL at 00:00Z on 2018-10-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 889 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, Tallahassee Rgnl, FL at 00:00Z on 2018-10-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 115 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
889 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
754 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
115 m²/s²
0-3 km storm-relative helicity
177 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

161 
WWUS20 KWNS 100944
SEL6  
SPC WW 100944
FLZ000-GAZ000-CWZ000-102100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 406
NWS Storm Prediction Center Norman OK
545 AM EDT Wed Oct 10 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  North Florida and Peninsula
  Southwest Georgia
  Coastal Waters

* Effective this Wednesday morning and afternoon from 545 AM
  until 500 PM EDT.

* Primary threats include...
  A few tornadoes likely

SUMMARY...Outer bands of hurricane Michael will continue to spread
inland through the morning, with an increasing risk of tornadoes in
the stronger cells.

The tornado watch area is approximately along and 75 statute miles
either side of a line from 25 miles west of Panama City FL to 35
miles northeast of Cross City FL. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 15035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 10, 3:45 AM CDTMesoscale DiscussionSPCHouston3 hr
Oct 10, 10:30 AM CDTMesoscale DiscussionSPCHouston105 min
Oct 10, 7:06 AM CDTMesoscale DiscussionSPCWakulla54 min
Oct 10, 12:29 PM CDTMesoscale DiscussionSPCBaker, Columbia, Duval, Nassau, Union3 hr
Oct 10, 1:44 PM CDTTornado WatchSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 20 more11 hr
Oct 10, 3:32 PM CDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 15 more118 min

Nearby

Tornado Watches in Georgia, 2018Tornado Watches in Florida, 2018Every tornado watch in 2018

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.