Alert archive / Florida / Tornado Watches in 2018

Tornado Watch 433

December 1, 20187 counties in Alabama; 15 counties in Florida; 5 counties in Georgia

The Storm Prediction Center issued this tornado watch at Dec 1, 2018, 11:16 AM CST for 7 counties in Alabama; 15 counties in Florida; 5 counties in Georgia. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Dec 1, 2018, 11:16 AM CST (17:16 UTC)
Expired
Dec 1, 2018, 6:00 PM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 27 counties

Coffee County, AL, Covington County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Escambia County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Leon County, FL, Liberty County, FL, Okaloosa County, FL, Santa Rosa County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Decatur County, GA, Early County, GA, Grady County, GA, Miller County, GA, Seminole County, GA

The radar

The Eglin Afb radar (KEVX), 31 km from the middle of the area, began a volume at 17:18 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Dec 1, 1:15 PM CSTFlash Flood WarningMOBEscambia, Santa Rosa6 hr
Dec 1, 1:24 PM CSTSevere Thunderstorm WarningTAEBay, Walton, Washington66 min
Dec 1, 1:43 PM CSTTornado WarningTAEBay, Washington47 min
Dec 1, 4:01 PM CSTTornado WarningTAEGadsden12 min
Dec 1, 5:16 PM CSTTornado WarningTAEWalton, Washington10 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, 5.3 hours before the alert went out and 133 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 12:00Z on 2018-12-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2018-12-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 259 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
976 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
259 m²/s²
0-3 km storm-relative helicity
531 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

211 
WWUS20 KWNS 011714
SEL3  
SPC WW 011714
ALZ000-FLZ000-GAZ000-CWZ000-020000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 433
NWS Storm Prediction Center Norman OK
1115 AM CST Sat Dec 1 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southeast Alabama
  Florida Panhandle
  Southwest Georgia
  Coastal Waters

* Effective this Saturday morning and evening from 1115 AM until
  600 PM CST.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...Scattered intense cells offshore will spread into the
watch area this afternoon, while other storms form slightly farther
north.  The strongest cells may be capable of damaging wind gusts
and isolated tornadoes.

The tornado watch area is approximately along and 70 statute miles
north and south of a line from 20 miles south southwest of Crestview
FL to 15 miles east northeast of Tallahassee FL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

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 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 25035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 1, 4:31 AM CSTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 2 more59 min
Dec 1, 1:35 PM CSTMesoscale DiscussionSPCCoffee, Covington, Dale, Geneva, Houston85 min
Dec 1, 3:07 PM CSTMesoscale DiscussionSPCAutauga, Bibb, Chilton, Clay, Coosa, Dallas and 10 more113 min
Dec 1, 3:38 PM CSTMesoscale DiscussionSPCCoffee, Covington, Dale, Geneva, Houston97 min
Dec 1, 5:28 PM CSTMesoscale DiscussionSPCColbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 7 more62 min
Dec 1, 5:53 PM CSTTornado WatchSPCCoffee, Covington, Dale, Geneva, Henry, Houston9 hr
Dec 1, 10:45 AM CSTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 4 more2 hr

Nearby

Tornado Watches in Florida, 2018Tornado Watches in Alabama, 2018Tornado Watches in Georgia, 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.