Alert archive / Florida / Tornado Watches in 2015

Tornado Watch 576

December 28, 201510 counties in Alabama; 13 counties in Florida; 5 counties in Georgia

The Storm Prediction Center issued this tornado watch at Dec 28, 2015, 11:04 AM CST for 10 counties in Alabama; 13 counties in Florida; 5 counties in Georgia. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Dec 28, 2015, 11:04 AM CST (17:04 UTC)
Expired
Dec 28, 2015, 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 28 counties

Butler County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw 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, Liberty County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, Clay County, GA, Decatur County, GA, Early County, GA, Miller County, GA, Seminole County, GA

The radar

The Eglin Afb radar (KEVX), 58 km from the middle of the area, began a volume at 17:12 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
30%
One or more gusts of 65 knots or more
10%
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

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

IssuedProductOfficeCountiesLasted
Dec 28, 11:37 AM CSTSevere Thunderstorm WarningMOBButler, Crenshaw26 min
Dec 28, 11:50 AM CSTTornado WarningMOBButler12 min
Dec 28, 12:31 PM CSTSevere Thunderstorm WarningMOBOkaloosa, Santa Rosa44 min
Dec 28, 12:51 PM CSTSevere Thunderstorm WarningMOBButler, Crenshaw39 min
Dec 28, 1:12 PM CSTSevere Thunderstorm WarningMOBCovington48 min
Dec 28, 1:40 PM CSTSevere Thunderstorm WarningTAEGeneva80 min
Dec 28, 1:55 PM CSTSevere Thunderstorm WarningMOBCovington35 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, 5.1 hours before the alert went out and 205 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 2015-12-28Temperature 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 2015-12-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.193958Sfc1 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
769 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
141 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.

556 
WWUS20 KWNS 281702
SEL6  
SPC WW 281702
ALZ000-FLZ000-GAZ000-CWZ000-290000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 576
NWS STORM PREDICTION CENTER NORMAN OK
1105 AM CST MON DEC 28 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHERN ALABAMA
  FLORIDA PANHANDLE
  EXTREME SOUTHWEST GEORGIA
  COASTAL WATERS

* EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1105 AM UNTIL
  600 PM CST.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

SUMMARY...THUNDERSTORMS ARE EXPECTED TO SPREAD FROM WEST TO EAST
ACROSS THE WATCH AREA THIS AFTERNOON WITH A RISK FOR A COUPLE OF
TORNADOES AND LOCALLY DAMAGING WIND GUSTS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES WEST NORTHWEST OF
DOTHAN ALABAMA TO 25 MILES SOUTHWEST OF PANAMA CITY FLORIDA.  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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 575...

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 21035.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 28, 6:41 AM CSTTornado WatchSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 27 more5 hr
Dec 28, 8:38 AM CSTMesoscale DiscussionSPCColbert, Franklin, Lauderdale, Lawrence, Limestone, Madison and 1 more67 min
Dec 28, 10:21 AM CSTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Blount, Bullock, Butler and 34 more84 min
Dec 28, 2:27 PM CSTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Dale, Geneva, Pike33 min
Dec 28, 3:31 PM CSTMesoscale DiscussionSPCBarbour, Russell29 min
Dec 28, 5:07 PM CSTMesoscale DiscussionSPCHouston53 min

Nearby

Tornado Watches in Florida, 2015Tornado Watches in Alabama, 2015Tornado Watches in Georgia, 2015Every tornado watch in 2015

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.