Alert archive / Florida / Tornado Watches in 2017

Tornado Watch 118

April 3, 201712 counties in Florida

The Storm Prediction Center issued this tornado watch at Apr 3, 2017, 12:32 PM CDT for 12 counties in Florida. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Apr 3, 2017, 12:32 PM CDT (17:32 UTC)
Expired: Apr 3, 2017, 7:00 PM CDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

Counties Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL

The radar

The Tallahassee radar (KTLH), 28 km from the middle of the area, began a volume at 17:35 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: 30%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Apr 3, 1:42 PM CDT	Severe Thunderstorm Warning	TAE	Bay, Calhoun, Gulf, Liberty	33 min
Apr 3, 2:42 PM CDT	Severe Thunderstorm Warning	TAE	Gadsden, Jefferson, Leon, Wakulla	33 min
Apr 3, 3:13 PM CDT	Severe Thunderstorm Warning	TAE	Jefferson, Leon	32 min
Apr 3, 3:38 PM CDT	Severe Thunderstorm Warning	TAE	Jefferson, Madison	37 min
Apr 3, 4:08 PM CDT	Severe Thunderstorm Warning	TAE	Madison	37 min
Apr 3, 6:09 PM CDT	Severe Thunderstorm Warning	TAE	Franklin, Gulf	36 min
Apr 3, 6:28 PM CDT	Severe Thunderstorm Warning	TAE	Franklin, Liberty, Wakulla	47 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, 5.5 hours before the alert went out and 31 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1400 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 580 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 136 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 9.3

Open this sounding in Storm Lab

The text

As transmitted.

734 
WWUS20 KWNS 031728
SEL8  
SPC WW 031728
FLZ000-CWZ000-040000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 118
NWS Storm Prediction Center Norman OK
130 PM EDT Mon Apr 3 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  North Florida
  Coastal Waters

* Effective this Monday afternoon and evening from 130 PM until
  800 PM EDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...A line of thunderstorms will continue to track eastward
across the FL Panhandle this afternoon into a moist and unstable air
mass.  Locally damaging wind gusts and an isolated tornado or two
are the primary threats.

The tornado watch area is approximately along and 70 statute miles
east and west of a line from 25 miles north northeast of Tallahassee
FL to 30 miles east southeast of Apalachicola FL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).

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 116...WW 117...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 27025.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 3, 6:43 AM CDT	Mesoscale Discussion	SPC	Bay, Calhoun, Escambia, Holmes, Jackson, Okaloosa and 3 more	2 hr
Apr 3, 7:06 AM CDT	Tornado Watch	SPC	Bay, Calhoun, Escambia, Gulf, Holmes, Jackson and 4 more	6 hr
Apr 3, 9:25 AM CDT	Mesoscale Discussion	SPC	Gadsden, Holmes, Jackson, Washington	65 min
Apr 3, 2:21 PM CDT	Mesoscale Discussion	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Jefferson and 5 more	54 min
Apr 3, 5:57 PM CDT	Mesoscale Discussion	SPC	Baker, Bradford, Clay, Columbia, Dixie, Duval and 17 more	93 min

Nearby

Tornado Watches in Florida, 2017 Every tornado watch in 2017

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.