Alert archive / Alabama / Tornado Watches in 2019

Tornado Watch 84

April 18, 201937 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida

The Storm Prediction Center issued this tornado watch at Apr 18, 2019, 3:49 PM CDT for 37 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2019, 3:49 PM CDT (20:49 UTC)
Expired
Apr 18, 2019, 11:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 40 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Blount County, AL, Butler County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lowndes County, AL, Marengo County, AL, Marion County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Winston County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL

The radar

The Birmingham radar (KBMX), 143 km from the middle of the area, began a volume at 20:51 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
40%
Ten or more severe wind reports
70%
One or more gusts of 65 knots or more
20%
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
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 18, 4:31 PM CDTSevere Thunderstorm WarningBMXSumter59 min
Apr 18, 4:38 PM CDTSevere Thunderstorm WarningMOBChoctaw52 min
Apr 18, 5:07 PM CDTSevere Thunderstorm WarningBMXGreene, Pickens53 min
Apr 18, 5:07 PM CDTSevere Thunderstorm WarningBMXGreene, Pickens53 min
Apr 18, 5:30 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington60 min
Apr 18, 5:44 PM CDTSevere Thunderstorm WarningMOBMobile, Washington61 min
Apr 18, 5:45 PM CDTSevere Thunderstorm WarningBMXHale, Tuscaloosa60 min
Apr 18, 6:15 PM CDTSevere Thunderstorm WarningBMXTuscaloosa45 min
Apr 18, 6:18 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington, Wilcox57 min
Apr 18, 6:20 PM CDTSevere Thunderstorm WarningBMXBibb, Hale, Perry70 min
Apr 18, 6:32 PM CDTSevere Thunderstorm WarningBMXFayette73 min
Apr 18, 6:36 PM CDTSevere Thunderstorm WarningMOBClarke, Mobile, Washington39 min
Apr 18, 6:38 PM CDTSevere Thunderstorm WarningBMXJefferson82 min
Apr 18, 6:46 PM CDTSevere Thunderstorm WarningBMXTuscaloosa44 min
Apr 18, 6:53 PM CDTSevere Thunderstorm WarningBMXChilton, Shelby82 min
Apr 18, 6:58 PM CDTSevere Thunderstorm WarningBMXJefferson, Walker65 min
Apr 18, 7:08 PM CDTSevere Thunderstorm WarningMOBBaldwin, Clarke, Conecuh, Escambia, Mobile, Monroe and 1 more67 min
Apr 18, 7:13 PM CDTSevere Thunderstorm WarningMOBButler, Clarke, Conecuh, Monroe, Wilcox62 min
Apr 18, 7:16 PM CDTSevere Thunderstorm WarningBMXMarion, Winston63 min
Apr 18, 7:32 PM CDTSevere Thunderstorm WarningBMXBlount, St. Clair57 min
Apr 18, 8:13 PM CDTSevere Thunderstorm WarningMOBBaldwin, Escambia62 min
Apr 18, 8:24 PM CDTSevere Thunderstorm WarningMOBButler, Conecuh, Covington, Monroe51 min
Apr 18, 8:34 PM CDTSevere Thunderstorm WarningMOBButler, Wilcox41 min
Apr 18, 8:43 PM CDTSevere Thunderstorm WarningBMXLowndes, Montgomery62 min
Apr 18, 9:10 PM CDTSevere Thunderstorm WarningMOBButler, Crenshaw65 min
Apr 18, 9:20 PM CDTSevere Thunderstorm WarningBMXBullock, Montgomery, Pike35 min
Apr 18, 9:39 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington51 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

Birmingham, AL (KBMX), launched 12:00Z, 8.8 hours before the alert went out and 143 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, Birmingham, AL at 12:00Z on 2019-04-18Temperature 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, Birmingham, AL at 12:00Z on 2019-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 132 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
960 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
132 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

270 
WWUS20 KWNS 182046
SEL4  
SPC WW 182046
ALZ000-FLZ000-CWZ000-190400-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 84
NWS Storm Prediction Center Norman OK
350 PM CDT Thu Apr 18 2019

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Western and southern Alabama
  Western Florida Panhandle
  Coastal Waters

* Effective this Thursday afternoon and evening from 350 PM until
  1100 PM CDT.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Scattered damaging wind gusts to 70 mph likely

SUMMARY...Line of strong to severe thunderstorms will spread east
from Mississippi through this evening. Damaging winds and a few
tornadoes are the expected threats.

The tornado watch area is approximately along and 110 statute miles
north and south of a line from 80 miles west northwest of Evergreen
AL to 35 miles east northeast of Evergreen AL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU4).

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 82...WW 83...

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 25035.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 18, 12:42 PM CDTMesoscale DiscussionSPCChoctaw, Greene, Sumter2 hr
Apr 18, 3:12 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 27 more2 hr
Apr 18, 5:58 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Chilton, Clarke, Dallas, Hale and 5 more92 min

Nearby

Tornado Watches in Alabama, 2019Tornado Watches in Florida, 2019Every tornado watch in 2019

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.