Alert archive / Alabama / Tornado Watches in 2020

Tornado Watch 497

October 10, 202012 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida; George County, Greene County, Wayne County, Mississippi

The Storm Prediction Center issued this tornado watch at Oct 10, 2020, 4:00 AM CDT for 12 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida; George County, Greene County, Wayne County, Mississippi. It was in force for 10 hr.

The area

The outline as issued.

The facts

Issued
Oct 10, 2020, 4:00 AM CDT (09:00 UTC)
Expired
Oct 10, 2020, 2:00 PM CDT
In force
10 hr
Issued by
the Storm Prediction Center
Strongest gust expected
60 kt

Counties Baldwin County, AL, Butler County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Escambia County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, George County, MS, Greene County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 105 km from the middle of the area, began a volume at 09:00 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
5%
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

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

IssuedProductOfficeCountiesLasted
Oct 10, 4:10 AM CDTTornado WarningMOBOkaloosa35 min
Oct 10, 4:53 AM CDTSevere Thunderstorm WarningMOBMobile37 min
Oct 10, 5:00 AM CDTTornado WarningMOBMobile30 min
Oct 10, 5:17 AM CDTTornado Warning Tornado observedMOBMobile28 min
Oct 10, 5:28 AM CDTTornado WarningMOBMobile17 min
Oct 10, 5:42 AM CDTTornado WarningMOBBaldwin, Clarke, Mobile18 min
Oct 10, 5:44 AM CDTTornado WarningMOBBaldwin31 min
Oct 10, 5:57 AM CDTTornado WarningMOBClarke, Mobile, Washington12 min
Oct 10, 6:01 AM CDTTornado WarningMOBCovington44 min
Oct 10, 10:45 AM CDTFlash Flood WarningMOBEscambia, Santa Rosa3 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

Birmingham, AL (KBMX), launched 00:00Z, 9.0 hours before the alert went out and 228 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 00:00Z on 2020-10-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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, Birmingham, AL at 00:00Z on 2020-10-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 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
2 J/kg
Mixed-layer CIN
-212 J/kg
Mixed-layer LCL
679 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
122 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

246 
WWUS20 KWNS 100851
SEL7  
SPC WW 100851
ALZ000-FLZ000-MSZ000-CWZ000-101800-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 497
NWS Storm Prediction Center Norman OK
350 AM CDT Sat Oct 10 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southern Alabama
  Florida Panhandle
  Southeast Mississippi
  Coastal Waters

* Effective this Saturday morning and afternoon from 350 AM until
  100 PM CDT.

* Primary threats include...
  A couple tornadoes possible

SUMMARY...A moist environment and strong low-level shear on the
eastern periphery of Tropical Storm Delta will support the
possibility of a couple of tornadoes through the morning, and
possibly into the afternoon.

The tornado watch area is approximately along and 65 statute miles
east and west of a line from 50 miles northwest of Evergreen AL to
30 miles south southwest of Pensacola FL. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

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 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 19040.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 10, 2:23 AM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Marengo and 5 more2 hr
Oct 10, 7:09 AM CDTMesoscale DiscussionSPCBaldwin, Conecuh, Escambia, Monroe2 hr
Oct 10, 11:13 AM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Clay, Cleburne, Coffee and 14 more2 hr
Oct 10, 12:47 PM CDTTornado WatchSPCBarbour, Bullock, Calhoun, Chambers, Clay, Cleburne and 15 more7 hr
Oct 10, 3:54 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Calhoun, Chambers, Clay, Cleburne and 12 more96 min

Nearby

Tornado Watches in Alabama, 2020Tornado Watches in Florida, 2020Tornado Watches in Mississippi, 2020Every tornado watch in 2020

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.