Alert archive / Alabama / Tornado Watches in 2017
Tornado Watch 498
The Storm Prediction Center issued this tornado watch at Oct 8, 2017, 1:41 AM CDT for 19 counties in Alabama; 9 counties in Florida. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 8, 2017, 1:41 AM CDT (06:41 UTC)
- Expired
- Oct 8, 2017, 10:00 AM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 28 counties
Autauga County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lowndes County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Wilcox County, AL, Bay County, FL, Calhoun County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL
The radar
The Ft Rucker radar (KEOX), 53 km from the middle of the area, began a volume at 06:40 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
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 40%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 8, 2:06 AM CDT | Flash Flood Warning | MOB | Conecuh, Covington, Escambia | 7 hr |
| Oct 8, 2:53 AM CDT | Flash Flood Warning | MOB | Butler, Conecuh, Covington, Monroe, Wilcox | 6 hr |
| Oct 8, 4:46 AM CDT | Flash Flood Warning | MOB | Butler, Wilcox | 4 hr |
| Oct 8, 6:15 AM CDT | Flash Flood Warning | MOB | Butler, Covington, Crenshaw | 3 hr |
| Oct 8, 8:16 AM CDT | Flash Flood Warning | TAE | Coffee | 3 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
Tallahassee Rgnl, FL (KTLH), launched 00:00Z, 6.7 hours before the alert went out and 174 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.
- Mixed-layer CAPE
- 738 J/kg
- Mixed-layer CIN
- -12 J/kg
- Mixed-layer LCL
- 1032 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 139 m²/s²
- 0-3 km storm-relative helicity
- 148 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.5
The text
As transmitted.
132 WWUS20 KWNS 080637 SEL8 SPC WW 080637 ALZ000-FLZ000-CWZ000-081500- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 498 NWS Storm Prediction Center Norman OK 140 AM CDT Sun Oct 8 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of South central and southeast Alabama The western Florida Panhandle Coastal Waters * Effective this Sunday morning from 140 AM until 1000 AM CDT. * Primary threats include... A couple tornadoes possible Isolated damaging wind gusts to 70 mph possible SUMMARY...The outer eastern convective bands of Nate will continue to pose the threat for a couple of tornadoes through the morning hours. The tornado watch area is approximately along and 60 statute miles east and west of a line from 25 miles north northwest of Troy AL to 45 miles south southwest of Panama City 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 497... 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 450. Mean storm motion vector 18040. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 7, 7:05 PM CDT | Tornado Watch | SPC | Baldwin, Clarke, Conecuh, Escambia, Mobile, Monroe and 1 more | 7 hr |
| Oct 8, 1:13 AM CDT | Mesoscale Discussion | SPC | Barbour, Bullock, Butler, Coffee, Conecuh, Covington and 12 more | 92 min |
| Oct 8, 9:04 AM CDT | Mesoscale Discussion | SPC | Autauga, Barbour, Bullock, Butler, Coffee, Conecuh and 13 more | 86 min |
Nearby
Tornado Watches in Alabama, 2017Tornado Watches in Florida, 2017Every 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.