Alert archive / Florida / Tornado Watches in 2018
Tornado Watch 427
The Storm Prediction Center issued this tornado watch at Nov 12, 2018, 11:46 AM CST for 4 states. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 12, 2018, 11:46 AM CST (17:46 UTC)
- Expired
- Nov 12, 2018, 7:00 PM CST
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 34 counties
Baldwin County, AL, Coffee County, AL, Covington County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Mobile County, AL, Bay County, FL, Calhoun County, FL, Escambia County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Terrebonne Parish, LA, George County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Stone County, MS
The radar
The Mobile radar (KMOB), 116 km from the middle of the area, began a volume at 17:46 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
- 40%
- One or more gusts of 65 knots or more
- 20%
- 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
- 50%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 12, 11:59 AM CST | Severe Thunderstorm Warning | MOB | Okaloosa, Santa Rosa | 13 min |
| Nov 12, 1:16 PM CST | Severe Thunderstorm Warning | TAE | Bay, Gulf | 26 min |
| Nov 12, 2:16 PM CST | Severe Thunderstorm Warning | TAE | Bay | 27 min |
| Nov 12, 3:26 PM CST | Severe Thunderstorm Warning | MOB | Okaloosa | 37 min |
| Nov 12, 4:50 PM CST | Tornado Warning | TAE | Holmes, Jackson, Walton, Washington | 25 min |
| Nov 12, 5:15 PM CST | Tornado Warning | TAE | Jackson | 16 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
Slidell Radar S, LA (KSIL), launched 12:00Z, 5.8 hours before the alert went out and 236 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 425 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 472 m²/s²
- 0-3 km storm-relative helicity
- 487 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.2
The text
As transmitted.
647 WWUS20 KWNS 121743 SEL7 SPC WW 121743 ALZ000-FLZ000-LAZ000-MSZ000-CWZ000-130100- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 427 NWS Storm Prediction Center Norman OK 1245 PM EST Mon Nov 12 2018 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southern Alabama Western Florida Panhandle Southeast Louisiana Southern Mississippi Coastal Waters * Effective this Monday afternoon and evening from 1245 PM until 800 PM EST. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms will continue to affect the watch area through the afternoon and early evening. The strongest cells will be capable of locally damaging wind gusts and isolated tornadoes. The tornado watch area is approximately along and 60 statute miles north and south of a line from 10 miles south southeast of Marianna FL to 35 miles south southwest of New Orleans LA. 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. && OTHER WATCH INFORMATION...CONTINUE...WW 426... 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 24035. ...Hart
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 12, 4:34 AM CST | Tornado Watch | SPC | Baldwin, Mobile | 7 hr |
| Nov 12, 7:54 AM CST | Mesoscale Discussion | SPC | Baldwin, Mobile | 2 hr |
| Nov 12, 11:25 AM CST | Mesoscale Discussion | SPC | Baldwin, Covington, Escambia, Geneva, Mobile | 95 min |
| Nov 12, 3:51 PM CST | Mesoscale Discussion | SPC | Coffee, Covington, Dale, Geneva, Henry, Houston | 114 min |
| Nov 12, 4:01 AM CST | Mesoscale Discussion | SPC | Ascension, Assumption, Iberia, Jefferson, Lafourche, Orleans and 9 more | 2 hr |
Nearby
Tornado Watches in Florida, 2018Tornado Watches in Alabama, 2018Tornado Watches in Louisiana, 2018Every tornado watch in 2018
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.