Alert archive / Alabama / Tornado Watches in 2017

Tornado Watch 27

February 7, 201712 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida

The Storm Prediction Center issued this tornado watch at Feb 7, 2017, 11:50 AM CST for 12 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Feb 7, 2017, 11:50 AM CST (17:50 UTC)
Expired
Feb 7, 2017, 6:00 PM CST
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
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

The radar

The Mobile radar (KMOB), 83 km from the middle of the area, began a volume at 17:51 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
50%
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
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Feb 7, 1:06 PM CSTSevere Thunderstorm WarningMOBBaldwin, Mobile39 min
Feb 7, 1:11 PM CSTSevere Thunderstorm WarningMOBMobile49 min
Feb 7, 1:46 PM CSTSevere Thunderstorm WarningMOBBaldwin, Mobile44 min
Feb 7, 2:02 PM CSTSevere Thunderstorm WarningMOBBaldwin, Mobile58 min
Feb 7, 2:58 PM CSTSevere Thunderstorm WarningMOBBaldwin, Mobile62 min
Feb 7, 3:01 PM CSTSevere Thunderstorm WarningMOBBaldwin59 min
Feb 7, 3:59 PM CSTSevere Thunderstorm WarningMOBBaldwin, Mobile46 min
Feb 7, 4:04 PM CSTSevere Thunderstorm WarningMOBBaldwin41 min
Feb 7, 4:44 PM CSTSevere Thunderstorm WarningMOBBaldwin35 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 226 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, Slidell Radar S, LA at 12:00Z on 2017-02-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 889 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, Slidell Radar S, LA at 12:00Z on 2017-02-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 194 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
889 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
562 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
194 m²/s²
0-3 km storm-relative helicity
190 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.4

Open this sounding in Storm Lab

The text

As transmitted.

652 
WWUS20 KWNS 071748
SEL7  
SPC WW 071748
ALZ000-FLZ000-CWZ000-080000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 27
NWS Storm Prediction Center Norman OK
1150 AM CST Tue Feb 7 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southwest Alabama
  The western Florida Panhandle
  Coastal Waters

* Effective this Tuesday morning and evening from 1150 AM until
  600 PM CST.

* Primary threats include...
  A few tornadoes possible
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Clusters of severe storms will continue to spread eastward
from Mississippi into Alabama through the afternoon.  The storm
environment will support the potential for a couple of tornadoes and
large hail with embedded rotating storms.  Damaging winds will also
be possible with any bowing segments that may evolve from storm
mergers and upscale growth of the storms.

The tornado watch area is approximately along and 70 statute miles
north and south of a line from 25 miles north northwest of Mobile AL
to 15 miles north northeast of Crestview 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 26...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 27035.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 7, 5:59 AM CSTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Mobile, Washington2 hr
Feb 7, 11:20 AM CSTMesoscale DiscussionSPCBaldwin, Butler, Clarke, Coffee, Conecuh, Covington and 6 more115 min
Feb 7, 2:44 PM CSTMesoscale DiscussionSPCBaldwin, Coffee, Conecuh, Covington, Dale, Escambia and 3 more91 min
Feb 7, 3:27 PM CSTSevere Thunderstorm WatchSPCBay, Calhoun, Gulf, Holmes, Jackson, Walton and 1 more3 hr
Feb 7, 4:33 PM CSTSevere Thunderstorm WatchSPCDixie, Franklin, Gadsden, Jefferson, Lafayette, Leon and 4 more4 hr
Feb 7, 5:24 PM CSTMesoscale DiscussionSPCCalhoun, Gadsden, Jefferson, Leon, Liberty, Madison and 2 more96 min
Feb 7, 5:58 PM CSTMesoscale DiscussionSPCAlachua, Baker, Bradford, Clay, Columbia, Duval and 5 more3 hr

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.