Alert archive / Alabama / Tornado Warnings in 2017

Tornado Warning 59, NWS Birmingham, AL

December 20, 2017Randolph County, Alabama

NWS Birmingham, AL issued this tornado warning at Dec 20, 2017, 10:38 AM CST for Randolph County, Alabama. It was in force for 14 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Dec 20, 2017, 10:38 AM CST (16:38 UTC)
Expired: Dec 20, 2017, 10:52 AM CST
In force: 14 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Randolph County, AL

The radar

The Atlanta radar (KFFC), 78 km from the middle of the area, began a volume at 16:38 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 was reported inside it

Time	Report	Where	Remark
Dec 20, 10:40 AM CST	TORNADO	2 Sw Crystal Lake, AL	A BRIEF, BOTTOM-OF-THE-BARREL EF-0 TORNADO MOVED ALONG AN EASTWARD TRACK JUST NORTH OF COUNTY ROAD 22 IN SOUTHERN RANDOLPH COUNTY, RESULTING IN ROOFING DAMAGE TO A BARN AND LIMITED TREE DAMAGE (SNAPPED BRANCHES AND SNAPPED, SLENDER PINE TREES) AS IT APPROACHED
Dec 20, 10:43 AM CST	TSTM WND DMG	1 Ese Crystal Lake, AL	TREE DAMAGE REPORTED ALONG U.S. HIGHWAY 431 NORTH OF ROANOKE. POSSIBLE TORNADO.
Dec 20, 10:45 AM CST	TSTM WND DMG	2 E Crystal Lake, AL	DAMAGE TO AT LEAST ONE TREE ALONG COUNTY ROAD 59 NORTH OF ROANOKE. POSSIBLE TORNADO.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 4.6 hours before the alert went out and 84 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 11 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 572 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: 242 m²/s²
0-3 km storm-relative helicity: 276 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

976 
WFUS54 KBMX 201638
TORBMX
ALC111-201715-
/O.NEW.KBMX.TO.W.0059.171220T1638Z-171220T1715Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Birmingham AL
1038 AM CST WED DEC 20 2017

The National Weather Service in Birmingham has issued a

* Tornado Warning for...
  Southeastern Randolph County in east central Alabama...

* Until 1115 AM CST
    
* At 1038 AM CST, a severe thunderstorm capable of producing a
  tornado was located over Crystal Lake, or near Roanoke, moving east
  at 40 mph.

  HAZARD...Tornado. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* Locations impacted include...
  Roanoke, Crystal Lake, Dickert, Roanoke Municipal Airport, Rock
  Mills and Rock Stand.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3314 8552 3323 8548 3320 8525 3313 8523
      3311 8523
TIME...MOT...LOC 1638Z 276DEG 36KT 3318 8544 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

89^GSatterwhite

2 follow-up statements

265 
WWUS54 KBMX 201642
SVSBMX

Severe Weather Statement
National Weather Service Birmingham AL
1042 AM CST WED DEC 20 2017

ALC111-201715-
/O.CON.KBMX.TO.W.0059.000000T0000Z-171220T1715Z/
Randolph AL-
1042 AM CST WED DEC 20 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1115 AM CST FOR
SOUTHEASTERN RANDOLPH COUNTY...
    
At 1042 AM CST, a severe thunderstorm capable of producing a tornado
was located over Crystal Lake, or over Roanoke, moving east at 40
mph.

HAZARD...Tornado. 

SOURCE...Radar indicated rotation. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

Locations impacted include...
Roanoke, Crystal Lake, Rock Mills and Roanoke Municipal Airport. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3314 8544 3321 8543 3319 8525 3313 8523
      3311 8523
TIME...MOT...LOC 1642Z 282DEG 33KT 3317 8541 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

89^GSatterwhite

258 
WWUS54 KBMX 201652
SVSBMX

Severe Weather Statement
National Weather Service Birmingham AL
1052 AM CST WED DEC 20 2017

ALC111-201701-
/O.CAN.KBMX.TO.W.0059.000000T0000Z-171220T1715Z/
Randolph AL-
1052 AM CST WED DEC 20 2017

...THE TORNADO WARNING FOR SOUTHEASTERN RANDOLPH COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore the warning has been cancelled.

LAT...LON 3314 8544 3321 8543 3319 8525 3313 8523
      3311 8523
TIME...MOT...LOC 1651Z 276DEG 36KT 3316 8529 

$$

89^GSatterwhite

The office that day

Everything else NWS Birmingham, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 19, 6:37 PM CST	Dense Fog Advisory	BMX	Autauga, Barbour, Bibb, Blount, Bullock, Calhoun and 33 more	11 hr
Dec 20, 7:21 AM CST	Areal Flood Advisory	BMX	Jefferson	3 hr
Dec 20, 7:54 AM CST	Flash Flood Warning	BMX	Jefferson	3 hr
Dec 20, 8:00 AM CST	Flash Flood Warning	BMX	Etowah	3 hr
Dec 20, 8:36 AM CST	Areal Flood Advisory	BMX	Calhoun, Clay, Cleburne, Randolph, St. Clair, Shelby and 1 more	3 hr
Dec 20, 12:09 PM CST	Special Weather Statement	BMX	Lee	36 min

Nearby

Tornado Warnings in Alabama, 2017 Every tornado warning in 2017 Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.