Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 2

January 1, 20118 counties in Alabama; Dade County, Georgia; 5 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Jan 1, 2011, 1:14 AM CST for 8 counties in Alabama; Dade County, Georgia; 5 counties in Tennessee. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: Jan 1, 2011, 1:14 AM CST (07:14 UTC)
Expired: Jan 1, 2011, 2:15 AM CST
In force: 61 min
Issued by: the Storm Prediction Center

Counties Cullman County, AL, DeKalb County, AL, Jackson County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Dade County, GA, Franklin County, TN, Giles County, TN, Lawrence County, TN, Lincoln County, TN, Marion County, TN

The radar

The Northeast Alabama radar (KHTX), 82 km from the middle of the area, began a volume at 07:17 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 2Jan 1, 3:10 AM CST

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 7.2 hours before the alert went out and 144 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1020 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 270 m²/s²
0-3 km storm-relative helicity: 398 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

397 
ACUS11 KWNS 010714
SWOMCD
SPC MCD 010714 
TNZ000-GAZ000-ALZ000-010815-

MESOSCALE DISCUSSION 0002
NWS STORM PREDICTION CENTER NORMAN OK
0114 AM CST SAT JAN 01 2011

AREAS AFFECTED...NRN AL AND ADJACENT SRN MIDDLE TN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 010714Z - 010815Z

SEVERE/TORNADO THREAT APPEARS TO INCREASING SLOWLY ACROSS THIS
REGION...AND MAY EXCEED THRESHOLD FOR WW ISSUANCE.

LATEST SURFACE ANALYSIS SHOW RELATIVELY DRIER/MORE STABLE BOUNDARY
LAYER ACROSS THE DISCUSSION AREA AS COMPARED TO AREAS SW...WITH THE
EXISTING AIRMASS HAVING ORIGINATED FROM FARTHER E WHERE SURFACE HIGH
PRESSURE REMAINS IN CONTROL.  HOWEVER...SLOW VEERING OF THE BOUNDARY
LAYER FLOW FROM A MORE ELY TO A MORE SLY DIRECTION IS ALLOWING VERY
SLOW MOISTENING -- AND THUS DESTABILIZATION -- BENEATH THE EXISTING
INVERSION.  

AS THIS OCCURS WITHIN A VERY FAVORABLE KINEMATIC
ENVIRONMENT...POTENTIAL FOR DAMAGING WINDS AT THE SURFACE AND/OR AN
ISOLATED TORNADO OR TWO IS LIKEWISE INCREASING.  WHILE STORMS WILL
BE UNLIKELY TO BECOME TRULY SURFACE BASED...DECREASING STABILITY IN
THE BOUNDARY LAYER MAY BE SUFFICIENT TO ALLOW SUFFICIENT SEVERE
POTENTIAL TO WARRANT NEW WW ISSUANCE.

..GOSS.. 01/01/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...FFC...OHX...BMX...HUN...

LAT...LON   34048727 34438757 35288759 35288535 34478548 33808704
            34048727

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 31, 10:46 PM CST	Tornado Watch	SPC	Fayette, Greene, Lamar, Marion, Pickens, Sumter and 3 more	5 hr
Jan 1, 3:10 AM CST	Tornado Watch	SPC	Autauga, Baldwin, Bibb, Blount, Butler, Calhoun and 34 more	7 hr
Jan 1, 6:06 AM CST	Mesoscale Discussion	SPC	Bibb, Calhoun, Cherokee, Chilton, Choctaw, Clarke and 13 more	114 min
Jan 1, 9:04 AM CST	Mesoscale Discussion	SPC	Baldwin, Butler, Clarke, Coffee, Conecuh, Covington and 9 more	56 min
Jan 1, 9:51 AM CST	Tornado Watch	SPC	Baldwin, Barbour, Bullock, Butler, Coffee, Conecuh and 10 more	4 hr
Jan 1, 12:32 PM CST	Mesoscale Discussion	SPC	Baldwin, Bullock, Butler, Coffee, Conecuh, Covington and 7 more	88 min

Nearby

Mesoscale Discussions in Alabama, 2011 Mesoscale Discussions in Tennessee, 2011 Mesoscale Discussions in Georgia, 2011 Every mesoscale discussion in 2011

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.