Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 4

January 1, 201115 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 1, 2011, 9:04 AM CST for 15 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida; 5 counties in Mississippi. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Jan 1, 2011, 9:04 AM CST (15:04 UTC)
Expired: Jan 1, 2011, 10:00 AM CST
In force: 56 min
Issued by: the Storm Prediction Center

All 23 counties

Baldwin County, AL, Butler County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dallas County, AL, Escambia County, AL, Lowndes County, AL, Mobile County, AL, Monroe County, AL, Pike County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, George County, MS, Greene County, MS, Harrison County, MS, Jackson County, MS, Stone County, MS

The radar

The Mobile radar (KMOB), 64 km from the middle of the area, began a volume at 15:07 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 3Jan 1, 9:55 AM CST

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 3.1 hours before the alert went out and 208 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: 1280 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 447 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 361 m²/s²
0-3 km storm-relative helicity: 384 m²/s²
Significant tornado parameter: 2.1
Supercell composite: 12.6

Open this sounding in Storm Lab

The text

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

605 
ACUS11 KWNS 011504
SWOMCD
SPC MCD 011504 
ALZ000-FLZ000-MSZ000-LAZ000-011600-

MESOSCALE DISCUSSION 0004
NWS STORM PREDICTION CENTER NORMAN OK
0904 AM CST SAT JAN 01 2011

AREAS AFFECTED...EXTREME SERN MS THROUGH SRN AL AND THE WRN FL
PANHANDLE

CONCERNING...TORNADO WATCH 2...

VALID 011504Z - 011600Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 2 CONTINUES.

TORNADO WATCH 2 WILL LIKELY BE REPLACED BY ANOTHER TORNADO WATCH
PRIOR TO 16Z THAT WILL INCLUDE THE BOOTHEEL OF MS...SRN AL INTO THE
WRN FL PANHANDLE.

SCATTERED THUNDERSTORMS WILL CONTINUE INTO THE AFTERNOON WITHIN
PRE-FRONTAL WARM SECTOR AND ZONE OF ASCENT ALONG WARM CONVEYOR BELT.
GREATEST POTENTIAL FOR SURFACE BASED STORMS EXISTS ALONG SRN PORTION
OF GULF COAST STATES FROM SERN MS INTO SRN AL AND THE WRN FL
PANHANDLE WHERE INFLUX OF MOISTURE HAS BEEN MAXIMIZED ALONG THE SWLY
LLJ AXIS. INSTABILITY WILL REMAIN MARGINAL WITH LIMITED WARMING OF
THE BOUNDARY LAYER...BUT GIVEN LARGE HODOGRAPHS AND NEAR SURFACE
BASED NATURE OF THE CONVECTION...SOME THREAT FOR SUPERCELLS AND
ISOLATED TORNADOES WILL PERSIST INTO THE AFTERNOON. THREAT IS MORE
LIMITED FARTHER EAST TOWARD SRN GA AND NRN FL DUE TO SELY LOW LEVEL
TRAJECTORIES WHICH SHOULD MAINTAIN A MORE STABLE BOUNDARY LAYER.

..DIAL.. 01/01/2011

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

ATTN...WFO...TAE...BMX...MOB...LIX...

LAT...LON   31098901 32478704 31758574 30718611 30328770 30108962
            31098901

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, 1:14 AM CST	Mesoscale Discussion	SPC	Cullman, DeKalb, Jackson, Lawrence, Limestone, Madison and 2 more	61 min
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, 9:51 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 Mississippi, 2011 Mesoscale Discussions in Florida, 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.