Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 73

February 1, 201110 counties in Alabama; Escambia County, Santa Rosa County, Florida; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 1, 2011, 3:44 PM CST for 10 counties in Alabama; Escambia County, Santa Rosa County, Florida; 8 counties in Mississippi. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: Feb 1, 2011, 3:44 PM CST (21:44 UTC)
Expired: Feb 1, 2011, 4:45 PM CST
In force: 61 min
Issued by: the Storm Prediction Center

Counties Baldwin County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Escambia County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Santa Rosa County, FL, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 22 km from the middle of the area, began a volume at 21:44 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 11Feb 1, 6:20 PM CST

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 9.7 hours before the alert went out and 163 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: 464 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 437 m²/s²
0-3 km storm-relative helicity: 526 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.

830 
ACUS11 KWNS 012145
SWOMCD
SPC MCD 012144
FLZ000-ALZ000-MSZ000-LAZ000-012245-

MESOSCALE DISCUSSION 0073
NWS STORM PREDICTION CENTER NORMAN OK
0344 PM CST TUE FEB 01 2011

AREAS AFFECTED...PARTS OF EAST CENTRAL AND SERN MS...SWRN AL...AND
WRN FL PANHANDLE

CONCERNING...TORNADO WATCH 10...

VALID 012144Z - 012245Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 10 CONTINUES.

AT 2130Z...REGIONAL RADAR IMAGERY SHOWED THE MORE DEFINED PORTION OF
A CONVECTIVE LINE MOVING EWD AT 35 KT THROUGH SERN MS...WHILE
FARTHER S OVER FAR SERN LA ACTIVITY WAS LESS DEFINED AND LIKELY
POSES A LOWER SEVERE THREAT.  THE SERN MS ACTIVITY WILL PROGRESS EWD
INTO SWRN AL INTO THE EARLY EVENING...AND SHOULD REACH THE FAR WRN
FL PANHANDLE BY 01Z.  MEANWHILE...PRE-CONVECTIVE LINE OF STORMS
SHOULD CONTINUE TO DEVELOP WITHIN WAA REGIME OVER SWRN AL AND
PERHAPS THE FL PANHANDLE THROUGH THE LATE AFTERNOON/EARLY EVENING.

OBJECTIVE ANALYSES INDICATED THE AIR MASS ACROSS WW 10 IS MARGINALLY
UNSTABLE /MUCAPE AOB 500 J PER KG/ WITH STRONG EFFECTIVE BULK SHEAR
/45-60 KT/ AND STRONG EFFECTIVE SRH /300-500 M2 PER S2/.  THIS IS
SUPPORTIVE OF ORGANIZED STORMS/SUPERCELLS.  HOWEVER...SURFACE BASED
INHIBITION /-50 TO -100 J PER KG/ SUGGESTS A LIMITED POTENTIAL FOR
ACTIVITY TO REMAIN OR BECOME SURFACE BASED.  THE LACK OF WIND GUSTS
TO REACH SEVERE LEVELS THUS FAR...MAY BE INDICATIVE OF THE
INHIBITION PRECLUDING STRONGER WINDS TO REACH THE SURFACE.

..PETERS.. 02/01/2011

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

ATTN...WFO...BMX...MOB...JAN...LIX...

LAT...LON   30228960 30918941 32298853 32278733 32018688 31288672
            30328686 29958729 29868832 30108911 30228960

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 1, 12:00 PM CST	Mesoscale Discussion	SPC	Baldwin, Escambia, Mobile, Washington	60 min
Feb 1, 1:03 PM CST	Tornado Watch	SPC	Baldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 3 more	7 hr
Feb 1, 5:54 PM CST	Mesoscale Discussion	SPC	Butler, Coffee, Conecuh, Covington, Crenshaw, Dale and 4 more	96 min
Feb 1, 6:46 AM CST	Mesoscale Discussion	SPC	Adams, Bolivar, Claiborne, Franklin, Hinds, Humphreys and 9 more	119 min
Feb 1, 8:40 AM CST	Tornado Watch	SPC	Adams, Amite, Claiborne, Copiah, Franklin, Hinds and 12 more	6 hr
Feb 1, 1:23 PM CST	Mesoscale Discussion	SPC	Amite, Copiah, Hinds, Jefferson Davis, Lawrence, Lincoln and 6 more	67 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.