Alert archive / Mississippi / Mesoscale Discussions in 2015

Mesoscale Discussion 13

January 3, 201517 counties in Alabama; 22 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 3, 2015, 2:54 PM CST for 17 counties in Alabama; 22 counties in Mississippi. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Jan 3, 2015, 2:54 PM CST (20:54 UTC)
Expired: Jan 3, 2015, 4:30 PM CST
In force: 96 min
Issued by: the Storm Prediction Center

All 39 counties

Bibb County, AL, Choctaw County, AL, Clarke County, AL, Dallas County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Lamar County, AL, Marengo County, AL, Marion County, AL, Perry County, AL, Pickens County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Choctaw County, MS, Clarke County, MS, Clay County, MS, Covington County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Lowndes County, MS, Monroe County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Wayne County, MS, Winston County, MS

The radar

The Columbus AFB radar (KGWX), 131 km from the middle of the area, began a volume at 20:54 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 3, 3:20 PM CST

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 8.9 hours before the alert went out and 156 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: 471 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 266 m²/s²
0-3 km storm-relative helicity: 377 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

944 
ACUS11 KWNS 032054
SWOMCD
SPC MCD 032054 
ALZ000-MSZ000-032230-

MESOSCALE DISCUSSION 0013
NWS STORM PREDICTION CENTER NORMAN OK
0254 PM CST SAT JAN 03 2015

AREAS AFFECTED...CNTRL/ERN MS...WRN AL

CONCERNING...TORNADO WATCH 1...

VALID 032054Z - 032230Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 1 CONTINUES.

SUMMARY...TORNADO RISK CONTINUES WITHIN WW 1...GREATEST OVER
E-CNTRL/SERN MS. THIS RISK ALONG WITH EXPECTED INTENSIFICATION OF A
FRONTAL SQUALL LINE IN CNTRL MS SHOULD ALSO DEVELOP INTO PARTS OF
WRN AL BY 23Z. A DOWNSTREAM TORNADO WATCH ISSUANCE IS LIKELY BY 22Z.

DISCUSSION...A PAIR OF SUPERCELLS CENTERED OVER COVINGTON/SMITH AND
JASPER COUNTY MS REMAIN IN THE MOST FAVORABLE
THERMODYNAMIC/KINEMATIC ENVIRONMENT AS ALLUDED TO IN MCD 0011.
DOWNSTREAM AIR MASS CONTINUES TO DESTABILIZE IN WRN AL WITH 67 DEG F
DEW POINTS NEAR THE MS/AL BORDER. ALTHOUGH BUOYANCY/INSTABILITY WILL
BE LESSER RELATIVE TO FARTHER S/SW...PRESENCE OF 200-300 M2/S2 0-1
KM SRH WILL SUPPORT PERSISTENCE OF UPDRAFT ROTATION. AMALGAMATION OF
UPDRAFTS WITH THE PRE-FRONTAL TSTM CLUSTER AND THE QLCS ALONG THE
EFFECTIVE COLD FRONT SHOULD YIELD AN INCREASINGLY MESSY CONVECTIVE
MODE WHICH MAY LIMIT TEMPORAL SUSTENANCE OF INDIVIDUAL SUPERCELL
UPDRAFTS DURING THE EVENING.

..GRAMS/HART.. 01/03/2015

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

ATTN...WFO...BMX...HUN...MOB...MEG...JAN...

LAT...LON   34448810 34268752 33618715 33048697 32668693 31978711
            31648738 31338810 31348878 31398945 31508991 31909016
            32788977 33348942 33898891 34448810

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 3, 12:00 PM CST	Mesoscale Discussion	SPC	Baldwin, Mobile	90 min
Jan 3, 1:43 PM CST	Mesoscale Discussion	SPC	Choctaw, Sumter, Washington	92 min
Jan 3, 3:18 PM CST	Tornado Watch	SPC	Autauga, Bibb, Blount, Chilton, Dallas, Fayette and 15 more	5 hr
Jan 3, 4:47 PM CST	Mesoscale Discussion	SPC	Autauga, Butler, Chilton, Conecuh, Coosa, Crenshaw and 6 more	58 min
Jan 3, 5:31 PM CST	Mesoscale Discussion	SPC	Choctaw	44 min
Jan 3, 5:59 PM CST	Mesoscale Discussion	SPC	Bibb, Colbert, Cullman, Fayette, Franklin, Greene and 11 more	61 min
Jan 3, 10:24 AM CST	Mesoscale Discussion	SPC	Amite, Clarke, Copiah, Covington, Forrest, Franklin and 26 more	2 hr
Jan 3, 11:04 AM CST	Tornado Watch	SPC	Adams, Amite, Choctaw, Claiborne, Clarke, Clay and 35 more	7 hr

Nearby

Mesoscale Discussions in Mississippi, 2015 Mesoscale Discussions in Alabama, 2015 Every mesoscale discussion in 2015

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.