Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 14

January 9, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Jan 9, 2011, 8:07 PM CST for 5 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jan 9, 2011, 8:07 PM CST (02:07 UTC)
Expired: Jan 10, 2011, 12:45 AM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 41 counties

Colbert County, AL, DeKalb County, AL, Franklin County, AL, Jackson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Crittenden County, AR, Lee County, AR, Phillips County, AR, St. Francis County, AR, Dade County, GA, Alcorn County, MS, Benton County, MS, DeSoto County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Fayette County, TN, Franklin County, TN, Giles County, TN, Hardeman County, TN, Hardin County, TN, Lawrence County, TN, Lincoln County, TN, McNairy County, TN, Shelby County, TN, Wayne County, TN

The radar

The Columbus AFB radar (KGWX), 115 km from the middle of the area, began a volume at 02:10 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 nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 2.1 hours before the alert went out and 182 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: 1850 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 105 m²/s²
0-3 km storm-relative helicity: 141 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.

164 
ACUS11 KWNS 100207
SWOMCD
SPC MCD 100207 COR
TNZ000-GAZ000-ALZ000-MSZ000-ARZ000-100645-

MESOSCALE DISCUSSION 0014
NWS STORM PREDICTION CENTER NORMAN OK
0807 PM CST SUN JAN 09 2011

AREAS AFFECTED...ERN AR THROUGH NRN MS...NRN AL...SRN TN AND EXTREME
NWRN GA

CONCERNING...HEAVY SNOW 

VALID 100207Z - 100645Z

CORRECTED FOR TYPO IN NEXT TO LAST SENTENCE IN SECOND PARAGRAPH

SNOW RATES SHOULD GRADUALLY INCREASE THIS EVENING...INITIALLY OVER
ERN AR...SWRN TN AND NRN MS...THEN SPREADING NEWD INTO NRN AL...SRN
TN AND EXTREME NWRN GA WITH TIME. RATES LOCALLY FROM 0.5 TO 1 INCH
PER HOUR WILL BECOME POSSIBLE. SNOW MAY MIX WITH SLEET...ESPECIALLY
FORM NRN MS THROUGH NRN AL.

LARGE CP AIRMASS IS ENTRENCHED OVER THE SERN STATES WITH WET BULB
TEMPERATURES BELOW FREEZING. THE COLD AIR WILL LIKELY REMAIN DEEP
ENOUGH FOR MOSTLY SNOW FROM NRN MS...NRN AL INTO SRN TN THIS
EVENING. LARGE EXPANSE OF PRECIPITATION CONTINUES DEVELOPING NEWD
AND IS ASSOCIATED WITH WIDESPREAD ISENTROPIC ASCENT ABOVE THE POLAR
AIRMASS. WV IMAGERY SHOWS A COMPACT VORT MAX OVER THE LOWER MS
VALLEY. THIS FEATURE WILL DEAMPLIFY AS IT EJECTS NEWD TOWARD THE TN
VALLEY. ZONE OF STRONGER DEEP ASCENT WILL GRADUALLY SHIFT NEWD
THROUGH CNTRL AND NRN MS...NRN AL AND SRN TN IN ASSOCIATION WITH THE
VORT MAX AND ITS ATTENDANT 60 KT SLY LLJ. POTENTIAL FOR AREAS OF
HEAVIER SNOW INITIALLY EXISTS FROM ERN AR INTO NRN MS AND SWRN TN.
SNOW RATES WILL GRADUALLY INCREASE FARTHER NE INTO NRN AL...S-CNTRL
AND SERN TN LATER THIS EVENING AS AN INITIALLY DRY LAYER BELOW 3 KM
MOISTENS THROUGH THE PROCESS OF EVAPORATIVE COOLING. FORECAST
SOUNDINGS INDICATE A DEEP ISOTHERMAL LAYER DEVELOPING WITH
TEMPERATURES BETWEEN 0 AND -5C WHICH WILL AUGMENT SNOWFLAKE GROWTH
THROUGH AGGREGATION AS ZONE OF STRONGER ASCENT SHIFTS NEWD. SNOWFALL
MAY MIX WITH SLEET OVER A PORTION OF NRN MS AND NRN AL WHERE WARM
ADVECTION ALONG LLJ MIGHT CONTRIBUTE TO A WARM NOSE ABOVE THE
SUBFREEZING LAYER.

..DIAL.. 01/10/2011

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

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

LAT...LON   35268648 35058546 34638531 34228617 34099011 34589125
            35269087 35358870 35268648

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 9, 8:27 PM CST	Mesoscale Discussion	SPC	Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 23 more	5 hr
Jan 9, 10:56 PM CST	Mesoscale Discussion	SPC	DeKalb, Jackson	5 hr
Jan 10, 2:06 AM CST	Mesoscale Discussion	SPC	Barbour, Bullock, Chambers, Lee, Macon, Pike and 2 more	6 hr

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Alabama, 2011 Mesoscale Discussions in Tennessee, 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.