Alert archive / Arkansas / Mesoscale Discussions in 2011

Mesoscale Discussion 11

January 9, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Jan 9, 2011, 7:09 AM CST for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jan 9, 2011, 7:09 AM CST (13:09 UTC)
Expired: Jan 9, 2011, 12:15 PM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 28 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Columbia County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Claiborne Parish, LA, East Carroll Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Hinds County, MS, Issaquena County, MS, Sharkey County, MS, Warren County, MS, Yazoo County, MS, Bowie County, TX, Cass County, TX

The radar

The Jackson/Brandon,MS radar (KDGX), 186 km from the middle of the area, began a volume at 13:13 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

Jackson, MS (KJAN), launched 12:00Z, 1.2 hours before the alert went out and 176 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: 1327 m above ground
0-6 km bulk shear: 64 kt
0-1 km storm-relative helicity: 75 m²/s²
0-3 km storm-relative helicity: 139 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.

623 
ACUS11 KWNS 091309
SWOMCD
SPC MCD 091309 
MSZ000-LAZ000-ARZ000-TXZ000-091815-

MESOSCALE DISCUSSION 0011
NWS STORM PREDICTION CENTER NORMAN OK
0709 AM CST SUN JAN 09 2011

AREAS AFFECTED...ARKLATEX SEWD INTO CNTRL MS

CONCERNING...FREEZING RAIN 

VALID 091309Z - 091815Z

FREEZING RAIN POTENTIAL WILL INCREASE THROUGH THE MORNING WITH HRLY
RATES TO AROUND 0.05 IN.

SURFACE ANALYSIS SHOWS SUB-FREEZING TEMPERATURES FIRMLY ENTRENCHED
ACROSS AR AND NRN MS...WITH A RATHER DRY BOUNDARY LAYER AND SOME
DECREASE IN TEMPERATURES STILL POSSIBLE THROUGH ADVECTION AND
EVAPORATIVE COOLING. AS DEEP LAYER WARM ADVECTION PROFILES
STRENGTHEN WITH APPROACHING UPPER TROUGH...SHIELD OF LIGHT TO
MODERATE PRECIPITATION WILL EXPAND NEWD ACROSS THE AREA.

MORNING SOUNDINGS INDICATE SIGNIFICANT WET-BULBING POTENTIAL ALOFT
FROM SHV TO JAN...BUT AS THE COLUMN SATURATES...SOME WARMING THROUGH
ADVECTION IS EXPECTED...WHICH WILL MAINTAIN A SLIGHTLY ABOVE
FREEZING WARM NOSE ALOFT. THESE PROFILES WILL FAVOR FREEZING
RAIN...ESPECIALLY NEAR AND JUST N OF THE SURFACE FREEZING LINE.
PRECIPITATION MAY BE MIXED WITH SLEET AT TIMES BUT THE WARMING ALOFT
COULD CHANGE IT BACK TO FREEZING RAIN COINCIDENT WITH THE ARRIVAL OF
THE HEAVIEST PRECIPITATION. A TRANSITION TO SLEET AND SNOW WILL
OCCUR WITH NWD EXTENT AND INTO THE DEEPER COLD AIR...FROM THE
ARKLATEX INTO CNTRL AR BY MIDDAY.

..JEWELL.. 01/09/2011

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

ATTN...WFO...JAN...LZK...SHV...

LAT...LON   33519210 33209103 33019044 32769032 32479027 32329031
            32159048 32069063 32579294 32939428 33479475 33789410
            33519210

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 9, 10:55 AM CST	Mesoscale Discussion	SPC	Bradley, Calhoun, Clark, Columbia, Dallas, Hempstead and 8 more	6 hr
Jan 9, 3:06 PM CST	Mesoscale Discussion	SPC	Attala, Carroll, Choctaw, Clarke, Copiah, Hinds and 21 more	4 hr
Jan 9, 1:28 AM CST	Mesoscale Discussion	SPC	Aransas, Bee, Brooks, Calhoun, Duval, Goliad and 9 more	2 hr
Jan 9, 2:11 AM CST	Severe Thunderstorm Watch	SPC	Aransas, Calhoun, Duval, Jim Wells, Kleberg, Nueces and 2 more	4 hr

Nearby

Mesoscale Discussions in Arkansas, 2011 Mesoscale Discussions in Louisiana, 2011 Mesoscale Discussions in Mississippi, 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.