Alert archive / Mississippi / Mesoscale Discussions in 2017

Mesoscale Discussion 7

January 2, 20179 counties in Alabama; 16 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 2, 2017, 7:08 AM CST for 9 counties in Alabama; 16 counties in Mississippi. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jan 2, 2017, 7:08 AM CST (13:08 UTC)
Expired: Jan 2, 2017, 8:45 AM CST
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 25 counties

Bibb County, AL, Choctaw County, AL, Greene County, AL, Hale County, AL, Marengo County, AL, Perry County, AL, Pickens County, AL, Sumter County, AL, Tuscaloosa County, AL, Clarke County, MS, Covington County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lauderdale County, MS, Lowndes County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Wayne County, MS, Winston County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 128 km from the middle of the area, began a volume at 13:08 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

Birmingham, AL (KBMX), launched 12:00Z, 1.1 hours before the alert went out and 189 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: 11 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 587 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 166 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

879 
ACUS11 KWNS 021309
SWOMCD
SPC MCD 021308 
ALZ000-MSZ000-021445-

Mesoscale Discussion 0007
NWS Storm Prediction Center Norman OK
0708 AM CST Mon Jan 02 2017

Areas affected...Parts of eastern MS and western AL

Concerning...Severe potential...Watch unlikely 

Valid 021308Z - 021445Z

Probability of Watch Issuance...5 percent

SUMMARY...An isolated threat for marginally severe hail may exist
with mainly elevated thunderstorms in the short term. Watch issuance
is not expected.

DISCUSSION...An elevated supercell that has since weakened produced
nickel sized hail in Rankin County MS at 1206Z.  Another elevated
thunderstorm has strengthened as it moved from Kemper County MS into
Sumter County AL at 13Z. This convection is being driven by
low-level warm air advection/lift, and MUCAPE has increased to
around 500-750 J/kg across the discussion area per 13Z RAP
Mesoanalysis. Although mid-level winds are not overly strong per the
observed 12Z soundings at LIX/BMX, there should be some increase in
winds at mid levels over the next several hours as a shortwave
trough over central/east TX moves across the lower MS Valley.
Continued low-level moist influx, some diurnal heating, and very
modest steepening of mid-level lapse rates should allow for an
increase in instability over the next several hours, which may allow
some of the strongest thunderstorms to pose a marginal large hail
and perhaps gusty wind risk. Watch issuance is not expected in the
near term across the discussion area for this initial activity,
although the severe risk will increase later this morning and
afternoon.

..Gleason/Guyer.. 01/02/2017

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   32128999 32998928 33558866 33708795 33418730 32758690
            32138747 31218911 31318988 32128999

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 2, 10:17 AM CST	Mesoscale Discussion	SPC	Baldwin, Clarke, Mobile, Washington	118 min
Jan 2, 11:22 AM CST	Tornado Watch	SPC	Baldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 8 more	9 hr
Jan 2, 12:59 PM CST	Mesoscale Discussion	SPC	Autauga, Barbour, Bullock, Butler, Chambers, Chilton and 17 more	2 hr
Jan 2, 2:03 PM CST	Mesoscale Discussion	SPC	Baldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 10 more	117 min
Jan 2, 3:46 PM CST	Tornado Watch	SPC	Barbour, Bullock, Coffee, Dale, Geneva, Henry and 3 more	8 hr
Jan 2, 5:36 PM CST	Mesoscale Discussion	SPC	Barbour, Bullock, Butler, Coffee, Covington, Crenshaw and 10 more	114 min
Jan 2, 2:06 AM CST	Mesoscale Discussion	SPC	Adams, Amite, Franklin, Jefferson, Wilkinson	114 min

Nearby

Mesoscale Discussions in Mississippi, 2017 Mesoscale Discussions in Alabama, 2017 Every mesoscale discussion in 2017

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.