Alert archive / Alabama / Mesoscale Discussions in 2018

Mesoscale Discussion 607

June 1, 201828 counties in Alabama; 16 counties in Georgia; 7 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2018, 12:25 PM CDT for 28 counties in Alabama; 16 counties in Georgia; 7 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Jun 1, 2018, 12:25 PM CDT (17:25 UTC)
Expired: Jun 1, 2018, 3:00 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 51 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Lamar County, AL, Lawrence County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Bartow County, GA, Carroll County, GA, Chattooga County, GA, Cherokee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Douglas County, GA, Fayette County, GA, Floyd County, GA, Fulton County, GA, Haralson County, GA, Heard County, GA, Paulding County, GA, Polk County, GA, Troup County, GA, Chickasaw County, MS, Clay County, MS, Itawamba County, MS, Lowndes County, MS, Monroe County, MS, Noxubee County, MS, Oktibbeha County, MS

The radar

The Birmingham radar (KBMX), 60 km from the middle of the area, began a volume at 17:25 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.

Severe Thunderstorm Watch 144Jun 1, 1:25 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 5.4 hours before the alert went out and 59 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: 1826 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 507 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 72 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

188 
ACUS11 KWNS 011725
SWOMCD
SPC MCD 011725 
GAZ000-ALZ000-MSZ000-012000-

Mesoscale Discussion 0607
NWS Storm Prediction Center Norman OK
1225 PM CDT Fri Jun 01 2018

Areas affected...Parts of northern GA through northern/central AL to
northeast MS

Concerning...Severe potential...Watch possible 

Valid 011725Z - 012000Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms are expected to increase in coverage this
afternoon across northern and central Alabama, parts of northern
Georgia, and possibly across parts of northeast Mississippi with
some of the storms becoming severe producing strong wind gusts and
large hail.  Severe thunderstorm watch could be needed for portions
of this region.

DISCUSSION...Trends in mosaic radar imagery and lightning data
indicated some increase in coverage with a band of storms advancing
to the south-southeast across northern AL, while additional storms
were developing along a surface boundary that extended from
north-central GA into central AL.  Despite a modest increase in
effective bulk shear, surface heating within a moisture-rich
environment and steep low- to mid-level lapse rates will contribute
to further destabilization through the afternoon.  These latter
factors suggest locally strong wind gusts and large hail will be
possible with stronger storms.

..Peters/Guyer.. 06/01/2018

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

ATTN...WFO...FFC...BMX...HUN...MEG...JAN...

LAT...LON   34668672 34618522 34318426 33158429 32808544 32718705
            32878812 33268912 33548928 34268874 34668672

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 1, 2:41 AM CDT	Mesoscale Discussion	SPC	Colbert, Lauderdale, Limestone, Madison	34 min
Jun 1, 1:29 PM CDT	Severe Thunderstorm Watch	SPC	Autauga, Bibb, Calhoun, Chambers, Cherokee, Chilton and 22 more	5 hr
Jun 1, 4:38 PM CDT	Mesoscale Discussion	SPC	Chambers, Lee, Russell, Tallapoosa	2 hr

Nearby

Mesoscale Discussions in Alabama, 2018 Mesoscale Discussions in Georgia, 2018 Mesoscale Discussions in Mississippi, 2018 Every mesoscale discussion in 2018

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.