Alert archive / Georgia / Mesoscale Discussions in 2018

Mesoscale Discussion 554

May 28, 20188 counties in Alabama; 66 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at May 28, 2018, 1:48 PM CDT for 8 counties in Alabama; 66 counties in Georgia. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: May 28, 2018, 1:48 PM CDT (18:48 UTC)
Expired: May 28, 2018, 4:45 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 74 counties

Barbour County, AL, Bullock County, AL, Chambers County, AL, Henry County, AL, Lee County, AL, Macon County, AL, Pike County, AL, Russell County, AL, Atkinson County, GA, Bacon County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Bibb County, GA, Bleckley County, GA, Brooks County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Clinch County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Coweta County, GA, Crawford County, GA, Crisp County, GA, Decatur County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Harris County, GA, Houston County, GA, Irwin County, GA, Jeff Davis County, GA, Jones County, GA, Lamar County, GA, Lanier County, GA, Laurens County, GA, Lee County, GA, Lowndes County, GA, Macon County, GA, Marion County, GA, Meriwether County, GA, Miller County, GA, Mitchell County, GA, Monroe County, GA, Montgomery County, GA, Muscogee County, GA, Peach County, GA, Pike County, GA, Pulaski County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Spalding County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taylor County, GA, Telfair County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Troup County, GA, Turner County, GA, Twiggs County, GA, Upson County, GA, Webster County, GA, Wheeler County, GA, Wilcox County, GA, Wilkinson County, GA, Worth County, GA

The radar

The Robins AFB radar (KJGX), 106 km from the middle of the area, began a volume at 18:48 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 6.8 hours before the alert went out and 169 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: 189 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 463 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 54 m²/s²
0-3 km storm-relative helicity: 106 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

270 
ACUS11 KWNS 281848
SWOMCD
SPC MCD 281848 
GAZ000-FLZ000-ALZ000-282145-

Mesoscale Discussion 0554
NWS Storm Prediction Center Norman OK
0148 PM CDT Mon May 28 2018

Areas affected...Portions of Georgia and southeastern Alabama

Concerning...Severe potential...Watch possible 

Valid 281848Z - 282145Z

Probability of Watch Issuance...40 percent

SUMMARY...An isolated tornado threat may develop to the northeast of
Alberto this afternoon. Trends will be monitored for a possible
Tornado Watch.

DISCUSSION...Latest NLDN lightning data from 1845Z shows an increase
in electrical activity within the last hour in the outer rainbands
to the northeast of Alberto's center. This is likely the result of
convective cells deepening as they move into an environment that has
become unstable (e.g., MLCAPE values of 1000-1500 J/kg) due to ample
insolation over the last several hours. The low-level wind field is
also increasing across the discussion area with regional VAD
profiles and RAP mesoanalysis suggesting 0-1 SRH values of 100-200
m2/s2. The low-level wind field is expected to continue increasing
this afternoon as Alberto progresses toward the area, which will
further elongate hodographs and may promote transient low-level
rotation and subsequent brief tornadoes.   

While radar analysis over the last hour shows some weak low-level
rotation with cells across the area, trends will be monitored for a
more robust threat and a possible Tornado Watch.

..Elliott/Hart.. 05/28/2018

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

ATTN...WFO...JAX...FFC...TAE...BMX...

LAT...LON   33028565 33448461 33248381 32908302 32428260 31888232
            30938257 30728295 30538324 30588381 30898467 31318533
            31818597 33028565

Nearby

Mesoscale Discussions in Georgia, 2018 Mesoscale Discussions in Alabama, 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.