Alert archive / Georgia / Mesoscale Discussions in 2020

Mesoscale Discussion 1697

September 16, 20205 counties in Florida; 9 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Sep 16, 2020, 3:08 PM EDT for 5 counties in Florida; 9 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 16, 2020, 3:08 PM EDT (19:08 UTC)
Expired: Sep 16, 2020, 5:15 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Tornado watch 491

Counties Gadsden County, FL, Jefferson County, FL, Leon County, FL, Madison County, FL, Wakulla County, FL, Brooks County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Grady County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Thomas County, GA

The radar

The Tallahassee radar (KTLH), 37 km from the middle of the area, began a volume at 19:09 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 7.1 hours before the alert went out and 37 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: 181 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 788 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 286 m²/s²
0-3 km storm-relative helicity: 397 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 15, 8:45 PM EDT	Mesoscale Discussion	SPC	Bay, Escambia, Franklin, Gulf, Okaloosa, Walton	2 hr
Sep 16, 12:09 AM EDT	Mesoscale Discussion	SPC	Bay, Calhoun, Escambia, Franklin, Gulf, Liberty and 4 more	2 hr
Sep 16, 5:14 AM EDT	Mesoscale Discussion	SPC	Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 7 more	2 hr
Sep 16, 6:55 AM EDT	Tornado Watch	SPC	Bay, Calhoun, Dixie, Escambia, Franklin, Gadsden and 14 more	14 hr
Sep 16, 12:18 PM EDT	Mesoscale Discussion	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 6 more	102 min
Sep 16, 7:34 PM EDT	Mesoscale Discussion	SPC	Duval, Nassau	116 min

Nearby

Mesoscale Discussions in Georgia, 2020 Mesoscale Discussions in Florida, 2020 Every mesoscale discussion in 2020

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.