Alert archive / Florida / Mesoscale Discussions in 2018

Mesoscale Discussion 1137

July 22, 2018Houston County, Alabama; 15 counties in Florida; 9 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2018, 3:05 PM CDT for Houston County, Alabama; 15 counties in Florida; 9 counties in Georgia. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Jul 22, 2018, 3:05 PM CDT (20:05 UTC)
Expired: Jul 22, 2018, 5:00 PM CDT
In force: 115 min
Issued by: the Storm Prediction Center

All 25 counties

Houston County, AL, Dixie County, FL, Gadsden County, FL, Gilchrist County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Lake County, FL, Leon County, FL, Levy County, FL, Liberty County, FL, Orange County, FL, Sumter County, FL, Suwannee County, FL, Taylor County, FL, Wakulla County, FL, Baker County, GA, Calhoun County, GA, Decatur County, GA, Early County, GA, Grady County, GA, Miller County, GA, Mitchell County, GA, Seminole County, GA, Thomas County, GA

The radar

The Tallahassee radar (KTLH), 110 km from the middle of the area, began a volume at 20:05 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, 8.1 hours before the alert went out and 107 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: 3735 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 715 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 102 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 7.6

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
Jul 21, 8:28 PM CDT	Mesoscale Discussion	SPC	Chambers, Henry, Lee, Russell	92 min
Jul 21, 10:29 PM CDT	Mesoscale Discussion	SPC	Butler, Coffee, Conecuh, Covington, Crenshaw, Escambia and 2 more	2 hr
Jul 22, 10:15 AM CDT	Severe Thunderstorm Watch	SPC	Coffee, Dale, Geneva, Henry, Houston	10 hr
Jul 22, 11:27 AM CDT	Mesoscale Discussion	SPC	Butler, Clarke, Coffee, Conecuh, Covington, Crenshaw and 6 more	63 min
Jul 22, 11:57 AM CDT	Severe Thunderstorm Watch	SPC	Baldwin, Butler, Clarke, Conecuh, Covington, Crenshaw and 5 more	7 hr
Jul 22, 12:58 PM CDT	Mesoscale Discussion	SPC	Butler, Clarke, Coffee, Conecuh, Covington, Crenshaw and 6 more	62 min
Jul 22, 1:56 PM CDT	Mesoscale Discussion	SPC	Baldwin, Bullock, Butler, Choctaw, Clarke, Coffee and 16 more	2 hr
Jul 22, 9:32 AM CDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 24 more	58 min
Jul 22, 6:39 PM CDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Citrus, Columbia, Dixie and 16 more	66 min

Nearby

Mesoscale Discussions in Florida, 2018 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.