Alert archive / Alabama / Mesoscale Discussions in 2017

Mesoscale Discussion 1602

August 30, 20174 counties in Alabama

The Storm Prediction Center issued this mesoscale discussion at Aug 30, 2017, 12:36 PM CDT for 4 counties in Alabama. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Aug 30, 2017, 12:36 PM CDT (17:36 UTC)
Expired: Aug 30, 2017, 2:30 PM CDT
In force: 114 min
Issued by: the Storm Prediction Center

Counties Baldwin County, AL, Clarke County, AL, Mobile County, AL, Washington County, AL

The radar

The Mobile radar (KMOB), 87 km from the middle of the area, began a volume at 17:35 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

Slidell Radar S, LA (KSIL), launched 12:00Z, 5.6 hours before the alert went out and 214 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: 1853 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 550 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 270 m²/s²
0-3 km storm-relative helicity: 310 m²/s²
Significant tornado parameter: 2.2
Supercell composite: 13.7

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
Aug 30, 1:00 AM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	90 min
Aug 30, 6:57 AM CDT	Mesoscale Discussion	SPC	Baldwin	2 hr
Aug 30, 10:22 AM CDT	Tornado Watch	SPC	Baldwin, Choctaw, Clarke, Mobile, Washington	8 hr
Aug 30, 12:10 PM CDT	Mesoscale Discussion	SPC	Barbour, Dale, Geneva, Henry, Houston, Russell	2 hr
Aug 30, 2:55 PM CDT	Mesoscale Discussion	SPC	Choctaw, Sumter, Washington	2 hr

Nearby

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.