Alert archive / Alabama / Areal Flood Advisories in 2021

Areal Flood Advisory 148, NWS Mobile, AL

July 20, 2021Clarke County, Washington County, Alabama

NWS Mobile, AL issued this areal flood advisory at Jul 20, 2021, 3:06 PM CDT for Clarke County, Washington County, Alabama. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: Jul 20, 2021, 3:06 PM CDT (20:06 UTC)
Expired: Jul 20, 2021, 6:15 PM CDT
In force: 3 hr
Issued by: NWS Mobile, AL
Area: Storm-based polygon

Counties Clarke County, AL, Washington County, AL

The radar

The Mobile radar (KMOB), 98 km from the middle of the area, began a volume at 20:06 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, 8.1 hours before the alert went out and 215 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: 737 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 628 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Mobile, AL wrote its last area forecast discussion before this areal flood advisory went out at Jul 20, 1:18 PM CDT, 1 hour 48 minutes earlier.

Area forecast discussion, Jul 20, 1:18 PM CDT, 1 hour 48 minutes before

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In the hours before

Special weather statement, Jul 20, 11:05 AM CDT, 4 hours 1 minute before

Special Weather Statement
National Weather Service Mobile AL
1105 AM CDT Tue Jul 20 2021

ALZ056>058-060-201700-
Conecuh AL-Butler AL-Covington AL-Crenshaw AL-
1105 AM CDT Tue Jul 20 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT THE FOLLOWING
COUNTIES...SOUTHEASTERN BUTLER...SOUTHERN CRENSHAW...EAST CENTRAL
CONECUH AND COVINGTON COUNTIES UNTIL NOON CDT...

At 1104 AM CDT, the strong thunderstorms were located along a line
extending from 6 miles southwest of Red Level to 7 miles southeast of
Opp, and moving north at 25 mph.

Wind gusts of 40 to 50 mph will be possible with these storms.

Locations impacted include...
Andalusia, Opp, Brantley, McKenzie, River Falls, Red Level, Dozier,
Heath and Gantt.

LAT...LON 3153 8616 3153 8620 3111 8619 3128 8677
      3175 8670 3159 8615 3154 8614
TIME...MOT...LOC 1604Z 196DEG 22KT 3133 8668 3118 8620

The office that day

Everything else NWS Mobile, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 7:00 AM CDT	Special Weather Statement	MOB	Baldwin	45 min
Jul 20, 7:53 AM CDT	Areal Flood Advisory	MOB	Baldwin	3 hr
Jul 20, 8:10 AM CDT	Special Marine Warning	MOB		65 min
Jul 20, 9:30 AM CDT	Areal Flood Advisory	MOB	Baldwin	3 hr
Jul 20, 10:03 AM CDT	Areal Flood Advisory	MOB	Baldwin, Escambia	3 hr
Jul 20, 11:05 AM CDT	Special Weather Statement	MOB	Covington	55 min
Jul 20, 12:23 PM CDT	Areal Flood Advisory	MOB	Butler, Covington, Crenshaw	3 hr
Jul 20, 10:20 AM CDT	Areal Flood Advisory	MOB	Wayne	3 hr

Nearby

Areal Flood Advisories in Alabama, 2021 Every areal flood advisory in 2021

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.