Alert archive / Alabama / Dense Fog Advisories in 2021
Dense Fog Advisory 9, NWS Birmingham, AL
NWS Birmingham, AL issued this dense fog advisory at Oct 4, 2021, 1:23 AM CDT for 8 counties in Alabama. It was in force for 8 hr.
The area
The counties it named.
The facts
- Issued
- Oct 4, 2021, 1:23 AM CDT (06:23 UTC)
- Expired
- Oct 4, 2021, 9:00 AM CDT
- In force
- 8 hr
- Issued by
- NWS Birmingham, AL
Counties Blount County, AL, Fayette County, AL, Lamar County, AL, Marion County, AL, Pickens County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL
The radar
The Columbus AFB radar (KGWX), 71 km from the middle of the area, began a volume at 06:25 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
Nashville Metro, TN (KBNA), launched 00:00Z, 6.4 hours before the alert went out and 277 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.
- Mixed-layer CAPE
- 1426 J/kg
- Mixed-layer CIN
- -2 J/kg
- Mixed-layer LCL
- 706 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 87 m²/s²
- 0-3 km storm-relative helicity
- 119 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 2.9
What forecasters said that day
The local office's own words before this dense fog advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Birmingham, AL wrote its last area forecast discussion before this dense fog advisory went out at Oct 4, 1:10 AM CDT, 13 minutes earlier.
Area forecast discussion, Oct 4, 1:10 AM CDT, 13 minutes before
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</html>Hazardous weather outlook, Oct 4, 1:12 AM CDT, 11 minutes before
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Local storm report, Oct 3, 9:54 PM CDT, 3 hours 29 minutes before
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</html>Local storm report, Oct 3, 9:56 PM CDT, 3 hours 27 minutes before
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<div class="status" id="status">Temporary Notice</div>
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</html>The office that day
Everything else NWS Birmingham, AL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 3, 8:04 PM CDT | Areal Flood Advisory | BMX | Fayette, Walker | 116 min |
| Oct 3, 9:05 PM CDT | Flash Flood Warning | BMX | Fayette, Jefferson, Marion, Walker | 3 hr |
| Oct 3, 10:59 PM CDT | Areal Flood Advisory | BMX | Jefferson | 3 hr |
| Oct 4, 12:53 AM CDT | Areal Flood Advisory | BMX | Jefferson, St. Clair, Shelby | 3 hr |
| Oct 4, 3:11 AM CDT | Flash Flood Watch | BMX | Autauga, Barbour, Bibb, Blount, Bullock, Calhoun and 30 more | 3 days |
| Oct 4, 9:37 AM CDT | Areal Flood Advisory | BMX | Lee | 3 hr |
| Oct 4, 11:51 AM CDT | Areal Flood Advisory | BMX | Russell | 3 hr |
| Oct 4, 12:20 PM CDT | Flash Flood Warning | BMX | Lee, Russell | 3 hr |
| Oct 4, 12:44 PM CDT | Areal Flood Advisory | BMX | Lowndes, Montgomery | 3 hr |
| Oct 4, 1:33 PM CDT | Flash Flood Warning | BMX | Montgomery | 87 min |
| Oct 4, 3:12 PM CDT | Special Weather Statement | BMX | Coosa | 33 min |
| Oct 4, 3:21 PM CDT | Flash Flood Warning | BMX | Lee, Russell | 3 hr |
| Oct 4, 3:28 PM CDT | Flash Flood Warning | BMX | Lowndes, Montgomery | 3 hr |
| Oct 4, 4:40 PM CDT | Areal Flood Advisory | BMX | Chilton, Coosa | 3 hr |
| Oct 4, 4:56 PM CDT | Flash Flood Warning | BMX | Chilton | 3 hr |
| Oct 4, 5:09 PM CDT | Special Weather Statement | BMX | Bibb | 36 min |
| Oct 4, 5:09 PM CDT | Special Weather Statement | BMX | Shelby | 36 min |
| Oct 4, 5:16 PM CDT | Severe Thunderstorm Warning | BMX | Bibb | 29 min |
| Oct 4, 5:22 PM CDT | Special Weather Statement | BMX | Shelby | 23 min |
| Oct 4, 5:43 PM CDT | Severe Thunderstorm Warning | BMX | Shelby | 47 min |
| Oct 4, 5:47 PM CDT | Severe Thunderstorm Warning | BMX | Bibb, Shelby | 43 min |
| Oct 4, 6:02 PM CDT | Special Weather Statement | BMX | Shelby | 28 min |
| Oct 4, 6:17 PM CDT | Special Weather Statement | BMX | Jefferson | 28 min |
| Oct 4, 6:34 PM CDT | Special Weather Statement | BMX | Jefferson | 26 min |
Nearby
Dense Fog Advisories in Alabama, 2021Every dense fog 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.