Alert archive / Alabama / Frost Advisories in 2020

Frost Advisory 8, NWS Birmingham, AL

November 17, 202020 counties in Alabama

NWS Birmingham, AL issued this frost advisory at Nov 17, 2020, 4:48 PM CST for 20 counties in Alabama. It took effect at Nov 18, 2020, 12:00 AM CST. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued: Nov 17, 2020, 4:48 PM CST (22:48 UTC)
In effect from: Nov 18, 2020, 12:00 AM CST
Expired: Nov 18, 2020, 8:00 AM CST
In force: 8 hr
Issued by: NWS Birmingham, AL

Counties Autauga County, AL, Barbour County, AL, Bibb County, AL, Bullock County, AL, Chilton County, AL, Dallas County, AL, Elmore County, AL, Greene County, AL, Hale County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Russell County, AL, Sumter County, AL, Tuscaloosa County, AL

The radar

The Birmingham radar (KBMX), 73 km from the middle of the area, began a volume at 22:49 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

Birmingham, AL (KBMX), launched 12:00Z, 10.8 hours before the alert went out and 74 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2609 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this frost 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 frost advisory went out at Nov 17, 3:07 PM CST, 1 hour 41 minutes earlier.

Area forecast discussion, Nov 17, 3:07 PM CST, 1 hour 41 minutes before

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Hazardous weather outlook, Nov 17, 2:50 PM CST, 1 hour 58 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 16, 9:21 PM CST	Frost Advisory	BMX	Blount, Calhoun, Cherokee, Clay, Cleburne, Etowah and 8 more	11 hr
Nov 17, 1:40 AM CST	Freeze Watch	BMX	Blount, Calhoun, Cherokee, Cleburne, Etowah, Marion and 3 more	7 hr
Nov 17, 8:51 AM CST	Freeze Warning	BMX	Blount, Calhoun, Chambers, Cherokee, Clay, Cleburne and 13 more	23 hr
Nov 17, 2:01 PM CST	Red Flag Warning	BMX	Barbour, Bullock, Dallas, Lee, Lowndes, Macon and 3 more	3 hr

Nearby

Frost Advisories in Alabama, 2020 Every frost advisory 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.