Alert archive / Alabama / Frost Advisories in 2017

Frost Advisory 3, NWS Huntsville, AL

October 24, 20174 counties in Alabama; Franklin County, Lincoln County, Moore County, Tennessee

NWS Huntsville, AL issued this frost advisory at Oct 24, 2017, 3:09 PM CDT for 4 counties in Alabama; Franklin County, Lincoln County, Moore County, Tennessee. It took effect at Oct 25, 2017, 2:00 AM CDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued: Oct 24, 2017, 3:09 PM CDT (20:09 UTC)
In effect from: Oct 25, 2017, 2:00 AM CDT
Expired: Oct 25, 2017, 8:00 AM CDT
In force: 6 hr
Issued by: NWS Huntsville, AL

Counties Jackson County, AL, Lauderdale County, AL, Limestone County, AL, Madison County, AL, Franklin County, TN, Lincoln County, TN, Moore County, TN

The radar

The Northeast Alabama radar (KHTX), 48 km from the middle of the area, began a volume at 20:12 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 12:00Z, 8.2 hours before the alert went out and 128 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: 19 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 958 m above ground
0-6 km bulk shear: 100 kt
0-1 km storm-relative helicity: -47 m²/s²
0-3 km storm-relative helicity: 19 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 Huntsville, AL wrote its last area forecast discussion before this frost advisory went out at Oct 23, 6:22 PM CDT, 20 hours 47 minutes earlier.

Area forecast discussion, Oct 23, 6:22 PM CDT, 20 hours 47 minutes before

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Nearby

Frost Advisories in Alabama, 2017 Frost Advisories in Tennessee, 2017 Every frost advisory 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.