Alert archive / Tennessee / Frost Advisories in 2020

Frost Advisory 9, NWS Morristown, TN

May 9, 202024 counties in Tennessee

NWS Morristown, TN issued this frost advisory at May 9, 2020, 3:26 AM EDT for 24 counties in Tennessee. It took effect at May 10, 2020, 12:00 AM EDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued: May 9, 2020, 3:26 AM EDT (07:26 UTC)
In effect from: May 10, 2020, 12:00 AM EDT
Expired: May 10, 2020, 10:00 AM EDT
In force: 10 hr
Issued by: NWS Morristown, TN

All 24 counties

Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Campbell County, TN, Cocke County, TN, Grainger County, TN, Hamblen County, TN, Hamilton County, TN, Jefferson County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Morgan County, TN, Polk County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Sevier County, TN, Union County, TN

The radar

The Knoxville radar (KMRX), 96 km from the middle of the area, began a volume at 07:27 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, 7.4 hours before the alert went out and 207 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: 3 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 1325 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: -50 m²/s²
0-3 km storm-relative helicity: 1 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 Morristown, TN wrote its last area forecast discussion before this frost advisory went out at May 8, 3:48 PM EDT, 11 hours 38 minutes earlier.

Area forecast discussion, May 8, 3:48 PM EDT, 11 hours 38 minutes before

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Hazardous weather outlook, May 8, 3:25 PM EDT, 12 hours 1 minute before

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        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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The office that day

Everything else NWS Morristown, TN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 9, 3:26 AM EDT	Freeze Warning	MRX	Blount, Carter, Claiborne, Cocke, Greene, Hancock and 8 more	31 hr

Nearby

Frost Advisories in Tennessee, 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.