Alert archive / Wyoming / Frost Advisories in 2021
Frost Advisory 1, NWS Rapid City, SD
NWS Rapid City, SD issued this frost advisory at Sep 20, 2021, 2:22 PM MDT for Campbell County, Crook County, Weston County, Wyoming. It took effect at Sep 21, 2021, 12:00 AM MDT. It was in force for 7 hr.
The area
The counties it named.
The facts
- Issued
- Sep 20, 2021, 2:22 PM MDT (20:22 UTC)
- In effect from
- Sep 21, 2021, 12:00 AM MDT
- Expired
- Sep 21, 2021, 7:00 AM MDT
- In force
- 7 hr
- Issued by
- NWS Rapid City, SD
Counties Campbell County, WY, Crook County, WY, Weston County, WY
The radar
The Rapid City radar (KUDX), 165 km from the middle of the area, began a volume at 20:25 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
Riverton, WY (KRIW), launched 12:00Z, 8.4 hours before the alert went out and 310 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
- 2 J/kg
- Mixed-layer CIN
- -57 J/kg
- Mixed-layer LCL
- 1254 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 25 m²/s²
- 0-3 km storm-relative helicity
- 25 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Rapid City, SD wrote its last area forecast discussion before this frost advisory went out at Sep 20, 11:21 AM MDT, 3 hours 1 minute earlier.
Area forecast discussion, Sep 20, 11:21 AM MDT, 3 hours 1 minute before
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</html>The office that day
Everything else NWS Rapid City, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 19, 8:41 PM MDT | Special Weather Statement | UNR | Ziebach | 49 min |
Nearby
Frost Advisories in Wyoming, 2021Every frost 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.