Alert archive / Montana / Frost Advisories in 2021
Frost Advisory 3, NWS Missoula, MT
NWS Missoula, MT issued this frost advisory at Sep 16, 2021, 7:41 PM MDT for 5 counties in Montana. It took effect at Sep 17, 2021, 12:00 AM MDT. It was in force for 9 hr.
The area
The counties it named.
The facts
- Issued
- Sep 16, 2021, 7:41 PM MDT (01:41 UTC)
- In effect from
- Sep 17, 2021, 12:00 AM MDT
- Expired
- Sep 17, 2021, 9:00 AM MDT
- In force
- 9 hr
- Issued by
- NWS Missoula, MT
Counties Flathead County, MT, Lake County, MT, Missoula County, MT, Ravalli County, MT, Sanders County, MT
The radar
The Missoula radar (KMSX), 40 km from the middle of the area, began a volume at 01:45 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
Spokane, WA (KOTX), launched 00:00Z, 1.7 hours before the alert went out and 165 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3129 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 13 m²/s²
- 0-3 km storm-relative helicity
- -43 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
488 WWUS75 KMSO 170141 NPWMSO URGENT - WEATHER MESSAGE National Weather Service Missoula MT 741 PM MDT Thu Sep 16 2021 MTZ003-005-171500- /O.NEW.KMSO.FR.Y.0003.210917T0600Z-210917T1500Z/ Flathead/Mission Valleys-Missoula/Bitterroot Valleys- 741 PM MDT Thu Sep 16 2021 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT FRIDAY... * WHAT...Temperatures as low as 35 will result in frost formation. * WHERE...Flathead Lake, Flathead Valley, Mission Valley, Polson, Bitterroot Valley, and Missoula. * WHEN...From midnight tonight to 9 AM MDT Friday. * IMPACTS...Frost could kill sensitive outdoor vegetation if left uncovered. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. && $$
2 follow-up statements
554 WWUS75 KMSO 170149 CCA NPWMSO URGENT - WEATHER MESSAGE...CORRECTED National Weather Service Missoula MT 749 PM MDT Thu Sep 16 2021 MTZ003-005-171500- /O.COR.KMSO.FR.Y.0003.210917T0600Z-210917T1500Z/ Flathead/Mission Valleys-Missoula/Bitterroot Valleys- 749 PM MDT Thu Sep 16 2021 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT FRIDAY... * WHAT...Temperatures ranging from the upper 20s to lower 30s will result in frost formation. * WHERE...Flathead Lake, Flathead Valley, Mission Valley, Polson, Bitterroot Valley, and Missoula. * WHEN...From midnight tonight to 9 AM MDT Friday. * IMPACTS...Frost could kill sensitive outdoor vegetation if left uncovered. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. && $$
467 WWUS75 KMSO 171442 NPWMSO URGENT - WEATHER MESSAGE National Weather Service Missoula MT 842 AM MDT Fri Sep 17 2021 MTZ003-005-171545- /O.EXP.KMSO.FR.Y.0003.000000T0000Z-210917T1500Z/ Flathead/Mission Valleys-Missoula/Bitterroot Valleys- 842 AM MDT Fri Sep 17 2021 ...FROST ADVISORY WILL EXPIRE AT 9 AM MDT THIS MORNING... $$
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 17, 2:16 PM MDT | High Wind Warning | MSO | Deer Lodge, Granite, Powell, Silver Bow | 31 hr |
| Sep 17, 2:16 PM MDT | Lake Wind Advisory | MSO | Flathead, Lake, Sanders | 31 hr |
| Sep 17, 2:16 PM MDT | Wind Advisory | MSO | Granite, Lake, Missoula, Powell, Ravalli | 31 hr |
Nearby
Frost Advisories in Montana, 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.