Alert archive / Montana / Flash Flood Watches in 2021
Flash Flood Watch 3, NWS Missoula, MT
NWS Missoula, MT issued this flash flood watch at Aug 2, 2021, 10:09 AM MDT for Lemhi County, Idaho; Deer Lodge County, Silver Bow County, Montana. It took effect at Aug 2, 2021, 12:00 PM MDT. It was in force for 7 hr.
The area
The counties it named.
The facts
- Issued
- Aug 2, 2021, 10:09 AM MDT (16:09 UTC)
- In effect from
- Aug 2, 2021, 12:00 PM MDT
- Expired
- Aug 2, 2021, 7:27 PM MDT
- In force
- 7 hr
- Issued by
- NWS Missoula, MT
- Flood severity
- None
Counties Lemhi County, ID, Deer Lodge County, MT, Silver Bow County, MT
The radar
The Missoula radar (KMSX), 167 km from the middle of the area, began a volume at 16:11 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
Great_falls, MT (KTFX), launched 12:00Z, 4.2 hours before the alert went out and 285 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
- 13 J/kg
- Mixed-layer CIN
- -239 J/kg
- Mixed-layer LCL
- 2022 m above ground
- 0-6 km bulk shear
- 12 kt
- 0-1 km storm-relative helicity
- -12 m²/s²
- 0-3 km storm-relative helicity
- 46 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
565 WGUS65 KMSO 021609 FFAMSO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Missoula MT 1009 AM MDT Mon Aug 2 2021 IDC059-MTC023-093-030600- /O.NEW.KMSO.FF.A.0003.210802T1800Z-210803T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Lemhi-Deer Lodge-Silver Bow- 1009 AM MDT Mon Aug 2 2021 ...FLASH FLOOD WATCH IN EFFECT THROUGH THIS EVENING... The National Weather Service in Missoula has issued a * Flash Flood Watch for portions of east central Idaho and west central Montana, including the following areas, in east central Idaho, Lemhi. In west central Montana, Deer Lodge and Silver Bow. This includes the following Specific Areas... Butte, West Valley near Anaconda, Highway 93 8 miles south of Salmon to Ellis, Highway 93 north of Ellis, Hwy 93 4th of July Creek to Tower Creek and Salmon River Road between North Fork and Shoup. * Through this evening. * Slow moving thunderstorms capable of producing heavy rain may result in flash flooding, including debris flows. * Backcountry roads, and current and former burn scars are particularly vulnerable to flash flooding, and may become impassable or cut off. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
1 follow-up statement
538 WGUS65 KMSO 030127 FFAMSO Flood Watch National Weather Service Missoula MT 727 PM MDT Mon Aug 2 2021 IDC059-MTC023-093-030230- /O.CAN.KMSO.FF.A.0003.000000T0000Z-210803T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Lemhi-Deer Lodge-Silver Bow- 727 PM MDT Mon Aug 2 2021 ...FLASH FLOOD WATCH IS CANCELLED... The Flash Flood Watch for portions of east central Idaho and west central Montana, including the following areas, in east central Idaho, Lemhi. In west central Montana, Deer Lodge and Silver Bow has been cancelled. The Flood Watch is cancelled. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures. $$ JK
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 6:30 PM MDT | Flash Flood Warning | MSO | Lemhi | 3 hr |
| Aug 1, 7:22 PM MDT | Areal Flood Advisory | MSO | Idaho | 113 min |
| Aug 1, 7:53 PM MDT | Areal Flood Advisory | MSO | Idaho | 112 min |
| Aug 1, 7:59 PM MDT | Areal Flood Warning | MSO | Lemhi | 3 hr |
| Aug 1, 8:15 PM MDT | Areal Flood Advisory | MSO | Idaho | 2 hr |
| Aug 1, 10:01 PM MDT | Areal Flood Advisory | MSO | Idaho | 119 min |
| Aug 2, 5:59 PM MDT | Dense Fog Advisory | MSO | Idaho | 17 hr |
| Aug 1, 6:30 PM MDT | Areal Flood Advisory | MSO | Flathead, Lake | 3 hr |
| Aug 1, 6:33 PM MDT | Areal Flood Advisory | MSO | Flathead | 3 hr |
| Aug 1, 6:40 PM MDT | Areal Flood Advisory | MSO | Silver Bow | 10 min |
| Aug 1, 6:46 PM MDT | Special Weather Statement | MSO | Flathead | 29 min |
| Aug 1, 6:49 PM MDT | Flash Flood Warning | MSO | Silver Bow | 97 min |
| Aug 2, 2:18 PM MDT | Special Weather Statement | MSO | Flathead | 42 min |
| Aug 2, 2:21 PM MDT | Special Weather Statement | MSO | Deer Lodge, Powell | 54 min |
| Aug 2, 2:54 PM MDT | Special Weather Statement | MSO | Silver Bow | 51 min |
| Aug 2, 3:05 PM MDT | Special Weather Statement | MSO | Flathead | 55 min |
Nearby
Flash Flood Watches in Montana, 2021Flash Flood Watches in Idaho, 2021Every flash flood watch 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.