Alert archive / Montana / Flood Watches in 2022
Flood Watch 2, NWS Missoula, MT
NWS Missoula, MT issued this flood watch at Aug 24, 2022, 1:32 AM MDT for 11 counties in Montana. It took effect at Aug 24, 2022, 12:00 PM MDT. It was in force for 32 hr.
The area
The counties it named.
The facts
- Issued
- Aug 24, 2022, 1:32 AM MDT (07:32 UTC)
- In effect from
- Aug 24, 2022, 12:00 PM MDT
- Expired
- Aug 25, 2022, 8:11 PM MDT
- In force
- 32 hr
- Issued by
- NWS Missoula, MT
- Flood severity
- None
Counties Deer Lodge County, MT, Flathead County, MT, Granite County, MT, Lake County, MT, Lincoln County, MT, Mineral County, MT, Missoula County, MT, Powell County, MT, Ravalli County, MT, Sanders County, MT, Silver Bow County, MT
The radar
The Missoula radar (KMSX), 2 km from the middle of the area, began a volume at 07:32 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.
What forecasters said that day
The local office's own words before this flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Missoula, MT wrote its last area forecast discussion before this flood watch went out at Aug 23, 2:45 PM MDT, 10 hours 47 minutes earlier.
Area forecast discussion, Aug 23, 2:45 PM MDT, 10 hours 47 minutes before
Area Forecast Discussion National Weather Service Missoula MT 245 PM MDT Tue Aug 23 2022 .DISCUSSION...A slow moving cut-off low pressure system, currently located along the northern Washington/British Columbia border, will continue to migrate eastward into northwest Montana through Thursday. An influx of moisture with this system will bring thunderstorm chances each afternoon and evening through Thursday. For the rest of this afternoon and evening, convection looks most favored across northwest Montana. Storm motion is expected to generally be less than 10 knots. This means that storms will likely form over the terrain with very little movement into the valleys. Under storm cores, very heavy rain will be possible. There is an outside chance that a heavy rain core could form over portions of Glacier National Park, including the Going-To-The-Sun Highway. For Wednesday into Thursday, moisture will further increase with precipitable water values over 1" (150-200% of normal) across much of western Montana and the Idaho panhandle. These values will again support very heavy rainfall under thunderstorm cores. With slightly more dynamics as the upper low approaches the region along with increased instability, convection is expected to be more widespread, especially across western Montana. Thunderstorms will again be capable of very heavy rain under their cores (0.75" per hour or more) and with the potential for convection to be more widespread, the threat for localized flash flooding is a real possibility (around 5% chance), especially if a storm forms over a recent burn scar or flood prone urban area. Gusty outflow winds up to 50 mph will also be possible ahead of these storms as they develop and move through the region. By Friday, the upper level low should have meandered into north central Montana. Atmospheric moisture levels will be on the decrease so the threat of heavy rain will be decreasing, however thunderstorms will remain a possibility. A trough of low pressure is expected to move through the region this weekend. As this trough approaches, a break down of the upper level ridge is expected on Saturday. Forecast models still vary a bit on how dramatic this ridge break down will be, but under typical patterns such as this, breezy to windy conditions can be expected. Cooler conditions, closer to seasonal normals are expected Sunday into Monday. Much drier air will also filter in with the trough, bringing an end to thunderstorm chances for at least a couple days. Forecast models continue to show high pressure building over the region for next week. Hot temperatures will return with many valleys likely reaching back into the 90s by mid week, though dry conditions will favor cool conditions at night. && .AVIATION...Thunderstorms are in the forecast again through this evening. A lack of wind shear or any stronger steering winds aloft means storms will move slowly and mostly be heavy rain producers. Thunderstorms have already begun initiating across northwest Montana and along the length of the Continental Divide. KGPI and KBTM have the greatest likelihood of seeing a storm through roughly 24/0100z. KMSO also could see a storm, though the threat looks slightly lower. Storms will largely end with sunset before more widespread convection develops Wednesday afternoon. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. &&
In the hours before
Special weather statement, Aug 23, 10:42 PM MDT, 2 hours 50 minutes before
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</html>The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 23, 10:42 PM MDT | Special Weather Statement | MSO | Flathead | 48 min |
| Aug 24, 1:14 PM MDT | Special Weather Statement | MSO | Mineral | 46 min |
| Aug 24, 5:39 PM MDT | Special Weather Statement | MSO | Ravalli | 51 min |
Nearby
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.