WWA Summary for Flood Watch Issued by PIH

Flood Watch

Flood Watch
National Weather Service Riverton WY
110 PM MDT Fri Sep 18 2026

WYZ001-191300-
/O.EXA.KRIW.FA.A.0006.000000T0000Z-260921T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yellowstone National Park-
Including the cities of Old Faithful, Lake, and Mammoth
110 PM MDT Fri Sep 18 2026

...FLOOD WATCH IN EFFECT THROUGH SUNDAY AFTERNOON...

* WHAT...Flash flooding caused by moderate to heavy rainfall is
  possible, especially in terrain and poor drainage areas.

* WHERE...Northwest Wyoming, including Yellowstone National Park.

* WHEN...Through Sunday afternoon.

* IMPACTS...Heavy rainfall may result in flooding of rivers, creeks,
  streams, and other low-lying and flood-prone locations. Flooding
  may occur in poor drainage areas and around steep terrain.

* ADDITIONAL DETAILS...
  - A slow moving weather system will move across Wyoming today
    through Sunday and bring rounds of showers and thunderstorms to
    the region, especially northern Wyoming. Any shower or
    thunderstorm could produce moderate to heavy rainfall across the
    Watch Area.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

&&

$$

Flood Watch
National Weather Service Billings MT
1103 AM MDT Fri Sep 18 2026

.A strong and slow moving weather system will impact the region
tonight through Sunday. Well above normal atmospheric moisture levels
combined with the dynamics from this storm system will provide the
potential for heavy rainfall during this period. Thunderstorms
embedded in the more general rainfall will have the potential to
produce flash flooding, particularly over recent burn scars.

MTZ029>031-034-036-040-042-056>058-063>068-138-139-141-169>173-228-
235-WYZ198-199-191715-
/O.CON.KBYZ.FA.A.0004.260919T0000Z-260921T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Musselshell-Treasure-Northern Rosebud-Northern Stillwater-Powder
River-Northern Park-Golden Valley-Red Lodge Foothills-Northern
Big Horn-Southern Rosebud-Judith Gap-Paradise Valley-Livingston
Area-Beartooth Foothills-Absaroka/Beartooth Mountains-Crazy
Mountains-Southern Big Horn-Southeastern Carbon-Northern Sweet
Grass-Bighorn Canyon-Northern Carbon-Pryor/Northern Bighorn
Mountains-Melville Foothills-Northeastern Yellowstone-Southern
Wheatland-Southwestern Yellowstone-Northeast Bighorn Mountains-
Sheridan Foothills-
Including the locations of Forsyth, Burgess Jct, Big Timber,
Fromberg, Crow Agency, Joliet, Red Lodge, Wilsall, Sheridan,
Emigrant, Billings, Lame Deer, Colstrip, Bridger, Broadus, Ryegate,
Pompeys Pillar, Melville, Harlowton, Fishtail, Pryor, Absarokee,
Clyde Park, Hardin, Hysham, Judith Gap, Columbus, Lodge Grass, Fort
Smith, Lavina, Roundup, McLeod, Cooke City, Livingston, and Custer
1103 AM MDT Fri Sep 18 2026

...FLOOD WATCH REMAINS IN EFFECT FROM 6 PM MDT THIS EVENING THROUGH
SUNDAY AFTERNOON...

* WHAT...Flooding caused by excessive rainfall is possible, along
  with Flash Flooding of recent burn scars.

* WHERE...All of South Central Montana, Portions of Southeast
  Montana, and Sheridan County Wyoming.

* WHEN...From 6 PM MDT this evening through Sunday afternoon.

* IMPACTS...Excessive runoff may result in flooding of creeks and
  other low-lying and flood-prone locations. Flooding may occur in
  poor drainage and urban areas.

* ADDITIONAL DETAILS...
  - 1 to 2.5 inches of rainfall is expected across the watch area
    tonight through Sunday. Locally heavier totals up to 4 inches are
    possible where thunderstorm activity is more persistent.
  - The Robertson Draw, East Side, Elk, and McGhee-Remington burn
    scars are particularly vulnerable to Flash Flooding and debris
    flows during the watch period. Any other burn scars from this
    summer will have elevated Flash Flood potential as well.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Please monitor forecasts and be alert for possible Flood Warnings.
Those living in areas prone to flooding should be prepared to take
action should flooding develop.

&&

$$

EA

Flood Watch
National Weather Service Great Falls MT
1039 AM MDT Fri Sep 18 2026

MTZ326-191200-
/O.CAN.KTFX.FF.A.0007.260919T0000Z-260920T0600Z/
/O.NEW.KTFX.FA.A.0008.260919T0000Z-260920T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gallatin Valley-
Including the cities of Bozeman and Gallatin Gateway
1039 AM MDT Fri Sep 18 2026


The Flash Flood Watch has been changed to a Flood Watch.

&&

...FLOOD WATCH IN EFFECT FROM 6 PM MDT THIS EVENING THROUGH SATURDAY
AFTERNOON...

* WHAT...Flooding caused by excessive rainfall is possible.

* WHERE...The Gallatin Valley in Southwest Montana

* WHEN...From 6 PM MDT this evening through Saturday afternoon.

* IMPACTS...Excessive runoff may result in flooding of low-lying and
  flood-prone locations.

* ADDITIONAL DETAILS...
  - Showers and thunderstorms capable of producing hourly rainfall
    rates up to 0.3 inch, with localized higher amounts, are
    possible.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.

&&

$$