Alert archive / Montana / Winter Storm Warnings in 2024

Winter Storm Warning 9, NWS Missoula, MT

May 22, 20246 counties in Montana

NWS Missoula, MT issued this winter storm warning at May 22, 2024, 8:25 AM MDT for 6 counties in Montana. It took effect at May 22, 2024, 6:00 PM MDT. It was in force for 18 hr. 28 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
May 22, 2024, 8:25 AM MDT (14:25 UTC)
In effect from
May 22, 2024, 6:00 PM MDT
Expired
May 23, 2024, 12:00 PM MDT
In force
18 hr
Issued by
NWS Missoula, MT

Counties Deer Lodge County, MT, Granite County, MT, Missoula County, MT, Powell County, MT, Ravalli County, MT, Silver Bow County, MT

The radar

The Missoula radar (KMSX), 87 km from the middle of the area, began a volume at 14:24 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 was reported inside it

TimeReportWhereRemark
May 23, 12:00 AM MDTSNOW 314 Wnw Seeley Lake, MTNorth Fork Jocko SNOTEL at 6330 feet. No additional snow depth increase after midnight.
May 23, 5:00 AM MDTSNOW 3.53 Nne Stevensville, MTPower was out since 140am.
May 23, 5:31 AM MDTSNOW 63 E Florence, MTLarge branches broken off. Power off and on. Power is out as of 730am MDT.
May 23, 6:00 AM MDTSNOW 96 Ssw Georgetown, MTPeterson Meadows SNOTEL at 7200 feet. This is a snow depth increase measurement. The snow water equivalent is around 0.60 inches.
May 23, 6:11 AM MDTSNOW 8.54 Wnw West Valley, MT0.55 snow water equivalent, 0.25 inches rain before it turned to snow. 0.80 total water.
May 23, 7:00 AM MDTSNOW 36 Sw Skalkaho Pass, MTSnow depth increase at Daly Creek SNOTEL at 5780 ft. Snow water equivalent was 0.50. The high yesterday was 48 degrees. Current 31 F.
May 23, 7:00 AM MDTSNOW 88 S Janney, MTBasin Creek SNOTEL at 7180 feet. It has been reporting 2 inch snow depth increase per hour since 5 am. It reported 0.30 of snow water equivalent from 6 to 7 am! 1.00 of total snow water equivalent so far. It continues to snow.
May 23, 7:00 AM MDTSNOW 89 Nw Philipsburg, MTBlack Pine SNOTEL at 7210 feet snow depth increase. Snow water equivalent is 0.80 inches.
May 23, 7:03 AM MDTSNOW 116 Sw West Valley, MTBarker Lakes SNOTEL at 8250 feet. 0.60 inches of snow water equivalent.
May 23, 8:00 AM MDTSNOW 222 Sw Conner, MTNez Perce Camp SNOTEL at 5650 feet. Only 0.20 inches of snow water equivalent. This location did not get under the main heavy deformation band.
May 23, 8:00 AM MDTSNOW 103 Wnw Georgetown, MTSocial media report, approximately 8 miles south of Philipsburg.
May 23, 8:00 AM MDTSNOW 118 S Janney, MTBasin Creek SNOTEL at 7180 ft. Snow depth increase was around 10 inches, but the 1.30 inches of snow water equivalent would suggest more fell.
May 23, 8:00 AM MDTSNOW 1216 W Charlos Heights, MTTwin Lakes SNOTEL at 6400 feet. 1.00 inch of snow water equivalent.
May 23, 8:00 AM MDTSNOW 142 S Porters Corner, MT
May 23, 8:13 AM MDTSNOW 31 S Clinton, MTBroken branches.
May 23, 9:00 AM MDTSNOW 62 Sw Newcomb, MT530 to 900am MDT is when they observed the snowfall. 0.58 of total precipitation. The low was 28 and the high was 57 degrees.
May 23, 9:00 AM MDTSNOW 64 E Corvallis, MT1.01 of snow water equivalent. 0.33 of rain fell before it changed to snow. 1.34 inches total precip.
May 23, 9:30 AM MDTSNOW 202 S Porters Corner, MTEstimated amount.
May 23, 10:00 AM MDTSNOW 1Drummond, MT
May 23, 10:00 AM MDTSNOW 3.51 Sse Walkerville, MT
May 23, 10:00 AM MDTSNOW 52 Ese Butte, MTA few telephone lines were down, some branches broken.
May 23, 10:00 AM MDTSNOW 5Avon, MT
May 23, 10:00 AM MDTSNOW 6Melrose, MTSnowed from 630 am until 10 am. Power fluctuated. 1.12 inches of water equivalent which includes rain and snow. 2.05 inches of water for the month of May so far.
May 23, 10:00 AM MDTSNOW 6.52 Ene Janney, MTEstimated 6 to 7 inches.
May 23, 10:00 AM MDTSNOW 121 Ene Elliston, MT
May 23, 10:00 AM MDTSNOW 149 E Skalkaho Pass, MT300 feet above the Gem Mtn store.
May 23, 10:00 AM MDTSNOW 185 Sw Porters Corner, MT
May 23, 11:00 AM MDTSNOW 129 E Skalkaho Pass, MTGem Mountain Mine. Snow started around 4 pm on the 22nd.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 2.4 hours before the alert went out and 241 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.

Skew-T log-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2024-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2024-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1135 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
133 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

286 
WWUS45 KMSO 221425
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
825 AM MDT Wed May 22 2024

MTZ006-231430-
/O.UPG.KMSO.WS.A.0008.240523T0000Z-240523T1800Z/
/O.NEW.KMSO.WS.W.0009.240523T0000Z-240523T1800Z/
Bitterroot/Sapphire Mountains-
825 AM MDT Wed May 22 2024

...WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO NOON MDT 
THURSDAY BITTERROOT/SAPPHIRE MOUNTAINS ABOVE 5000 FEET...

* WHAT...Heavy snow expected Bitterroot/Sapphire Mountains above 
  5000 feet. Total snow accumulations between 4 and 19 inches. Snow 
  rates will exceed 1 inch per hour at times. Snow amounts will vary 
  considerably with changes in elevation.

* WHERE...Lolo Pass and Highway 93 Sula to Lost Trail Pass.

* WHEN...From 6 PM this evening to noon MDT Thursday. The heaviest 
  snow rates are expected midnight to seven am MDT.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute. 
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ007-231430-
/O.UPG.KMSO.WS.A.0008.240523T0000Z-240523T1800Z/
/O.NEW.KMSO.WS.W.0009.240523T0000Z-240523T1800Z/
Butte/Blackfoot Region-
825 AM MDT Wed May 22 2024

...WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO NOON MDT 
THURSDAY BUTTE/BLACKFOOT REGION ABOVE 5000 FEET...

* WHAT...Heavy snow expected Butte/Blackfoot Region above 5000 feet. 
  Total snow accumulations between 1 and 26 inches. Mountain passes 
  and easily accessible areas should get less than a foot whereas 
  higher elevations and more remote areas will receive the higher 
  amounts. Snow rates will exceed 1 inch per hour at times. Snow 
  amounts will vary considerably with changes in elevation.

* WHERE...MacDonald Pass, Butte, Homestake Pass, and Georgetown Lake.

* WHEN...From 6 PM this evening to noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute.  
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IDZ009-010-231430-
/O.UPG.KMSO.WS.A.0008.240523T0000Z-240523T1800Z/
/O.NEW.KMSO.WW.Y.0040.240523T0000Z-240523T1800Z/
Western Lemhi County-Eastern Lemhi County-
825 AM MDT Wed May 22 2024

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO NOON 
MDT THURSDAY LEMHI COUNTY ABOVE 4500 FEET...

* WHAT...Snow expected Lemhi County above 4500 feet. Total snow 
  accumulations between 2 and 11 inches. Accumulations above 6 
  inches are only expected in isolated, very remote locations.

* WHERE...Bannock Pass, Highway 28 Tendoy to Lone Pine, Highway 93 
  Lost Trail Pass to Gibbonsville, Lemhi Pass, and Williams Creek 
  Summit.

* WHEN...From 6 PM this evening to noon MDT Thursday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Thursday morning commute.  Heavy, wet snow 
  accumulating on trees with their leaves out could weigh them down 
  and cause significant tree damages and possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$
5 follow-up statements
130 
WWUS45 KMSO 222155
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
355 PM MDT Wed May 22 2024

MTZ006-231800-
/O.CON.KMSO.WS.W.0009.240523T0000Z-240523T1800Z/
Bitterroot/Sapphire Mountains-
355 PM MDT Wed May 22 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
BITTERROOT/SAPPHIRE MOUNTAINS ABOVE 5000 FEET...

* WHAT...Heavy snow expected Bitterroot/Sapphire Mountains above 
  5000 feet. Total snow accumulations between 4 and 19 inches. Snow 
  rates will exceed 1 inch per hour at times. Snow amounts will vary 
  considerably with changes in elevation.

* WHERE...Highway 93 Sula to Lost Trail Pass and Lolo Pass.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute. 
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ007-231800-
/O.CON.KMSO.WS.W.0009.240523T0000Z-240523T1800Z/
Butte/Blackfoot Region-
355 PM MDT Wed May 22 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
BUTTE/BLACKFOOT REGION ABOVE 5000 FEET...

* WHAT...Heavy snow expected Butte/Blackfoot Region above 5000 feet. 
  Total snow accumulations between 1 and 26 inches. Lower 
  elevations, including Butte 2 to 6 inches. Mountain passes and 
  easily accessible areas should get less than a foot whereas higher 
  elevations and more remote areas will receive the higher amounts. 
  Snow rates will exceed 1 inch per hour at times. Snow amounts will 
  vary considerably with changes in elevation.

* WHERE...Butte, Homestake Pass, Georgetown Lake, and MacDonald Pass.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute.  
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IDZ006-222300-
/O.NEW.KMSO.WW.Y.0041.240522T2155Z-240522T2200Z/
Southern Clearwater Mountains-
255 PM PDT Wed May 22 2024

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 PM PDT THIS AFTERNOON 
ABOVE 4000 FEET...

* WHAT...Snow Above 4000 feet. Total snow accumulations 1 to 4 
  inches from 4000 to 5000 feet. 3 to 7 inches above 5000 feet and 
  higher amounts of 7 to 12 inches in the highest terrain.

* WHERE...Dixie and Elk City.

* WHEN...Until 3 PM PDT this afternoon.

* IMPACTS...Travel could be affected. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

IDZ009-010-231800-
/O.CON.KMSO.WW.Y.0040.240523T0000Z-240523T1800Z/
Western Lemhi County-Eastern Lemhi County-
355 PM MDT Wed May 22 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
LEMHI COUNTY ABOVE 4500 FEET...

* WHAT...Snow expected Lemhi County above 4500 feet. Total snow 
  accumulations between 2 and 11 inches. Accumulations above 6 
  inches are only expected in isolated, very remote locations.

* WHERE...Highway 93 Lost Trail Pass to Gibbonsville, Lemhi Pass, 
  Bannock Pass, Highway 28 Tendoy to Lone Pine, and Williams Creek 
  Summit.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Thursday morning commute.  Heavy, wet snow 
  accumulating on trees with their leaves out could weigh them down 
  and cause significant tree damages and possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

JK
733 
WWUS45 KMSO 222212
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
412 PM MDT Wed May 22 2024

IDZ006-231800-
/O.EXP.KMSO.WW.Y.0041.000000T0000Z-240522T2200Z/
/O.EXB.KMSO.WW.Y.0040.240522T2212Z-240523T1800Z/
Southern Clearwater Mountains-
312 PM PDT Wed May 22 2024

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 AM PDT THURSDAY ABOVE 
4000 FEET...


* WHAT...Snow Above 4000 feet. Total snow accumulations 1 to 4 
  inches from 4000 to 5000 feet. 3 to 7 inches above 5000 feet and 
  higher amounts of 7 to 12 inches in the highest terrain.

* WHERE...Dixie and Elk City.

* WHEN...Until 11 AM PDT Thursday.

* IMPACTS...Travel could be affected. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

MTZ006-231800-
/O.CON.KMSO.WS.W.0009.240523T0000Z-240523T1800Z/
Bitterroot/Sapphire Mountains-
412 PM MDT Wed May 22 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
BITTERROOT/SAPPHIRE MOUNTAINS ABOVE 5000 FEET...

* WHAT...Heavy snow expected Bitterroot/Sapphire Mountains above 
  5000 feet. Total snow accumulations between 4 and 19 inches. Snow 
  rates will exceed 1 inch per hour at times. Snow amounts will vary 
  considerably with changes in elevation.

* WHERE...Highway 93 Sula to Lost Trail Pass and Lolo Pass.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute. 
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ007-231800-
/O.CON.KMSO.WS.W.0009.240523T0000Z-240523T1800Z/
Butte/Blackfoot Region-
412 PM MDT Wed May 22 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
BUTTE/BLACKFOOT REGION ABOVE 5000 FEET...

* WHAT...Heavy snow expected Butte/Blackfoot Region above 5000 feet. 
  Total snow accumulations between 1 and 26 inches. Lower 
  elevations, including Butte 2 to 6 inches. Mountain passes and 
  easily accessible areas should get less than a foot whereas higher 
  elevations and more remote areas will receive the higher amounts. 
  Snow rates will exceed 1 inch per hour at times. Snow amounts will 
  vary considerably with changes in elevation.

* WHERE...Butte, Homestake Pass, Georgetown Lake, and MacDonald Pass.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute.  
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IDZ009-010-231800-
/O.CON.KMSO.WW.Y.0040.240523T0000Z-240523T1800Z/
Western Lemhi County-Eastern Lemhi County-
412 PM MDT Wed May 22 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
LEMHI COUNTY ABOVE 4500 FEET...

* WHAT...Snow expected Lemhi County above 4500 feet. Total snow 
  accumulations between 2 and 11 inches. Accumulations above 6 
  inches are only expected in isolated, very remote locations.

* WHERE...Highway 93 Lost Trail Pass to Gibbonsville, Lemhi Pass, 
  Bannock Pass, Highway 28 Tendoy to Lone Pine, and Williams Creek 
  Summit.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Thursday morning commute.  Heavy, wet snow 
  accumulating on trees with their leaves out could weigh them down 
  and cause significant tree damages and possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

JK
038 
WWUS45 KMSO 230324
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
924 PM MDT Wed May 22 2024

MTZ006-231800-
/O.CON.KMSO.WS.W.0009.000000T0000Z-240523T1800Z/
Bitterroot/Sapphire Mountains-
924 PM MDT Wed May 22 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
BITTERROOT/SAPPHIRE MOUNTAINS ABOVE 5000 FEET...

* WHAT...Heavy snow expected Bitterroot/Sapphire Mountains above 
  5000 feet. Total snow accumulations between 4 and 19 inches. Snow 
  rates will exceed 1 inch per hour at times. Snow amounts will vary 
  considerably with changes in elevation.

* WHERE...Highway 93 Sula to Lost Trail Pass and Lolo Pass.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute. 
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ007-231800-
/O.CON.KMSO.WS.W.0009.000000T0000Z-240523T1800Z/
Butte/Blackfoot Region-
924 PM MDT Wed May 22 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
BUTTE/BLACKFOOT REGION ABOVE 5000 FEET...

* WHAT...Heavy snow expected Butte/Blackfoot Region above 5000 feet. 
  Total snow accumulations between 1 and 26 inches. Lower 
  elevations, including Butte 2 to 6 inches. Mountain passes and 
  easily accessible areas should get less than a foot whereas higher 
  elevations and more remote areas will receive the higher amounts. 
  Snow rates will exceed 1 inch per hour at times. Snow amounts will 
  vary considerably with changes in elevation.

* WHERE...Butte, Homestake Pass, Georgetown Lake, and MacDonald Pass.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute.  
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ005-231600-
/O.EXB.KMSO.WW.Y.0040.000000T0000Z-240523T1600Z/
Missoula/Bitterroot Valleys-
924 PM MDT Wed May 22 2024

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 10 AM MDT THURSDAY...

* WHAT...Wet snow. Total snow accumulations of a trace to 3 inches. 
  Locations just above the valley floor may see higher snow amounts. 
  Snow will favor the Bitterroot Valley.

* WHERE...Missoula and Bitterroot Valleys.

* WHEN...Until 10 AM MDT Thursday.

* IMPACTS...Travel could be affected. Heavy, wet snow accumulating 
  on trees could weigh down branches and cause tree damages and 
  possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

IDZ006-231800-
/O.CON.KMSO.WW.Y.0040.000000T0000Z-240523T1800Z/
Southern Clearwater Mountains-
824 PM PDT Wed May 22 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 AM PDT 
THURSDAY ABOVE 4000 FEET |...

* WHAT...Snow Above 4000 feet. Total snow accumulations 1 to 4 
  inches from 4000 to 5000 feet. 3 to 7 inches above 5000 feet and 
  higher amounts of 7 to 12 inches in the highest terrain.

* WHERE...Dixie and Elk City.

* WHEN...Until 11 AM PDT Thursday.

* IMPACTS...Travel could be affected. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

IDZ009-010-231800-
/O.CON.KMSO.WW.Y.0040.000000T0000Z-240523T1800Z/
Western Lemhi County-Eastern Lemhi County-
924 PM MDT Wed May 22 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT THURSDAY 
LEMHI COUNTY ABOVE 4500 FEET...

* WHAT...Snow expected Lemhi County above 4500 feet. Total snow 
  accumulations between 2 and 11 inches. Accumulations above 6 
  inches are only expected in isolated, very remote locations.

* WHERE...Highway 93 Lost Trail Pass to Gibbonsville, Lemhi Pass, 
  Bannock Pass, Highway 28 Tendoy to Lone Pine, and Williams Creek 
  Summit.

* WHEN...Until noon MDT Thursday.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Thursday morning commute.  Heavy, wet snow 
  accumulating on trees with their leaves out could weigh them down 
  and cause significant tree damages and possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

JK
441 
WWUS45 KMSO 230749
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
149 AM MDT Thu May 23 2024

MTZ005-231600-
/O.UPG.KMSO.WW.Y.0040.000000T0000Z-240523T1600Z/
/O.EXB.KMSO.WS.W.0009.000000T0000Z-240523T1600Z/
Missoula/Bitterroot Valleys-
149 AM MDT Thu May 23 2024

...WINTER STORM WARNING IN EFFECT UNTIL 10 AM MDT THIS MORNING...

* WHAT...Heavy wet snow. Additional snow accumulations up to three 
  inches.  Accumulating snow on trees branches will be capable of 
  breaking branches and creating power outages.

* WHERE...Missoula and Bitterroot Valley.

* WHEN...Until 10 AM MDT this morning.

* IMPACTS...Plan on slippery road conditions. The hazardous 
  conditions could impact the Thursday morning commute. Snow on 
  trees could cause breaking branches and power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ006-231800-
/O.CON.KMSO.WS.W.0009.000000T0000Z-240523T1800Z/
Bitterroot/Sapphire Mountains-
149 AM MDT Thu May 23 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT TODAY 
BITTERROOT/SAPPHIRE MOUNTAINS ABOVE 5000 FEET...

* WHAT...Heavy snow expected Bitterroot/Sapphire Mountains above 
  5000 feet. Total snow accumulations between 4 and 19 inches. Snow 
  rates will exceed 1 inch per hour at times. Snow amounts will vary 
  considerably with changes in elevation.

* WHERE...Highway 93 Sula to Lost Trail Pass and Lolo Pass.

* WHEN...Until noon MDT today.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute. 
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ007-231800-
/O.CON.KMSO.WS.W.0009.000000T0000Z-240523T1800Z/
Butte/Blackfoot Region-
149 AM MDT Thu May 23 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT TODAY 
BUTTE/BLACKFOOT REGION ABOVE 5000 FEET...

* WHAT...Heavy snow expected Butte/Blackfoot Region above 5000 feet. 
  Total snow accumulations between 1 and 26 inches depending on 
  elevation. Lower elevations, including Butte, expect 2 to 6 
  inches. Mountain passes and easily accessible areas should get 
  less than a foot whereas higher elevations and more remote areas 
  will receive the higher amounts. Snow rates will exceed 1 inch per 
  hour at times. Snow amounts will vary considerably with changes in 
  elevation.

* WHERE...Butte, Georgetown Lake, Homestake Pass, and MacDonald Pass.

* WHEN...Until noon MDT today.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute.  
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IDZ006-231800-
/O.CON.KMSO.WW.Y.0040.000000T0000Z-240523T1800Z/
Southern Clearwater Mountains-
1249 AM PDT Thu May 23 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 AM PDT THIS 
MORNING ABOVE 4000 FEET |...

* WHAT...Snow Above 4000 feet. Total snow accumulations 1 to 4 
  inches from 4000 to 5000 feet. 3 to 7 inches above 5000 feet and 
  higher amounts of 7 to 12 inches in the highest terrain.

* WHERE...Elk City and Dixie.

* WHEN...Until 11 AM PDT this morning.

* IMPACTS...Travel could be affected. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

IDZ009-010-231800-
/O.CON.KMSO.WW.Y.0040.000000T0000Z-240523T1800Z/
Western Lemhi County-Eastern Lemhi County-
149 AM MDT Thu May 23 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT TODAY 
LEMHI COUNTY ABOVE 4500 FEET...

* WHAT...Snow expected Lemhi County above 4500 feet. Total snow 
  accumulations between 2 and 11 inches. Accumulations above 6 
  inches are only expected in isolated, very remote locations.

* WHERE...Highway 93 Lost Trail Pass to Gibbonsville, Bannock Pass, 
  Williams Creek Summit, Lemhi Pass, and Highway 28 Tendoy to Lone 
  Pine.

* WHEN...Until noon MDT today.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Thursday morning commute.  Heavy, wet snow 
  accumulating on trees with their leaves out could weigh them down 
  and cause significant tree damages and possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$
875 
WWUS45 KMSO 231507
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
907 AM MDT Thu May 23 2024

MTZ005-231615-
/O.CAN.KMSO.WS.W.0009.000000T0000Z-240523T1600Z/
Missoula/Bitterroot Valleys-
907 AM MDT Thu May 23 2024

...WINTER STORM WARNING IS CANCELLED...

The heavy snow threat is ending. Watch out for downed trees and tree 
branches from the earlier snowfall.

$$

IDZ006-231615-
/O.CAN.KMSO.WW.Y.0040.000000T0000Z-240523T1800Z/
Southern Clearwater Mountains-
807 AM PDT Thu May 23 2024

...WINTER WEATHER ADVISORY IS CANCELLED...

The snow threat is ending. 

$$

MTZ006-231800-
/O.CON.KMSO.WS.W.0009.000000T0000Z-240523T1800Z/
Bitterroot/Sapphire Mountains-
907 AM MDT Thu May 23 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT TODAY 
BITTERROOT/SAPPHIRE MOUNTAINS ABOVE 5000 FEET...

* WHAT...Heavy snow Bitterroot/Sapphire Mountains above 5000 feet. 
  Additional snow accumulations of 1-2 inches.

* WHERE...Lolo Pass and Highway 93 Sula to Lost Trail Pass.

* WHEN...Until noon MDT today.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute. 
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MTZ007-231800-
/O.CON.KMSO.WS.W.0009.000000T0000Z-240523T1800Z/
Butte/Blackfoot Region-
907 AM MDT Thu May 23 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT TODAY 
BUTTE/BLACKFOOT REGION ABOVE 5000 FEET...

* WHAT...Heavy snow Butte/Blackfoot Region above 5000 feet. 
  Additional snow accumulations up to two inches.

* WHERE...MacDonald Pass, Homestake Pass, Georgetown Lake, and Butte.

* WHEN...Until noon MDT today.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the Thursday morning commute.  
  Heavy, wet snow accumulating on trees with their leaves out could 
  weigh them down and cause significant tree damages and possibly 
  power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in 
your vehicle in case of an emergency. The latest road conditions for 
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IDZ009-010-231800-
/O.CON.KMSO.WW.Y.0040.000000T0000Z-240523T1800Z/
Western Lemhi County-Eastern Lemhi County-
907 AM MDT Thu May 23 2024

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT TODAY 
LEMHI COUNTY ABOVE 4500 FEET...

* WHAT...Snow Lemhi County above 4500 feet. Additional snow 
  accumulations up to two inches.

* WHERE...Highway 93 Lost Trail Pass to Gibbonsville, Highway 28 
  Tendoy to Lone Pine, Lemhi Pass, Bannock Pass, and Williams Creek 
  Summit.

* WHEN...Until noon MDT today.

* IMPACTS...Travel could be very difficult. The hazardous conditions 
  could impact the Thursday morning commute.  Heavy, wet snow 
  accumulating on trees with their leaves out could weigh them down 
  and cause significant tree damages and possibly power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road 
conditions for the state you are calling from can be obtained by 
calling 5 1 1.

&&

$$

What forecasters said that day

The local office's own words before this winter storm warning 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 winter storm warning went out at May 22, 4:06 AM MDT, 4 hours 19 minutes earlier.

Area forecast discussion, May 22, 4:06 AM MDT, 4 hours 19 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
406 AM MDT Wed May 22 2024

...Heavy Snow in the Higher Terrain Across Lemhi County into
Southwest Montana by Thursday Morning...

.DISCUSSION...The strong low pressure system is currently moving
into Washington this morning. The low is still anticipated to
slide towards southern Idaho by tonight then lift towards the
northeast on Thursday over Yellowstone National Park. The path of
this low will bring widespread precipitation to the Northern
Rockies with most locations experiencing rainfall totals in excess
of a half of an inch over the next 48hrs. Snow levels will drop
tonight to around 4500-5500 feet. The bulk of the precipitation
will be across Lemhi county into southwest Montana by Thursday
morning during the lowest snow levels causing significant
snowfall. The Bitterroot, Sapphires and mountains of southwest
Montana are expected to receive over a foot of new snow by
Thursday morning. Lost Trail and Homestake along with portions of
Highway 1 have a 60-80% chance of receiving over 6 inches of new
snow tonight into Thursday morning. The uncertain of this system
is how low will the snow levels become by Thursday morning and
which communities will be impacted by heavy snow. Areas that are
being closely monitored is Philipsburg to Georgetown Lake, Deer
Lodge to Butte and Tendoy to Gilmore Summit.

A second low pressure system is still expected to move through the
region on Saturday causing more widespread precipitation. The
latest guidance is indicating more of a broad system keeping the
snow levels higher, but impacts to mountain passes could be an
issue by Sunday morning.

A ridge of high pressure is still anticipated to for the first
half of next week causing a warming and drying trend.

&&

.AVIATION...The low pressure system is being to make its way into
Washington this morning then track into southern Idaho tonight.
Rain showers are already being experienced in northwest Montana
tonight, even impacting KGPI. The precipitation will be increasing
in coverage and intensity throughout the day along with lowering
ceilings. All terminals will be impacted by this system over the
next 24 hours. Snow levels will be lowering causing the
precipitation to change over to snow tonight for KBTM.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Watch from this evening through Thursday morning
     for Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

ID...Winter Storm Watch from this evening through Thursday morning
     for Eastern Lemhi County...Western Lemhi County.

&&

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 22, 8:25 AM MDTWinter Weather AdvisoryMSOMissoula, Ravalli28 hr

Nearby

Winter Storm Warnings in Montana, 2024Every winter storm warning in 2024

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.