*UPDATED* Rain and Snow To Start Your Work Week

The National Weather Service
Building a Weather-Ready Nation


Summary | Forecast | Monitoring & Reporting Snowfall | Safety

A strong storm off the west coast early this week will result in a moist southwest flow with a few embedded disturbances throug the middle of the week. The southwest flow will be relatively warm at first, with precipitation expected to be rain in the lower elevations and snow in the mountains. This will change Monday night into Tuesday as a cold front moves across western Wyoming. This front will lower snow levels to the valley floor in most places. Western mountain ranges of Wyoming will likely experience periods of light to occasionally moderate snow through the middle of the week. However, the most significant snowfall is expected to occur Monday into early Tuesday when periods of heavy snow will be possible. Snow accumulations across the western mountains Monday into Tuesday morning should range between 5 and 10 inches with higher amounts on southwestern facing slopes. Snowfall between 1 and 3 inches could fall in the western valleys and basins depending upon how quickly the rain changes to snow on Monday night. People with travel plans over mountain passes should be prepared for winter driving conditions.

Please monitor the weather this week as it is expected to remain unsettled through the week and into next weekend.

CLICK LOOP TO ENLARGE

The above loop shows the model depiction of expected 6 hour snow accumulation. The green wind barbs show the expected wind speeds at 700 MB. The loop begins at midnight Sunday, and goes through early Wednesday morning.

Image Key:

Light Purple = Less than 1 inch of snow accumulation during the 6hr period

Gray = 1 to 2 inches

Yellow = 2 to 3 inches

Blue = 3 to 6 inches

Red = 6 + inches (or at least 1 inch of snow per hour!)

The time stamp is in the bottom right hand corner of the animation. For help with how to read "Z" time, click on this link.

Click here for more information on how to read a wind barb.

CLICK LOOP TO ENLARGE

The above image shows the same model's depiction of expected 6 hour liquid precipitation (both rain and the liquid equivalent to the snow fall shown on the left). The yellow wind barbs represent the expected surface wind speeds in knots. The loop begins at midnight Sunday, and goes through early Wednesday morning.

Image Key:

Light Pink and Purple = Less than .1 inch of liquid during the 6hr period

Blue Shades = .1 to .3 inch

Gray to Green Shades =.3 to 1 inch

The time stamp is in the bottom right hand corner of the animation. For help with how to read "Z" time, click on this link.

Click here for more information on how to read a wind barb. 

CLICK IMAGE TO ENLARGE

The above image shows the expected storm total snowfall from Sunday night through early Wednesday morning. 

 CLICK LOOP TO ENLARGE

The above loop shows the 700MB Temperatures (image and light blue lines) and surface wind. Note the gradual cooling of the airmass through the period. This explains why the snowfall depicted by the model in the animation in the above left box expands with time.

For reference, the 700MB temperatures below generally correspond to the following snow levels:

H7 Temp.          Snow Level

-7C                     5000ft
-6C                     5500ft
-5C                     6000ft
-4C                     6500ft
-3C                     7000ft
-2C                     7500ft
-1C                     8000ft
 0C                     8500ft
 1C                     9000ft

 

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