Weekend Outlook & First Look At Monday’s Storm

Published Friday 5/6 8:25 am

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On Saturday a system will pass to our north and may trigger some thunderstorms in the mountains Saturday afternoon with snow around 11,000 feet. The Models diverge by Sunday evening. One model is showing a very significant system moving into the region through Tuesday evening. Another model is showing a weaker, faster-moving system with spotty showers on Monday moving out of the area fairly quickly.


The ridge of high pressure has started moving east. As a result, winds are switching to the southwest resulting in warm overnight temperatures and a few clouds.

High-resolution model guidance is showing highly elevated CAPE values late this afternoon and early evening east of Hwy 550. If this verifies, then a rumble of thunder and maybe some graupel can’t be ruled out later today. I have low confidence that it will result in any significant rainfall but with the highest CAPE values so far for this year in the area, I also can’t rule it out completely.

CAPE values between 7 and 8 pm

A system will pass well to our north on Saturday. The tail end of the system is likely to trigger some showers and thunderstorms, especially in the higher elevations. On Sunday, precipitation chances drop slightly. Gusty winds will be a factor for the next several days. The models are in good agreement that, with a couple of exceptions in the NW San Juans, very little beneficial precipitation will fall this weekend.

GFS precipitation through Sunday afternoon

Euro precipitation  through Sunday

The GFS has been going crazy with the next system which it shows coming in Sunday night and departing late on Tuesday. If the GFS verifies, it is going to impact travel and vegetation throughout the state. The Euro, on the other hand, is downplaying the next system. It shows a fast mover, with precipitation breaking out Monday morning and wrapping up later in the day. As I mentioned yesterday, these models are both acting out of character. The GFS usually moves systems too quickly through the area. The Euro usually is slower and deeper with the progression of  storms to the east.

This will be interesting. Here are the Euro runs for liquid precipitation and snow for the system on Monday.


Here are the very impressive liquid precipitation and snow totals from the latest GFS run.


GFS snow

That is quite a difference. I cannot remember these two models ever swapping error biases in such a dramatic fashion.

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