Have no fear, the end is near! When our inversion breaks down and what comes next


The countdown is on!

As if you need another weekend to look forward to Friday, let me give you one: That's the day our 'death ridge' of high pressure (as many in the weather community have been calling it) begins to break down, allowing for a much-needed change in the weather pattern. By that I mean...our inversion should break up beginning Friday! (HOORAY!)

When and how will it break down?

WHEN: It will take a bit of time for the inversion to mix out, but I expect it to happen gradually through the day Friday, leading way to some sunshine (mixed with clouds) over the weekend. You'll certainly notice hints of change by Friday.

HOW: When our low cloud deck gets situated, it locks the cold air in place at the surface (AKA, the valley floor). Since very little has changed in our weather pattern over the last 7-10 days, this cloud layer is hugging us tight. In order to break up an inversion, you need a storm and or some sort of wind event. On Friday, I think we'll see the influence of both of those factors - at least, enough so to push out the thickest of our stratus.

By Friday, a weak cold front is taking aim at the state of Idaho, and should push through sometime late in the day or in the evening. This will be the real 'inversion-buster', and could even bring a wintry mix into the forecast for the Treasure Valley briefly on Friday.

This wintry mix could mean a mixture of rain and snow, periods of snow, and even freezing drizzle late Friday. Why? Because it's been SO cold on the valley floor (temperatures will not have been above freezing in more than a week by this point), so even if this system sends rain falling, once it breaks through that layer of low clouds and into the frozen part of the atmosphere near the ground, some of those drops may turn to snow, or just a 'freezing rain' type of precipitation.

We'll keep an eye on Friday afternoon/evening for a brief window of wet weather. Worst case scenario, it could give us a quick taste of winter driving conditions, and what those may look like in the future.

This is all thanks to that pattern change I mentioned in the first paragraph. As our ridge 'breaks down' or flattens, it opens the door for storms, (or, at least a couple of systems resembling storms) which are generated out in the Pacific Ocean. From there, we should return to a more normal setup for this time of year, at least for the time being. That means, temperatures will warm up in the lower valleys back to around average, (or, normal), and we at least have a fighting chance of seeing some wet weather.

So what about these 'storms?' How will they impact the mountains?

Friday's front looks to be pretty weak, but the hope is that we'll be able to squeeze a couple (or few) inches of snow out of it in the mountains, especially our ski areas. This first shot of moisture doesn't look to be super impressive or strong, so I don't think it will be a game-changer of a storm.

Latest model runs have started to dry the forecast out a bit over the weekend. There's a chance for a few snow showers in the mountains through Saturday (but again, nothing big), while the valley now looks to see just a mix of sun and clouds. Most precipitation will stay north of a Boise-Burns line through the weekend.

There's another system that may try to swing through early next week, but we're still pretty far from that one to know the details. For now, I'm not seeing anything super potent as far as snow, but we'll watch to see if models can come into better agreement on the track of other approaching systems down the road. Fingers crossed something will bring a good shot of snow for the mountains!

Beyond the 7-day:

Sometimes I hesitate to include long-range outlooks in my forecast or articles, as they are so volatile...and WILL change. But, that being said, here's a look at what some of NOAA's long-range forecast hints at as far as trends in temperature and precipitation:

Although I don't love to see the 'drier than average' pattern sticking around (or at least the better probability of it), I am hopeful that a favored chance of 'colder than normal' tempeartures will impact our region. Obviously, the hope is that it will keep our mountanis colder, holding what snowpack we do have in place.

The takeaway:

If you're sick of the inversion, you can rejoice that the end is near (and hopefully we can keep another ridge of high pressure far away for awhile). If you're a snow-lover, it's about time to start breaking out the snow dances (if you haven't been doing them already).

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