Valleywx.com: An Up And Down Week Ahead

The cold weather pattern of January is over, but don’t tell your thermometer yet. Huntsville’s noon temperature was only 39 with a wind chill of 32, and a lot of Tennessee temperatures were in the upper 20s and lower 30s with some patchy road ice in the western part of the state according to TDOT.

It’s not going to be “warm” on a consistent basis anytime soon, but it will not be able to get quite as cold as it did last month. That leaves us in border country – the land between the warmest and the coldest.

That also puts us position for a stormier weather pattern than what January offered this region. You know that from Sunday’s rain (1 to 3 inches of good soaking rain) and from what is coming this way on Tuesday and Tuesday night. In all, we may have some places south and east of Huntsville that get as much as 4 to 5 inches of rain in a seven day period; that’s the most in a long time!

Tuesday’s storm system is just strong enough to be on guard for a small threat of severe weather. The Storm Prediction Center’s morning outlook places a low-end 5% risk over the western edge of the Tennessee Valley, Mississippi, and Louisiana for Tuesday afternoon and evening.

day2probotlk_1730_any

Once those storms move east of US 43, the threat is very, very low due to questionable instability (fuel for the storms). It will be windy and wet as all of that moves through; some power outages are possible due to falling trees just from the soggy, thawing ground being so soft. Wind gusts to 40 MPH are possible ahead of the storms on Tuesday evening.

Then, there’s the other issue of “where did all of that snow go?” Remember last week (how could you forget) when that European model showed a foot of snow around here?

How do you go from that being a possibility to almost nothing?

It’s simple. That’s a model. Models are tools used to build the forecast. Think of it this way: the future has an unlimited number of possibilities, but only a few of those possibilities are actually “probable” or “reasonably likely” outcomes. In a follow-up to that post, I wrote that you could expect a shift to the north with lower snow totals, and that is what has happened. The storm system didn’t magically disappear; it just isn’t likely to move through as far south as that particular model had suggested.

This happens more frequently than you know; it was just more widely known this time because the idea was so fantastic (and it spread like a wildfire on social media).

Well, here we are, and the guidance has done as expected. Rain through here this week and snow to the north with each system. This is the morning GFS guidance showing total accumulation through Wednesday and through Sunday (it adds it up without considering melting):

I drew in the black line to show where “accumulating” snow is more likely and less likely. You will see on our Seven Day Forecast that there is some snow potential for Sunday, but as of this writing it does not look like we will have everything together for a big one.

The expectation is that a cold front blows through here Saturday night dropping temperatures into the lower 30s, and an upper-air trough digs in overhead helping produce some light wintry precipitation through Sunday evening.

Limiting factors for accumulating snow in the Tennessee Valley are things like ground temperatures warming up this week, air temps near or above freezing while snow falls, and the relatively light nature of the precipitation.

There could be a few areas that get an inch or two of snow; I won’t discount that completely, but we are too early in the game to really give you any accurate idea of where that could happen. That’s why you see a “chance of light snow” in the forecast and no other real details.

Could it change? It sure could! Anytime you are that close to a big snow like the one just north of us, you have to be wary of any shifts in the paths of these systems.

-Jason
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