Do You Want A White Christmas?

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We’ll get to that in a few minutes. My guess is most would, as long as it wasn’t too much snow. I saw a computer forecast last night for Christmas week that I wanted to share with you. before I do that though…let’s talk cold.

Our morning low @ KCI was 14°, making this AM the coldest since 2/12/12 when the temperature dropped to 5°. St Joseph, MO dropped to 10° to tie a record low for the date (1976).

Interesting, it’s VERY possible we can go from record lows to record highs (or darn close) over the next 10 days or so, as the Plains are about to be flooded with warm air that (with minor exception) will stick around through the 7-10th of December (at least). Highs will fluctuate from the 50s to the 60s with some 70s now out of the question. See yesterday’s blog for specific details on record highs for the 1st 7 days of the month. Sunday and Monday (3rd-4th) look like there could be a good run to near record highs.

I saw something interesting, and the basis for the warmth heading this way is what the modelling has been showing for days (at least the EURO, GFS as usual is playing catch-up). The flatter flow being created in the Plains states being created by a decent storm complex in the Gulf of Alaska and the NE Pacific Ocean will be flooding the mainland, especially areas from the Mississippi River westwards with some very mild Pacific air. This flow along the northern West Coast means HEAVY rainfall, to the tune of some 10-20″ of rain from San Francisco up through the coastal areas of WA/OR. Check out the forecast out there through the next 5 days!

Pretty darn impressive.

I saw something today on twitter and it reminds me that meteorologists need to be careful about forecasting storms more than 5-7 days away during this time of the year. As you know the EURO model is widely seen by most forecasters to be the most accurate model that can be used, compared to the American model (GFS). With that said, there are even times through that the EURO freaks out and forecasts things that don’t happen (or even come close) and that was the case about 10 days ago when it forecasted this for today.

This was the forecast 10 days ago from the EURO…

This is reality, off the upper air map from this AM.

Things could be more out of line. No major storm in the desert SW threatening us with some heavy precipitation, or even the potential of some snow somewhere nearby. No signs then of a small scale snow system across the NE part of the country. The model started to get a better idea about what would happen today about a day and a half afterwards and to be fair it was really showing the potential for a dramatic warm-up as early as last Wednesday for the beginning of December. So yes even this reliable model in many cases can have a giant hiccup.

I bring this up because there is a climate model that forecasts for months in advance called the CFSv2 model. Yesterday it issued this forecast for the days leading up for Christmas (snowfall forecast). Courtesy: Weatherbell

Their is the individual model run and then several ensemble runs (you’re looking at the ensemble runs) Ensemble runs are basically runs of the same model with minor variations/tweaks to the initial conditions. When you do that, you can get different results farther down the road in a forecast.

So what you’re looking at above is the snow coverage leading up to Christmas. You can see that 3/4 models have the region under a blanket of snow (giving us a White Christmas) and one model suggests over 6″ of snow will be on the ground! I have little faith in any output this model generates. Sometimes it’s mildly useful when averaging out 5-10 of the runs together because this model is all to well known for the flipflop method of forecasting. One day there will be a HUGE arctic outbreak and another day there will be a major heat wave. Hence the reason I put little faith in the output of the model. I do look at it though about 2-3 times a week because I look at everything. May not help out the forecast much, but I find all the data interesting to watch evolve.

It really is amazing how far we’ve come over the last 10 years, really the last 20 years with the weather and the internet and the availability of all this data, whether on a daily basis to make a 7 day forecast or on a monthly or seasonal forecast to make longer range outlooks.

Have a great Tuesday!


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