70's FOLLOWED BY SNOW? IT MUST BE MARCH...
Tuesday was a day to appreciate. Highs around the region soared into the mid 60s to low 70s. Iowa City was one of the warmest in my area topping out at 71 delightful degrees. Just look at the extent of the 70's around the central Midwest at mid-afternoon.
Highs in Cedar Rapids have now been in the 60s for three consecutive days. Compare that with February 13-15th when there were 3 straight days of highs below zero. In fact, over an 11 day stretch February 6th-16th the temperature never got higher than 9 degrees. Ouch, bad memory there.
Here's another way to look at the extremes we've recently experienced by way of temperature departures. The 14th of February the high of 6 below in Cedar Rapids, was 39 degrees below normal. Tuesday the high of 68 was 25 degrees above the norm (and 73 degrees warmer than we were with that 6 below reading just 3 weeks ago). Throw in the wind chill which hit 40 below a couple times in February and Tuesday felt more than 100 degrees warmer than when the cold was at its worst!
Since March 1st you can see how the warmth has steadily built on a daily basis.
Well, we've got one more very warm day to enjoy before temperatures start trending colder. The change will be initiated by a cold front which is set to come through the region Wednesday night. Ahead of that highs will easily hit the 60s with the potential to again reach 70 in spots. The wild card will be clouds and showers (perhaps a thunderstorm) that rolls through Wednesday morning). Most of the guidance ejects any lingering showers out of the area late morning or early afternoon which could allow for some breaks in the clouds. If so, highs in the low 70s are a strong possibility, especially in the southern half of my area. Dew points will reach the 50s which will give the air a real spring feel. Here's what the EURO has for highs.
With the warmth and moisture there is a good chance that showers and thunderstorms develop along the advancing cold front Wednesday evening and push across the Mississippi overnight. No severe weather is anticipated but you can see the EURO lightning flash density indicating a line of thunderstorms entering eastern Iowa around 7:00 PM. We'll see if indeed storms pop and how well they hold together after dark when instability decreases.
Overall, rain should be in the quarter to half inch range. A few spots could do better if a couple robust updrafts can develop. The EURO has this for rain totals.
Behind the front temperature begin a gradual decline but overall should be fairly seasonal in the 40s and 50s through the weekend. Unfortunately, the cooling gets more pronounced next week. Look what the 6-10 day outlook holds.
Now, here's the really big change from yesterday which involves the track of our next storm. Today's models have really dialed in on an upper level ridge that builds into SC Canada late weekend. That creates an upper level block that forces a strong closed low to take more of a southerly track and remain south of my area. You can see it here.
This block was not nearly as pronounced yesterday which allowed models to bring the system and its energy further north directly across my region. That allowed precipitation to fall as plain old rain. Now precipitation type becomes an issue as dynamic cooling looks to bring enough cold air to produce some snow. It will be wet and how soon we transition from rain and how heavy the precipitation falls, will determine how much snow falls. We are very early in the game and confidence is low as to how this comes together. All I'm concerned about now are the trends which are certainly colder and snowier. Both the EURO and GFS develop a band of snow Sunday night and Monday morning that pivots north across the region. Both develop accumulating snow. I'll put up the early projections just to show you the trends but I stress these are not forecasts just raw model guidance. There will be changes and they could be significant so keep that in the back of your mind.
The Canadian GEM
As you can see there is a lot of range in model output. Some are heavier south, some centrally focused, and others more concentrated on the north. This suggests models are having a hard time latching onto trends and I have low confidence on where the snow sets up. I will say that more times than not, the snow band ends up further north when cold air is initially an issue which favors the northernmost solution of the EURO. With that in mind, I will say the northern half to third of my area looks most vulnerable at this time.
Additionally, the upper air pattern looks very active the next 10 days or so with another strong system similar to this indicated later next week. Whatever happens, we appear to be going into a wet period that will take us well into March. Here is what the GFS shows for total precipitation the next 16 days.
As I conclude this blog, the temperature in Cedar Rapids and the Quad Cities at 2:00 AM Wednesday is still 61 degrees. Needless to say Wednesday is going to get off to a very mild mild start. If we can end the showers early enough and break the clouds for some afternoon sunshine, 70 degree temperatures are a real possibility, particularly over the southern half of my area. Enjoy the warmth and as always, roll weather...TS
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