Winter | What Might the U.S. Expect?

The winter of 2013-2014 was unusually cold for the eastern 2/3 of the continental United States. Iowa endured the 9th coldest in 142 yrs. What might we expect for this coming winter? To help answer that question, the scientists at the Climate Prediction Center published their latest outlook on November 20. It is an interesting read at this link. I will summarize.

The Jet Stream is a huge river of air in the upper atmosphere. It guides weather systems around the globe. Colder Arctic air is kept north of the Jet in the northern hemisphere. Warmer air is to the south of it. One type of flow is called zonal where the Jet tends to travel in a general west to east direction across the globe like this first image below from January 31, 2014.

Notice Alaska is north of the Jet in the cold air. It enters the California coast and sweeps across the country. Entering the coast, it tends to bring needed moisture from the Pacific. The eastern states are in a normal zone of cold, some snow, and clouds. In the summer months, the zonal flow is farther to the north across Canada giving more of the U.S. warm temperatures and pleasant weather.

San Francisco State University | http://virga.sfsu.edu/

 

Another type of flow is amplified. An amplified pattern creates a wavy arrangement like this from January 27, 2014. Four important observations should be mentioned about this pattern.

  1. The pattern was persistent for much of the past winter.
  2. The Jet entirely missed the western states leaving them dry.
  3. Most of Alaska was in a warm air mass south of the Jet.
  4. A polar vortex, swirl, of very cold air was delivered to the eastern states.

San Francisco State University | http://virga.sfsu.edu/

 

This amplified pattern worsened the drought in the western states, gave the eastern states their unusually cold winter, and gave Alaska record warmth.

The temperature hit 62 degrees at Port Alsworth, on Lake Clark, on Monday, tying the highest January temperature ever recorded in the state, the National Weather Service reported. Nome peaked at 51 degrees, topping the city’s warmest January with a temperature typical of early June, forecasters said. In Anchorage, snow continued melting Tuesday in the latest of 15 consecutive days with temperatures at 32 degrees or above. As of Monday, it was the city’s fourth warmest January ever recorded.

What might be expected this winter?

It is expressed in probabilities based upon the output from several models and the behavior of El Niño. The temperature probabilities look like this. White is a very uncertain region. There are equal chances for below, near, and above normal temperatures. The predictions don’t favor any of them. Darker blue favors below normal. Darker orange favors above normal. The west coast and all of Alaska are orange.

Map by NOAA Climate.gov | Climate Prediction Center

Precipitation probabilities look like this. The darker green across southern California and the Gulf states favors more precipitation than normal, but not by much. The California region really needs this to come true. Alaska could see more coastal precipitation, but less in the interior.

Map by NOAA Climate.gov | Climate Prediction Center

So there you have it. Wait and see what happens. Good luck in your region.

 

 

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23 thoughts on “Winter | What Might the U.S. Expect?

    • Yep…I thought of you in writing about this knowing you were well versed in probability concepts.

      Our public radio stations in Iowa are all linked for statewide coverage. When they give a forecast during segments, they use language that doesn’t account for the range of possibilities in the geography of the state. There are times when temps range 30-50˚ from corner to corner, for example.

      “Highs today 10˚ to 40˚. Winds south at 20 and north at 25. Skies clear to cloudy.”

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  1. Lately I’ve noticed the weather people saying “there is a chance of isolated tornadoes”. Huh? What’s the other kind? Lines of tornadoes? Crowds of tornadoes? Coveys of tornadoes?

    Here in Joplin, located near the intersection of four states, I’ve noticed that the jet stream is always teasing us, shifting unpredictably above and below us. We are at a nexus and it makes forecasting something of a joke, and just to compound the joke, one station insists on giving separate long-range forecasts for each of the four sectors. No need to get out the calculator though, the four are always about the same and usually wrong.

    Liked by 1 person

    • Yes, they ought to work on a different expression. Most of the tornadoes are isolated. They will come in clusters around certain intense storms. I looked for a good example on the google. So many images are faked with software these days, I decided not to link to any.

      I hope the Jet stays to our north more this winter than last.

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  2. There was a time when weather, and weather related events, was presented to us almost entirely by TV/Radio ‘weather personalities’, who may, or may not, have had an actual background in meteorology. These personalities became very convenient scapegoats when the information given to them, most likely based on barometric pressure and current sky conditions, proved incorrect. Shoot the messenger.

    Today, we still have weather personalities, but we also have tons of easily accessed, and instantaneously available computer model based information from people who know what they’re talking about. When it comes to weather forecasting, I prefer mine straight up, no mixers, and definitely without overly dramatic fear-fueled commentary. It’s interesting enough as is. 🙂

    Liked by 1 person

    • I couldn’t agree with you more. I love having the multiple sources. It is a challenge to sift to find the best. That is a problem I can accept gladly.

      I remember watching early broadcasts as a kid on our local tv station. He had magnetic symbols of H and L with a clockwise or counterclockwise swirl that must have been activated by some rotating lights near the camera. He drew in the fronts.

      We’ve come a long way.

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  3. Last winter was weird for us too, though not as deadly as your Vortex. It was dry most of the winter, very worrisome. Fortunately we got a deluge in late winter which almost caught us back up. You never know. One upside to the wet spring was it put the kibosh on nesting yellowjackets. The colonies never really got going. Really nice come August. Hope your winter this year is less extreme. Thanks for the weather post. 🙂

    Liked by 1 person

  4. It’s interesting to see the probability of various types of weather in the different regions of the US. So far it’s been colder than normal here.

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  5. I really liked the way NOAA shared their prediction. Especially the explanation about how statistics work. That is, that even though it is probable that our area will likely be cold and a bit wetter than typical there is still a possibility of that not happening.

    Still. I am a fan of NOAA but really … the persimmons and squirrels beat them to the punchline. The worrisome thing? All three agree I will need to wear a lot of sweaters!

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