Monday, April 24, 2017

Monday Weekly Weather Summary: Rough Start, Smooth Finish

Good morning. Well the weekend turned out the opposite as expected. Sunday was the nice day and Saturday was quite dreary. The models did not handle disturbances along the frontal boundaries well at all.

This week starts rocky then really brings in some late spring like warmer weather.

A low pressure system will track up and along the coast tomorrow and part of Wednesday...

This will cause peroids of rain for Tuesday into midday Wednesday. Today will also be mostly cloudy as this system approaches.

Things then clear out nicely for Thursday and Friday with mostly sunny skies and temperatures in high 70s...

I will take a closer look at the weekend later this week, but right now things are looking good.


  1. Hi Willy, welcome to hurricane season. Although with a potential El Nino developing by fall, it might not be much of a season in the Atlantic. And so much for the winter weather drama season. Winter finally seemed to arrive in the second week of March, and we had a white Daylight Savings Time arrival on the 14th (not much to dream of, though, and one less hour to do it). But of course it didn't last long, with Spring on the horizon. I took a look at season snowfall totals from EWR -- third lowest since 2010. About the same as 2013, but not as bad as the snow drought of 2012. Roughly half as much as in 2011 and 2014.

    I just saw two interesting articles on what might have been going on this past winter. You were in good company back in October expecting a fairly robust snow season, given all of that snow that was falling on Siberia and Mongolia. Judah Cohen had some interesting comments about that at a February workshop on changes in the Arctic and its influences on mid-latitude climate. In Bob Henson's article about this conference on the WU site, Cohen is quoting as saying “The pattern was conducive to an active jet stream that likely contributed to the fire-hosing of California with moisture but also flooded North America with mild maritime air for much of the winter . . . In an ironic twist, extensive Eurasian snow cover may have actually contributed to a milder North American winter, the opposite of what I have been preaching for much of my career.”

    The pattern, I gather, is the striking temperature trend over the past decade or so of a warming Arctic and a cooling western Asian land mass. One factor that Henson mentions was that cold zonal air flows from Siberia to the Pacific helped to squash that warm water "blob" south of Alaska that drove the polar jet down into the middle and eastern US during the past few years. I would guess that the continuing zonal QBO winds didn't help either. With that QBO, I'm guessing that we didn't need an El Nino to push warm Pacific air into the eastern Atlantic and help strengthen the ridges.

    It was also interesting how those two big stratospheric warming peaks in the Arctic didn't do much to weaken the polar vortex. Maybe the mid-March cooldown had something to do with the second strat warming peak in February, but those strong zonal flows in the Northern Hem seemed to keep the cold air bottled up. And hey, with higher Arctic sea and air temps, maybe the troposphere heights were a little bit higher than in the past, giving a bit more "cushion" against increased pressure from above? Obviously this is just my SWAG, gotta see what an expert like Cohen sez on that.


    1. Correction == EASTERN ASIAN LAND MASS, not Western. Like, Siberia, Outer Mongolia. Jim G

  2. PART 2 -- Another big factor that kept the cold air in the far north was that the NAO stayed mostly positive, which didn't give much time for a Greenland high to block a dipping arctic jet and send it down into Kentucky. The zonal pattern kept the big wind rivers flowing in line, mostly. I tripped across a second interesting article about a Chinese Academy of Science study that supposedly finds a strong relation between solar wind speeds and the NAO and Northern Atlantic temperature patterns, even on a short-term basis. A quick search shows that this isn't a new idea, but I gather that the Chinese study shows a stronger and more day-to-day effect from solar winds on what goes on in the North Atlantic waters and atmosphere.

    Perhaps this helps to explain why the NAO seems so unpredictable. Maybe eventually the researchers will get a handle on it . . . but things will only get that much more complex! In your winter forecasts, perhaps you will eventually need to add an analysis about what's going on at the surface of the sun! Oh well, the reality of weather is inherently very complex, and maybe that's what makes it so much fun!

    I'm glad that you are continuing to regularly comment on the spring weather, even if it's not as interesting as the winter dynamics. We will have to see how the tropical storm season evolves -- it did get an early start. Best, Jim G.

    1. That is really interesting research you cited Jim. That cold blob developing in the pacific in relation to the colder eastern Asia def had to be a major factor as it caused that pacific jet to strengthen. It is interesting what Cohen said, I will be sure to go read the recap of that workshop he had. The great thing about weather and climate is that it is always changing. We base forecasts off of long range models and historical data but we only have a pin prick of data in relation to the age of the earth. Who knows the next 100 years can end up being much different than the last with climate trends. I agree though, we need to nail down that NAO better. It really is impossible to predict from my experience. That Chinese reaseach sounds interesting however, I will take a look.

      As you mentioned if we go to a big El Nino we can be in for some boring times ahead but we will have to see how this evolves. Even the ENSO is very hard to predict when trying to nail down magnitude and positioning. I always start to watch all this more closely once summer rolls in.

      Thanks for following. I will pass along any research I find over too you over the next few months. You do the same.

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