SOME FRESH THOUGHTS ON WINTER...
As advertised Wednesday was a blustery day but at least temperatures were more tolerable. That's a sign that today has the makings of an even warmer day that could see highs within 3-6 degrees of records (the top 90% for November 19th). I don't see us quite getting that warm but a 70 is certainly possible from roughly I-80 south. Here are the existing records for some cities in my area. Notice all were established in 1942, what a day back then!
The Quad Cities....77, 1942
Cedar Rapids....... 75, 1942
Dubuque............... 74, 1942
The GFS is advertising highs that look like this. These could end up 1-3 degrees warmer with a stiff south wind, mostly sunny skies, and good mixing.
The readings you see above are about 20-25 degrees above the seasonal norms. Here's the departures.
Winds will continue to be an issue as the gust in the 20-30 mph range, maybe a bit higher east of the Mississippi.
The positive news for the weekend is that models continue to trend further south with the storm system that 2 days ago was soaking much of the region with .50 to 1.50" inches of precipitation. A stronger push of high pressure delivers more dry air in recent guidance and that means any rain should be confined to my far southern counties, essentially near or even south of HWY 34. Where there are showers they look light and confined to late Saturday afternoon ending Saturday night. Here's what the latest GFS is showing for amounts.
The EURO is just a bit further north but again keeps totals light even in my southern counties.
The most interesting trend in today's models is a system that spins up next week just before Wednesday's big Thanksgiving travel day. We're in the very early stages of development so much can change but it currently seems there will be a wintry side to the storm with the potential for snow to disrupt travel in some part of the Midwest. The threat looks greatest across the northern half of Iowa into Minnesota and Wisconsin at this early juncture.
Here's the surface depiction of the two systems next Tuesday at noon. First the EURO.
Now the GFS which is only about 75 miles further south. In other words there's very good agreement on strength and intensity for this early in the game.
Winter has left us alone the past couple of weeks but something I continue to watch towards December is the development of blocking in NE Canada. The GFS extended shows this 500mb pattern December 14th. This is what you look for if you are one of those oddities like me that enjoys cold stormy (snowy) weather.
These teleconnections would support that type of upper air look with the AO (Arctic Oscillation) in negative territory the first 20 days of December. The negative phase would suggest the potential for cold air to get involve in the pattern.
The NAO (North Atlantic Oscillation) is shown going strongly negative, which implies building heights and blocking in Canada. Storms and cold cut under the block and can access the eastern 2/3rds of the nation.
The CFSv2 climate modeling also shows this 500mb structure December 7-14th. Terry would like to see this develop.
While this all looks good on paper, it is just a snapshot of what today's modeling implies roughly 2 weeks from now. It certainly can change and sometimes does so it needs to be monitored and refined. However, I can say this, if the trends shown are correct there will be some winter fun and games come December. That would be quite different than the past few Decembers which in general have been mild with minimal snow in the central Midwest.
The other issue that will be a player this winter is the La Nina which is looking pretty stout. The NWS in La Crosse put out a tweet showing all the La Nina winters since 1949. What they depict is a wide variety in overall temperatures from warm to cold. In other words, all La Nina's are not created equal. Things like blocking, sea surface temperatures in areas outside of the tropical Pacific, and key phases of teleconnections such as the MJO influence the outcome. What I expect, have noticed over the years, and have already mentioned a number of times is that La Nina winters tend to bounce around with some ugly periods of wintry conditions followed by periods of relative warmth and inactivity. I guess you could say major ups and downs. The question becomes, do we see more of the ups or downs which create the anomalies you see below! Time will tell. Roll weather...TS
Hey, before you go this is cool. Sargent Trainer of the Iowa State Patrol was on duty the day of the derecho in Linn County. He encountered the violent winds of the storm and pulled underneath of a Cedar Rapids overpass. As the winds increased, he fired up his radar and captured a gust of 93 mph. Imagine the rates he would have measured had he been on top of the bridge in a more exposed position. The ticket for such a speed would have been 190 dollars. Try as he might, Trainer was unable to catch the offender.
The storm went on to produce winds in Cedar Rapids that the NWS estimated were as high as 140 mph. You can get the inside scoop on this "superstorm" (now the costliest storm in U.S. history) in my book, Derecho 911, Iowa's Inland Hurricane. Save by ordering early and taking advantage of our LIMITED TIME OFFER for the low price of $25.95. It's a coffee table style book that is color with more than 100 pages of pictures, graphics, and diagrams. It's intensly researched and will be the authoritative account of this remarkable Iowa storm. For more information or to get your autographed copy click the link below. Thank you and roll weather...TS