Fall Arkansas Weather Outlook: Like Everything Else in 2020, INCONSISTENT !!!

        GoodMorning, Evening, and Night friends, family, and followers! Thanks' for coming here to the Arkansas Weather Hawk's Blog today! I appreciate everybody's continuing support! In this post I'm going to breakdown my expectations of this Fall leading into this Winter! As if the Year 2020 couldn't get crazy enough with everything else going on in the world, the Weather decided to join the Purge too! Arkansas weather like everything else in 2020, has been on strike, and protesting! We have had 44 Tornadoes so far as of October 2020, our yearly average is 33.... So there's that! We started off the Fall Season with Severe Weather, and will likely finish off the Fall Season with Unusually Dry Weather! Let's break this down! 

         So about Halloween 2020, I expect this cooler trend in the temperatures to continue. I was looking over previous runs of the GFS (Global Forecasting System), I've been seeing a warming trend in daytime highs during the week leading up to Halloween. On Halloween day itself, I do expect the daytime highs to be rather comfortable, in the 70s. But the Nighttime Low's on the other hand have been trending rather cooler in the week or so leading up to Halloween due in part to a couple of advancing Cold Fronts moving through the state, the temperatures are projected at this point to be in the 40s for nighttime Low's! 40 Degree Temperatures, In October, that's unseasonably awesome. As far as Moisture goes, we are transitioning into what's called a La Nina Weather Pattern, which will set in throughout the rest of the Fall, and Winter, due in part to that, we have been experiencing lower than normal precipitation totals this fall here in Arkansas, even though we started the fall with Severe Weather. We've gotten some rain thanks to Hurricane Laura, and Delta, but outside of that, we've gotten nothing. Had it not been for the Two Hurricanes that have impacted Arkansas, we probably wouldn't have the Fall Rainfall totals that we currently have thus far, and for an Arkansas Fall, that say's a lot. Heading into Halloween, I'm expecting this dry trend to continue with cooler than average nighttime temps, and inconsistent daytime high's. Halloween will be Cool, and dry I'm suspecting! This is just a Forecasted expectation, not a Fact! 

        Now looking past Halloween, on to Thanksgiving, and the rest of the Fall Season! Okay, there's an atmospheric phenomenon called the "Arctic Oscillation," I talked about this a little bit last year, but I'll briefly go over it. In the Arctic the Cold Arctic Air is contained in the Arctic by the Polar Jet Stream(Jet of Strong Winds Circling the Globe.) When pressure is high across the U.S.A for example, the Polar Jet Stream is locked up in the Arctic region of the Globe around the North Pole. When atmospheric pressure is Low across the U.S.A, the Polar Jet stream can move, dip, and shift further to the south into the U.S.A bringing the Cooler Arctic Air behind it, that Arctic Air Mass is referred to as the "Polar Vortex." When the Polar Vortex shift south into the U.S.A, that movement of the Vortex is referred to as the "Arctic Oscillation." When the Pressure is High, and the Cold Air is Locked up, that set's the U.S.A Up for Warmer than Average, or Above Normal, that's referred to as a "Positive Phase Arctic Oscillation." When the pressure is Low, and the Polar Vortex has flexibility to move, that's referred to as a "Negative Phase Arctic Oscillation," which then set's the U.S.A up for cooler, or below average temperatures. Now, naturally positive A/O's usually mean a warmer than average temperatures for the Central Sections of the United States, but on the Flip-Side, the A/O turned Negative in the Last Week of September/First Week of October 2020. So now, Arkansas, along with Central sections of the U.S are experiencing cooler than normal temperatures. The A/O is expected to stay in a Negative Phase throughout the rest of Fall, and possibly beyond, this means a cooler than average Thanksgiving, and Halloween, and at least First Week of December.... But, this doesn't mean everyday will be Cooler, there will be 70-80 Degree days in there. But those nighttime Low's will drop, keep that in mind for Halloween, and Black Friday Shoppers! Below I will include some maps courtesy of aer.com Weather Blog! 

So this map is the October 12th ensemble(set) of predictions. The Ensemble basically show's the A/O trending Negative through the middle into the end of October. 

Just to stick to the subject here, which is cooler air in the mid U.S.A, let's just talk about that. So this map is the Global Temperature map of the GFS Model. You see Arkansas in the U.S.A, you see how due to that negative trending A/O the temperatures in Arkansas remain Cooler than average (Blue color shown over Arkansas). 

This is through October 22nd, the GFS continues to show cooler than average temperatures due to a trending Negative Phase A/O. I have no reason to believe that this will significantly change heading into November, and into Thanksgiving. 

The Meteorological Possibilities for Early Winter remain unclear, but with a La Nina setting up, that will jeopardize any substantial chances for precipitation, La Nina Weather Patterns tend to limit precipitation. La Nina patterns also tend to limit cooler air in the south due to the higher pressures. So as we get deeper into the Winter with a La Nina in place, I wouldn't be surprised if the A/O started trending back Positive...  But Let's get through Fall first, because Long-Range Weather Forecasting can be more Miss than Hit at times, so I don't want to go too far with my "Wishcasting." Thank You To Everybody for coming here to the Arkansas Weather Hawk's Blog, I love You all for you Support, and Have a Great Day, Evening, and Night!