Dave Murray’s 2017 Long Range Fall Forecast

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ST. LOUIS, MO – As we say goodbye to Summer, we begin to wonder just how fast Winter will take hold.  That will depend a lot on  how el Niño will be developing, if it develops at all. Let’s take a look at my thoughts for Fall 2017 in St. Louis.

 September 2017

I have been around forecasting St. Louis weather for a long time and most think September is a great month. While quiet weather likes to keep control, it is a month that can bring a variety of weather especially when it comes to temperatures. I have seen some Septembers where the month is just perfect day and night, some when cold weather settles in quickly, and, going back into the 70’s and 80’s, some Septembers that were a real beast with hard core summer weather. So it is still a tricky forecasting month. The key this September will be the el Niño…yes, no, or maybe. Many times the early stages of el Niño can’t be trusted.

The warmth of the summer will try to keep its base as we go through the month of September, especially during the first two weeks of the month. Then temperatures will settle back to about where we should be for the end of September. It may be a struggle to start as all the area schools kick into gear, including a full slate of fall sports, then fall will come on strong. However, I think that when we add the numbers up the month will be above average. We have not seen that in a while. The problem will be a Pacific Ocean temperature pattern that can’t make up its mind. When it comes to el Niño it’s “to be or not to be” and that is a question because indecision and weather forecasting are never a good match. But we need to pay attention because ocean temperatures in the Pacific have a huge impact on the weather over North America. One other feature, I don’t see any freezes but there will be a few nights late in the month that will get farmers and gardeners thinking about it, as temperatures dip into the 40’s. That will get us thinking about the season and the start of the Fall trees starting to change color.

On to the moisture for the month of September and this is a month that is typically dry. But I am not thinking this September is bone dry, but I’m also not thinking it is super wet…just better. I think the mini drought pattern that got established during the summer will start to ease going through the month. Let’s think we that we have to make up for some lost time. One feature that will be a big time watcher is tropical action in the Gulf of Mexico. September is the peak time of these large ocean storms. Let’s keep an eye on the central and western Gulf, especially some home-grown close to shore action in the western Gulf. It is not the best news for the harvest season but I think that when we check the rain gage at the end of the month that rainfall will be above average

Things to look for in September

  • Harmless black and yellow garden spiders are common around the house
  • Look for puffballs and other fall mushrooms
  • Listen for migrating birds during the evening hours

September  2017 Highlights:

  • A see-saw temperature pattern…the first half of the month will be on the warm to hot side
  • Rainfall will kick into gear…rare for September
  • Watch for spin ups in the Gulf to add to the rain totals for the region

October 2017

In my book, October is the heart of the Fall season and typically one of the best months of the year. It is known for its pleasant and dry weather. Any summer heat and especially that humidity drops out of the picture and is typically a very dry month. That is great news for the farmers getting in the seasonal harvest. Winter is far from taking over and the vast majority of Octobers will follow this pattern. But we have also seen October wash-outs, with 2009 leading the way with over 12 inches of rain. So let’s see what direction I think we will be heading.

October is filled with mild days and cool to chilly nights.  The fall colors really kick into gear.  It is also a month where we lose a lot of daylight as we swing well into Fall and get ready for winter. It is perfect weather to wrap up the harvest season for the area farmers and home gardeners. Winter is far from taking over and the last several years this has played out to a tee.  However this October, I think the cool to chilly weather will take hold quickly and take us through the entire month. Of course, there will be a few days of warm temperatures, especially during the day, but when we add up the month I am thinking October will run below average for temperatures. In fact, there are some signs it will run well below average. Let’s think of a frost and even a hard freeze any time after the 15th. The cool temperatures along with the days getting shorter and shorter offer the true gift of Fall, the changing colors of the trees. I am thinking the color will be pretty good. Let’s look for the peak color occurring during the last week of the month.

As for moisture, October is known for its dry weather. The problem with the norm is the iffy pattern of water temperatures in the Pacific. I am always going back to el Niño, will it or won’t it kick in. As a result of this indecision, I don’t think this is a bone dry month. I’m not concerned about a drought set up because there will be rain this October, with the best shot mid to late month. Yes, some of the hayrides and pumpkin picking could be a little soggy. Overall October should average out to be slightly above average when it comes to rainfall. The tropics will play a little part in this, like in September. There is also what we call the second season for strong to severe thunderstorms, with a history of that book getting opened in late October and early November. We will see two thunderstorm events in that stretch of time. But the second season is limited this year. Will we see any snow in October? That is  pretty tough to come by. Snow bunnies, don’t rush the season but let’s not be surprised if there are a few snow flurries around after the 25th

Things to look for in October

  • Persimmons start to ripen
  • Look for spiders ballooning on gossamers on clear, windy days
  • The juncos arrive from Canada

October 2017 Highlights:

  • Cool to chilly temperatures much of the month…a few warm days…but temperatures will be below to well below average for the month
  • Not looking like a bone dry month…expecting above average rainfall with some thunderstorms and late season tropical spin
  • Let’s not get excited about snow…but snow flurries will be a watcher late in the month

November 2017
November can keep some great Fall weather going, but it’s also a month that can shake us back to reality by letting us know we are heading out of Fall and into the Winter season. Yes, we are living on borrowed time. Fall shuts down and Winter comes knocking at the door. The changing of the Fall colors is over and temperatures both day and night have a steady drop. Can it snow in November? Yes, but typically it is limited.But the snow bunnies tend to get interested late in the month. However, November snows are more shocking than big. So let’s see what’s going on with a look at November in St. Louis.

November can bring a wide variety of weather, but it’s not winter yet.  The key will be that el Niño. What the heck is it going to do? But this indecision becomes important as we head into November and the three months of winter. Temperatures day and night take a steady drop off. I’m thinking this November will bring on a chill rather quickly. Now, it’s not blast after blast from central Canada but the flow from the North Country is going to open up fairly quickly this November. Sure, there will be a few mild spells, but its that northern flow that will be in control as the westerly flow weakens. As a result, let’s think the month will average out a little bit below average when we add up the numbers. I think the last two weeks will bring the biggest chill, including Thanksgiving. The overall dry pattern will tend to make the cool a little bit stronger.

On to the moisture patterns, the shutdown of the westerly flow and the opening up of air from central Canada will result in a drier than normal pattern. It’s a month that typically brings the return of steady and all day rains and November can be a very wet month, but I don’t think this will be the pattern that sets up. We do have to keep an eye out on a continuation of the second season of thunderstorms, but I think they will struggle in this month of November. So, let’s go with the idea that November will bring a slightly below average rainfall. What about the snow bunnies? Let’s think we will see some flurries, even a little snow that could coat the ground before we sail into the month of December

Things to look for in November

  • Birds begin gathering at the feeders
  • Scan the leafless trees for paper nest of the bald-faced hornets
  • Woodchucks are asleep in underground nests

 November 2017 Highlights:

  • More of a northerly flow in control for much of the month…expect some bouncing of temperatures but this November is not mild…below average temps expected
  • Not much in the way of severe storms and thinking rainfall will be a little below average
  • How about snow? Not going to rule out flurries and light snow

The focus during the Fall season will be rather impressive temperature swing from mild to warm to rather chilly to cold over the three month period. Some of that is normal, but this will have an accelerated pace this Fall. The key is whether this is going to be an el Niño season or not. That is the big question. I think el Nino will be weak at best and that plays a big part in my Fall forecast. If this idea holds, it will play a major part in my Winter outlook. But that is a long way off. My winter forecast will be out in November and already working on some ideas that could make some people happy. Bu t until then lets enjoy Fall, the changing colors, football, and pumpkins​.

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