Dave Murray’s Long-Range 2017 Summer Forecast


ST. LOUIS, MO (KTVI)- The long strange ride of Spring is coming to an end. We saw lots of warmth but also some impressive cold shots in the month of March, which did a job on the vegetation. Of course, we also saw plenty of thunderstorm action. It’s been a ride. The big question is will that ride slow down in the summertime or does the roller coaster ride we are known for continue. The summer forecast is never easy.

June 2017

El Niño may be pulling itself together but for the first month of the summer season I'm thinking it’s a non-player. Of more importance are some of the patterns that developed in the Spring and thinking at least a few of these features will come into play for the month of June. So spring will take us into the first summer month of the season. The bouncing of the temperatures we have been seeing will continue. I think we will see a fair share of warm to hot weather but it’s no blow torch of heat. Also like the Spring, there will be two even three cool shots this month. When we add it all up, June temperatures should be near to a little bit below average.

On to the rainfall patterns for this June and we are in that no-man's land of neutral water temperatures in the Pacific Ocean. This makes the moisture patterns tough to forecast in the long term. Now, typically, June is a very wet month in St. Louis, one the wettest we see all year long. However, I think this June will not live up to its reputation. There will be several waves of rain and the classic June thunderstorms. There may even be some severe weather, 3 to 4 weather events that need to be watched. But that would be a little on the low side for a typical June. I think the core rain and storms will be to our east and southeast. One other wrench that could get tossed in to the mix is early tropical development in the Gulf of Mexico, especially the western Gulf. But I don't think that comes into play this June. So when we check the rain gage at the end of the month, I think the rainfall numbers will be slightly below average for this June. That may be a concern as we go through the summer season in St. Louis.

Things to look for in June

  • Watch for birds carrying food to their young
  • Check evergreens for bagworms
  • The cattail blooms are covered with pollen

Major Points For June 2017

  • Bouncing temperatures...plenty of warmth but also a few fast in and out cool snaps keeping hard core heat in check
  • Not expecting any record heat and no 100° plus heat
  • June is typically very wet...not expecting that...there will be severe weather but thinking rainfall will be slightly below average for the month

July 2017

July is the heart of the Summer season. Even if the summer is on the cool side, July typically comes in with flying summer temperatures. It is always “what degree of hot." Is it a month with hit and miss surges of Summer of does it just pound away at the region all month long. How hot July gets will also set the stage for how much thunderstorm action we can expect.

July is the middle of the summer season and is typically an easy month to lay out in the long term forecast. But with weather, nothing is easy. The beginning stages of el Niño will be one of the big players but I am not thinking it is strong enough to be a big time factor for July 2017. That means there will be plenty of hot weather, but I am not thinking it’s a long lasting beast of a month with day after day of classic St. Louis heat and humidity. The cold eastern Indian Ocean, the developing el Niño, which looks like a weak to moderate one,  will keep July temperatures in check. Yes, there will be many days with highs in the 90°s but only one maybe two  hanging around 100 degrees. The bigger feature will be plenty of humidity coming up from the Gulf of Mexico. This will keep temperatures during the day from getting out of control but will result in warmer than average nighttime lows. That's a big feature for our comfort index. I’m not expecting any record heat; those are crazy numbers in July. But it is July...it is St. Louis...head to the local pool or find a garden sprinkler and slow the pace. When we are done, temperatures will be near average.

On to rain and thunderstorms, I don't see any pounding drought this July. Yes, there will be dry weather but there will be enough waves of thunderstorms to keep the vegetation from frying. The exception to that if we get a little run of that dry heat which we have seen some of that the last two summers. That’s a concern because that dries the vegetation very quickly. Not seeing a lot of that this July, so expect some classic St. Louis July thunderstorms. That means fast in and fast out not all day rains. The focus will be on mid to late afternoon and early evening. Not expecting any western Gulf of Mexico tropical action but that is a growing concern. When we add up the numbers, I think July will end up with near average rainfall.

Things to look for in July

  • Birds songs have subsided...the birds busy raising their young
  • Long-tailed weasels breed from now through August
  • Watch for hummingbirds bringing their young to feeders

Major Points For July 2017

  • Not a beast of a July, but a solid summer month with plenty of heat. Humidity could be a brute
  • Lots of 90°+ but 100° will be limited to 1 or 2 days
  • A fair share of summer thunderstorms...no tropical action...rainfall will be near average

August 2017

August is the month to slow down and take it easy. If you don’t, the summer season can quickly pass you by. Vacation time comes to an end, high school sports kick into high gear, and by mid to late month the school bells are ringing once. Time flies and by mid-August we are saying, ‘What happen to the three months of summer.’

The developing el Niño is still only a watcher in the month of August. I just don’t think it is a big factor. But  it is developing and that means we are coasting in the month of August. Ocean temps are slow to respond to changes and that's why el Niño is just a watcher.  It’s looking like a hot month, but a typical hot August. I think there will be one or two cooler runs at us and that will result in temperatures for August being very close to average. I have no concerns about record heat but plenty of 90° plus and a run at 100° plus for a day or two. Either way you look at it, the start of high school and college sports will be a challenge at times.

What about the patterns for rain and thunderstorms? Wet weather is looking rather limited for much of the month. It may be a little late summer drought settling in with below average rainfall expected. Even with 2 to 3 shots of thunderstorms, the rainfall totals will struggle when we add up the numbers. The drier weather may have a late season effect on the corn and soybean crops and on hay production. There is one catch to my thinking on the August rainfall patterns and that's a chance that tropical development in the western Gulf of Mexico. The waters in the Gulf are very warm and that is a concern in late summer for a tropical spin up. If something does pull itself together, this will greatly alter the rainfall numbers for this August. That’s an impossible call in a long term forecast, especially in the third month of the summer season. Just a little disclaimer to put on the table.

Things to look for in August

  • Look for large flocks of purple martins gathering for the fall migration
  • Late summer molt and drab colors in robins and other birds
  • Wild cherries and wild grapes begin to ripen

Major Points For August 2017

  • Typical temperatures for this August...hot but nothing extreme
  • Rainfall and thunderstorms will run below average...some drought concerns for the end of summer
  •  The possible wrench in August rainfall is tropical development in the western Gulf of Mexico

All summer long it’s a watch party to see how el Niño will be developing. I am not expecting it to be a big player in the summer season, but that’s a different story for the Fall and Winter.  The next long range forecast will be for the Fall season but that is a long way off. Until then, let’s enjoy the fun and the weather of summertime in St. Louis.