Dave Murray’s 2018 long-range Summer forecast

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ST. LOUIS, MO – It was a slow, slow start to Spring, one of the worst March-to-April stretches that we have seen in a long time. It was chilly to cold and wet. Some folks think that the start to the Spring season paves the way for clues to the Summer season. Will it be a beast, an easy cruise, or something in-between? Also, rain and storms or lack thereof are always a big feature. I never turn my back on any concepts and ideas, so let’s get going with a look at the month of June in St. Louis.

Data pix.

June 2018

The focus for the first month of Summer will be the continuing fade of La Nina going into a neutral position not only for June but for the entire summer. If and when El Niño returns, it would be for the Winter season. But the keyword is neutral and that typically means weird times ahead. With that said, the painfully slow transition into Spring means a slow transition into the Summer season. Even though it’s time for summer to become the main act, the change in temperature will be taking place in slow motion. I’m expecting some wild swings when it comes to temperature, nothing gets established. There will be some rather cool periods but there will be a few fast, hot swings too. It’s a month of contrast. Those hot swings will pop us into the 90's. 100 degree plus weather can happen in June. In fact, 17 of our record highs at 100 plus were in June. Though we will have swings, the hot and dry spells could get us too 100 plus. It will be weird for summer clothes choices. At times, we will need a light jacket and at other times...no shoes, no shirt, no problem. Expect a wild ride and when we add up the temperatures for June let’s think near to slightly above average. With the warmth, the bugs and mosquitos will be making a fast comeback.

On to the moisture patterns and this will also be interesting to watch. Large-scale neutral ocean temperatures mean nothing is ordinary. There will be a real mix of dry versus wet with the core of the wet reacting to the big temperature swings I’m expecting. You know what that means, an uptick of June thunderstorms which can be fast and mean. With the works when it comes to severe weather, I’m thinking there will be three storm impact periods this June. That would be below average. They will typically last four to six hours and then move on. However, those four to six hours can really mean business, each having the potential to go severe. As a result, rainfall for June will be near to slightly above average. There will be flash flood concerns with each of the three events but there will also be a lot of dry time. With all the events that happen in June, we will have to keep a close eye on the short-term forecast and how that will interfere with outside plans. Let’s think some indoor backup plans are in order.

Things to look for in June

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

The major points of June 2018

  • Wild temperature swings...ranging from rather cool to very hot periods
  • Expect a few runs of 90 degree plus temperatures and I would not be surprised to see one or two 100 plus degree days
  • Watch for swings in the moisture pattern from too dry to too wet...three intense thunderstorm events with the works
Data pix.

July 2018

July is all about the heart of the summer season in St. Louis and in turn this is typically the hottest month of the year. Many times, it is by far the hottest, even if a summer is considered cool. The forecast question in July is will it be a constant pounding of heat and humidity from start to finish or do we get a break from the oven from time to time? Temperatures are also important because the trend will drive the July moisture makers, a.k.a. thunderstorms.

Typically, you would think the month of July would be the easy part of the summer forecast. Many times, it is. But, not so fast this summer. This could go every which way and, in turn, I’m feeling a little uneasy. Here’s the catch. There is going to be intense summer heat over the western United States into the Great Plains, north to south. That hard-core summer weather is a little too close for comfort. I have seen something like this really toss a curve ball our way. It will not be a beast for us all month long but the beast will not be tamed. I think we will see several attacks of the dry heat from the Plains. When there is a lack of humidity, it feels pretty good but the temperatures surge quickly. So, I’m thinking a rather hot month with limited cool spells. In July, every single daily heat record is 100 degrees plus so records are tough to break. But this is a similar pattern that set up in 2012, with eight new records in July. I don't see a repeat of those numbers but a few record highs will be possible. Breaks in the heat will be hard to come by. It’s a month to find some shade, head to the local pool, and slow the pace down.

With above average temperatures, what’s up with July when it comes to rain and thunderstorms. Things will go dry and go dry rather quickly as we get into the month of July, meaning limited moisture and limited summer storms. Remember, I'm thinking we’ll see surges of dry heat from the west. Dry heat has an intense effect on the vegetation. We will start to see that the vegetation asking for water and the rivers will be dropping. There should be two rounds of thunderstorms that will keep us from getting into a severe drought. Those storms will bring some fast heavy rain along with high winds and lightning, and, in some cases, local flash flooding. So, classic St. Louis summer thunderstorms. Rainfall for the month will be below average.

Things to look for in July

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

The major points for July 2018

  • Here comes summertime...classic July... Plenty of heat... cooler breaks will be limited
  • Records for the month are tough to break...but I would not be surprised to see a few go down
  • Rain and storms will struggle... thinking the drought will come back into the picture
Data pix.

August 2018

The month of August is an interesting month. Many are still thinking about slowing down and taking it easy, but not so fast. Things are about to ramp up.  High school sports kick into gear. All the schools are ready to get back to work. Before you know it, we are all saying ‘what happened to summer?’.

August is another tough call in the long term. More heat will be on tap but some bending of the jet stream will increase the cooling breaks in the strong summer heat. So, let’s think a bit less hot. The concern like in July is the hot and dry weather still hanging in the Plains building eastward from time to time. So, yes, a few cooling shots from the north will keep the summer furnace from getting totally out of control but there will be plenty of heat with above average temperatures for the month. I think there could be one or two runs at record highs. I don't think it will be as hot as July. The dry heat always means a big afternoon warm up, but also allows for decent cooldowns at night. That always helps.

So, what does that mean for moisture? With a few cool pushes from the northwest, we will see one or two hits of fast-moving and intense thunderstorms. Classic summer storms…these are never all day rains but will help ease the building drought from June and especially July. However, I do think the month will average out on the dry side, slightly below average for rain. Remember, rain is typically limited in August anyway. Keep the hoses out and ready to go as moisture patterns flip around.  We do have to watch the tropics in August for a sneaky system in the western Gulf of Mexico. I am thinking the chances of that will be very small this August.

Things to look for in August

  • Large flocks of purple martins gathering for fall migration
  • Late summer molt produces drab colors in robins and other birds...they are not sick
  • Wild cherries and wild grapes begin to ripen

The major points for August 2018

  • A few cooling shots from the north this August...but the blowtorch from the Plains is the main weather maker
  • The heat continues with a few daytime record highs possible...above average temperatures
  • Rainfall will be a little better than July but ending up slightly below average

The focus during the Summer season will be a neutral pattern with the global ocean temperatures leading to some forecasting trickery, both short and long-term. The real Summer focus will be the intensely hot and dry weather in the Plains and how often it blows into the middle of the nation. That trend will also lead to increasing drought concerns. The next long-range forecast will be for the Fall season but that is a long way off. Until then, let’s enjoy and fun and the weather of summer-time in St. Louis.


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