Glenn Zimmerman’s Long-Range Summer 2019 forecast

ST. LOUIS, MO - It would be really easy to make a summer forecast like this: Hot, humid, and some chances of rain. There could be a stretch of heat and a stretch of dry. It seems like it’s always like that in St. Louis and generally, it wouldn’t be wrong. But this year, it could be a little more than that and a little different. The biggest concern is the pattern that has developed, not just the pattern of the last month, but the pattern of the last year. We have been wet. The ground is saturated. In fact, the Climate Prediction Center shows the soil moisture at almost 99% capacity for this time of year. And not just here, it stretches into the upper Midwest and the Plains. That points to more flooding. Is this a repeat of 1993? The short answer is no. But flood impacts this summer could be ongoing...especially along the bigger rivers.

Locally, with our ground being saturated, flash flooding will occur faster and more often than normal. That is something to keep in mind if you are planning a float trip or a camping trip near a river. Water run-off with any kind of rain could come fast and furious. So, let’s keep an eye on the sky and on the forecast before you make plans this summer.

June is typically one of the wettest months of the year. In fact, in 2015, we had over 13 inches of rain leading to flooding. We have generally been in a wet pattern over the last couple of months: April was wet, May has been wet, and that wet trend could continue through June. With that, we will see some warm temps. Normally, June high temps average in the lower 80s, and lows average in the upper 60s. I think overall, temps will average above normal, but that will be because the low temps could be above normal...not the highs.

July is normally the hottest month of the year although it seems that August is hotter. Rain and storms are also part of the month. We have a joke in the weather office that each year the July 4th forecast is 'partly cloudy, hot and humid, with a chance of storms.' It seems to work out that way every year. I think July has a chance to be pretty wet too. Why? Remember that wet saturated ground we have? The atmosphere will feed off that moisture and produce more rain. We saw that happen in 1993 with all the flood waters in the area. This year, we don’t have that kind of flood, but the ground is definitely wet. So, rain could be a factor again in July. And like June, temps will average above normal because the low temps will average very warm.

August is the dog days of summer. It seems like the warmest and most humid days happen in August. We have definitely had some hot August days and nights. Actually, temps average just below July, making it the 2nd warmest month of the year. I think this year will once again be very warm because of wet ground and warmer than normal low temps. As for rain, wet begets wet. So, the wet ground will have a roll in rain and storms. I don’t think August is as wet as June and July, but I think we will average above normal for rain.

Overall...and warm, humid, and wet summer.

For the summer forecast Glenn Zimmerman spoke to Kevin Deitsch, the Warning Coordination Meteorologist for the St. Louis office of the Nation Weather Service, Erin Cooper, an educator for the St. Louis Science Center with a background in chemistry, and the rulers of the playground, Ms. Mikol's kindergarten class at Rose Acres Elementary.

More details on the Ozark National Scenic Riverways: https://www.nps.gov/ozar/index.htm

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