Good Monday everyone. Our Memorial Day is the day I have chosen to finally put out the Summer Forecast. Before I get into the outlook itself… I do want to talk a bit about the weather for today and the next few days.

Showers and thunderstorms will increase across the state today and many of these storms will put down torrential rains that can lead to some local flooding concerns and a few could go severe for a time. The same can be said for Tuesday as well. Here are your radars to track the storms…

More storms could really get cranking around here by Thursday as severe weather will be possible by that time.

Now to the main event… The Summer Forecast.

Let me begin by saying I do not put as much effort into the forecast for summer as I do for the winter… and it’s not even close. People don’t pay that much attention to a summer prediction but will go crazy waiting for the winter outlook. That said… I have done enough research to hopefully give you guys a decent enough forecast for the next three months.

Last summer was a VERY chilly one around here and we actually called for just that type of a pattern weeks ahead of the June first start to meteorological summer.I was very confident in where we would go heading into last summer. My confidence is nowhere near as high this go around as there are many conflicting signals. I’m not going to bore you with a lot of fancy weather talk as you guys only want to know what I am expecting for the summer ahead. But… I will give some of the details behind the magic eight ball… I mean… forecast.

One thing to keep in mind as we begin June is the amount of water in the ground following one heck of a wet May. Most of the state is running WAY ahead of normal in the rainfall department and soil moisture heading into summer is something I like to look at closely when making a seasonal outlook. Generally… a wet ground, combined with green and lush vegetation, does not bode well for true heat around here. That is exactly what we have out there right now as we enter summer. Just look at how far ahead of normal much of the state is for the month of May…

Again… that is showing the departure from normal for the Month and shows much of the state anywhere from 3″-10″ above normal for rainfall.

That is more of a local way to look at the weather. On a more worldwide scale… we have to take a look at the state of the Equatorial Pacific Ocean waters. We started out this year with abnormally warm waters in this region. El Nino was moderate to borderline strong until early Spring. Now… the waters are doing a complete 180 and are heading toward a La Nina. Many of the seasonal forecast models suggest La Nina may reach moderate status in the coming months and stay there into the fall and winter months. You can see this with the graph below…

Since 1950… there are only a handful of years that have made this strong a switch from El Nino to La Nina. Those years are: 2007, 1998, 1995, 1988, 1983 and 1964. More on those years in a bit.

One thing I also like to look at is the seasonal forecast models that give us their best shot at showing which parts of the country will be cool or hot and wet or dry. Two of the ones I look at are both saying something similar… cooler and wetter than normal.

                  

Those two look pretty darn similar in terms of placement and magnitude for both temps and rainfall. It should be noted neither of these models handled the May forecast very well as both appeard to be too cool with their forecasts.

Given how wet the month of May has been… I thought it would be prudent to check on how other summers turned out after a very wet month of May. I used Lexington for the study as this May is going to go down as, at least, the 4th wettest May on record. I took the top 10 wettest Mays of all time ( this monyh will make the 6th May in the last 14 to make the overall May top ten wet list) and lumped all the following summers together to see how what the average temp looked like. I then took our list of years that featured a similar switch from El Nino to La Nina and averaged those summer temps. The difference in the two data sets is pretty striking…

                          Top 10 Wettest May                                                                   Similar La Nina Flip Years

    

As you can see… history suggests when Lexington has a top 10 wettest May on record… the following summer turns out cooler than normal. That, to an extent, matches with what the seasonal forecast models are showing for the next three months.

The fact the Pacific is switching from an El Nino to a La Nina argues for the exact opposite with a warmer than normal signal showing up for our region. What is a forecaster to do? Well… this forecaster wanted to look to see if any of the same years actually showed up in both data sets. Sure enough… two years made both lists… 1995 and 1983. Both featured top 10 wettest Mays on record for Lexington and both years saw El Nino give way to La Nina.

To be honest… 1995 was a year I was looking at closely to begin with as that spring featured quiet weather for March and April before severe weather and flooding took over for May. In looking closely at 1995 and 1983… both have their flaws as NO analog year is ever perfect… but I like the overall theme they show.

Here is what I am thinking for Summer 2010…

Temps: Slightly above normal

Rainfall: Above Normal

I am expecting the summer to start off with June averaging near or even slightly below normal for temps and above normal for rain. July should see a continuation of the back and forth with the temps with near normal rains. August is the month that should see our temps really ramp up with above to much above normal readings possible. Rainfall from thunderstorms should average above normal for the month.

Summer Headlines

– With a wet ground and the overall pattern I see setting up… this summer will be remembered as a very humid one.

– I am expecting a total of 17-22 90 degree temperate days June through August.

– Thunderstorms should be rather common this summer and with a lot of juice in the air… flash flooding issues will likely be with us. This is also a pattern that can produce a higher than normal amount of summer severe storms.

The Hurricane Season

– A very active tropical season is likely in the Atlantic basin. I am expecting 15-20 named storms with 10 of those becoming hurricanes… 3 of which could become major.

– The water temps in the Gulf of Mexico and the Caribbean are much above normal right now and this will only aide in getting these storms cranking.

– There is an increased threat for our region to get rain from any storm that makes landfall in the Gulf late this summer into fall.

So… there you have it. It is far from my best work… but it will have to do I guess.

I will udpate the storm threat for the next few days as needed… take care.