Thursday, July 12, 2018

Extreme heat & high pressure continue to dominate the Mid-South

It's summer. It's hot. We know it's coming every year, but somehow it always feels worse when it does arrive. The big weather maker to highlight for the next week is in fact the heat. Heat index values are expected to climb well over 100 degrees for the rest of the week and even into the beginning of next week. For the past couple of days, several of our counties have been included in a Heat Advisory for these dangerous heat indices. A Heat Advisory is issued when heat index values are expect to rise above 105 degrees. While the current Heat Advisory will expire this evening, given the forecast, it will be back before long!

Late afternoon warning map shows the Heat Advisory in orange. A Special Weather Statement, also highlighting heat potential, is shown in tan and also includes the Heat Advisory counties.

As we head into the weekend, be sure to remember some heat safety tips. I would also suggest finding a pool to cool off in!


Tomorrow and this weekend

Hot, muggy, afternoon showers. With any summertime pattern, like we are in right now, those three phrases are the ones to live by. Expect temps to stay a few degrees above average the next few days with dew points hanging in the 70s. This will provide that sticky feeling we all love during the summertime.


I'm sure many are wondering about our precipitation chances. Well, it looks like our afternoon pop-up showers and thunderstorms will hold on for now. Scattered showers and thunderstorms will likely develop each afternoon with coverage decreasing once the sun sets. This translates to a 20 to 30% chance each day. Whether you have plans to head to Levitt Shell or the Memphis Botanic Gardens for concerts or have other outdoor plans this weekend, things will likely stay muggy, but any afternoon showers should be on the downward slope by evening. 

Saturday and Sunday look to have the same old song and dance on the surface, but not necessarily in the middle and upper atmosphere. While temps will stay in the mid 90s during the daytime and "cool" into the upper 70s at night, the high pressure system that has been dominating our weather pattern will begin to lose strength. 

GFS shows a ridge pattern initially that begins to lose strength into Sunday. By Monday and next week, a mid-level trough begins to take its place. (Pivotal Weather)
With any meteorological phenomena, it usually takes some time for things that start aloft to reach the surface. So while the ridge appears like it will break down aloft, it will take some time for the extreme heat to go away. 


Beginning of next week

While we may not begin to feel the implications of the ridge weakening and the trough taking over, we will notice some increased thunderstorm coverage for the first half of the week. Temps will stay mild, muggy, and in the mid 90s Monday and Tuesday with overnight temps coasting in the upper 70s, proving little nighttime relief.

As for our rain chances, each day will likely have a few more showers and thunderstorms than we have seen in recent times. Typically in this pattern, they fizzle out after sunset, so that is good to keep in mind when making evening plans. 

GFS loop from Saturday evening through Tuesday evening shows scattered showers each day. (TropicalTidbits)


Second half of next week

With the mid-level trough digging into the eastern half of the U.S for the second portion of the week, expect things to finally cool off just a tiny bit compared to the above average temperatures and extreme heat we've been having recently. 


The Climate Prediction Center releases daily graphics highlighting the 6 to 10 day temperature and precipitation outlooks for the U.S. They currently span from next Wednesday through the following Sunday. On average over the period, temps will likely stay right around average here in Memphis with precipitation being a little higher than average for summertime. I don't know about you, but I could use some more showers and a little less heat. Stay cool until then!

The Climate Prediction Center's 6 to 10 day outlook shows a near normal temperature outlook over the Mid-South. (NOAA/CPC)

The Climate Prediction Center's 6 to 10 day outlook shows a slightly above average (33%) precipitation outlook over the Mid-South. (NOAA/CPC)

Caroline MacDonald
MWN Meteorologist Intern

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