Saturday, June 11, 2016

Details on summertime conditions in the Mid-South this coming week

A dry (finally!) and less humid (yeah!) yet still warm week is unfortunately in the rearview mirror. We now turn our attention to a hot, humid summer-like weather pattern ahead.

OK, it may not be THAT bad!

Today (Saturday) was a transition day as humidity increased (dewpoints reached the mid 60s to near 70), temperatures were the warmest yet this year (exceeding yesterday's "warmest" by a couple more degrees at 95), and a few summertime airmass showers popped up in north MS, which is a good indicator that moisture and instability is working its way north from the Gulf of Mexico.


A dry continental airmass of Canadian origin dominated surface conditions the past week, but it has moved away with high pressure over the western Atlantic and southeast states now pulling warm moist Gulf air into the region on southerly wind. Meanwhile, at the upper levels a large, hot ridge of high pressure sits overhead. This combination has meant above normal temperatures and increasing humidity to start the weekend with a few afternoon showers forming to our south where moisture is a little more plentiful.

The North American Model (NAM) depiction of dewpoints at 7pm this evening, showing widespread values near 70 degrees across the region. 70 is generally the level where most people really start to notice it getting sticky.
By Sunday, continuing southerly wind will increase dewpoints (a measure of humidity in the air) to the lower 70s, which is very "sticky" for most people. With increasing moisture and plenty of instability from above normal temperatures, expect more scattered afternoon and early evening shower and thunderstorm activity tomorrow and for it to extend further north into the metro. Higher rain chances should help keep temperatures down just a few degrees though. Rain showers will diminish in the evening with the setting sun.

The Global Forecast Ssytem (GFS) model for Sunday evening shows a large ridge of high pressure dominating the central portion of the country. It is providing the above normal temperatures for the area "under" the ridge.
By Monday and Tuesday, the upper levels change a bit as high pressure breaks down over our region as an upper level disturbance cuts into the ridge and moves across the Mid-South. With continuing abundance of very warm, unstable air and high humidity levels, scattered thunderstorms are again expected each day, primarily in the hottest part of the day. With the disturbance lingering, rain chances may be slower to diminish in the evening hours Monday and possibly Tuesday.

The upper level ridge begins to get a "ripple" in it by Monday as an upper level disturbance (yellow/orange shading) strengthens a bit resulting in a weak upper level low according to the GFS model. This will be the trigger for more widespread (though likely still scattered) convection early this week. It will take a couple days for the low to move east of us.
With that disturbance moving out, another looks to move in on Wednesday, continuing the chances of scattered daytime thunderstorms. Heat and humidity will continue to be an issue as well though days with the higher rain chances should see heat indices remain below the 100° mark we see this weekend as temperatures remain in the lower 90s.

As we head into the end of the week, it appears that weak low pressure drops in to our east with a cool front dropping south from the Ohio Valley into the Mid-South late Thursday or early Friday. As expected, that means more rain and thunderstorm chances, but also slightly cooler temperatures, especially by next weekend when highs should be back down in the mid 80s. Being that that is still a week away, and this is summer, that could all change. For now, be prepared for daily rain chances, humid conditions, and varying degrees of heat depending on cloud cover and coverage of thunderstorms each day.

After the early week upper level energy departs, a weak cold front will drop south into the region by late this week, providing additional chances of showers and thunderstorms, but also temperatures that are closer to normal for next weekend. Graphic courtesy NOAA/NWS.
Fortunately, the increase in clouds and scattered showers will also mean lower ozone levels prefer sunny, hot high pressure days. Those who have experienced breathing issues the past couple of days due to the Code Orange and Code Red conditions should "breath easier" as we head into the new week. Click here for the complete detailed MWN Forecast and check back regularly this week as rain chances in particular could change from day to day!

A couple notes on #TeamMWN

Finally, I want to take a moment to make a public thank you to one of #TeamMWN's longtime social media nowcasters. Patrick Luckett has been with MWN for nearly 4 years (!) and been a very reliable member of the team. He's stayed up late, gotten up early, and worked long hours to keep you all well-informed with his great updates on our social media accounts in good weather and bad. Patrick has accepted a full-time job this summer with the Department of Defense here in the Mid-South as he finishes up his schooling and prepares to become a "real meteorologist." :-) I know he'll do a great job wherever life takes him. You may see /PL fill in a couple of times here this summer, but his regular schedule with MWN is coming to a close. Please join me in wishing him well!

And while I'm on the #TeamMWN topic, many regular followers know that William Churchill (/WC) served MWN for a good while as well and recently stepped aside as he begins a career with the National Weather Service. William will be getting married this summer and finishing his NWS internship then starting his career later in 2016. I also wish William and Kylie all the best and thank him, again, for his dedication to MWN the past few years!

Erik Proseus
MWN Meteorologist

Follow MWN on Facebook, Twitter, and Google+
Visit on the web or on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

No comments: