Sunday, July 25, 2021

"Real" summer is underway, and here to stay, across the Mid-South

Summer 2021 so far

While we saw some above normal temperatures in the month of June, the overall average for the month was 1.0 degrees below normal and the highest temperature recorded (officially) in Memphis was 94 degrees. July typically features highs in the low 90s and low in the mid 70s. Through the 23rd, we had only observed two days with above average temperatures and both were a single degree above average. Sixteen days were below average. So while it was hot, it wasn't abnormal, nor excessive.

Weather records for the first 24 days of July. The temperature departures from normal for each day are in the red box. The warmest temperature, relative to normal, so far this month was yesterday. (NWS)

That changed on Saturday. The high of 95 degrees was the hottest so far this year and today will likely meet or exceed that. Combined with dewpoints in the mid 70s, which is sultry and means there is a great deal of moisture in the air that makes it harder to sweat off the heat, the first Heat Advisory of the summer was issued. Today was the second. Tomorrow will be the third. Heat indices are making it to 105 degrees or higher in the afternoons. But how long will this hotter pattern last?

Early this week - scattered relief

A weak front (I almost hesitate to call it that) will move into northern sections of the Mid-South. So while we will start Monday on track for similar conditions to this weekend (disgusting upper 70s for low temps), clouds will increase and scattered showers and thunderstorms are expected mainly in the afternoon. We'll still reach the low 90s for highs, but there's a good chance many areas will get some relief as thunderstorms form - whether it be from actual rain or rain-cooled air spreading out from nearby thunderstorms. With the front nearby, dewpoints will likely "pool," meaning they build-up just ahead of the front. Since the front will not move through, we'll basically just sit in the soup. Expect extremely muggy conditions where rain or outflows are not helping a bit.

HRRR model radar simulation from Monday morning through Monday evening shows the likelihood of scattered showers and thunderstorms during the warmest part of the day. Exact storm location is not predictable, but overall coverage in a region is. Model ≠ gospel. (WeatherBell)

Tuesday will be fairly similar to Monday with warm and muggy conditions to start the day, heat building into the low 90s and afternoon scattered storms, though maybe a few less than Monday, as the front washes out to our north. Both days will likely see heat indices reach 105 or worse, at least until rain-cooled air invades an area. These are the invasions we root for.




Wednesday-Friday - more heat

As high pressure aloft builds back over the area from the west by Wednesday and for the rest of the week, oppressive conditions return as any shower than tries to form in the heat will be squashed quickly by the downward motion of air under the ridge aloft. Very little relief is expected overnight with lows in the mid to upper 70s. Afternoon highs should have no trouble reaching the mid 90s, and could touch the upper 90s late in the week in spots. Wind will be light. Sweat will be plentiful. Feels like temperatures will exceed 105, thus Heat Advisories are likely.

The European model ensemble shows a massive ridge of high pressure aloft over all but the northeast portion of the country between Wednesday-Sunday. The center of the high is over the central Plains and stretches southeast into the Mid-South. Warm colors indicate anomalously high (or warm) values. A 5-day average of 594 (or 5,940 meters) is very strong high pressure. (WeatherBell)


Next weekend

Another front looks to try and make a push towards the region from the north. The best we can hope for now is scattered showers of relief in the afternoons, but highs remain probably toward the middle range of the 90s. Further in voodoo land, a summer frontal passage is shown in long-range models early the following week. That is about like seeing snow 8-10 days out on the models in the winter. Don't get your hopes up just yet, even though the weather crap apps on your phone may show 80s ten days out.



Heat caution

Heat is rough on a person's body, and it gets worse with time. The more consecutive days with little relief, the more it takes a toll. It hasn't been this hot yet this summer. Please take it easy. Frequent breaks, plenty of non-alcoholic beverages (especially water or sports drinks), and shade as much as possible if you have to be out. Watch out for those pets too. They need lots of water and shade if they can't come in. And finally, you would never do it on purpose, but check the back seat before exiting your vehicle. We don't want any unnecessary deaths from children left in vehicles!


Heat exhaustion and heat stroke is also real - I have recent experience with a healthy, young relative who passed out while driving after working outside all day and totaled his truck when he drove it into a telephone pole. (Thankfully, he was fine other than recuperating from the heat!) It's not worth pushing it "just a little bit longer."




Erik Proseus
MWN Meteorologist

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Thursday, July 15, 2021

Cooler temps and wet weather on the way

While it was hot out there today, it’s nothing unexpected this time of year. Average highs are in the low 90s, and we were right around that today. We’re now about halfway through the month and so far it has actually been cooler than average here in the Mid-South and for much of the southern U.S. as a whole! 

Temperature anomaly (departure from average) for the month of July so far across the U.S. (WeatherBell)

We are very lucky that we haven’t seen the extreme heat western states have been experiencing - some areas in the west are seeing high temperatures more than 15 degrees above average for the month, yikes! Wildfire season has already been awful out there and will only get worse in the coming months as the heat intensifies the terrible drought. High in the atmosphere wildfire smoke could blow over our area from western fires at times for the rest of the summer and into the fall, which could make our skies hazy and our sunsets more red periodically. Keep an eye out!

Trough sets up this weekend

More wetness and below average temperatures are on the way as we end this week and start the next one. Unfortunately, this means the weekend is looking pretty wet. We have seen persistent areas of low pressure that have affected the Memphis area all through the late spring and early summer, and as we head into mid-summer that trend looks to continue. By the weekend, a trough, or a dip in the overall atmospheric flow across the United States, will once again bring a period of wet weather to the region. This “dip” will be accompanied by a weak front that will stall out near or just south of the area and provide the focus for multiple rounds of showers and storms this weekend and early next week. No drought concerns here for the foreseeable future!

The European model depiction of the weak mid-level trough that will keep our weather unsettled and cooler than normal this weekend. No extreme heat on the horizon locally! (WeatherBell)

Friday

Friday looks to be a fairly typical summer day, with rain chances a bit higher than the past few days, particularly late afternoon and evening. As we quickly warm up into the low 90s again Friday afternoon, scattered showers and storms will pop up across the area. the Storm Prediction Center doesn't have our area highlighted for potential severe weather so general thunderstorms with heavy rain will be the primary threat. The sagging weak front begins to have more influence over the area beginning Friday night, with rain chances actually increasing a bit. 

Weekend

Showers and storms will continue through the overnight hours and into Saturday morning. Saturday looks quite wet overall. We’ll wake up to widespread showers and storms which will continue into the afternoon and evening, perhaps tapering into the afternoon and evening to scattered just rain showers. The clouds and rain will hold our temps down in the mid-80s, once again several degrees below average. 

Sunday looks to be just as wet, so it’s a good weekend for indoor activities. Some of the storms could contain heavy rainfall, so flash and urban flooding could be a concern for some spots, especially if the same areas see repeated heavy rainfall after receiving a good amount Friday night and Saturday. Highs will only top out in the low to mid 80s on Sunday, and it’s looking quite similar for Monday, with widespread rain and storms and highs in the low to mid 80s. 

Next week

As the front moves south of our area and the trough moves east, rain chances should diminish a bit as we head towards the middle of the week with more typical scattered afternoon showers and storms. Highs will slowly rebound back into the upper 80s to near 90 degrees by Wednesday. All of this added moisture will only increase humidity levels across the area, so feels like temps will be quite high in the afternoon sun. Rainfall totals will likely be wide ranging across the area as it will be highly dependent on storm location. A couple inches of rain is a good bet for all of us, with some areas likely seeing more and some seeing a bit less. As always, when thunder roars, go indoors, and stay tuned for any updates should a Severe Thunderstorm or Flash Flood Warning be issued this weekend.

The NWS Weather Prediction Center forecast of total rainfall through Monday shows that much of the area is likely to pick up 1.5-2.0" of rain with this next system. (WeatherBell)

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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