Friday, July 10, 2020

Summer high pressure ridge to take hold, bring very hot temperatures


Over the past week or so we have been under a repetitive pattern with below or near average temperatures and pop up thunderstorms. As we move into the middle of July, we will really be feeling a 'dog days of summer' vibe with much lower rain chances and above average temperatures. This is due to something we know all too well from past years, the dreaded summer ridge. By the beginning of next week a high pressure ridge will move in and situate itself over the eastern U.S. This will allow  afternoon highs to reach the mid to upper 90s for most of next week. High pressure is also notorious for squishing out any rain chances due to sinking motion of the air under a high. That will definitely be the case heading into mid July!

European model ensemble data showing a high pressure in the mid levels situated over much of the US, including the southeast, beginning by mid-week next week. The color shading represents departure from normal pressure values, so this ridge is "anomalously strong." (WeatherBell)

The European model ensemble shows extremely low rain chances, as often found with a ridge, for the middle part of July. The top half of the graph shows rainfall over time for each member of the ensemble system, while the bottom shows the mean, or average, of the individual members. (WeatherBell)

Saturday - Sunday

This time of year is often referred to as ' MCS', or Mesoscale Convective System, season as most of our rain and thunderstorm activity is produced by these fast-moving complexes. These systems will bring us our last few rain chances on Saturday and Sunday before we dry out next week. Saturday will consist of partly sunny skies afternoon highs in the low 90s, much like Friday. However, due to northwesterly flow, an MCS in northwest Arkansas could approach the area during the afternoon time. This would likely bring a chance of thunderstorms across the metro but whether or not this complex will fall apart as it approaches remains uncertain. [ Saturday morning UPDATE: thunderstorm chances this afternoon will indeed be very minimal. ]

Our best rain chance for the next several days will come early Sunday morning. Most of Saturday night will be dry with lows in the mid 70s but a secondary system will move through the area bring another potential round of thunderstorms. If it materializes and moves through, Sunday would start off wet but throughout the day skies will become partly cloudy with afternoon highs warming into the low 90s once again.  

The Friday mid-day high-resolution NAM model "forecast radar" from Saturday morning through Sunday afternoon shows the first potential MCS Saturday falling apart to our west, while another Sunday morning has a better chance of bringing us rain. Model are challenged with these types of systems though, so this likely will change! (

Monday- Tuesday

After the rain chances on Sunday, the dry pattern begins to take hold for early next week as the western ridge begins making its way toward the eastern half of the US. Monday morning will start off in the lower 70s and will be our coolest point for a while as overnight lows stay in the mid to upper 70s over the coming week. The warming trend continues with afternoon highs warming into the lower 90s. Tuesday will be more of the same with plenty of sunshine and afternoon highs in the mid 90s. This makes for early next week to be perfect pool weather! 

Wednesday- Friday

By Wednesday, the high pressure ridge will be fully in place thus continuing the dry pattern but bringing extremely hot temperatures across the metro. A daily pattern of mostly sunny skies with afternoon highs in the mid-upper 90s and lows in the upper 70s is what we expect through late next week. Afternoon highs may even reach 100 Thursday and Friday! Heat indices will also be extremely high, reaching well above 100 and possible reaching the 110s. This will likely prompt heat advisories or warnings. While working out in the extreme heat this coming week, there are a few key things to remember in order to stay safe. Make sure to take frequent breaks from the heat. Drink plenty of water and wear sunscreen! Overnight lows that barely drop below 80 will make the heat even less bearable as there will be little relief overnight.

Forecast temperatures for the third week of July from the European model ensemble. (

Allison Paige
MWN Meteorologist Intern

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Saturday, July 4, 2020

June 2020 Climate Data for Memphis, TN

June Climate Recap

For the third consecutive month, cooler than normal temperatures prevailed into June, though by less than a degree for the month. Only 11 of the 30 days in June were above average and only four of those were after the 9th. Drier than average conditions also continued into June but not by much. There were only two days on which more than 1/2" of rain fell.

Severe weather occurred on a couple of days in the first week of the month. Sub-severe hail fell in eastern Shelby County on the late afternoon of the 4th. A more widespread severe weather event, a mesoscale convective system featuring straight line wind that measured 58 mph at Memphis International Airport, struck during the early afternoon on the 5th. Scattered reports of trees down on power lines and small hail were received with power outages scattered across the metro as well. Finally, a slow-moving storms produced flash flooding in southeast Shelby County into Olive Branch on the 9th.

Memphis International Airport, Memphis, TN

Average temperature: 78.9 degrees (0.7 degrees below average) 
Average high temperature: 88.1 degrees (0.8 degrees below average) 
Average low temperature: 69.6 degrees (0.7 degrees below average) 
Warmest temperature: 95 degrees (7th) 
Coolest temperature: 61 degrees (11th) 
Heating Degrees Days: 0
Cooling Degree Days: 423 (15 below average) 
Records set or tied: None 
Comments: The month of June featured 11 days that rose to 90 degrees or higher, or about three days less than average. 

Monthly total: 3.33" (0.30" below average) 
Days with measurable precipitation: 10 (1.0 day above average) 
Wettest 24-hour period: 1.02" (23rd) 
Snowfall: None 
Records set or tied: None 
Comments: None

Peak wind: North/58 mph (5th) 
Average wind: 7.8 mph 
Average relative humidity: 67% 
Average sky cover: 50% 

 Click here for a daily statistical recap for Memphis International Airport.

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 77.2 degrees 
Average high temperature: 88.6 degrees 
Average low temperature: 67.2 degrees 
Warmest temperature: 94.4 degrees (30th) 
Coolest temperature: 57.3 degrees (1st) 
Comments: None 

Monthly total: 3.07" (automated rain gauge), 3.15" (manual CoCoRaHS rain gauge) 
Days with measurable precipitation: 12 
Wettest date: 1.03" (21st) (via automated gauge) 
Snowfall: None 
Comments: None 

Peak wind: South/29 mph (9th)
Average relative humidity: 77% 
Average barometric pressure: 29.95 in. Hg
Comments: None

Click here for a daily statistical recap for Bartlett, TN.

MWN Forecast Accuracy

MWN average temperature error: 1.80 degrees 
MWN forecast temperatures within 2 degrees of actual: 74% 
MWN average dewpoint error: 2.20 degrees 
MWN forecast dewpoints within 2 degrees of actual: 66% 

MWN's forecasts extend out five periods (2.5 days, or roughly 60 hours). Historical accuracy statistics can be found here.

Climate Outlook - July 2020

The July climate outlook for the United States from the Climate Prediction Center is shown below. Above average temperatures are forecast for the vast majority of the nation, except the interior northwestern U.S. Odds favor above average temperatures for Memphis (49%) versus only a 18% chance of below average temperatures. Memphis' average temperatures for July is 82.7 degrees.

Wetter than normal weather is expected in the southeastern U.S., as well as in the northern Plains. Drier than average weather is forecast for the southern Rockies into the Front Range and western High Plains, as well as portions of the Great Lakes. For Memphis, odds favor average rainfall, which historically is 4.59 inches in July. 

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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder