August 2015 Climate Data and Forecast Accuracy

August Recap

Temperatures were above normal the past few months but that trend reversed itself in August with a slightly cooler than average month, despite reaching 98° for the highest temperature of the month. In fact, most of the month saw daily temperatures within a few degrees of average (above or below), but a several days of well below normal temperatures from the 20th-28th contributed to the below normal monthly average.

Precipitation was above average for the driest month of the year climatologically, but was concentrated on just a few days. Rainfall of 2.61" on the 5th (a daily record) was about 1/4" short of the normal precipitation for the entire month. Through August, Memphis International Airport continues to narrow its annual rainfall deficit, which now stands at just 1.41", or about 96% of normal.

There was one severe weather day in August, which was the 5th. This day recorded the highest official wind gust for the month as well as record rainfall. Thunderstorms downed trees and power lines and heavy rainfall produced some areas of flash flooding in the metro.

Severe weather reports received by NWS-Memphis on August 5, 2015 in the metro.
Tree  symbols are downed trees, Green/blue symbols are flash flooding.

Memphis International Airport, Memphis, TN

Temperature
Average temperature: 80.7 degrees (1.3 degrees below average)
Average high temperature: 90.4 degrees (0.9 degrees below average)
Average low temperature: 71.0 degrees (1.7 degrees below average)
Warmest temperature: 98 degrees (3rd, 4th)
Coolest temperature: 61 degrees (25th, 26th)
Records set or tied: None
Comments: None

Precipitation
Monthly total: 4.11" (1.23" above average)
Days with measurable precipitation: 6 (0.8 days below normal)
Wettest 24-hour period: 2.73" (5th-6th)
Total Snowfall: None
Records set or tied: Daily record - 2.61" on August 5th
Comments: With just 3 days of rainfall above 0.5" and a record rainfall on the 5th, overall the month was dry despite the monthly total being above normal.

Miscellaneous
Peak wind: Northwest/45 mph (5th)
Average wind: 6.0 mph
Average relative humidity: 65%
Average sky cover: 50%

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

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN

Temperature
Average temperature: 77.2 degrees
Average high temperature: 89.4 degrees
Average low temperature: 66.6 degrees
Warmest temperature: 97.5 degrees (3rd)
Coolest temperature: 54.7 degrees (26th)
Comments: None

Precipitation
Monthly total: 3.46" (automated rain gauge), 3.52" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 7
Wettest date: 1.14" (5th) (via automated gauge)
Total Snowfall: None
Comments: None

Miscellaneous
Peak wind: Northwest/27 mph (7th)
Average relative humidity: 81%

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: 76%
MWN average dewpoint error: 2.18 degrees
MWN forecast dewpoints within 2 degrees of actual: 69%

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

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Summertime weather sticks around into September

Though "meteorological summer" ended on August 31, Mother Nature isn't paying any attention to the calendar as summertime conditions continue well into September. We've started off the month with a couple of days in the 90s and, unfortunately, the long-range forecast includes many more as we head into the Labor Day weekend, also the opening weekend of the college football season.

The weather pattern is dominated by an upper level pattern more akin to mid-summer than early fall as a ridge high pressure aloft encompasses much of the eastern, central, and southern U.S. This ridge, as evidenced in the video loop below by the light red/mauve colors, looks to morph a bit over the next 10 days but generally it remains fairly well entrenched across a good part of the U.S. This will mean continued above normal temperatures for at least the next week with very low rain chances.

Video above shows a loop of the next 10 days of upper level [18,000'] heights as forecast by the Wednesday mid-day GFS model. Mauve/light red colors are high pressure, which sticks around for much of the next week or more.

As for the beginning of the Delta Fair this weekend, Labor Day celebrations, and the kickoff to the Memphis Tigers football season on Saturday evening, expect heat to build, resulting in high temperatures in the mid 90s during the afternoons (low 90s at kickoff at Liberty Bowl Memorial Stadium on Saturday) and low to mid 70s for early morning lows from now through early next week.

A couple of days ago I thought a cold front may push through early next week, but that scenario looks to be delayed by at least a few days, so 90°+ weather could last well into next week. Rain chances will be no better than the isolated thunderstorms that happened to form right over the city on Wednesday afternoon. Hang in there though - once this heat breaks, I expect it'll be downhill into autumn! We'll just have to wait a little longer than some of us might like! For the complete MWN Forecast, check out our mobile apps (links below) or click here for our mobile-formatted forecast page.

NOAA total rainfall estimates through Labor Day are very low - almost nothing.

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!