Monday, January 18, 2016

A Warm 2015 Memphis, TN Annual Climate Recap

2015 Annual Recap

Overall, 2015 was a warm year with lengthy dry periods that were offset by wet streaks that resulted in near normal precipitation for the year. January continued the dry weather that ended 2014 with moderate to severe drought in place by the end of the month. The month started cold but ended near average. February turned very cold, as the second half of the month was the coldest such period on record (by over 5 degrees). A little over 2" of snow was recorded from multiple events. March will best be known for the significant snowfall on the 4th-5th (3.6" at the airport, but up to 6" outside the city) and record cold temperatures following.

There was no thunder in 2015 until well into April, which is very unusual. Speaking of April, the weather turned warm and dry and severe weather was well below normal and this pattern continued into May. With the exception of a chilly Memphis in May Barbecue Fest weekend, May was warm and severe weather remained minimal. June and July continued the warm and dry trend until a deluge of rain fell late in June, which began a week of below normal temperatures that included the July 4th weekend, which also recorded a flash flood event due to heavy rainfall. Scattered wind and hail reports were observed on a few June days, but the main severe weather event was a storm complex with widespread 50-60 mph wind on July 14th that resulted in 30,000 MLGW customers without power.

Severe weather and flash flooding struck again on August 5th and set the tone for a cooler than average month (despite high of 98 degrees on the 3rd and 4th which were offset by a cool end to the month) with drier than average conditions for the remainder of the month. Summer was slow to depart in September with well above normal temperatures and very dry conditions interrupted by one wet day that produced 85% of the month's total rainfall. Warmth continued into October, which delayed the start of the cool fall season, and dry weather continued until the last week of the month.

November and December ended the year very warm, each ending in the top 5 warmest months on record. November was very wet (8th wettest on record with over 10" of precipitation) with a few minor severe weather reports and some flash flooding on the 17th. Precipitation slowed in December, ending below average, but the most notable severe weather of the year occurred just before Christmas with multiple long-track violent tornadoes occurring in north MS on the 23rd, including EF-3 damage in Holly Springs (Marshall Co.) Multiple warm weather records were set during Christmas week as the mercury touched 80 degrees the day after Christmas for the only the 2nd time in December on record. It was also the first time on record that no sub-freezing temperatures were recorded in the month of December at Memphis International Airport.

All severe and winter weather reports in the metro area received by NWS-Memphis in 2015. Click for larger image.

All tornado tracks for 2015 in the Memphis warning area. Click for larger image. Graphic courtesy NWS-Memphis.

Memphis International Airport, Memphis, TN

Average temperature: 64.3 degrees (1.2 degrees above average)
Average high temperature: 73.4 degrees (0.9 degrees above average)
Average low temperature: 54.9 degrees (1.3 degrees above average)
Warmest temperature: 99 degrees (July 20, July 29)
Coolest temperature: 9 degrees (January 8)

Heating degree days: 2650 (315 below average)
Cooling degree days: 2479 (221 above average)
Days at or above 90 degrees: 77 (12.7 days above average)
Days at or below 32 degrees: 41 (1.8 days below average)
Last freeze/first freeze: March 24-November 12 (233 day growing season)

Records set or tied: February 23 (28° - tied coolest high), March 6 (15° - record low), July 20 (81° - tied warmest low), July 29 (82° - warmest low), October 3 (59° - coolest high), October 15 (93° - record high), October 23 (69° - tied warmest low), November 4 (67° - warmest low), November 5 (66° - tied warmest low), November 27 (63° - tied warmest low), December 11 (77° - tied record high), December 12 (76° - record high, 67° - warmest low), December 22 (70° - tied record high), December 23 (73° - tied record high, 63° - warmest low), December 24 (76° - tied record high), December 26 (80° - record high/2nd warmest December high), and December 27 (77° - tied record high).
Comments: 2015 was the 10th warmest year on record (64.3°), December was the 2nd warmest on record (54.1°), November was the 4th warmest on record (57.8°), and February was the 7th coolest on record (36.2°).

Temperatures for the year (lows/highs) are plotted in dark blue against the normals (brown), record highs (red) and record lows (light blue).  Where the dark blue extends above or below the brown indicates temperatures above or below normal, respectively.

Monthly total: 52.66" (1.02" below average)
Days with measurable precipitation: 114 (16.3 days above average)
Days with 1"+ precipitation: 16 (1.4 days below average)
Wettest day: 3.40" (July 3)

Total Snowfall: 5.9" (2.1" above average)
Days with a trace or more snowfall: 8
Greatest snow depth: 4" (March 5)

Records set or tied: Only one daily record rainfall amount occurred in 2015 - July 3 (3.40").
Comments: November was the 8th wettest on record (10.16") and January was the 9th driest on record (1.30").

Precipitation accumulation for 2015 is plotted as the dark green line, compared with a normal year in brown. With a few exceptions, precipitation remained below normal for much of the year, making a little headway in late winter and the summer and then nearly getting back to average the last 6 weeks of the year.

Precipitation totals for the NWS-Memphis area of responsibility with individual totals plotted. Graphic courtesy NWS-Memphis.

Peak wind: North/48 mph (July 14)
Average wind: 7.4 mph

Click here for monthly/daily statistical recaps for Memphis International Airport.

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 61.5 degrees
Average high temperature: 73.3 degrees
Average low temperature: 52.0 degrees
Warmest temperature: 99.0 degrees (July 29)
Coolest temperature: 7.9 degrees (January 8)

Heating degree days: 3482
Cooling degree days: 2211

Annual total: 55.33" (automated rain gauge), 57.19" (manual CoCoRaHS rain gauge)
Wettest date: 3.59" (November 17)

Total Snowfall: 5.5"
Days with a trace or more snowfall: 11
Greatest snow depth: 4.0" (March 5)

Peak wind: West/35 mph (July 14)
Average relative humidity: 77%
Average barometric pressure: 30.08" Hg

Click here for monthly/daily statistical recaps for Bartlett, TN.

MWN Forecast Accuracy

Number of forecasts produced and rated in 2015: 556
MWN average temperature error: 2.30 degrees
MWN forecast temperatures within 2 degrees of actual: 64.7%
MWN average dewpoint error: 2.25 degrees
MWN forecast dewpoints within 2 degrees of actual: 67.4%

MWN's forecasts extend out five periods (2.5 days, or roughly 60 hours) and the numbers above represent the error/accuracy of the entire 2.5 day period. Historical accuracy statistics can be found here.

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