Sunday, January 19, 2020

Memphis, TN Annual Climate Summary for 2019

2019 Annual Recap

Memphis weather in the year 2019 will be remembered for some very wet months that led to one of the rainiest years on record, as well as fairly large temperatures swings month-to-month. Overall the year ended in the upper echelon of warm years with a 0.4 degree departure from average. Precipitation-wise, eight of the twelve months of 2019 were above average, three by more than four inches and one of those (October) setting a new monthly record. In sum, the year ended fourth wettest on record.


Month-by-month recap

The precipitation anomaly for the year started in month #1 as January recorded about 3/4" of rain above average. Temperatures also averaged a bit above normal. January also featured the only measurable snowfall for 2019, 0.2" on the 19th. The trend was more pronounced in February with warm and wet weather continuing. In fact, it was the eighth wettest February on record and featured three days with more than an inch of rain, one of those greater than two inches. The warmth early in the month, with multiple 70+ degree days was broken up by a couple of cold spells, but overall warmth. Heading into meteorological spring, the weather turned much cooler and drier relative to average. March averaged less than two degrees warmer than the preceding month with two-thirds of the days below average. Four inches of rain fell, but that is more than an inch below normal.

Heading into April, temperatures rebounded to near average while precipitation returned to above average status with almost eight inches falling for the month over eleven rain days. Heading into May, temperatures rose above average, including one record - a 73 degree low temperature on the 21st. In fact, for the second half of the month, not a single day had below normal temperatures. Precipitation was about where it is expected climatologically.

Summer was wet with the three months of June, July and August recording a total of over 21.5 inches of rain, or almost 10.5 inches above normal. June finished 5th wettest on record and July 11th wettest, while August was also above normal. Because of all the precipitation, summer was also, on average, cooler than normal. In fact, a record morning low of 62 degrees was set on July 25 - a rarity when summer mornings usually start at or above 70. August temperatures started to warm more as expected, but couldn't make up for the relative cool conditions in June and July.

Typically temperatures relax heading into September, particularly the latter half of the month, but 2019 was an anomaly as the month was the warmest on record. September typically is about seven degrees cooler than August. Not in 2019, as it actually ended 1.3 degrees warmer than the usual hottest month of the year! All but one day in September recorded a high at or above 89 degrees and there were 13 days with highs of 95 or higher, including the hottest day of the year - 100 on the 16th! Not a single day recorded below average temperatures. Part of the reason for the heat was a temporary drought that lasted throughout the month, with only 0.12" of rain for September, third driest on record.

The heat continued into the first week of October as the month started with three consecutive daily high temperature records (96, 97, and 98 degrees) before a very wet system moved through on the 6th and 7th, dropping nearly 4.5" of rain. Nearly the entire rest of the month featured below average temperatures and many more rain events. October set a record for wettest in history with almost 13" of rain, including another six and one-half inches in the last week of the month. Two daily rainfall records were broken during the month, putting the city more than 20 inches of rain above normal with two months left to go in the year.

Once the script flipped cold in mid-October, it continued into November with no days above average through the first 18. In fact, the cold was reinforced mid-month with two days featuring record lows (20 degrees on the 12th and 17 on the 13th) and a record cold high temperature of 30 degrees also on the 12th. In fact, snow flurries also occurred on both the 11th and 12th. Temperatures warmed the second half of the month, including a high of 70 on Thanksgiving Day. A decent amount of precipitation in the final third of the month brought the total closer to average, though still finishing more than an inch below a typical November.

Finally, December didn't cool off at all, with a monthly average temperature that was just shy of November's average and a mix of above and below normal days. Precipitation again finished below average with just over 4 inches recorded. Snow flurries also fell twice during the month.

A month-by-month summary of average temperatures and precipitation can be found below.


Severe weather

In 2019, the Memphis office of the National Weather Service issued 294 combined Severe Thunderstorm and Tornado Warnings in their service area (161 Severe Thunderstorm and 43 Tornado). It is notable that the combined warning number is the fewest issued by NWS-Memphis in the past 20 years (at least). The previous lowest was 250 in 2013. With respect to Severe Thunderstorm Warnings, the 161 issued were also the lowest in the past 2 decades, lower than the previous record of 213 in 2013. The 43 Tornado Warnings ranked eighth fewest in the past 20 years. Also in 2019, there were 13 Tornado Watches and 9 Severe Thunderstorm Watches issued by the Storm Prediction Center that included some portion of the Memphis service area.

The Mid-South recorded 26 tornadoes, most weak, during 2019. There were four EF-2 tornadoes, all in northeast MS, with the rest rated EF-0 or EF-1. Within the eight-county Memphis metropolitan area, there were four tornado touchdowns. Most notable was an EF-1 twister that hit southeast Memphis on October 21st. In addition, EF-0 tornadoes touched down in western Tipton County, northwest Marshall County, and southeast Tunica County. For the year, the NWS-Memphis office received 268 severe weather reports (convective) within their service area.




The following represents a statistical recap of the weather for 2019 in Memphis. Another recap of  weather across the Mid-South for 2019, produced by the National Weather Service in Memphis, will be published soon.

Memphis International Airport, Memphis, TN


Temperature
Average temperature: 63.5 degrees (0.4 degrees above average)
Average high temperature: 72.7 degrees (0.7 degrees below average)
Average low temperature: 54.3 degrees (0.4 degrees above average)
Warmest temperature: 100 degrees (September 16)
Coolest temperature: 17 degrees (November 13)

Heating degree days: 2899 (66 below average)
Cooling degree days: 2479 (221 above average)
Days at or above 90 degrees: 90 (25.7 days above average)
Days at or below 32 degrees: 46 (3.2 days above average)
Last freeze/first freeze: March 24-November 12 (233 day growing season)

Records set or tied: There was only one monthly average temperatures that placed in the top ten warmest or coldest on record. September was the warmest on record, averaging 83.5° and featuring three daily record high temperatures and an all-time record high temperature for the month. In all, seven daily warm weather records and four daily cold weather records were set in 2019. These included:
  • May 21 (73°, record high minimum)
  • July 25 (62°, tied record low)
  • September 17 (99°, record high)
  • September 18 (99°, record high)
  • September 27 (95°, tied high record)
  • October 1 (96°, record high)
  • October 2 (97°, record high)
  • October 3 (98°, record high and all-time October max. temperature)
  • November 12 (30°, record low maximum and 20°, record low)
  • November 13 (17°, record low)

Comments: After 2018 ended just a bit warmer than the 30-year climate average for temperature, 2019 ranked in the top 17% warmest (tied for 24th) in the 146-year historical record at Memphis. 90 days saw high temperatures at or above 90 degrees (tied for 11th most on record). 46 days experienced freezing or sub-freezing temperatures.

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.

Precipitation
Annual total: 73.65" (19.97" above average)
Days with measurable precipitation: 120 (12.3 days above average)
Days with 1"+ precipitation: 27 (9.6 days above average)
Wettest day: 3.39" (October 6)

Total Snowfall: 0.2" (3.6" below average)
Days with a trace or more snowfall: 8 (5.2 above average)
Days with 1" or more snowfall: 0 (1.2 below average)
Greatest snow depth (6am CST): 0

Records set or tied: The total precipitation for the year (73.65") ranks 2019 fourth wettest on record. The month of February (8.78") was the eighth wettest on record. The month of June (9.51") was the fifth wettest on record. The month of September (0.12") was the third driest on record. The month of October (12.95") was the wettest on record. Daily records included:
  • June 7 (2.80")
  • July 16 (2.28")
  • October 6 (3.39")
  • October 26 (3.01")

Comments: Overall, 2019 ended as the wettest year in the 148-year record in Memphis. 27 days recorded an inch or more of liquid precipitation; six days had more than 2" and two days recorded more than 3".


Precipitation accumulation for 2019 is plotted as the dark green line, compared with a normal year in brown. Precipitation climbed above normal early in the year (by mid-February) and remained well above average the remainder of the year. A wet summer and record wet October pushed the anomaly even higher as the year went on, ending 20" above average.

Miscellaneous

Peak wind gust: West / 67 mph (June 19)
Average wind: 7.6 mph
Average relative humidity: 70%
Average sky cover: 60%

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

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN


Temperature (data not available Sep 24-Oct 5)
Average temperature: 61.6 degrees
Average high temperature: 72.5 degrees
Average low temperature: 51.5 degrees
Warmest temperature: 100.1 degrees (September 16)
Coolest temperature: 14.6 degrees (November 13)

Heating degree days: 3329
Cooling degree days: 2131

Precipitation
Annual total: 61.31" (automated rain gauge), 68.05" (manual CoCoRaHS rain gauge)
Wettest date: 3.33" (April 13) (automated gauge)

Total Snowfall: 0.2"
Days with a trace or more snowfall: 5
Greatest snow depth: 0.2" (January 20)

Miscellaneous
Peak wind: South-southwest / 35 mph (March 9)
Average relative humidity: 78%
Average barometric pressure: 30.05" Hg

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

MWN Forecast Accuracy


Number of MWN forecasts produced and verified in 2019: 542
MWN average temperature error: 2.23 degrees
MWN forecast temperatures within 2 degrees of actual: 71.1%
MWN average dewpoint error: 2.04 degrees
MWN forecast dewpoints within 2 degrees of actual: 66.1%

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.

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

Friday, January 17, 2020

Sunshine on the way, but so is winter cold! First, a bit more rain...

It seems like ever time we look the forecast shows another day of soggy and warm-ish conditions. We have had over 5 inches of rain so far this January making our winter feel much more like spring! Thankfully good news is coming! Rain chances stick around Friday night and Saturday but a cold front moves through bringing sunny conditions back! Thankfully this cold front has very little instability ahead of it, so no severe weather threat (and probably not even any thunder)! Winter definitely returns with lows in the 30s and 20s, but wind chills in the teens by Monday morning. Rain chances do return late next week as another systems begins to take shape.



Friday and Saturday

Cloudy and cool for your Friday afternoon. A chance at a passing shower can't be ruled out but hopefully we can enjoy a mostly dry evening before showers move back into the area. Temperatures will fall slightly after sunset but begin warming ahead of the cold front during the overnight hours (we've seen this a few times this week now!).

Rain will begin late Friday night and continue into Saturday. Though rain chances do stick around, this system will not be a washout. Rain totals will be around a half an inch for most areas. Most of the rain activity will be out of the region by noon Saturday. Morning temperatures will be in the upper 50s but quickly drop off by late afternoon with the passing of the cold front. Overnight temperatures continue to fall towards 30 with some outlying areas seeing lows in the upper 20s Sunday morning.

The high-resolution NAM3 model forecast radar valid 12pm (noon) Saturday. (WxBell)
The high-resolution NAM3 model forecast temperatures valid 10am Saturday. (WxBell)
Sunday -Wednesday

Sunny and cold! Finally a day with zero rain chances! Sunday brings sunshine back into the forecast with afternoon highs only in the 40s. Winds shift out of the north creating very chilly conditions. Overnight temps fall into the mid 20s. Make sure to cover up any outdoor faucets and bring in any plants or animals. Monday will be our coldest day with temperatures struggling to stay above freezing and wind chills in the 20s all day. Sunshine and chilly temperatures stick around for Tuesday, but clouds begin to build back on Wednesday.

The GFS model forecast temperatures valid 8am Monday Morning. (WxBell)

Thursday - Friday

Warmer temperatures return Thursday as clouds continue to increase throughout the day. A few showers are possible but rain chances increase overnight. Friday rain returns ahead of another cold front into next weekend. Something to watch moving forward!


Paige Davide
MWN Meteorologist Intern

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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

Friday, January 10, 2020

Severe storms likely early Saturday morning - what to expect

[ Updated at 5:00PM - timing of storms, increasing flooding risk, updated graphics ]

A surface low pressure system with a connecting cold front is situated over north central Texas and southern Oklahoma. This low will deepen and dig toward Arkansas Friday night before it begins lifting out toward the northeast. Most of the models agree that the low will move right up the Mississippi River. This may serve to prolong the period of thunderstorms some, as the line will not move east as fast while the low pressure center is moving parallel to it. 

Detailed outlook for the metro

Thanks to a strong surface high pressure system situated to our east, winds are fairly strong and from the south. In fact, a  Wind Advisory has been posted for the entire area as gusts could reach 25-30 mph this afternoon and 30-40 mph tonight. This will allow abundant moisture from the Gulf of Mexico to reach the Mid-South. With abundant moisture and a strong front to lift the moist air, a line of convective storms will form ahead of the cold front in eastern Texas and propagate through northern Louisiana and Arkansas before crossing the Mississippi River into western Tennessee and Mississippi. The main concern with this event will be the squall line as most models show little in the way of discrete storms ahead of the line. Models have focused in on a potential severe weather window of 3:00-9:00am Saturday morning.




The high-resolution NAM3 model forecast radar valid from midnight tonight through 6pm Saturday gives us an idea of what to expect as the line crosses Memphis proper in the 5-9am window. (WeatherModels.com)


Flooding threat

Over the past couple weeks, we have received 1.5-3" inches of rain across the area. This means our ground is pretty wet and a Flash Flood Watch has been issued due to the expectation of additional heavy rain. Ahead of the line, showers are possible, which will only aid in saturating the ground. However, this system may produce 2-3" of rainfall by mid-morning Saturday. A significant concern with this event will be flooding. Low lying areas should be avoided or monitored closely to ensure your safety. It is especially important that you exercise extreme caution when driving at night in or after heavy rain. The condition of the roadways is difficult to gauge in the dark! Remember: Turn Around, Don’t Drown!

Straight-line wind threat

The wind energy associated with this system is very significant. With surface wind gusts over 30 mph and wind of 80-90 mph at just 5,000' above us, the stage is set for a potential damaging event as wind with this system could reach hurricane strength in spots. That means we may be seeing surface wind on the magnitude of 70+ mph! A Severe Thunderstorm Warning with winds this high should be taken as seriously as a Tornado Warning! Take action and take cover in an interior room on the lowest floor, away from windows, if a Severe Thunderstorm Warning is issued. With saturated ground, it won’t take much for trees or possibly power poles to be knocked over, so make sure to charge all devices are charging overnight to ensure you can still receive weather updates and other information if the power goes out.

Tornado threat

The tornado threat with this event appears to be limited to a low potential for spin-ups, however these cannot be ruled out. Higher tornado threats exist to our southwest in southern AR, northern Louisiana, and western Mississippi. However, with storms moving at highway speeds due to the magnitude of the wind, even a spin-up tornado can move very quickly. Be ready to act if a warning is issued!


We also highly recommend you have multiple ways of receiving warning information. That includes commercial TV and radio, NOAA Weather Radio, Wireless Emergency Alerts on your cell phone, as well as a configurable mobile warning app like SW+ Alerts in the MemphisWeather.net app. SW+ Alerts is a low-cost, highly-customizable method of receiving warnings for specific locations you program in. It will even wake you up for the most severe warnings overnight! Learn more and download the app at App.MemphisWeather.net.



After the storm

Despite all the excitement Saturday morning, Saturday afternoon looks much better! There may be trees down or power outages, but weather conditions themselves improve. A few straggling showers are possible and it will remain breezy, but clouds will begin to decrease into the evening hours with temperatures hanging out in the mid 50s during the afternoon before falling into the 30s overnight. 

Paige Davide
MWN Meteorologist Intern

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

Saturday, January 4, 2020

December 2019 Climate Data for Memphis, TN

December Climate Recap

Following one of the colder Novembers on record, the script flipped in December as a major pattern change over the U.S. resulted in very warm temperatures across the eastern 2/3 of the country, an area which had been well below average in November. The mid-month period featured relatively "average" temperatures, and even a couple of very minor frozen precipitation events. However, warmth to start, and especially end, the month set the tone. In fact, the week surrounding Christmas Day (Dec. 23-29) was one of the warmest such weeks on record. Overall, the month ended more than four degrees above average.

The U.S. temperature anomaly (departure from normal) for the month of December shows well above normal temperatures across much of the nation east of the Rocky Mountains, while predominantly below average temperatures were present in the western U.S. The pattern was nearly a completely reversal of November temperatures. (WeatherBell)
December precipitation typically averages just under six inches, being one of the wetter months of the year climatologically. In 2019, rainfall was fairly well spread out with no prolonged wet or dry periods. For the month, just over four inches fell. Thunderstorms occurred on the 6th and 16th, but no severe weather was reported, nor warnings issued. Heavy rain on the 16th prompted a Flood Advisory for the southern portion of the greater metro.

There were two minor winter precipitation events, both on the backside of rain events, on the 10th and 17th. Only a trace or sleet or snow was recorded on each day. The most impact-ful "cold weather" event though was a coating of black ice on elevated roadways the morning of the 18th, resulting in dozens of crashes and major bridges and overpasses shutting down until the ice melted. More on this heavy frost/black ice event can be found in this blog post.

Google traffic data from the morning of the 18th when black ice caused major issues city-wide.


Memphis International Airport, Memphis, TN


Temperature
Average temperature: 47.7 degrees (4.1 degrees above average)
Average high temperature: 56.7 degrees (4.6 degrees above average)
Average low temperature: 38.8 degrees (3.7 degrees above average)
Warmest temperature: 71 degrees (28th)
Coolest temperature: 26 degrees (11th, 18th)
Heating Degrees Days: 526 (139 below average)
Cooling Degree Days: 0 (2 below average)
Records set or tied: None.
Comments: Nine days recorded a low temperature at or below freezing, x.x days more than average for the month.

Precipitation
Monthly total: 4.04" (1.70" below average)
Days with measurable precipitation: 7 (2.7 days below average)
Wettest 24-hour period: 1.42" (16th)
Snowfall: Trace
Records set or tied: Record snowfall tied - trace (10th).
Comments: Two days had rainfall exceeding one inch. A trace of snow and sleet fell on the 10th and snow flurries fell on the 17th.

Miscellaneous
Peak wind: West/25 mph (29th)
Average wind: 7.0 mph
Average relative humidity: 73%
Average sky cover: 60%

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

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN


Temperature
Average temperature: 46.1 degrees
Average high temperature: 56.0 degrees
Average low temperature: 36.8 degrees
Warmest temperature: 70.1 degrees (25th)
Coolest temperature: 23.8 degrees (19th)
Comments: None

Precipitation
Monthly total: 3.69" (automated rain gauge), 3.99" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 11
Wettest date: 1.43" (29th) (via automated gauge)
Snowfall: Trace
Comments: A bit of sleet and snow fell on the 10th and snow flurries fell on the 17th.

Miscellaneous
Peak wind: West/32 mph (29th)
Average relative humidity: 81%
Average barometric pressure: 30.08 in. Hg
Comments: None

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

MWN Forecast Accuracy

MWN average temperature error: 2.41 degrees
MWN forecast temperatures within 2 degrees of actual: 67%
MWN average dewpoint error: 2.50 degrees
MWN forecast dewpoints within 2 degrees of actual: 61%

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

Climate Outlook - January 2020

The January climate outlook for the United States from the Climate Prediction Center is shown below. Above average temperatures are forecast for the southeast, spreading north towards the Ohio Valley and west into the Southern Plains. Below average temperatures are expected in the western U.S. Odds favor above average temperatures for Memphis, at 43% (versus only a 24% chance of below average temperatures). Memphis averages 41.2 degrees for the month.



Wetter than normal weather is expected for the Ohio and Tennessee Valleys into the Mid-Atlantic and southeast U.S., as well as the High Plains. For Memphis, odds favor above average rainfall (43% chance), which historically averages nearly four inches.

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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