April 2023 Climate Report for Memphis, TN

April Climate Recap

April ended cool and slightly wetter than normal in Memphis. Temperatures averaged almost two degrees below normal, driven more by below average high temperatures than below average low temperatures. The warmest day of the month actually ended up being early in April, when on the 4th, the average temperature was 18 degrees above average and a high temperature record was set at 87 degrees. Two days later, the high was 53 degrees! Temperatures returned to near average levels into mid-month. The last ten days of the month were much cooler than normal and drove the overall temperature for the month below average.

Precipitation occurred regularly throughout the April, but featured a few very wet days due to periods of thunderstorms, a few of which were severe. Two and a half inches of rain fell on the 5th-6th and nearly the same again on the 21st-22nd, accounting for all but an inch of the month's total. There were 11 rain days for the month, just above normal. Scattered wind damage occurred on the 1st, 5th, and 16th, while large hail fell in eastern Shelby County on the 27th.

Memphis International Airport, Memphis, TN

Temperature 

Average temperature: 61.3 degrees (1.9 degrees below average) 

Average high temperature: 70.8 degrees (2.6 degrees below average) 

Average low temperature: 51.8 degrees (1.2 degrees below average) 

Warmest temperature: 87 degrees (4th) 

Coolest temperature: 40 degrees (24th) 

Heating Degrees Days: 133 (3 above average)

Cooling Degree Days: 32 (44 below average) 

Records set or tied: Record high (87 degrees on the 4th)

Comments: No days dropped to freezing or below and no days reached 90 degrees.

Precipitation 

Monthly total: 6.38" (0.51" above average) 

Days with measurable precipitation: 11 (1.4 days above average) 

Wettest 24-hour period: 2.50" (20th-21st) 

Snowfall: None

Records set or tied: Daily record high - 2.37" (21st)

Comments: None

Miscellaneous 

Peak wind: West-northwest/52 mph (15th) 

Average wind: 8.9 mph 

Average relative humidity: 64%

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: 61.1 degrees 

Average high temperature: 72.8 degrees 

Average low temperature: 50.1 degrees 

Warmest temperature: 89.3 degrees (4th) 

Coolest temperature: 36.9 degrees (24th) 

Comments: None 

Precipitation 

Monthly total: 6.28" (automated rain gauge), 6.01" (manual CoCoRaHS rain gauge) 

Days with measurable precipitation: 12

Wettest date: 2.20" (21st) (via automated gauge) 

Snowfall: None

Comments: None

Miscellaneous 

Peak wind: South-southwest/32 mph (15th)

Average relative humidity: 65% 

Average barometric pressure: 30.02 in. Hg

Comments: None

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

 

MWN Forecast Accuracy

MWN average temperature error: 2.12 degrees 

MWN forecast temperatures within 2 degrees of actual: 65% 

MWN average dewpoint error: 3.05 degrees 

MWN forecast dewpoints within 2 degrees of actual: 53% 

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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Looking ahead to the Memphis in May #BSMF forecast

The times they are a changin'!  Here's a look at the temperatures anomalies (departure from average) for the past 10 days:

Temperature anomaly for the period April 22-May 21, 2023 (CDAS data via WxBell)

You'll notice the massive area of cold weather (relative to normal) that has encompassed the central and eastern U.S. Locally, it depicts temperatures that averaged about 8 degrees below normal for that 10-day period. We'll be transitioning out of that pattern over the next couple of days into something more akin to early summer as a large ridge of high pressure that was over the western U.S. shifts east. Here are the forecast temperature anomalies for Saturday through Wednesday, May 6-11:

The blue areas large turn orange (above average), while the western U.S. flips cool, as a large trough replaces the high pressure ridge out west, as it shifts east into the Plains. With average highs nearing 80 degrees this time of year in Memphis and lows near 60, above average means some of you who have wanted to see some 80s will get your wish! 

Weather pattern changing

With that warmth comes a significant increase in humidity as well, as dewpoints rise from the 30s (where they have been for several days) to the 60s, which is supportive of thunderstorms. And thus, an unsettled, warm, and humid forecast... just in time for the kickoff of Memphis in May's Beale Street Music Festival, back in Tom Lee Park for the first time in four years.

Enjoy the next couple of days as sunny skies and highs near 70 are expected Wednesday are followed by increasing clouds but still comfortable temperatures in the mid 70s Thursday. 

Opening day of Music Fest

On Thursday night, a warm front moves north with humid air trailing and encounters "northwest flow" at the upper levels. This upper air pattern, which often occurs in late spring and summer, allows thunderstorm complexes from the Plains to move southeast into the mid/lower Mississippi Valley. It appears that we may be in for one of those early Friday, perhaps arriving pre-dawn. This doesn't present as a very severe event, but showers and thunderstorms are likely Friday morning, especially along and north of the broader I-40 corridor, including all of northeast AR and west TN. 

The Tuesday morning European model forecast precipitation from Thursday afternoon through Friday afternoon shows an area of precipitation diving southeast across the Mid-South in "northwest flow." (WeatherBell)

It appears that once morning rain moves out/dissipates, we'll have a moderately humid and warm afternoon with highs in the upper 70s and dewpoints rising into the lower 60s. There will be chances of shower or thunderstorm redevelopment in the afternoon and evening, but rain chances look lower during Music Fest gate hours than they are earlier in the day. Pack your cute rain boots or throw-away flip-flops though - it's not called Memphis in Mud for nothing!

Weekend forecast

The weekend forecast is less certain from a specificity standpoint, but overall appears to be very warm, humid, and capable of producing additional scattered showers and thunderstorms, depending on the existence and timing of upper level disturbances that move through the early summer airmass. If you're going to the river for great music this weekend, monitor forecasts leading until then and be prepared for showers on short notice!

This general pattern looks to stick around into early next week as no big cold fronts are currently on the horizon to bring sunny spring weather back, at least that we can pinpoint right now!

Erik Proseus
MWN Meteorologist

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Beautiful spring weather may be interrupted by severe weather on Saturday

A cloudy and cool Easter weekend gave way into a pleasant early week for the Memphis Metro. As the weekend approaches, we prepare for our next round of rain and the possibility of severe weather that could disrupt some Saturday evening plans.

Thursday

A low pressure system is currently sitting over southern Mississippi, this will bring clouds and some passing showers in the afternoon to evening hours. Due to the positioning of the low pressure to our south, rain will be moving to the west, rather than its usual eastward motion, as it rotates counter-clockwise around the low. Despite the clouds and rain, temperatures reached the mid 70s for highs and will drop into the upper 50s overnight.

Visible satellite from Thursday afternoon shows the center of the low-pressure over southern Mississippi with western moving clouds over Memphis. (College of DuPage)

Friday

Clouds will begin to be more broken throughout the day on Friday as the low pressure to the south begins to weaken and moves off to the northeast. Temperatures will be warmer ahead of the next system with highs in the mid 70s and lows in the lower 60s.

Saturday

The Storm Prediction Center has placed the Memphis Metro in a Slight Risk (level 2 of 5) for severe storms on Saturday.

A level 2 out of 5 severe weather risk has been issued for Saturday. (SPC)

Highs temperatures nearing 80 and dewpoints climbing into the mid 60s will provide the fuel for this system, and a cold front moving across the great plains towards the east coast be the spark for these storms to start to form. Some prefrontal showers are possible in the morning. Due to the time difference between these storms and a line expected to move through, they will not have much of a limiting impact on the later storms. 

Isolated storms are possible in western Arkansas when they are first forming in the afternoon, but they quickly become linear over central Arkansas by late afternoon. As the storms approach the metro, they will lose daytime heating and some intensity. Once the line nears the river around midnight it should begin to break up, meaning that our Arkansas counties have a slightly higher chance of seeing some severe storms, but strong to severe storms are possible across the whole metro. The primary threats with this system will be strong winds, large hail, and locally heavy rainfall.

The high-resolution NAM model shows what the radar could look like from 5am Saturday to 1am Sunday. The line should begin to break up as it nears the river. (WeatherBell)

Sunday-Thursday

The front will be followed by clear skies and highs in the mid 60s. Skies will remain clear as temperatures build back into the 80s early next week before the next chance of rain near the end of next week

Carter Bentley
MWN Intern

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March 2023 Climate Report for Memphis, TN

March Climate Recap

Temperatures for the month of March in Memphis averaged 0.9 degrees above normal, though that departure was driven exclusively by overnight lows averaging more than two degrees above normal due to extensive cloud cover and precipitation. Those same conditions actually resulted in daytime high temperatures averaging below normal for the month.  March started out with highs in the 70's, followed by a cold front on the 8th that pushed highs into the 50's & even upper 40's by the 13th.  After a brief warm-up, another reinforcing front resulted in highs in the 40's and 50's from the 18th to 22nd and lows dropping into the mid 20's on the 19th and 20th, freezing many early blooming plants. Highs rose back above normal to the 60's to 70's for the remainder of the month, with lows in the 40's and 50's.

March's precipitation was almost three inches above normal and totaled nearly nine inches for the month. Overall, rain fell on almost half of the days during the month with a few rounds of severe weather mixed in as well. Over three inches of rain was recorded from the 1st to the 3rd.  Additional rain fell from the 8th thru the 12th, 16th-17th, 21st-22nd, and 1.6 inches fell on the 24th.  Light amounts fell from the 27th through the end of the month. Thunderstorms occurred on the 1st-3rd, 12th, 24th and 31st. Sporadic wind damage and flash flooding were reported across the metro on the morning of the 3rd and the evening of the 24th. Hail was also reported in northern Marshall County on the evening of the 1st. 

To end the month, a severe weather outbreak, producing multiple strong tornadoes from a small handful of supercell thunderstorms, affected the Memphis region on the evening of March 31. A total of 14 tornadoes touched down in the Memphis County Warning Area (CWA), which encompasses west TN, northeast AR, the Missouri bootheel, and north Mississippi. Three of these tornadoes were rated EF-3 and another five were EF-2. The graphic below summarizes their tracks.  More information from the NWS can be found here & in our recent blog post here.

Tornado tracks from March 31-April 1 in the NWS-Memphis county warning area

All NWS warnings issued and subsequent storm reports received for March 31-April 1

Memphis International Airport, Memphis, TN

Temperature 

Average temperature: 55.1 degrees (0.9 degrees above average) 

Average high temperature: 63.7 degrees (0.5 degree below average) 

Average low temperature: 46.4 degrees (2.1 degrees above average) 

Warmest temperature: 79 degrees (23rd & 26th) 

Coolest temperature: 25 degrees (19th & 20th) 

Heating Degrees Days: 318 (34 below average)

Cooling Degree Days: 20 (2 above average) 

Records set or tied: None

Comments: Five days dropped to freezing or below. A cold snap mid-month, with lows of 25 degrees on both the 19th and 20th, was damaging to early growth on plants. However, the last spring freeze of the season occurred on the 20th, only two days later than average.

Precipitation 

Monthly total: 8.67" (2.93" above average) 

Days with measurable precipitation: 14 (3.5 days above average) 

Wettest 24-hour period: 2.04" (1st-2nd) 

Snowfall: None

Records set or tied: None

Comments: None

Miscellaneous 

Peak wind: West/38 mph (24th) 

Average wind: 9.5 mph 

Average relative humidity: 66%

Average sky cover: 56%

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

 

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN

Temperature 

Average temperature: 54.0 degrees 

Average high temperature: 64.6 degrees 

Average low temperature: 44.2 degrees 

Warmest temperature: 83.5 degrees (26th) 

Coolest temperature: 26.1 degrees (14th) 

Comments: None 

Precipitation 

Monthly total: 8.25" (automated rain gauge), 7.75" (manual CoCoRaHS rain gauge) 

Days with measurable precipitation: 15

Wettest date: 1.63" (24th) (via automated gauge) 

Snowfall: None

Comments: None

Miscellaneous 

Peak wind: 33 mph (occurred twice - from the northwest on the 24th and south on the 31st)

Average relative humidity: 69% 

Average barometric pressure: 30.05 in. Hg

Comments: None

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

 

MWN Forecast Accuracy

MWN average temperature error: 2.13 degrees 

MWN forecast temperatures within 2 degrees of actual: 67% 

MWN average dewpoint error: 2.13 degrees 

MWN forecast dewpoints within 2 degrees of actual: 64% 

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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Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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Meteorologist Erik Proseus is an NWA Digital Seal Holder

Recap of the March 31, 2023 tornado outbreak in the Memphis area

A severe weather outbreak, producing multiple strong tornadoes from a small handful of supercell thunderstorms, affected the Memphis region on the evening of March 31-April 1. A total of 14 tornadoes touched down in the Memphis County Warning Area (CWA), which encompasses west TN, northeast AR, the Missouri bootheel, and north Mississippi. Three of these tornadoes were rated EF-3 and another five were EF-2. The graphic below summarizes their tracks.

Within the eight-county Memphis metropolitan area covered by MemphisWeather.net (MWN), there were four tornado paths. Detail on each of these is summarized below. More detailed information from NWS-Memphis on all 14 tornadoes can be found here.  

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Cross/Crittenden/Tipton County Tornado

Rating:                 EF-3

Est. Peak Wind:   150 mph

Path Length:        73.00 miles

Path Width (max):   1600 yards (0.91 miles)

Fatalities:             4

Injuries:               26

Start Time:           4:30pm

End Time:            5:54pm

Approx. Speed:    52 mph

Summary:

The "Wynne Tornado" touched down in western Cross County, AR at 4:30pm, spawned by the same supercell thunderstorm that resulted in tornado damage in North Little Rock earlier. The storm moved quickly east-northeast across Wynne with EF-3 strength, ravaging Wynne High School and destroying multiple residences. Slightly weaker, it passed north of Earle, AR (Crittenden Co) and crossed farmland before regaining EF-3 strength as it crossed Corna Lake in far western Tipton Co (west of the Mississippi River) before crossing the river and producing EF-2 damage in Wilder Farms (Tipton Co), eventually lifting near Burlison.

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Tipton/Haywood County Tornado

Rating:                 EF-3

Est. Peak Wind:   150 mph

Path Length:        39.53 miles

Path Width (max):   2000 yards (1.14 miles)

Fatalities:             1

Injuries:               28

Start Time:           5:48pm

End Time:            6:29pm

Approx. Speed:   58 mph

Summary:

The "Covington Tornado" originated from the same supercell thunderstorm as the Wynne tornado, and touched down six minutes before the Wynne tornado lifted, meaning the supercell produced twin tornadoes for that six-minute period over Tipton Co. This tornado touched down at 5:48pm just northwest of Munford and moved quickly northeast while increasing in strength as it approached Highway 51 south of Covington. Several homes and businesses were completely destroyed and many more were significantly damaged. Fifty-three power poles had to be replaced along Highway 51 south of Covington. The elementary and middle schools sustained heavy damage, as did additional homes along Highway 54. A couple of large metal power poles were bent to the ground as the tornado widened to a mile in width as it moved across rural area east of Covington. It continued east-northeast across farmland and Hatchie River wetland before weakening and eventually lifting north of Brownsville in Haywood Co. 

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Tunica/DeSoto County Tornado

Rating:                 EF-2

Est. Peak Wind:   130 mph

Path Length:        22.87 miles

Path Width (max):   1200 yards (0.68 miles)

Fatalities:             0

Injuries:               0

Start Time:           7:31pm

End Time:            8:02pm

Approx. Speed:   47 mph

Summary:

The "Prichard-Nesbit Tornado" touched down just northeast of the Tunica airport, moving northeast, mainly through rural areas of Tunica and DeSoto Co. Snapped and uprooted trees were observed in Tunica and southwest Desoto county.  Roof damage occurred after passing thru the Arkabutla bottom, with extensive tree damage and damaged or destroyed homes noted west of Highway 301.  Between Baldwin & Fogg Rd there was EF-2 damage and the tornado dissipated southwest of Nesbit.

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Marshall County Tornado

Rating:                 EF-1

Est. Peak Wind:   95 mph

Path Length:        8.13 miles

Path Width (max):  100 yards

Fatalities:             0

Injuries:               0

Start Time:           8:27 pm

End Time:            8:37 pm

Approx. Speed:   50 mph

Summary:

An EF-1 tornado touched down in Marshall county west of Highway 311, moving northeast before dissipating about ten minutes later northeast of Slayden. Primary damage was to hardwood trees that were snapped or uprooted, while one home also sustained roof damage.

Shelby County Damaging Wind

Finally, MWN surveyed the Sea Isle area of southeast Memphis, near I-240 and Mt. Moriah Road leading into the area of Quince and Estate, as well as American Way between Getwell and Mt. Moriah Roads. Over this large area, many mature hardwood trees were uprooted or had large branches snapped by strong wind. Trees were observed to have fallen on houses, vehicles, and power lines/poles, resulting in additional damage and thousands of customers without power. Near American Way and Getwell, a high-voltage transmission tower was bent over (though a photo of the tower prior to the storm suggested that it may have had preexisting damage that had weakened the structure). In addition, there were three fatalities, including two children, due to a tree falling on their home on South Edgewater Road in the area of Memphis International Airport.

Given the scattered nature of the damage and no "ground path" observed, the damage was due to straight-line wind on the edge of a strong supercell that moved by just to the east of this area into Germantown. The National Weather Service and NEXRAD radar corroborates that this damage was caused by up to 85 mph wind generated by the "forward flank downdraft" of the supercell.

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
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A windy and stormy Wednesday ahead - details on potential threats

After severe storms have battered the Southeast for the past two weeks, we unfortunately have another severe risk this week. Today, we will warm up into the mid-80s with mostly cloudy skies as the warm sector takes over. The severe threat today clips the metro, but will stay to the northwest mostly, with our threat moving in tomorrow. After last Friday's severe weather, any preparations need to be made ahead of time, especially for areas impacted by the last storm system. The worst of this system appears to be well north of the Mid-South, but we are still in a heightened severe weather risk zone.

Overview

A strong storm system is going to be moving across the country, causing severe weather to impact millions from the Great Lakes to the Gulf Coast. Most of the northern metro is under an Enhanced Risk (Level 3/5) Wednesday with the southern half mostly in a Slight Risk (Level 2/5). This can still change as we get closer to the event. This means that severe weather is possible to likely in the area, but that does not necessarily mean your exact town will see severe weather. The timeframe for our biggest concern is looking to be early afternoon into the evening, with more specific timing as we get closer to the event. Some pop-up showers and storms are possible ahead of the main threat too, which could play a factor into the instability, or the storm fuel that is required to produce severe weather.

Tornado Threat

The Enhanced and Slight risks can be broken down into threat by severe weather type, including tornadoes, damaging winds, and hail. Starting with the tornado threat, compared to the last few events the threat for tornadoes is lower than last week, but still present. Our area lies between the 2% and 5% risk for tornadoes, meaning that the threat for tornadoes is low, but one could still spin up with any storms that become severe. Any showers and storms during the day before the main threat could keep instability in check, which could help limit the threat.

Tornado risk for Wednesday (NOAA/SPC)

Damaging Wind Threat

While the tornado threat is in the lower side, this is looking to be more of a damaging wind threat for our area. Outside of storms, we could see gusts above 30 mph during the day with higher winds aloft. The metro lies mostly in the 30% risk area, which is the chance of seeing 60+ mph winds within a 25 mile radius of a location. The southern half of the metro lies within a 15% risk area. Any storm that becomes severe will be capable of damaging winds as broken storms move arrive during the afternoon and more of a squall line in the early evening hours. Power outages and wind damage will be possible so make sure any loose objects are to up and secure.

Damaging wind risk for Wednesday (NOAA/SPC)

Hail Threat

Most storms that become severe do have hail potential, and so we do have a hail risk for tomorrow's event. Our hail threat is not as high as northern states impacted by this same event, but we do have a 15% chance of hail within 25 miles of a location. Along with a hail threat, we also have a threat for minor flooding during the afternoon and evening as 1-3” of rain is possible. Avoid low-lying areas and roadways and do not drive through flooded areas.

Hail risk for Wednesday (NOAA/SPC)

Summary

Timing: early afternoon into the mid-evening

Overall threat: Enhanced (level 3/5) (west TN, northeast AR) to Slight (level 2/5) (north MS)

Tornado risk: 2-5% within 25 miles

Wind risk: 30% within 25 miles

Hail risk: 15% within 25 miles

Preparation

Use today and Wednesday morning to prepare for potential severe weather. That includes being ready to use your safe place if necessary, having outdoor items secured, and having multiple ways of receiving weather warnings, including LOCAL TV/radio, NOAA Weather Radio, Wireless Emergency Alerts on your phone, and a reliable weather warning app, such as StormWatch+ that is programmed ahead of time.

Kailah Gordon
MWN 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
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Another Friday night, another elevated severe weather threat...

One week ago - last Thursday - we were preparing for a Friday night special, a Moderate Risk zone that extended from Memphis into Mississippi. While Memphis escaped the worst of that system, many in north Mississippi cannot say the same. It's Thursday again, and like last week, another severe weather event is lining up for Friday night. This time it appears to be aiming a bit further north. While no two weather events are alike (and this one is a different scenario than last week), it does serve to remind us that we are now into the grips of "The Pollening" season, a.k.a. spring severe weather season. So let's chat about tomorrow night.

Overview of Friday's severe weather threat

The potential for severe weather tomorrow night has been monitored by the Storm Prediction Center and local meteorologists since Monday. As of today, the event has come into better focus and the more general global models have "handed off" the details to the higher resolution models that provide additional clarity. The risk level has accordingly increased to the point where the Memphis metro is now in a level 4 (of 5) Moderate Risk for severe weather. This means that severe weather somewhere in the area is likely, not necessarily in your neighborhood, but probably within the greater metro somewhere. The timeframe of most concern for big storms is 4pm-midnight Friday. A few thunderstorms of the more general variety, and more than likely some showers, are possible during the day. These may play a role in the ultimate outcome in the evening in fact.

Tornado threat

The Moderate Risk can be broken down by severe weather type to provide additional information on the probability of specific threats. Starting with the tornado threat, we have a 15% risk of tornadoes within 25 miles of any location in the metro. In addition, there is a 10% chance of a strong tornado (EF-2+) within 25 miles. This threat level drives the overall Moderate Risk for the event, as it is certainly elevated and worth preparing for... just in case. There will be plenty of strong wind and "spin" (or shear) in the atmosphere to support rotating storms if they can get going. However, as the Memphis NWS stated this morning in their discussion, "...this system is not a slam dunk. One potential area for failure is the presence and duration of Friday morning showers." As mentioned in the paragraph above, early-day precip could limit the storm fuel available later in the day, reducing the severe weather risk locally. This will bear watching, as it certainly contributed to a reduction in instability last Friday night north of the MS/TN state line.

Damaging wind threat

In addition to the tornado threat, the more likely scenario is a damaging wind event. As mentioned, there will be a LOT of wind energy with this system, from the surface up. Wind gusts outside of storms tomorrow afternoon and evening could easily top 40 mph and the winds aloft will also be screaming, contributing to storms moving at highway speeds once they form. The wind risk is 30%, which is the chance of 60 mph or higher wind gusts within 25 miles. In addition, there is a 10% risk of 75 or greater mph wind. I would expect that any storm will be capable of damaging wind, and it's likely that we will have a broken to solid line of storms move through in the evening hours, which could lead to widespread power outages and wind damage. If it's outside and not very secure, you risk losing it in the storms.

Hail threat

Most severe storms are capable of hail, and that risk also exists tomorrow night, though it is not as elevated of a risk as wind, at 15% chance within 25 miles. While large hail is not a major threat, it is also something to keep in mind. Rainfall for the event is also expected to be in the 1-2" range. Minor flash, urban, or stream flooding is possible during the evening hours. As always, you know to turn around and don't drown. Avoid the low-lying areas and roadways that are prone to holding water during and immediately after heavy rain.

SUMMARY

Timing: 5pm-11pm Friday

Overall Threat: Moderate Risk (level 4 of 5)

Tornado Risk: 15% (10% chance of an EF-2+) (level 4 equivalent)

Wind Risk: 30% (10% chance of 75+ mph) (level 3 equivalent)

Hail Risk: 15% (level 2 equivalent)

Flooding Risk: 15% (Slight Risk - level 2 of 4)

Preparation

Be prepared to execute your severe weather plans anytime after 5pm Friday. That includes being ready to use your safe place if necessary, having outdoor stuff secured, and having multiple ways of receiving weather warnings, including LOCAL TV/radio, NOAA Weather Radio, Wireless Emergency Alerts on your phone, and a reliable weather warning app such as StormWatch+ that is programmed ahead of time. Storms will be moving quickly so lead time could be reduced. 

Once the final line of storms moves through late in the evening, the severe weather risk ends. Fortunately it won't be too deep into the night when that occurs. We'll provide routine updates via our social media channels shown below throughout the event to keep you informed and safe!

Also, once this threat passes, know that there is another severe weather risk next Tuesday. We'll take them one at a time!

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

Details on severe weather threat for Friday evening (March 24)

A severe weather  outbreak is expected late this afternoon and evening across the Lower Mississippi Valley. The Memphis metro is on the northern edge of where the strongest storms will be possible. This blog post will go into the details, and is effective as of 11:30am Friday. Note that the severe weather outlook graphic (embedded in the slide above) will be updated a couple more times today. This blog will likely not. I don't expect a lot of change, and even if the "lines" on the outlook move a bit. The threats and your response should really not change.

Atmospheric setup

The setup for this event is a developing low pressure system that will move southwest to northeast across Arkansas this afternoon and evening, dragging a cold front with it. Very strong wind fields will result in plenty of energy for this system to tap into. Turning of those winds with height will mean there will also be plenty of wind shear to result in strengthening and maintenance of storms once they develop. Instability, particularly once you get north into west TN, will be a factor to watch. It will not be as high as areas to our south where better chances of tornadoes exist. All of these factors will be maximized during the evening hours (6pm-midnight or so). Let's look at the individual storm threats.

Damaging wind

This will be our main threat tonight. There is a 30% chance of severe wind (roughly 55 mph or higher) within 25 miles of you location. There is also at least a 10% chance of 75 mph wind, shown by the black hatched area in the graphic below. We WILL get a squall line that will move through the metro. That is most likely in the 8-10pm timeframe for Memphis (earlier west, later east). High wind will be likely, some gusts could reach hurricane force.

Tornadoes

Tornadoes will be a secondary threat. There are two areas these could develop. First, in supercells that form ahead of the line (after 6pm). These are most likely in MS and northern LA, but they'll move rapidly northeast, towards southwest TN. The threat for these is higher to our south, in the MS Delta, where instability is expected to be highest. Secondly, in the squall line itself, where tornadoes could "spin-up" within the line. There is more than enough shear for this to happen, and they could also be strong, but would not likely last very long. The chance of occurrence in 10% for west TN and northeast AR and 15% in the southern metro and further south. The entire area also has a 10% chance of an EF-2 or stronger tornado due to the strong wind shear expected.

Large Hail

Large hail is the least of the the three main threats. There is about a 10% chance of occurrence for all of us. Hail would be most likely in any supercells that form (again, mainly in north MS), thus there is also a 10% risk that hail could be 2" in diameter or larger in the more unstable air south of Memphis (black hatched area below).

Flash or urban flooding

There will be a LOT of water falling in a short period of time this evening. Atmospheric moisture levels are very high. So, flash flooding is possible, small creeks and streams will rise, and low-lying areas in the concrete jungle will likely become hazardous. The NWS has placed the northern half of the Mid-South in a moderate risk (3 of 4) for excessive rainfall that could lead to flash flooding, while the southern half is in a Slight Risk (2 of 4). Rainfall amounts will easily exceed an inch in a few hours, and could approach 2-3" north of I-40. Turn around, don't drown!

Limiting factors

We've had questions about whether the morning rain that dropped south to about the state line, along with a cooling north breeze and lower dewpoints, would limit the severe potential this evening. I say "probably not." 

Radar loop from 9:30am Friday, showing the rain-cooled air dropping south. The warm/moist air is poised just to the south of that area where rain fell and will move back north this afternoon.

The strong southerly wind and higher dewpoints are only a couple counties south of us. As the low forms and starts moving northeast, it will drag that warmer and more unstable air back to the north. By this evening, we'll likely be right back where we were forecast to be by the models, which leads to the setup described above. The northern areas of the metro and places north already had a slightly lower risk of severe storms, and especially supercell storms, than places to the south. That really doesn't change. So I think the current severe weather outlook from SPC (first image above) factors all of that in. It will definitely be something we watch though! If instability does not rise as expected in west TN, perhaps it will slightly limit the severe threat. Let's prepare for the worst and hope for the best though!

Prepare

It's time to finalize your plans for this evening. Be where you know you can get to shelter if need be and be ready to act quickly. Storms will be fast-moving. Expect a line of storms with high wind between about 8-10pm. Make sure stuff outside is tied down. Know the counties around you and stay weather aware so you know when it is getting close. Finally, have multiple ways to get warning information, as any one could fail in severe weather. We recommend a NOAA Weather Radio, local TV outlets, Wireless Emergency Alerts on your smartphone, and a more customizable app option, such as our StormWatch+ app for Android and iOS. Of course, keep those devices charged today! Power outages are expected tonight.

Erik Proseus
MWN Meteorologist

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One more round of rain, then an early spring freeze for some

As we sit here on the tenth of March, most are tired of rain. Despite February actually ending a bit below average for precipitation, more than 1 of every 3 days of the month saw rain fall. January recorded more than double the usual rainfall for the month. And for the first third of March, rainfall has reached 75% of the usual amount for the entire month... and the next system this weekend could push us to near 100% of normal before the month is half over! 

We've also gotten used to above average temperatures. December-February (meteorological winter) was the 7th warmest on record, and not a single day in March has been below average, though the past couple have been right at it. Trailing the rain this weekend, a cold snap is also coming. Let's dive in... first a reminder that you lose an hour Sunday morning, but at least the sun remains up past 7pm next week! 

First, more rain, and a few storms

Today is a nice break from the rain the past few days, but it is temporary (so enjoy it!). Temperatures are cool in the 50s, and will be that way tomorrow too. But at least we do have some sunshine between the clouds today. Clouds return early tomorrow and we'll start the day in the upper 30s - the coolest morning in about three weeks! Rain showers return ahead of an approaching cold front by Saturday afternoon. Not a washout, but scattered throughout the afternoon with an isolated thunderstorm also possible. 

The Friday morning run of the high-resolution NAM model forecasts rain to begin Saturday afternoon and continue through mid-morning Sunday, at least. A few storms are also likely in the pre-dawn hours Sunday.  (WeatherBell)

By Saturday night, rain and thunderstorm chances quickly ramp up with the front due in early Sunday morning. A few storms ahead of the front early Sunday morning (pre-dawn, but after midnight) could sport gusty wind and hail, mainly in the Mississippi Delta. The city of Memphis is currently in a level 1 (Marginal) severe weather risk, but a level 2 (Slight) risk is posted just south of the city along the Mississippi River.

Overnight rain transitions to scattered showers Sunday morning into the early afternoon, mainly in north MS. Forecast rainfall is around an inch, a bit more in north MS. Clouds stick around in the afternoon before clearing out late in the day or evening. 

After the rain, prep for a potential late-season freeze

Behind Sunday's front, cold high pressure begins to build into the central and eastern U.S. for the coming week. We'll be on the southern fringes of this Canadian airmass, but it is cold enough that we'll feel its effects for multiple days! 

The Friday morning European model forecast for mid-day Tuesday shows cold high pressure sprawled across the Midwest with an influence all the way to the Gulf Coast. An active pattern continues on the west coast while a Nor'Easter brings snow to the major metros in the Northeast. (WeatherBell)

Sunshine will be abundant to start the week but look for highs to only reach around 50 degrees Monday and Tuesday. Low temperatures Monday through Wednesday mornings will be in the 30s throughout the metro. The potential for damage to early season foliage will be highest Tuesday morning when skies are clear and wind dies down, allowing temperatures to drop below freezing for a few hours outside the city (especially in west TN and northeast AR), and possibly touch freezing inside the city limits. Widespread frost is likely in all but the warmest locations. Wednesday morning could see another freeze mainly east of the city in west TN, but likely frost for all once again. 

The European model ensemble shows the probability of below freezing temperatures on Tuesday morning - near certain for areas surrounding Memphis in all directions except south, and not to be discounted in Memphis proper. (WeatherBell)

As the Canadian high shifts east, temperatures will warm on southerly wind Wednesday afternoon, back to near 60. Of course, with a few days of dry weather, you have to know more rain is not far off! At this time, we're monitoring Thursday night into St. Patrick's Day for the next cold front and rainmaker. Behind this one? NOAA's Climate Prediction Center believes there remains a decent chance of below average temperatures. Perhaps March will be the counterweight to the warmth of the past few months?

The temperature outlook for March 18-24, following the cold front late next week. It is fairly rare to see below average temperatures predicted for nearly all of the CONUS. (Not shown, precipitation is also favored to be slightly above average locally.) (CPC/Pivotal Weather)

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
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MWN is a NOAA Weather Ready Nation Ambassador

Meteorologist Erik Proseus is an NWA Digital Seal Holder