Monday, May 29, 2017

Memphis in May-hem: 105 mph microburst damage in Frayser

WOW, that was quite a storm!

Memphis Light Gas and Water reports that, at peak, 188,000 customers were without power at some point after the monstrosity hit on Saturday night, darkening large portions of Shelby County. High wind also affected portions of Tipton and DeSoto Counties.

There will be more time to recap the entire event later, but in this post I'd like to focus on one particular area of damage where the highest wind likely occurred. The damage occurred at and around the Memphis Police Department Training Academy near the intersection of Highway 51 and North Watkins in Frayser. This is where the severe storm moving southeast intersected an outflow boundary moving southwest from storms that were occurring north of the metro.

It is typical for colliding outflow boundaries in an unstable airmass to produce new storms. We see it all the time. In this case, when pre-existing storms along one outflow boundary encountered the other outflow, mayhem resulted. What would have been a more "typical" severe wind event became a more rare one when explosive development produced a very strong microburst that landed on the area in question and spread out to the east and south, pushed by storms moving at near highway speeds. It is estimated from these damage photos, particularly the swath of trees that collapsed or were uprooted in the first image below, that wind speeds were near or exceeded 100 mph. This is corroborated by radar data that indicates wind of more than 100 mph just 1000' above ground in the hardest hit areas, which was likely forced to the ground by the microburst near the MPD Training Academy.

Wind that spread out from that area across north Memphis and south into downtown and midtown was likely in the 60-80 mph range. Aerial photo and radar documentation is shown below.

Aerial photo showing the classic ground signature of a very strong microburst, with a stand of trees collapsing under the weight of approximately 100 mph wind. You'll notice they all fell in roughly the same direction. Photo taken over US 51, northeast of  North Watkins.

Another angle on the above photo, annotated to show the path of the wind as it blew from northwest to southeast, fanning out slightly from a point where the wind came crashing down from above and spreading out in the path the storm was taking.


An aerial shot of part of the MPD Training Academy showing damage to structures and uprooting of large trees.

Additional damage from overhead in the area of US 51 and North Watkins.

Another view of the same damage shown in the image above.

One more photo, taken west of the MPD Academy showing trees uprooted and additional damage.

Wind velocity data from the Terminal Doppler Weather Radar (TDWR) south of Memphis International Airport detected wind speeds greater than 100 mph just under 1,000' above the US 51/Watkins area at 10:51pm. A rush of air loaded with very heavy precipitation likely resulted in that wind being forced to the surface in the form of a microburst, causing the damage seen above. Image credit: Kevin Terry, who was thinking fast enough to archive the event as it was occurring!
Full credit and many thanks to Casey Kirby of Memphis Police Department's Air Support Division for providing the full set of aerial photos exclusively to MWN!

The National Weather Service in Memphis has posted this preliminary assessment of the storm:



I'd also like to use this venue to re-post what I wrote on Facebook Sunday night after having a chance to wrap my head around the events of the night before:

It's easy to get frustrated, but the guys and gals at MLGW are working hard on their holiday weekend to try and make your day a little brighter (literally). Personally, I greatly appreciate their hard work and sacrifice, as well as all those in public service who are working extra this weekend, even though I don't have power yet either! 
Also, shout-out to all our colleagues in the weather enterprise, from SPC to US National Weather Service Memphis Tennessee to the TV mets and others, who did a phenomenal job leading up to, during, and after "Memphis in Mayhem!" 
Finally, I owe a huge debt of gratitude to MWN intern Meteorologist Alex Herbst who covered 95% of last night's event on my, and your, behalf. Between my working weather for 901Fest, racing home to beat the storm, then promptly losing electricity and most cell coverage when it hit, without Alex being on top of things the entire time, this feed would've been largely silent. I and MWN followers alike thank you for your dedicated service, Alex. You have a bright future ahead of you, at much larger endeavors than this one! 
Everyone stay safe, be grateful, and thank a utility worker this week! And don't forget it's Memorial Day weekend - take a minute to remember those who paid the ultimate sacrifice so that we can moan and groan over our #FirstWorldProblems
I appreciate each and every one of you who choose to follow MWN and tell others about this service...
Thanks again to all of you who have offered your appreciation for our presence before, during, and after the storm. Those comments keep us going!  We'll have a more detailed recap in the days ahead.  Be sure to follow us on social media at the links below for regular updates following this storm and updates on current weather in the Memphis area!

Best to you all on this Memorial Day,

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

Saturday, May 27, 2017

Details on today's storm potential, timing, and severe weather threats

3:55 PM UPDATE:

Late afternoon storms are not as organized as expected earlier today, with most widely scattered cells remaining north of the metro. Late evening storms are still on track with an ETA in the far northern metro after 8pm and closer to 9-10pm in the city and after 11pm in north MS. Primary threat remains high wind with a lesser threat of hail and an isolated tornado. An updated severe weather graphic can be found immediately below. Latest information will be on our social media feeds and app.




Severe weather remains a distinct possibility later today and tonight. Up until about 9am (as a few storms were sliding by safely to our north), I expected the only storms we would be dealing with would be an overnight complex (mesoscale convective system, MCS, is the technical term). As morning model data started coming in, particularly the hourly high-resolution data, it became clear that we would need to carefully watch the late afternoon hours as well.

There are some indications, albeit varied, that a cluster of storms in southern MO this morning would grow and take a similar path to the storms earlier this morning, but moving through a more unstable environment, they could build south into the metro by late afternoon to early evening. Thus, a change to the forecast to include that chance.

These storms, if they get this far south, will bring the possibility of heavy rain, some hail, and severe wind (60+ mph), as well as lightning of course. If you have outdoor plans, keep a close eye on the sky and your favorite weather sources and have a plan B!

The early "wave" of storms could also do a number on the potential for severe weather overnight. Though storms would still be expected, they could potentially be moving into a much less favorable environment for severe weather.

The arrival timing on overnight storms remains around 11pm-2am 8pm-2am (earlier north of Memphis, later south). If the atmosphere is unadulterated by prior storms, there is a good chance they could be severe with high wind, hail, constant lightning, and heavy rain that could cause localized flash flooding. In addition, a supercell storm embedded in a squall line could develop enough rotation to produce a brief tornado. If the overnight storms move into a more stable environment behind prior storms, the severe potential likely goes down, but the storms would still be expected to occur.

Here are the severe weather probabilities from the Storm Prediction Center:

Severe weather probabilities are for within 25 miles of a point. Those probabilities for Memphis are printed on the graphic. Hatched areas have decent probabilities of "significant severe" storms - very strong wind, large hail, or strong tornadoes.
To our north, in the Moderate Risk, we could see images tomorrow of widespread wind damage across a large area from southern MO into the MS/OH River conjunction.

Please stay tuned to our social media channels for the latest information. They are linked below. In addition, due to the possibility of overnight severe weather, we highly recommend you download the MWN mobile app if you haven't already, then add StormWatch+ Alerts and set them up for your specific location so that you can receive push notifications of impending severe weather for locations YOU are concerned about. Again, links below.

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

Friday, May 26, 2017

Memorial Day weekend fireworks, from Mother Nature

A perfectly lovely few days to end this week, and what looks to be another set of nice days early next week, will book-end a warm, breezy, and muggy Memorial Day weekend that will also feature storms that have the potential to be severe. Let's take the weekend day by day...

Today

The windiest day of the forecast, a strong southerly flow of air off the Gulf of Mexico will prime the pump for this weekend's activities. Humidity also increases as dewpoints rise into the mid 60s on wind that gusts over 30 mph at times this afternoon. Though we haven't reached 90° yet this year (the average first 90° day is May 24), today will be quite warm with highs in the mid to upper 80s. Clouds will also slowly increase this afternoon and evening, but don't forget the sunscreen anyway if you are headed to the pool or other outdoor locations to celebrate the end of the school year or the start of the first "honorary" weekend of summer!

Saturday

With a ton of outdoor activities going on, fortunately most of Saturday looks to remain dry. We're watching for the possibility of a cluster of storms forming and possibly affecting the metro during the morning hours. Those may or may not happen, but keep an eye out. If lightning strikes, jump out of the pool - yikes! Humidity continues to rise as dewpoints cross the sweaty 70° mark and wind remains somewhat gusty out of the southwest all day. Despite temperatures reaching similar levels to Friday, a good deal of instability in the atmosphere will be "capped off" by warm air aloft, preventing thunderstorm development. Can't rule out a stray shower, but most of the afternoon and evening will stay dry. Good news if you're headed for Memphis in May's 901Fest, the Memphis Redbirds game, etc.
Dewpoints over 70° are expected as far north as the Ohio River on Saturday afternoon according to this morning's high-resolution NAM model. That will make for a sweaty day with heat indices in the lower 90s. (PivotalWx)


Saturday Night

All weather folks' eyes are on the overnight hours Saturday night as a risk of severe storms exists. Areas north of I-40 are under an Enhanced Risk of severe weather (category 3 of 5), while areas along and south of the interstate are one category lower, a Slight Risk. To our north, a Moderate Risk (category 4 of 5) is forecast for areas north of Jonesboro to Dyersburg.

One or possibly two thunderstorm complexes will affect the metro, most likely anytime after midnight, though there is a risk starting about 10pm or so if the first round comes early. If you have evening plans Saturday, keep an eye on your favorite weather source(s) and be prepared to pack up and find shelter if storms come early. The threats associated with overnight storms are primarily torrential rain, dangerous lightning, high wind (above 60 mph), and possibly hail. A brief tornado also cannot be completely ruled out. Our severe weather outlook graphic is shown below. Storms will have a higher probability of severe weather north and west of Memphis, but could still pack a punch as they move into the metro.


Sunday

Most overnight storm activity should be done by about daybreak Sunday, however lingering showers or a stray thunderstorm are possible early in the day. Planning to run the Memphis in May Great American River Race? Dress for warm, muggy conditions and scattered showers as well as a breeze! The cold front that brings storm chances to an end doesn't arrive until Sunday night, so we expect rejuvenation of scattered storms as the atmosphere heats back up Sunday afternoon and evening. The metro is under a Slight Risk once again for severe storms capable of hail or damaging wind. All outdoor activities need a "rain plan B" on Sunday. It will remain humid as well with highs in the lower 80s and breezy southwest wind.  Rain chances diminish overnight Sunday night as the front moves through.

A Slight Risk of severe weather (category 2/5) exists Sunday as a cold front approaches by evening from the northwest. Storms are mainly possible during the PM hours with damaging wind and hail the main threats.

Memorial Day to mid-week

The holiday itself actually looks pretty pleasant! Rain will be gone, though high clouds are still expected. Under partly sunny skies, humidity falls and highs reach the lower 80s (which will feel much more comfortable than Sunday's lower 80s due to more pleasant humidity levels).


Tuesday also looks dry and warm with seasonal temperatures in the mid 80s. As we head into the middle to latter part of the week, a summer-like pattern takes hold with PM thunderstorm chances each day, highs in the mid 80s, and lows in the 60s.

The *NEW* GOES-East!

Yesterday, in conjunction with NOAA's Atlantic hurricane season forecast (more on that in a minute), the brand new (AMAZING!) geostationary satellite, GOES-16, was assigned a permanent spot over the eastern United States with full resolution of the western Atlantic and eastern U.S. It will go "operational" in it's new position in November if everything stays on track. Be sure to check out the first in a MWN Blog series on the technological "game-changer" satellite we published earlier this week.


Atlantic hurricane season forecast

Despite already having an "early-bloomer" tropical system in April this year (Arlene), the official start of hurricane season is next Thursday, June 1. Yesterday, NOAA released their forecast for the season, predicting that an above normal season is "most likely" this year. Here's the breakdown on what the federal meteorologists predict for the coming year:



Stay weather aware this weekend and be sure you are following us on our social channels below, as well as have StormWatch+ set to wake you if necessary, and only in the most urgent cases, on Saturday night. You can find it in the MWN app for iOS and Android. Links for more info and to download are below.

Have a safe Memorial Day weekend!

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

Wednesday, May 24, 2017

GOES-16: A Weather and Climate Game-Changer


Part 1 in a special MWN Blog series

When it comes to weather forecasting, meteorologists are often only as good as the technology and data they have access to. Perhaps one of the greatest leaps forward for the weather enterprise in the 21st Century is not even on this planet, but rather orbiting well above it. One satellite has the capability of changing how we see many facets of our atmosphere.

GOES-16, the satellite formerly known as GOES-R, is the latest and greatest in a long line of weather satellites placed into orbit by the United States. (Geostationary satellites use a letter designation prior to reaching orbit, then switch to a number once reaching orbit.) Launched back on November 19, 2016, the satellite has been undergoing a number of post-launch tests for the past several months. The plan is for GOES-16 to be providing its full suite of data and imagery in the coming month or so, with certification to be "fully operational" before the end of 2017. In the meantime, some non-operational or “unofficial” data is available, leaving many atmospheric scientists gawking and giving hope that this new generation of satellites will further expand our knowledge of weather and climate, both on earth and in space.

The GOES-16 satellite is equipped with many new pieces of technology that separate it from its predecessors. The Advanced Baseline Imager (ABI) is the "camera" that points towards earth and contains many more than 3 times as many imagery bands, or channels, as the current GOES satellites. Meanwhile, perhaps the most unique new tool aboard GOES-16 is the Geostationary Lightning Mapper (GLM), which will allow scientists to gain a new perspective of where lightning occurs via a sensing platform in geosynchronous orbit over the western hemisphere.

The GOES-16 satellite system has five unique instruments for sensing the environment, from space to earth. Three of those are for monitoring space weather and the other two (the Advanced Baseline Imager [ABI] and the Geostationary Lightning Mapper[GLM]) sense the atmosphere surrounding the earth. (Image courtesy: NASA)
Satellite data is incredibly valuable to meteorologists as it provides a unique perspective of our weather and planet. While ground-based instrumentation is important, that merely allow us to observe what is occurring at the surface, as with weather stations, or in the lowest several thousand feet of the atmosphere with radar. Satellite imagery, like visible, infrared, and water vapor loops, provides a top-down view of what is going on above us that cannot be gathered from other sources. The imagery from GOES-16 has also been greatly improved, providing more frequent updates, with higher resolution, that can be zoomed-in to focus on active weather phenomena.

A comparison of the full-disk imagery available from a current GOES satellite (GOES-13, right) and the new GOES satellite (GOES-16, left). (Image courtesy: NOAA/NASA)
Think of it this way. You are going to replace a digital camera that takes pictures with a resolution of 5 megapixels, but only every 5 seconds. The new camera you buy has 20 megapixel resolution and can snap a picture every second! That is a great improvement right? 4 times better resolution and 5 times faster! Now add in that your old camera had 5 filters that could be applied and your new one has 16. That's how GOES-16 compares to its predecessors!


So what makes this satellite so important for the future of weather and science? Those who study weather, climate, space, and other environmental factors have reached the limit of what can be observed with the current satellites that have been in existence for about 20 years. GOES-16 will provide a wealth of new, and very valuable, information for climate scientists, meteorologists, and other researchers for the next couple of decades. In fact, an identical satellite, GOES-17, will be launched into orbit in spring 2018. While GOES-16 will be moved into an orbit that best covers the eastern U.S. in the next several months, GOES-17 will take up the position over the western U.S. within the next two years to provide complete coverage of the western hemisphere with the new satellites.

With the fire-hose of  new data, we will be able to observe the atmosphere above us with greater precision than ever before. This allows for improvements in severe weather warning lead time, detection of flash flood threats and wildfires in remote areas, volcanic ash that is a significant hazard to air travel, quicker recognition of rapid changes in tropical cyclone strength, and even dust over the oceans that hinders their formation. As we learn how to use the wealth of GOES-16 data, it will become a vital tool for atmospheric scientists for years to come.



You can learn more about GOES-16 and the entire series of GOES satellites, as well as view additional imagery, by visiting the GOES-R website hosted by NOAA and NASA. We have already shared some very cool "preliminary, non-operational" imagery from GOES-16 on our social media channels, such as that shown above, and we look forward to bringing you much more in the coming months and years!

One of the early images beamed back to Earth from GOES-16 shows an oblique view of  our planet with the moon in the background. (Image courtesy NOAA)
This is part 1 in an MWN Blog series on GOES-R. Part 2 will provide additional details on the capabilities of the instruments aboard the satellite system, including all of the channels of information available via the Advanced Baseline Imager, and the Geostationary Lightning Mapper. Stay tuned!

Alex Herbst, Meteorologist
MWN Intern

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

Saturday, May 20, 2017

Cooler weather expected for the last week of May

It's been a while since I've blogged on local weather patterns. As you know, we have several other methods to get your daily dose of MWN, including our Facebook and Twitter feeds, full-featured website and mobile web, as well as our mobile apps for iOS and Android, though this is our vehicle for the most in-depth discussions. Honestly, May is unbelievably crazy and there just is precious little time to maintain the blog. That's why I'm thankful for people like MWN intern/meteorologist (or "little mets" as he has been known to reference the #TeamMWN interns) Alex Herbst who contributes here occasionally as well.

One reason why May is crazy busy - in fact the primary one - is MWN's contributions to Memphis in May. We are proud to be the official weather provider of the festival for the third consecutive year! That means that we have a presence on-site in the operations area in Tom Lee Park nearly every hour that the gates are open to the public, as well as providing ancillary forecasting services leading up to all events. It's time-consuming, but very rewarding to be part of an awesome team of staff and volunteers that make Memphis in May a huge success year in and year out! I'm also indebted to my loving and understanding wife (of 20 years this week!) and daughters, who I will have to reintroduce myself to this week! I'll have more on the Memphis in May experience in another post. In the meantime, let's turn our attention to weather for the week ahead.

Early week

A cooler week is expected across the region in the wake of a cold front that arrives early Sunday morning. Clouds diminish Sunday with a northwest wind ushering in cooler, drier air that results in highs only in the mid 70s. It should be a delightful day overall.

The surface map early Sunday morning shows a cold front just east of the metro with rain chances moving out and cool high pressure building in from the Plains. (NOAA/NWS)
Monday will be similar, with cooler morning lows in the upper 50s and highs back to the mid 70s. Clouds increase late Monday ahead of a reinforcing cold front that arrives Tuesday. Moisture will be fairly limited but scattered showers are expected on Tuesday with the front. I'm not expecting a rain out or any major threats. Highs will remain in the 70s.

The GFS forecast model shows about 1/4" or so of precipitation falling from Tuesday morning through Wednesday morning in the metro. (PivotalWx)

Late week

By Wednesday, a large trough of low pressure will occupy in Midwestern states with clouds and showers wrapping around it into the Mid-South. Rain chances are at least as good as Tuesday, if not higher, and it will be a breezy, cool day with temperatures mainly in the 60s.

A large upper level low pressure system, shown here by the GFS model at about 18,000' on Wednesday, will provide showers and cool weather for mid-week. (PivotalWx)

On Thursday, temperatures start to rebound as the trough lifts out. Abundant sunshine will end the week with highs back in the mid 70s Thursday and lower to mid 80s Friday and Saturday, as low temperatures moderate back to the 60s by weeks end. Find the complete forecast on our app or here.

Enjoy the cooler week ahead.  As we head into Memorial Day weekend, the heat typically starts to build (and this year appears to be no exception) and we'll be looking for ways to cool off!



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

Thursday, May 11, 2017

April 2017 Climate Data for Memphis, TN

April Recap

April continued playing from the same sheet of music as most other months over the past year.  Of the previous 12 months, 9 were in their respective top 10 warmest, with April 2017 ending as tenth warmest. Daily temperatures were above normal on all but 7 days last month. With respect to precipitation, April is typically wet and the month didn't disappoint, ending just shy of an average month at the airport and more than an inch above average at MWN in Bartlett.

April typically is about the peak of severe weather season in the Mid-South. The airport recorded thunder on 9 days, or about twice a week. Severe weather occurred in the metro on the 21st, 29th and 30th. On the 2nd, non-thunderstorm wind caused some damage to trees, while the other 3 days were thunderstorm-related. Flash flooding was reported in Covington on the 21st. On the 29th, thunderstorm wind produced some damage across the metro and hail fell in DeSoto County during the evening. The 30th saw severe storms in the morning that caused wind damage, some significant, in various places across the metro. Two specific cases were documented on our blog, in which severe wind uprooted trees in Bartlett. There were also multiple other reports of trees and power lines down across the area.

Photos of tree damage in Bartlett on April 30. Photo credits: Erik Proseus, MWN.

Memphis International Airport, Memphis, TN


Temperature
Average temperature: 66.6 degrees (3.7 degrees above average)
Average high temperature: 76.9 degrees (3.9 degrees above average)
Average low temperature: 56.4 degrees (3.5 degrees above average)
Warmest temperature: 88 degrees (29th)
Coolest temperature: 44 degrees (7th, 8th)
Heating Degrees Days: 57 (80 below average)
Cooling Degree Days: 114 (39 above average)
Records set or tied: None
Comments: April 2017 was the tenth warmest April on record.

Precipitation
Monthly total: 5.36" (0.14" below average)
Days with measurable precipitation: 13 (3.4 days above average)
Wettest 24-hour period: 1.06" (30th)
Snowfall: None
Records set or tied: None
Comments: None

Miscellaneous
Peak wind: Southeast/46 mph (3rd)
Average wind: 9.6 mph
Average relative humidity: 68%
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: 66.3 degrees
Average high temperature: 77.6 degrees
Average low temperature: 55.2 degrees
Warmest temperature: 88.0 degrees (14th)
Coolest temperature: 37.9 degrees (8th)
Comments: Data only covers the period April 1-23.

Precipitation
Monthly total: 6.72" (automated rain gauge through April 23, then additional rainfall recorded via manual gauge), 7.12" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 9
Wettest date: 1.54" (22nd) (via automated gauge)
Snowfall: None
Comments: Data only covers the period April 1-23, except the monthly total, which is accurate through the end of the month.

Miscellaneous
Peak wind: West/26 mph (5th)
Average relative humidity: 72%
Average barometric pressure: 30.02 in. Hg
Comments: Data only covers the period April 1-23.

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

MWN Forecast Accuracy

MWN average temperature error: 2.07 degrees
MWN forecast temperatures within 2 degrees of actual: 66%
MWN average dewpoint error: 2.42 degrees
MWN forecast dewpoints within 2 degrees of actual: 56%

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

Tuesday, May 9, 2017

Warm, Wet, and a Little Wild - Your Week Ahead for Memphis

May is officially here across the Mid-South and Mother Nature may have finally snapped out of her early spring funk. Warmer temperatures, sunny skies, and occasional rumbles of thunder are in the forecast for your week ahead. But not to worry, we start off this week by walking on sunshine.


Walking on Sunshine
After a chilly end to last week, temperatures have warmed up nicely across the metro to start the new work week. Expect that pattern to continue into Thursday with highs reaching the mid 80s, overall running about five degrees warmer than average. Gone are those chilly nights too, with lows this week mostly staying in the mid 60s.

What is keeping us warm here across the Southeast? A ridge of high pressure remains over most of the central United States, and with little movement out of a cut-off low centered in eastern Canada, the overall upper air pattern is pretty jammed up. This is the atmosphere's version of a traffic jam, though it resembles one more likely seen in Los Angeles or New York than Memphis (unless you happened to be westbound on I-40 out east this morning...).

The Mississippi River as observed in Memphis reached minor flood stage on Tuesday morning. It is expected to crest over the weekend.

The big weather story grabbing the headlines early this week around Memphis, however, is the mighty Mississippi River. The river reached flood stage of 34 feet early on Tuesday and is expected to keep rising slowly. It should peak at around 36 feet when it crests on Saturday. Most impacts are felt inside the levees on the Arkansas side of the river with farmland covered by water. It'll drop back below flood stage by the middle of next week as it slowly recedes.

Wet Weather Returns
By Thursday, the ingredients in the atmosphere get moving again, as an upper level trough digs into the Mid-South. This will bring the chance of showers and thunderstorms into Memphis by Thursday evening, with a marginal (1 out of 5) chance of these storms being severe. The rain chance continues to build into Friday morning, but most of the precipitation is expected to exit the region by mid-afternoon.

The Day 3 Storm Prediction Center (SPC) Convective Outlook shows a marginal (1 out of 5) chance of severe weather near Memphis on Thursday.

Second Verse, Same as the First?
Once the wet weather clears out of our area on Friday, the coming weekend may resemble much of what we saw to start off May. With sunny skies returning for Saturday and Sunday, temps will rebound from the cool off on Friday into the mid to upper 70s. It'll be a perfect weekend to go check out the International Salute to Colombia, all part of the Memphis in May festivities, as well as the Memphis Airshow, which has announced that not one, but TWO jet teams - the USAF Blue Angels AND the Canadian Forces Snowbirds - will be performing Saturday and Sunday in Millington!

Be sure to stay on top of all the weather this week around the Mid-South by checking us out on social media, following us on Facebook and Twitter. Also, download our app from your app store to keep tabs on our human-powered MWN forecasts. Enjoy your week, Memphians!

Alex Herbst, Meteorologist
MWN Social Media Intern

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

Thursday, May 4, 2017

Storm recap: wind damage in Bartlett, TN Sunday morning (4/30/2017)

As many folks were in worship services this past Sunday morning, a series of storms moved across the metro with high wind and torrential rain. Two in particular hit portions of Bartlett very hard with severe winds.

To set the stage, a great deal of rain fell over the previous week, including over 3 inches the previous weekend, another storm that dropped more than an inch mid-week, and finally another inch-plus over the weekend on which the storm damage occurred, leaving the ground saturated and vulnerable to falling trees in the high wind.

Early morning storm

The first round of strong storms in Bartlett occurred between 8:30-9:00pm.  Here's a radar loop that ends around 8:15, just prior to the storms reaching Bartlett.

Those storms produced straight-line wind that uprooted 5-6 mature trees, including the very large oak shown below, near and just southwest of the intersection of Billy Maher Road and Old Brownsville on the north side of Bartlett. No warning was in effect at the time.

An uprooted tree that fell at the corner of Billy Maher and Old Brownsville in north Bartlett during the 8:30am storm. There were several others in the same area that also feel during that storm. Photo credit: Erik Proseus.

Late morning storm

Behind that storm, another severe storm embedded in a larger area of heavy rain raced north at 55 mph through east Memphis and into Bartlett between 11:30-12:00pm. This storm was warned in advance for the likelihood of high wind. Here is the radar wind velocity loop from that storm, which shows the light blue colors (wind of about 60 mph) moving over Bartlett at 11:40am:
This storm cause more extensive damage. In fact, I was able to trace an approximate path based on fallen trees from Stage Road and Kirby-Whitten in the middle of Bartlett north to Old Brownsville Road east of Oak Road, a distance of nearly 4 miles. The map below shows the areas where fallen trees and damage occurred, with the most extensive damage on Broadway Street south of Shadowlawn Road, where 4-5 mature, large oak trees were uprooted. In addition, in the Easthill subdivision south of the Broadway damage, multiple large trees were also uprooted, including one that fell over a house, splitting it in two. Just south of the Easthill subdivision, in the wooded Bartlett-Ellendale Cemetery, one large oak tree was snapped off about 30 feet above the ground. Pictures of this damage are shown below.

An approximation of the wind damage path through Bartlett around 11:45am Sunday morning. Highlighted areas are where downed trees and/or damage was noted, with the direction they fell indicated by the arrows.

Photos taken of tree damage during the late morning storms in Bartlett. These photos were taken at Bartlett-Ellendale Cemetery, Easthill, Broadway Street, and Old Brownsville. Photos credit: Erik Proseus.
An analysis of the direction that trees fell (as shown in the map above) and the lack of damage to any structures other than those hit by falling trees indicates that the damage was likely the result of straight line wind, produced by a microburst (or perhaps multiple bursts). A microburst is produced by strong downdrafts from thunderstorms. The fact that the ground was saturated made it possible for lower than normal wind speeds to uproot the trees, although a couple of trees that were snapped well up the trunk indicate that there were some very severe winds in the storms.

Based on damage indicators and degree of damage used by the National Weather Service, in my estimation the straight-line wind associated with each event was likely severe (60 mph or stronger) with roughly 75 mph wind gusts required to uproot trees of the size that were toppled. The trees that were snapped off could have seen wind gusts of 80+ mph. This wind is equivalent to an EF-0 to low-end EF-1 rating had it been a tornado. However, there are no indications from my unofficial assessment that a tornado occurred in these cases.

Tipton County Tornado

Finally, I'll end with the official NWS survey of a tornado that occurred nearly at the same time as the early damage in Bartlett. An EF-0 caused minor damage in Covington, TN, in Tipton County. Here is the NWS survey report:
.Tornado in Covington Tennessee...

Rating: EF0
Estimated Peak Wind: 75 MPH 
Path Length /Statute/: 2.1 miles 
Path Width /Maximum/: 100 yards
Fatalities: None
Injuries: None

Start Date: Apr 30 2017
Start Time: 0846 AM CDT 
Start Location: 1.6 S Covington
Start Lat/Lon: 35.5403/-89.6447

End Date: Apr 30 2017
End Time: 0850 AM CDT
End Location: 0.9 ENE Covington 
End Lat/Lon: 35.5699/-89.6341

SURVEY SUMMARY:
Damage primarily to trees and power poles.
Minor damage to Crestview Middle School. 

Erik Proseus
MWN Meteorologist

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

Wednesday, May 3, 2017

Rain, rain, go away... it's Memphis in May!

It's Memphis and it's early May and that means Beale Street Music Fest weekend and "Memphis in Mud," right? Well, perhaps, but not because of rain during the festival this year! More on the weekend in a minute, but first we have to create some of that wet dirt!

Tonight through Friday

Low pressure is developing to our west and will track across the Mid-South over the next 24 hours. That certainly doesn't mean beautiful sunny weather, and indeed a rainy couple days are in store beginning this evening. As high pressure moves east, rain that has been threatening to cross the river all afternoon, but running into a figurative "wall," is now busting through, setting the stage for a wet night. A few claps of thunder are possible, but we're not expecting a major storm event.


By the early morning hours Thursday a cold front will arrive, setting the stage (note the subliminal music fest  reference) for a windy, cold, wet day as the low pressure system slowly inches its way through the region. Under the low, abundant cloud cover, showers, and cold air advection (meaning cold air is moving into the area) will hold temperatures nearly steady after the morning low in the mid 50s. Add in a northwest wind gusting to 25-30 mph and "feels like" temperatures will be in the 40s all day! That's roughly 30-35 degrees cooler than it felt today. You will definitely need to get the warm raincoats back out of the closet when you head to work or school in the morning!

Low pressure will move over the Mid-South over the next 48 hours, bringing rainfall, cold temperatures, and gusting northwest wind. Fortunately it departs by Friday evening (the last frame in the loop). Click here if image doesn't animate.


Thursday night will see continued showery weather with temperatures falling into the lower to mid 40s for lows by Friday morning. The wind will still be blowing, so expect it to feel like the 30s on the way out the door Friday morning. Ay caramba!, as they would say in the Memphis in May honored country of Columbia!


Any lingering showers will lift east of the metro during the morning as the low departs to the east, allowing for some sunshine to make an appearance by Friday afternoon and getting temperatures back up to the "cool" range in the 60s. Wind will still be gusty so keep that coat handy. Total rainfall amounts of an inch or so are expected.

Music Fest forecast

Friday night sees the opening of the gates for Music Fest weekend and though the rain will be done, it will be rather chilly with temperatures in the 50s, a breeze off the river, and - yes - some mud from previous days' rainfall. Cute boots that wouldn't be harmed by a little "use" are in order, ladies!


The weekend looks much improved. A warming trend is expected (though Saturday evening could still be a bit cool), wind dies down, and we'll see full sunshine both days, which will help with the mud situation. I'll be down at the river all weekend as the official weather partner of Memphis in May, keeping all of you, the staff, and volunteers, safe and comfortable. This weekend should be a pretty easy one, but they aren't all that way, as you well know!


Next week also looks great through at least mid-week if not longer as a broad area of high pressure settles over the central U.S., providing mostly sunny skies and more seasonal temperatures.

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