MWN Lightning Round: awesome local weather, a west TN quake, KMEM is StormReady, and a note on T.S. Erika

Decided it would be a good idea to hit a few topics all at once today, so here comes another edition of the MWN Lightning Round!

Awesome weather week

I don't know many people complaining about this week's weather. For late August, you can't be disappointed with morning lows in the 50s for many, afternoon highs in the mid 80s, abundant sunshine, and low dewpoints! We have one more day to copy/paste that forecast, then humidity starts creeping back up as wind shifts back to the south.

By this weekend, we'll be back to "near normal" for this time of year - lower 90s afternoons, lower 70s morning, and a little more humidity. The good news is there still is no appreciable rain chance in the 7-day forecast. Looking further out, NOAA thinks the first 10 days or so of September will feature slightly higher rain chances and above normal temperatures (which means 90s). Don't worry, this week's weather will be back before long! Fall is not too far away!

Temperature outlook for September 3-9, 2015, which shows a 70% probability of above average temperatures in the metro during this period. Summer may not quite be done!

Tipton County Earthquake

Tuesday morning at 8:26am, a magnitude 3.5 earthquake struck the Mid-South, centered a few miles north of Covington in Tipton Co. There were many reports of people feeling the tremor, especially north of the metro, including Lauderdale County. Fortunately, it was too weak to cause damage, but it is a good reminder that the New Madrid fault lies very near the area. For those of you who saw our post on Twitter and Facebook (below) and shared, commented, or liked it, thanks. It was all in good fun (especially since there were no major ramifications). The post went viral with over 100,000 views in 24 hours (and climbing). :-)

We stand with Tipton County. #TNQuake #TiptonStrong
Posted by MemphisWeather.net on Tuesday, August 25, 2015

Memphis International Airport becomes StormReady

About a month ago, Memphis International Airport (KMEM) achieved an important designation. No, not the first airport with a "Grit and Grind" spokesperson, but the first airport in Tennessee (and  only the 16th nationwide) to earn the "StormReady" designation from the National Weather Service. From the Airport Authority newsletter, the designation is "for demonstrating excellence in the preparation and planning for severe weather."

Jim Belles, Meteorologist in Charge of the NWS's Memphis Forecast Office; Cedric Simon, Memphis Int'l Operations Duty Manager; Stephen Kearney, NWS meteorologist; Terry Blue, MEM Vice President of Operations; and Gary Woodall, NWS Warning Coordination Meteorologist. Photo courtesy MSCAA. 

According to the National Weather Service, "StormReady helps arm America's communities with the communication and safety skills needed to save lives and property--before, during and after the event. StormReady helps community leaders and emergency managers strengthen local safety programs."  So the next time severe weather threatens the airport, rest assured that airport officials have a plan and are ready to execute it at a moment's notice to keep patrons and operations safe.

Tropical Storm Erika struggling, but has potential

As of Wednesday afternoon, Tropical Storm Erika is being affected by moderate to strong wind shear as it moves towards the Caribbean. This shear has weakened the storm and will continue to affect it for a couple of days. However, if Erika can survive the shear, much more conducive conditions await as the storm approaches the Bahamas, and potentially Florida, in a few days.

Computer models have narrowed in on a track that takes the storm north of Puerto Rico and into the Bahamas this weekend, while also strengthening it as it leaves hostile conditions behind. From there, it's difficult to say what Erika will do, but those along the Florida east coast will need to closely monitor the system. Multiple scenarios take Hurricane Erika up the east coast of Florida early next week.

NHC Forecast track for T.S. Erika as of Wednesday afternoon. The last forecast point just off the Florida east coast is valid Monday afternoon and indicates a hurricane with 75 mph  maximum sustained wind.

By the way, Saturday marks the 10-year anniversary of Katrina's landfall on the Gulf Coast. That year, 2005, was also the last time a major (category 3+) hurricane made landfall in the U.S., a 10-year drought that is unprecedented in the modern era. Hate to say it, but we're overdue. For the latest information on Erika, see the MWN Tropical Page.

Erik Proseus
MWN Meteorologist

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MWN Lightning Round: On heat, haze, and high-latitude auroras

It's once again time for the MWN Lightning Round, in which we hit a few different topics in rapid succession and let you get on about your day, armed with insightful new information!

Heat Builds as High Pressure Expands

A hot day was once again tempered just a bit by thunderstorm-induced cloud cover today, although high humidity values still pushed the heat index over the century mark this afternoon. With a large upper-level ridge continuing to expand the next two days, fewer storms are expected, thus we expect highs to reach their full potential in the mid to upper 90s. Combined with dewpoints in the 70s, we'll see heat index values near or exceed the danger level of 105° Tuesday and Wednesday. Practice the heat safety tips below and check out our complete guide to staying safe on a Memphis summer day!

Remember also that successive hot days have a cumulative effect and heat illness can occur more quickly in the same heat when there is less opportunity to recover from previous days. Overnight lows in the upper 70s can provide little relief.

Walk Like an Egyptian - in the Saharan Dust

If our previous article on a lone thunderstorm casting a shadow into Alabama wasn't enough to convince you, we have another example of how weather hundreds (or thousands!) of miles away can affect an area.

You may have noticed on your way home from work today that the sun seemed filtered and the sky hazy when looking off in the distance. Although there was a veil of high cirrus clouds from earlier thunderstorms, there also was a noticeable haze. It wasn't just summertime urban air pollution you were seeing. In fact, it was a thin veil of dust from the Saharan desert!

The dust was transported across the Atlantic Ocean into the southern U.S. on trade winds. This is the same dust that is sometimes mentioned in Atlantic tropical discussions as a deterrent to tropical organization. The dust was even mentioned in today's air quality forecast discussion issued by the Shelby County Health Department:

A combination of local emission sources and transported Saharan dust are creating very hazy skies as the particles are easily remaining suspended in the very humid conditions over the Mid-South. 

We've written one other time about dust that actually accumulated on vehicles and outdoor objects - that was April 2014 from dust storms in the Central Plains. This dust has a much more exotic origin and won't be enough to create a coating, but is reducing visibility just a bit. The image below shows the concentration of Saharan dust over the Atlantic Ocean and into Central America and the southern U.S.

Saharan dust thickness at 7pm Monday is shown in this model graphic from WxBell Analytics.

Storms Originating on the Sun Reach Earth

Another long-distance connection - this one farther than the Sahara to the Mid-South - is occurring today as well. A geomagnetic storm on the sun hurled multiple coronal mass ejections (CMEs) at the Earth over the past couple of days. Today, the strongest of these reached our magnetic field and prompted space weather warnings indicating a blackout of low-frequency radio waves over North America. The "Planetary K-Index" is a scale used to measure the strength of these waves, which are then tied to expected impacts. The index spiked this afternoon at a magnitude 8. This is strong enough to have some effect on power grids, radio waves, and communication with aircraft, as well as on orbiting spacecraft.

The Planetary K-Index spiked at a level 8 this afternoon as a strong CME bounced off the earth's magnetic field.
Image courtesy SWPC.

In addition, strong CMEs tend to produce more vivid aurora borealis, which can be seen further south from the poles as they get stronger. Some northern U.S. locations could have a decent chance of seeing the aurora tonight if skies are clear. While there is some chance of aurora dipping farther south, it is highly unlikely we'll see the northern lights in the Mid-South.

An aurora map produced by KATV meteorologist Ryan Vaughan (@ryanvaughan on Twitter) indicates a low probability of  aurora viewing into the central U.S.

More really cool graphics, animations, and information can be found on the Space Weather Prediction Center's homepage.

Erik Proseus
MWN Meteorologist

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MWN Lightning Round: A trio of astronomical events on Friday!

The MWN Lightning Round returns! This Friday, March 20, will feature not one... not two... but THREE astronomical events!

Vernal Equinox - SPRING!

The official first day of spring is Friday, March 20. Specifically in Memphis, the equinox occurs at 5:45pm CDT, when the sun crosses the equator from south to north. For the next 6 months, the sun will remain north of the equator, resulting in the usual hot, sultry summer in the Mid-South!

The orientation of the sun to the earth on the vernal equinox

In an odd technicality, while equinox means "equal parts day and night," the length of the day in most places is not actually a precise 12 hours on March 20. In Memphis, our 12-hour day was on March 17, when the sun rose and set at 7:09 (am and pm respectively). The reason for this is because the earth's atmosphere refracts, or bends,  sunlight, such that we can actually see the sun rising (and setting) a little before (after) it technically occurs. For more details, we invite you to check out this article from TimeandDate.com.

The Missing Supermoon

A supermoon occurs on Friday! But don't get too excited... A supermoon, or perigee moon, occurs when a full or new moon makes its closest approach to Earth, thus making it look larger than usual. By a looser definition, it occurs "with the moon at or near (within 90% of) its closest approach to Earth in a given orbit." By this definition, there are 6 supermoons in 2015. However, this month's supermoon, which also coincides with the equinox and an eclipse (see below) is a NEW moon, meaning it is 100% obscured by the Earth's shadow. Thus, the "missing supermoon!"

Total (solar) eclipse of the heart

The third in our astronomical trilogy will require an expensive plane ticket to be able to see in person, as it won't be visible in the Americas either. (Basically, we realized we're telling you about a bunch of stuff you won't be able to experience firsthand...) A total solar eclipse will occur in the wee hours of the morning Friday with best viewing over northern Europe and into Greenland.

A solar eclipse occurs when the Earth, moon, and sun all line up in such a way that the moon blocks the sun for viewers on Earth, either partially or totally (thus the type of eclipse). The next eclipses visible in Memphis will be a partial lunar eclipse in the early morning hours on April 4 and a total lunar eclipse on September 27. The next solar eclipse viewable locally occurs August 21, 2017 - a near total eclipse! (We'll be sure to remind you...)

Cool astronomy stuff like these events (at least the supermoon and eclipses) can be watched live, or later, on the internet if you can't shuck out the cash to fly to where they are visible. There are several good sites, but we especially like Slooh.com.

So there you are - 3 astronomical events all occurring on the same day!

Erik Proseus
MWN Meteorologist

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MWN Lightning Round: weekend forecast, holes in the clouds, and NWS on Twitter

The MWN Lightning Round is back with three topics for this fabulous fall Friday!

1. First, and most important, the weekend forecast! Lots of activities again going on around town this weekend as fall gets into full swing. The weather will cooperate for most of them, but it will be warm with slightly increased humidity levels. For today, high clouds will stream overhead but no rain is expected and temps will reach the mid 80s, similar to yesterday. Friday night football looks great with temps near 80 at sunset and a light northeast breeze.

For Saturday, another day not unlike the last couple. Clouds will be a bit thicker, but the rain chance is still very low and not worth worrying about. Temps will once again reach the mid 80s, but morning lows will be a bit higher (mid 60s) as humidity increases. If you're headed to Oxford for the Memphis-Ole Miss football game, expect cloudy skies, a slight rain chance, and temps near 80 at kickoff.

A developing trough to our south is responsible for the clouds this weekend. As it moves northeast into the southeastern U.S., rain chances also go up a bit for us, mainly Sunday. Earlier this week, some models were hinting at a Sunday washout but that does not appear to be the case now. Scattered showers are expected though and will be more numerous to our southeast, over northeast MS into AL. Temps will be a few degrees cooler Sunday due to the showers in the area. A warm and dry pattern sets up for next week until another true fall cold front moves in by week's end.

Weekend rainfall forecast from the NWS. Precip (mainly Sunday) could average 0.10" in the metro with heavier amounts to the southeast. Graphic courtesy NOAA/NWS/WPC.

2. A unique cloud formation was observed over the Tuscaloosa, AL region this morning. A "hole punch" cloud, or fallstreak hole, caught the eye of a bunch of smartphone-toting folks, who captured pictures of the event. An example, from the Twitter feed of James Spann, is shown below. Hole punch clouds are typically formed when aircraft fly through an area of supercooled water droplets. In the aircraft's wake, rapid cooling takes place and introduces ice crystals into the air, causing the water droplets to evaporate. This leaves a hole in the cloud and ice crystals below it! For more on hole punch clouds, including some cool pics, see articles from the Cloud Appreciation Society and Wikipedia.

Fallstreak cloud over Tuscaloosa, courtesy James Spann on Twitter (@spann).

3. The National Weather Service is officially joining Twitter! OK, so many NWS offices have been there for some time, but as with any new product or service from the NWS, there is an "experimental" phase in which they test the waters and solicit feedback. As of October 31, their use of the service becomes "operational," meaning NWS offices are expected to utilize the medium for information sharing.

There literally is no faster way to share and receive information than Twitter. Breaking news almost always breaks there first these days. While the use of Twitter will be a "complementary" service at the NWS, they expect to "disseminate important information about hazardous weather conditions" and Twitter "will also be used for public outreach and education and to direct users to official NWS Web sites." The NWS stresses that users should not rely on their Twitter feeds for warning information. To this point, the NWS has not indicated if or when their experimental use of Facebook will become operational.

You already know that you can follow MemphisWeather.net on Twitter and Facebook (links below), but did you know that we have automated feeds of severe weather watches and warnings for each metro county on Twitter? Learn more and find your county's feed here.

Hope everyone has a great weekend! We'll be watching for our next big fall front late next week.

Erik Proseus, MWN Meteorologist

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MWN Lightning Round: Mid-South twisters, raining mud, and BSMF weather

The Lightning Round of weather returns today with a look at three interesting and important topics related to Mid-South weather.  First up...

April 28 Tornadoes

The National Weather Service has completed surveys of three Mid-South tornadoes that occurred on Monday, April 28 as severe weather swept through the region.

The first occurred before 7am, embedded within the morning squall line, right here in Shelby County. An EF-0 w/ wind of 75-80 mph struck the Bolton community causing roof and tree damage. A Tornado Warning was issued for that storm as the first children were arriving to area schools, sending them straight to their tornado positions upon arrival at school.

The second, and most publicized, occurred in the mid-afternoon hours, striking the city of Tupelo with 150 mph wind. The fast-moving EF-3 tornado was long-tracked, lasting 26 minutes and covering 24 miles. There was one fatality that has not been confirmed as a direct result of the tornado, as well as at least 40 injuries.

Tupelo, MS gas station after tornado moved over the town. Photo credit NWS-Memphis

The last twister occurred west of Union City during the late afternoon hours when most attention was focused tornadic supercells in central MS.  An EF-2 with max wind of 130 mph crossed from Obion Co., TN into Fulton Co, KY. It moved a 700 lb weight 15 feet and bent a steel trailer.  More information on all of these storms, as well as additional damage pictures, can be found on the NWS-Memphis website.

Raining mud!

Mid-Southerners were surprised to see a dirty residue on their vehicles after light rain fell on Tuesday. After some research, we discovered that dust storms in the Plains were to blame! The dust was lofted high into the atmosphere and carried east on strong upper-level wind, then deposited as it fell into clouds and light rain over the Mid-South. When the sprinkles evaporated, the dirt was left behind! If you missed it, we wrote a more detailed blog on the topic Tuesday afternoon.

Beale Street Music Festival weather

Staying on the topic of mud... Mother Nature's calendar must be really messed up as it appears she forgot to schedule rain for this weekend's typically-muddy Beale Street Music Festival! In fact, the weather really couldn't be much better. No rain, actually very little cloud cover, is expected throughout the weekend with temperatures climbing from the lower 70s today to the upper 70s Saturday to the mid 80s by Sunday. One thing you may not have needed at many other music fests in recent history that will be a necessity this weekend? Sunscreen. Let's hope the weather is as good in 2 weeks for the BBQ Contest as well as the following weekend for the Sunset Symphony!

We hope everyone has planned some outdoor activities for this great spring weekend in Memphis, TN!

Erik Proseus
MWN Meteorologist

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On a cold start to the year, average last freeze dates, and weekend rain

We introduced the MWN Lightning Round about a week ago to provide small bites of weather info that we think would interest our readers.  Today's edition focuses on just how cold it's been so far this year, when (typically) the coldest of the air is behind us, and a quick look ahead at an unsettled weekend.

A cold start to 2014

According to the National Weather Service in Memphis (Web, Facebook, Twitter), 2014 is in the Top 10 for coldest starts to a year since 1900.  January averaged just over 5 degrees below normal and February averaged 4.4 degrees below normal, but the first couple of weeks of March have continued the trend, averaging nearly 6 degrees below normal through yesterday.  It's no surprise then that we're moving into the ranks of the coldest years on record, but I didn't realize that it was Top 10 worthy!  Here's the official word from the NWS:

Last freeze dates

Also according to the NWS, we're fast approaching our usual "last freeze date" - or the date that (on average) we see our last 32 degree reading of the spring.  For Memphis, that date is March 19 (and according to the MWN Forecast, we may get close to freezing again on Monday/St. Patty's Day, so that is not unusual).  Though the climate record is not nearly as long, the Agricenter's average last freeze is March 28, so folks in outlying areas especially still have another couple of weeks when a freeze is not at all unusual.  Spring cold fronts often bring a shot of cold, dry Canadian air that can drop temperatures to 32.  The good thing about cold weather in March is that it typically doesn't last long.

Weekend weather

As a perfect segue from the cold weather talk, this weekend's rainy but mild weather will be followed by a brief cold spell. As an example of the typically-brief cold spells discussed above, the low Monday morning will be near freezing, but by Tuesday afternoon we'll be well into the 60s again!  Until then, though, we'll be dealing with a series of disturbances/low pressure systems that will track through the region.  While temperatures in the mid to upper 60s are expected this afternoon and tomorrow, rain (some of it occasionally heavy) will move over late Saturday into Sunday morning.

It appears we may get "dry-slotted" for part of Sunday as the drier area around the low moves overhead, but wrap-around precip will follow Sunday evening and overnight as strong northerly wind picks up and temperatures fall.  We expect all precipitation to be gone by the time the coldest air arrives early Monday morning, but Sunday night could be cool and wet, and definitely breezy!  Highs Sunday will be near 60, but could begin falling on that strong north wind by afternoon.  If you have weekend outdoor plans, get them done on Saturday morning or early afternoon when rain chances are lowest. Again, check out the MWN Forecast for details on this weekend's forecast.

Multi-model average of temperatures through Monday morning. Forecast hours along the bottom, starting at 7am Friday (so 24 = 7am Saturday, etc.), temperature scale along the left. This average shows temps into the 40s by Sunday evening after remaining in the upper half of the 50s Saturday night.

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The MWN Lightning Round debuts!

Today marks the debut of a new feature of the MWN Blog we're calling "The MWN Lightning Round."  We hope to publish The Lightning Round a few times a week (that maybe optimistic, but hopefully at least a couple times), though it will not be on a set schedule.  The nature of The Lightning Round won't necessarily lend itself to a set schedule.

Nearly every day, we come across an item or two that we think you'd enjoy, but which we don't have a good way to share with you for whatever reason.  So in this feature, we'll touch briefly on a number of subjects, which could include quick forecast updates or commentary, vignettes, a cool pic, a weather-related article or story, a little Weather 101, a mythbuster, or just something we want you to know about.  Most will have a Memphis or Mid-South connection, but some will be just be cool weather-related stuff that we think you'll like!

The number of items in each lightning round will vary, but we'll aim for 3-4 to keep it from getting too long, while allowing you to explore deeper into each topic via links to other sources, if applicable.  The goal is to provide a little more information than we have been covering on the blog in the past, but are more than we would typically get into on Facebook or Twitter.  We'll still provide the usual blog fare - including forecast discussions leading up to weather events of significance separately, recaps of said events, in-depth commentary, climate recaps, etc., but this will hopefully keep your appetite for MWN content satiated between these other posts!

Since it's new, we want your feedback!  If you have an idea for a topic that would go well in The Lightning Round, send it to us on social media or leave a comment in any blog post.  If you hate the whole concept, let us know.  If you enjoy it, let us know that too!

Without further adieu, The FIRST MWN Lightning Round......

Spring forward!

Tonight at 2am CST, we spring forward and it magically becomes 3am CDT.  Most people set their clocks before going to bed, but some stay up until 2am just to see an hour pass by in a second (as if an hour doesn't seemingly pass by in that amount of time nearly every day at some point).  A few places in the U.S. (Arizona and Hawaii most notably) still don't change their clocks twice a year like we do, and I think they're onto something.  For me, year-round DST would be just fine.

The only major drawback for meteorologists (who use Greenwich Mean Time, aka Zulu time, aka military time, aka UTC time) is that the major computer models come in an hour later, as they are run on UTC time.  It's also easier in the Central timezone to convert UTC to Standard Time than Daylight Time, but I'll get over it to get an extra hour of daylight in the evenings.  Also remember that clock-changing time should also be battery-changing time for your smoke detectors and weather radios, both of which we highly recommend.  For more on the history of Daylight Saving (not Savings) Time, see this article.

Congrats to an MWN team member

Earlier this week, MWN Social Media Intern William Churchill was offered a graduate level teaching assistantship position for the 2014-2015 school year by the Atmospheric Sciences Department at Mississippi State University.  William has interned for MWN since last April and is finishing up his undergraduate studies in Professional Meteorology at MSU this May.  He will then pursue an M.S. degree in Meteorology starting this fall.  (Mississippi State University, for those who don't know, has become one of the leading meteorology programs in the region, especially noted for turning out well-prepared broadcast meteorologists, but also now boasts a full atmospheric sciences program, including doctoral studies.)

William hails from the Memphis area, having graduated from Arlington High School in 2009 and has been a fabulous addition to the MWN team the past year.  I know you appreciate his hard work on our social media channels, as well as frequent blog posts, as much as I do. Congrats William on this well-deserved appointment!

SKYWARN Storm Spotter Class next week

Next Thursday, March 13, from 6:00pm-8:00pm, MemphisWeather.net and Mid-South Storm Chasers will jointly host one of two storm spotter classes scheduled for the Memphis area this spring.  The class, which is free and open to the public and does not require pre-registration, will be held at Bartlett United Methodist Church, 5676 Stage Road in Bartlett, west of Bartlett Blvd and in front of Bartlett High School.

Taught by the National Weather Service, the class will cover the basics of storm development and features of severe weather, how to spot and what to look for, common "look-alikes" to severe weather, and most importantly, how and what to report.  The class is for all ages, but especially for pre-teens and up.  At the end of the NWS-led class, yours truly will lead a short session on using Twitter and the #mSpotter hashtag to report severe weather via social media, with reports relayed immediately to the NWS.  The #mSpotter program has been very successful in the past couple of years with the rise of social media use and I'll provide details on how you can participate.  If you have an interest in weather or it has been a couple of years since your last spotter class, plan to join us Thursday night!  A list of other classes scheduled across the Mid-South can be found here.

That's it for this edition of The MWN Lightning Round!  Let us know what you think or if you have ideas for topics to explore by commenting below.

Erik Proseus
MWN Meteorologist

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