Monday, June 29, 2009

Beautiful sunset to end a very nice day

It's been a really nice summer day here in the Mid-South. Though temps were still quite warm (high of 93 at Memphis Int'l), the humidity bottomed out near 25% as dewpoints sunk to 50! It was a dry heat. ;-) The day ended with a gorgeous sunset as cirrus clouds streaked the western sky. A cool night can be expected in outlying areas tonight with temps falling into the 60s. Tomorrow could be a couple of degrees warmer than today, though humidity levels will remain low. Rain chances appear in time for the holiday weekend - find the complete forecast at

Humidity heads south with cold frontal passage

What a difference 24 hours makes! Temperatures this morning are anywhere from 10-15 degrees cooler than yesterday at this time. WXLIVE! is currently sitting at 64 degrees - yesterday is was 79. In fact, a record maximum low temperature was set once again yesterday with a low of 81 degrees at midnight last evening (it dropped to 82 yesterday morning, but the low recorded is a 24-hour low).

This cooldown is thanks to a frontal system that moved through yesterday. If you were outside during the late afternoon or evening, you could probably start to feel the difference as a fresh north breeze was blowing and humidity was dropping. Though it was still hot, the official temperature got to only 94 - breaking a string of 11 straight days of 95+ weather.

For the next couple of days, I expect we will continue to see low humidity levels, though temperatures will remain in the 90s (lower half, not upper!). Morning lows will fall into the 60s for most Mid-Southerners through mid-week.

The Independence Day forecast is now posted at - I'll have more detail on the blog in a couple of days on what to expect with your fireworks forecast.

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Saturday, June 27, 2009

Heat continues for two more days

Memphis International Airport tied another record low temperature this morning - the maximum low for the day. Provided a stray thunderstorm doesn't cool it off before midnight tonight, we will tie the record of 81 set in 1978. Given the extreme heat and abundance of humidity, the National Weather Service has pulled the Excessive Heat Warning out of the bag of tricks for the second time this week. High temps will top out in the upper 90s to near 100 today with the humidity making it feel like 105-110 this afternoon. Stay indoors if possible, or make sure you are taking plenty of precautions if you must be in the heat.

The heat- and humidity-breaking cold front we have been waiting for for almost two weeks now arrives tomorrow (see the map above valid at 7pm Sunday)! With only a small chance of thunderstorms, the high for Sunday will still be near 97, so Heat Advisories will likely still be in effect. However, behind the front much drier air infiltrates the Mid-South and "cooler" temperatures (actually, just closer to normal) move in too. For the start of the work week, high temperatures will be near 90 to the lower 90s with negligible humidity. The best part will be the mornings when lows will drop into the 60s!! it will continue to be dry throughout most of next week with moderating humidity levels. No extreme heat is in the extended forecast though after this weekend!

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Thursday, June 25, 2009

Weather wrap-up for Thursday, June 25

The heat continues across the Mid-South, though a few degrees cooler than earlier this week and also less humidity, therefore Heat Advisories have not been issued since the "cool front" passed through Tuesday night. We may see them return though for Saturday as heat index values will once again climb near 105 or higher. Another front looks like it will be coming through Sunday night, so that may end the string of 95+ degree days and drop the humidity levels once again. For Friday, ozone levels have crept up in the city and will be high enough tomorrow to cause problems for those with certain respiratory problems. Thus, a Code Orange Ozone Alert has been issued and an Ozone Action Day declared. Take precautions in this heat.

Today marks the 9th day of 95 degree heat, with at least two more coming (maybe Sunday too). The rain chances with Sunday's front will be low and a very weak front will get close enough tomorrow to perhaps spark an isolated cell or two late in the afternoon or evening Friday. Maybe someone will get lucky and get a few drops!

Speaking of heat, it's hot, but not necessarily record-breaking, until yesterday morning when the old maximum low temperature of 80 degrees was eclipsed by a balmy 81 degree low! The old record stood for nearly 80 years. Record highs are running in the lower 100s so I don't think we'll see any high temp records broken in this current streak.

In other news, I have added some additional damage photos from the Elmore Park area of Bartlett to the album of pictures I took of the damage from the Mid-South derecho on June 12. If you haven't read my event analysis or checked out the radar and satellite loops, home video of the storm as it passed through, and damage photos, I encourage you to do so. You can find the information by clicking here.

Finally, NASA is set to launch the newest weather satellite into orbit tomorrow (June 26). GOES-O will lift off aboard a Delta IV rocket if the weather holds up. (How about that for ironic? A weather satellite is delayed going into space due to the weather??) GOES-O will live in storage mode among its siblings, GOES-10, -11, -12, and -13, in an orbit 22,300 miles above the Earth. It will be called into service should there be a failure of one of the other operational satellites. For more information on GOES-O, see these links: (NASA) (NOAA)

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Tuesday, June 23, 2009

Few storms to end a HOT day

These pictures are what you would see if you were the MWN weather station looking east-southeast (top), south (center), and west (bottom) - click them to enlarge the pics. A few storms popped up in the evening hours along the very weak cold front that was passing through. The center picture shows the outflow of the storms jsut south of the station with some cumulus clouds along it. Wind gusted to 21 mph and the temperature dropped a good 10 degrees with the frontal passage, bringing a welcome relief from highs that topped out at 100 degrees at Memphis International Airport this afternoon. This is the highest temperature recorded since a 101 reading on July 29, 2008 and only the second 100 degree June reading in the past 14 years (June 30, 2005 was the other). With the cool frontal passage, humidity will be lower for the next few days, so while temps will still reach the upper 90s, heat indices should remain near or below 105. A "cool spell"? Whatever you want to call it...

Addendum: I added a couple of pics below, taken about 25 minutes later (8:30pm) of a storm just to the south as the sun was setting. Enjoy!

Excessive Heat Warning until 7pm Tuesday

The National Weather Service has upgraded the Heat Advisory to an Excessive Heat Warning for the metro area. Temps at noon are already in the mid 90s with heat index values near 110. Highs will top out near 100 this afternoon, though heat index values have likely peaked and will remain steady. The dewpoint (amount of moisture in the air) is very high ahead of a "cool front" moving into the region tonight (from the east - which is called a "back door" cold front). The temperature and dewpoint combine to produce the heat index. I expect dewpoints to slowly drop this afternoon, so as temps rise a few more degrees, the heat index should remain steady in the 108-113 F range. Mid-Southerners should take all precautions necessary today if they must be outdoors, or if at all possible to remain out of the heat entirely. Click here for heat safety information from the National Weather Service.

As the front passes through, dewpoints will be somewhat lower tomorrow and for a few days. So, though temps will not necessarily drop any behind the front, lower humidity values will mean lower heat indices and possibly the end of Heat Advisories after today.

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Sunday, June 21, 2009

Welcome to summer!

...and you're thinking, "what rock have you been under? It's been 95 for four days with no end in sight!" Well, I can technically say "welcome to summer" today because June 21 is the official first day of summer. The summer solstice occurred this morning at 12:45am CDT. The solstice is the point in time when the Earth's axis is most inclined toward the sun, yielding the longest day of the year for the Northern Hemisphere, thus the beginning of our summer. It is also the day when the apparent position of the sun is the highest in the sky for those in the Northern Hemisphere. The graphic above from the Wikipedia article on the summer solstice shows the illumination of the Earth at the summer solstice. Notice that the areas around the Arctic circle get light all day as the Earth rotates, while those areas near the south pole are in darkness all day. So, welcome to summer!

Also, Happy Father's Day, dads!! I'm proud to be one of you! Thank God for our children!

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Saturday, June 20, 2009

Forecasting a heat wave

Believe it or not, there are a few interesting things that play into a forecast like the one we have right now - which calls for plenty of sun and mid 90s or higher through the middle of next week (at least). Being that I am a perfectionist, with a forecast like this, it's the little things that make it right.

The heat wave we're experiencing is due to a huge ridge of high pressure positioned from the surface all the way to the upper levels of the atmopshere. It is this high pressure that is steering the storms we had a week ago well to our north now. The best place to start with a forecast during conditions like this is persistence - what did it do yesterday and the day before and how will it be different today? The only differences are those "little things" - the strength and position of the ridge (stronger=hotter), the amount of moisture in the atmosphere (more moisture=more clouds and less ability to warm), the moisture near the surface, which affects the dewpoint (recent rains=moister ground=higher dewpoints and less ability to warm, but higher humidity), and wind (more wind=more mixing of the atmosphere and less ability to warm). So when deciding whether it will be 95 and 98, one has to take into account all of these factors.

As we head into early next week, many of these factors will be working to try and offset each other. While the ridge of high pressure will tend to move away and weaken slightly (promoting slightly cooler temps), without rain the ground is getting drier by the day, thus promoting lower dewpoints during peak heating, but causing the near-surface air to warm more freely. The result would be temperatures continuing to be nearly as hot, while heat index values lower slightly. Combine that with a few more clouds during the afternoons as the high moves slightly further west, and perhaps we'll see the Heat Advisories dropped by early next week.

Until then, the ridge holds, the sun beats down relentlessly, and the heat continues. Please take all necessary precautions against the heat - the longer it lasts, the more prone to heat exhaustion you will become. Be sure to check on the elderly and young children, as well as your pets, during this early season heat wave.

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Thursday, June 18, 2009

Heat Advisory extended until 7pm Friday

A Heat Advisory has been extended for the entire region until 7pm Friday. Afternoon high temperatures the next couple of days will be in the mid 90s, to possibly the upper 90s on Friday, with heat indices near 105. Overnight lows will provide little relief, only dropping into the mid 70s. Be sure to take precautions against the heat if you must be outside, including wearing light-colored, loose-fitting clothing (or swimsuits!), drinking plenty of water or other non-alcoholic beverages, and staying the shade as much as possible. Don't forget to check on those most susceptible to the heat: young children, the elderly, and your pets!

Fortunately, as of mid-morning, most residents now have power restored after last Friday's storm - less than 5,000 customers remain out. I have written an event analysis on the storm which you can find on It contains commentary and analysis, damage pictures (as well as some of the awesome sunset that evening!), radar and satellite loops, etc. Check it out!

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Wednesday, June 17, 2009

Event analysis of Mid-South Derecho - June 12, 2009

I have put together, and posted on, an event analysis of the mesoscale convective system/derecho that blasted through Memphis and many parts of the Mid-South on Friday afternoon, June 12, 2009. There are many damage photos, links to radar and satellite loops, storm reports, and commentary on the event. I also have several photos of the spectacular sunset that occurred that evening, after passage of the storm system. Check it out, download the PDF if you wish, and feel free to pass the link on to others who might be interested and comment on the report here if you'd like. I'm interested in your feedback! The PDF report can be found here.

Tuesday, June 16, 2009

New cloud type?

An Iowa woman's photo from 2006 have scientists and others debating whether a new cloud type has been discovered. There currently are only three main cloud types: cumulus, stratus, and cirrus. One group is working with the Royal Meteorological Society to prepare a case for the World Meteorological Organization to get them classified as a new type, while researchers and scientists in the other camp say they are another form of cumulus and have been documented before. The AP article can be found here: What are your thoughts? Leave the cloud types alone, or add a 4th cloud type (which might be analogous to adding a planet in the solar system)?

Monday, June 15, 2009

Storms tracking across northern portions of Mid-South

A line of severe t'storms are training across the northern Mid-South from northeast Arkansas into west Tennessee. These storms are beginning to drift south towards the metro Memphis area as an outflow boundary moves south from the storms, forcing new development ahead of the southeast-moving line. Some funnel clouds have been reported in these storms, though tornado warnings are no longer in effect. The Storm Prediction Center is expected to issue a Severe Thunderstorm Watch for the Memphis area by 6pm as scattered severe thunderstorms are possible this evening. Stay with for the latest severe weather information, including interactive radar and the latest warnings, and be sure to sign up for WXLIVE!-Severe Weather to get warnings e-mailed to you as they are issued.

Saturday, June 13, 2009

Brief recap of 6/12/09 Memphis derecho

My comments here will be brief as a full-length commentary with pics is in the works. A major convective system (derecho) passed overhead the WXLIVE! sensors of at 5pm, lasting about 20-25 minutes. Tornado sirens were activated and my family headed for the interior closet during the peak of the storm. The NWS confirmed a 150 yard path length EF-1 tornado touched down in Bartlett very near where my parents live (within a mile). Trees, tree limbs, flagpoles, some street signs and traffic signals, and even a couple of buildings were damaged or destroyed by the wind. 139,000 people were without power at it's peak on the Memphis Light, Gas & Water network (greater Memphis). (See link to the right for the current outage map or click here.)

I wish to apologize profusely for the abrupt loss of severe weather alerts (and many other features of during the height of the storm. The computer equipment that produces the information and alert e-mail suffered a major power and internet connectivity loss at 5pm as the storm passed. The outage lasted 19 hours, with internet down an additional 3.5 hours. All service is now restored. While the data loss is regrettable, there was simply nothing that could be done given the current resources available.

Friday, June 12, 2009

Beautiful sunset to end a destructive weather day

More pics of damage and some commentary once I have power restored. I guess I'm just 1 of 100K...

Possibility of severe weather later today

The Storm Prediction Center has upgraded the area into a MODERATE RISK for severe weather, as seen in the graphic above, and issued a Severe Thunderstorm Watch until 7pm for the metro counties except Fayette and Marshall, until 7pm. A cold front has effectively stalled over the region (as evidenced by upper 70s temps and lower humidity over northeast AR and northwest TN and much warmer, moister air over the metro area and points south). In addition, an upper-level trough is moving in from the west and has sparked a convective system to form in northeast OK. This system will propagate east-southeast into an environment that is very unstable, causing it to likely become stronger. The system has already produced wind over 80 mph in parts of northeast OK, taking on characteristics of a derecho (think Hurricane Elvis...).

In addition, due to the front and unstable airmass, scattered thunderstorms will likely form ahead of this convective system over the Mid-South as we near 90 degrees by mid-afternoon. Any of these storms could produce large hail and high wind. I expect that the derecho will move into the area by rush hour to early evening. Whether it passes directly through the city remains to be seen, but the potential track is close enough that Mid-South residents should prepare for the possibility of damaging straight-line wind wherever it passes. Secure loose items outdoors and be prepared for possible power outages. will have complete severe weather coverage, including the latest watches, warnings, and interactive StormView Radar.

Thursday, June 11, 2009

Weather pics of the day

Snapped these pics on my way into work this morning as clouds were breaking up from the early morning storms. The sun was just starting to peek through. They were both taken looking east around 7:45am near Memphis International. Comments?

Storms re-develop and move into metro Memphis

Storms have fired over eastern AR and are moving quickly east across mainly northern portions of the Memphis metro area, though a few showers are also traversing the southern part of Shelby County. Expect showers and t'storms to continue to develop on and off throughout the day with a few possibly pulsing briefly to severe limits. The main threats are hail to the size of quarters and wind gusts to 50-60 mph.

Wednesday, June 10, 2009

Summertime pattern shapes up over the Mid-South

It's been a while since I posted my own thoughts, so it's probably time. I use this blog to not only write about my opinions on weather and other topics, but pass along information that I think may interest my readers. Lately, I've been in "passing along" mode, so today it's a forecast discussion.

However, I first want to send out a thank you to all of you who check The MWN Blog regularly, or who just happen to drop in searching for a certain topic. In the past 2 weeks or so, we touched a couple of milestones. The blog's visitor count since July 2008, when visitor tracking was added, hit 13,000 on June 3rd. In addition, the page view count went over 20,000 on May 28. I know there are plenty of you who also read this through means other than just on the blog site (the only place visitors are tracked), such as Facebook, Blogged, by e-mail subscription, etc. Thank you for relying on the writings here to keep you informed and maybe even mildly entertained. ;-)

On to more important topics, like the weather! Summertime has definitely arrived, even though the calendar says it's still 11 days away. The signs of summer are building upper level high pressure, south wind pushing very warm humid air into the region, stalled fronts sparking scattered showers and thunderstorms, and the occasional Ozone Advisory! We've had all of these in the past week. The summertime forecast, which can occasionally be fairly mundane, is anything but that when a frontal boundary approaches as we have now. You never know exactly where or when the next cluster of storms is going to appear! I generally don't like blanketing "chance of rain" forecasts out for days on end, but unfortunately that generally ends up being accurate at the end of a summer day. Some folks will get very wet (like Tipton County this morning) and some won't get a drop!

A frontal system will move into the area tomorrow, providing an increased chance of t'storms, some of which could pulse above severe limits with hail or damaging wind gusts, especially during peak heating hours. The front will hang out for a couple of days before retreating back to the north as high pressure re-builds over the region this weekend. Until then, we can expect the daily thunderstorm chance, highs in the upper 80s to near 90, and dewpoints that make for uncomfortably humid conditions. By early next week, the upper-level high really starts to assert itself and we're looking at the potential for the hottest days of the year yet (mid 90s are possible) with a fair amount of humidity still hanging on. In fact, we could see the first mentions of heat indices over 100 degrees. Memphis summer is definitely back!

Monday, June 8, 2009

Tornadoes near Denver, CO - June 7, 2009

As reported by 7NEWS/ out of Denver, as many as 5 tornadoes touched down in Colorado on Sunday afternoon, June 7, two in metro Denver. A slideshow of viewer-submitted photos can be found here. The area around Aurora seemed to take the biggest hit with damage reported at the Southlands Mall. The NWS storm damage report can be found here. Also, check out this article with raw home video of the storm. Preliminary estimates are that the Aurora storm produced EF-1 damage with wind of 86-110 mph.
Photos courtesy Brittany McKown and Shelley Alley

May 2009 climate stats and forecast accuracy

May 2009 was a very wet and warm month in Memphis, which most of you know without any statistics to prove it. Following are climate summaries for Memphis International Airport and Bartlett, TN.

Memphis International Airport
At the official recording station for Memphis, the average temperature was 71.6 degrees, which was 1.0 degrees above normal. The highest temperature for the month was 91 degrees (the only day at or over 90 degrees), recorded on the last day of May, and the lowest was 52 on the 18th. However, even though the average temperature was above normal, the average high temp was 0.7 degrees below normal. This was offset by an average low temperature that was 2.8 degrees above normal. The average high and low can be explained by above normal cloud cover (17 cloudy days) and precipitation, which kept highs down but lows up.

Precipitation totaled 7.73", which was over 2.5" above the normal of 5.15". There were 13 days with measurable rainfall recorded (plus 5 days with a trace of precipitation), two days with more than an inch of rain, and one of those days had more than two inches of rain. Nine days recorded thunder. The peak wind gust was 38 mph on the 27th. Click here for the NWS recap.

WXLIVE! in Bartlett
In Bartlett, WXLIVE! recorded an average temperature was 70.0 degrees, with a max of 92.1 on the 31st (the only day above 90) and a min of 45.2 degrees on the 18th (note that is 7 degrees colder than the airport). Precipitation totaled 6.29". The peak wind gust was 30 mph on 5/13. Click here for the MWN recap.

May Accuracy
The MWN Forecast accuracy statistics are finalized as well. For the month of May, the MWN forecast beat out the computer models and the NWS forecast in the dewpoint category, but narrowly came in second in the temperature category, 0.12 degrees behind the National Weather Service average. This is only the 4th month in the past 18 that MWN has not beaten every model in the temperature category. MWN temperature error for May was 2.05 degrees, which was the most accurate month by MWN in 8 months.

Tuesday, June 2, 2009

Thunderstorms in the distance to end the day

After storms started the day in the area (see previous blog post), this is the view to the east from northern Shelby County as the sun sets on the day. The storm is dissipating with a top near 30,000 feet. -More rain and t'storms expected tomorrow, with potentially heavy rain overnight Wednesday. Rain is also expected for at lesat the first half of Thursday.

Weather requirements for a shuttle ferry flight

Thanks to prolonged weather issues in Florida, Space Shuttle Atlantis landed about a week ago at Edwards AFB in California, rather than its preferred location at Kennedy Space Center.  In order to get the shuttle back to Florida, a ferry flight is required.  Those ferry flights are taking place now.  The process is very interesting and suffice it to say, weather plays the biggest role in getting the shuttle back to FL.  It actually takes 4 flights and a couple of days to get the shuttle back to KSC on the back of a modified Boeing 747 used by NASA for just this purpose.  The shuttle will be making a stop pretty close to the Mid-South on it's return trip - landing at Columbus AFB, Columbus, MS, shortly after 1:30pm this afternoon.  Posted on a NASA Ferry Flight blog, here's a portion of what Ferry Ops Manager Don McCormack had to say about weather impacts to the flight plan:

...the Orbiter has a very restrictive set of atmospheric/weather requirements.  We must, at all cost, avoid rain in flight.  Flying through rain will damage the Orbiter's thermal protection system and result in a costly and long delay before the Orbiter's next flight.  We also try very hard to avoid exposing the Orbiter to severe weather on the ground, which could also cause damage.  The Orbiter cannot be exposed to temperatures less than 15 F either in flight or on the ground and the Orbiter cannot fly at an altitude where the pressure is less than 8 psia.  These requirements typically limit our altitude to an 11,000 to 16,000 ft range [typically, commercial jets cruise at 30,000-39,000 feet].  So, the SCA/Orbiter route is largely driven by the bases that are available and the weather en route.

In addition, the SCA [Shuttle Carrier Aircraft, the modified 747] has a very limited range when ferrying the Orbiter.  That range depends primarily on the weight of the Orbiter and the air temperature.  Winds are also a factor.  The heavier the Orbiter is, the less fuel we can load into the SCA, pure and simple.  Without going into a lot of technical details, hotter air is less dense air and that too significantly impacts the performance of the aircraft.

Pretty cool huh?  Find out more about this mission by visiting NASA's blog.  Watch in-flight video of the first leg of the trip here or flight track the SCA here.

T'storms greet morning commuters

Picture taken from northern Shelby County of storms towards downtown Memphis. Keep an eye on StormView Radar today.

Monday, June 1, 2009

The heat is ON!

Welcome to the first day of meteorological summer, defined by the weather community as the period June-July-August.  Yesterday was officially the first 90 degree day in Memphis, though my station on Bartlett has hit it 3 times in the past 5 days, with a high of 92 yesterday!  We're looking for another 1-2 degrees of heat over yesterday, so I would not be surprised to see a couple of gauges in the metro area approach 95.  Remember to wear light-colored, loose-fitting clothing, take frequent breaks if you are working outside, and drink plenty of water or other non-alcoholic beverages to remain hydrated.  And don't forget your outdoor pets!  Make sure they have plenty of water and shade too.

It's also a Code Orange Ozone day, so those with respiratory problems, the very young, and the very old, all need to take it easy today.  On the bright side, MATA has a new program where all buses and trolleys are only 25 cents on Code Orange days, to encourage mass transit.  Why don't you give it a try?

The forecast calls for another hot day tomorrow before a cold front provides some relief in the form of clouds and precipitation for mid-week.  We'll then be dry but warming again as we head into next weekend.  Stay up to date with the latest forecast at!