Saturday, December 31, 2022

Return of warmth brings a risk of severe storms, and a few words to close out 2022

Another year with overall above average temperatures and precipitation is wrapping up, though this month will end up slightly cooler than average, but marked by large temperature swings. It's also been wet this month with nearly 6 inches of rain. The major cold spell that marked the days leading up to and through the Christmas weekend has reversed course, with well above average temperatures the past couple of days, which will lead us right into 2023. Of course, 60s at this time of year means we need to keep an eye on the potential for storms as the pattern changes once again!

Ringing in 2023 with warm air

As for the New Year's weekend, you really can't ask for much better, particularly for outdoor celebrations, as temperatures will be in the 60s today and Sunday during the day and in the 50s overnight. In addition, rain chances are basically nil, so grab the light jacket if you are headed out tonight and enjoy your time responsibly! Despite a lack of rain, lots of clouds will mark the sky condition with maybe some afternoon peeks of sunshine later this afternoon and again Sunday afternoon. 


As we head into the first Monday of 2023, the next major trough of low pressure starts to approach the area and precipitation chances ramp up as gusty south wind brings in even more humid air, forcing temperatures towards the 70 degree mark. Best chances of rain Monday are in the afternoon and scattered thunderstorms will be possible as a warm front moves through the area. A couple of these could be strong with a few strong wind gusts and small hail, but the warm front itself will escort in an airmass with a bit more instability that sets the stage for overnight storms.

An early look at forecast radar for Monday afternoon from the high-res NAM model shows the potential for a batch of storms to move through with a warm front. This is NOT the most likely time for severe weather, which would be during the wee morning hours on Tuesday. (WeatherBell)

Severe weather potential Monday night

Monday night is the most likely time for severe weather, as storm chances increase late in the night. However, the trend today versus yesterday is for a slightly lower chance of severe storms in our area. To our southwest though, severe storms containing high wind and a few tornadoes appear likely from east TX into LA and the southern half of AR. Nonetheless, heavy rain and thunderstorms are likely overnight locally, and probably late at night (after midnight) as the system moves east. Due to more uncertain severe weather parameters, including instability levels and stronger upper level dynamics, the chance for severe weather in the Memphis area currently sits in the level 1-2 range (Marginal to Slight Risk). The storms could produce a few strong to severe wind gusts, as well as copious lightning and periods of heavy rain that could result in minor flooding with saturated soil and a couple of inches of rain expected. Stay abreast of this situation for later updates as details are still to be refined and our risk could increase.

The greatest severe weather risk is to our southwest, although severe storms are possible in the metro as they move out of AR into north MS and west TN late Monday night. (NWS/SPC)

Rest of the week trends "normal"

A few lingering showers could last into Tuesday morning, but we should see a general drying trend Tuesday afternoon, even as the cold front associated with the overnight system finally moves through. Because most of the day will be in the warm sector, any breaks in the clouds could easily push the temperatures up to 70 degrees, which might spark a few showers along the front late in the day.

Beyond that, dry conditions and another cooldown is expected from mid-week to next weekend. Highs recede to the 40s to end the week as lows drop to near freezing, which is much more typical for this time of year. 

Looking ahead to 2023!

I'd like to close with a word of sincere appreciation for following MemphisWeather.net this past year and continuing to tell friends and family in the area about us! We're grateful that you include MWN as one of your trusted local weather sources and we look forward to a great year in 2023! 

Our plans for 2023 include a significant shift in our delivery of information online, particularly via mobile app, as well as more timely updates in a live format. Of course, we'll be continuing our tradition and calling to serve as a training ground for the next generation of talented young weather professionals, as they hone their skills in a practical, real-world environment. Our interns are the best and we're grateful for their service to us, and all of you! Special thanks to MWN veteran Caroline Sleeper who wraps up her second stint as a meteorology intern today and then finishes up her Master's Degree this spring! She is looking forward to "landing" a career in aviation meteorology, while gaining hours as a private pilot.

Blessings and good health in the New Year!


Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Tuesday, December 20, 2022

"Arctic Blast" - Video Forecast Discussion - December 20, 2022

As the coldest December air in 33 years prepares to infiltrate the Mid-South just ahead of the busy holiday weekend, we review the atmospheric setup, the timing, the impacts, how to best prepare, and how long this cold spell will last! Below are a couple of the graphics used in the video to help summarize the event. 


 





Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Thursday, December 15, 2022

Winter arrives! Brace for cold air (...and winter shenanigans?)

First half of December wet and warm

We have dealt with almost two solid weeks of cloud cover, periods of fog, and multiple rainy systems and thunderstorms to start December. The result was 4-6" of rain, saturated ground, and a bunch of Mid-Southerners fighting Season Affective Disorder (making us feel SAD heading into the Christmas season)! Despite all this damp weather, the Drought Index valid this past Tuesday is a bit discouraging: 

The Drought Index valid December 13 indicates we still have a ways to go to get out from under our summer/fall drought, though areas south of I-40 in west TN could be out of the abnormally dry conditions as soon as next week. (UNL)

I expect we'll see improvement in next week's edition as it tends to lag actual conditions just a bit. But it is also proof that it takes prolonged wet weather to dig out from under a long-term drought! I suspect if you were to try and dig a hole in your yard, you would have some trouble once you get below the top 2-4"! That is drought -- not the standing water on top of the yard!

For the first two weeks of December, despite feeling cool and damp, the average temperature is actually 6.8° above normal! That is driven by both above average highs and lows, but low temperatures in particular have been quite warm for December thanks to all the cloud cover keeping us from dropping anywhere close to freezing since the 1st. That will change quickly now following yesterday's cold front. Readings near 60° are over for the month!

Second half of December brings the chill

A large dome of Arctic air has dropped across much of the eastern 2/3 of the nation, resulting in high temperatures locally in the 40s for the next week. We'll also get down to freezing nearly every morning for the next week. High pressure will control the weather for the majority of this time period resulting in mostly sunny skies. A cold front on Monday looked to potentially bring some precipitation, but it is starting to look like it may not be able to tap into enough moisture in the air to produce more than clouds, drying out as it approaches us Monday. If very light precip were to occur, it would likely be rain. 
The European model ensembles from Wednesday morning (supported by other long-range model data) indicate a chilly airmass in the week behind yesterday's front with even colder air poised to dive southeast over the northern Plains. A 5° departure from normal would equate to highs in the 40s and lows near freezing, on average. (WeatherBell)

Behind that front, we'll have a couple more dry and cool days before a massive shot of polar air that will dive into the central U.S. will shove its way southeast into the Mid-South. While the next week will be chilly, the airmass arriving late next week promises to be #StupidCold, just in time for Christmas weekend. Early indications are that we may not rise above freezing for a few days over the Christmas holiday with wind chills probably into the single digits! As for precipitation....


Maybe?!

With all the usual caveats - it's a week out, it's the Mid-South, we have bluffs and I-40 (kidding!!) - the front will be potent enough that it could definitely generate precipitation, probably on Thursday the 22nd. 

Weather forecast map valid Thursday morning, Dec. 22. Polar air dropping through the central U.S. reaches the Mid-South with the potential for a quick shot of snow along the front. (NWS)

Factors that will have to be considered: timing (of the day) and near-surface temperatures, available moisture, system dynamics, etc. One negative factor to a potentially "good" snowfall is the speed of this system. The polar airmass will hit quickly and with a fury. Precipitation won't linger around as the very dry air behind the front quickly shuts precipitation off. Long-range models are not super helpful right now, but the ensembles of those models (which we use at longer ranges to detect trends, not details) are hinting at a quick shot of snow with the front. The MWN Forecast carries a chance of rain and snow on Thursday. We'll keep you posted as we get closer! What you should prepare for though is bitterly cold air for Christmas weekend!

The same European model ensemble model temperature anomaly data shown above, only for December 22-29, showing that cold blast from the northern Plains encompasses much of the eastern U.S. A 12° departure from normal would mean highs averaging near 40° and lows in the low 20s. (WeatherBell)

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Wednesday, December 14, 2022

Perspective on the 35th anniversary of the West Memphis tornado

[ This blog post was originally posted on the 25th anniversary of the West Memphis tornado of 1987. I am resurfacing it ten years later, on the 35th anniversary, for multiple reasons. 1) It was a significant and deadly event, which could have MUCH worse had the tornado hit the dog track packed with spectators. 2) And as the first in a triplicate of major weather events in a roughly two-week span, it also sparked the flame in me that continues to burn to this day, resulting in a career in aviation weather that has been fruitful and rewarding, as well as a side business that provides another outlet to exercise my passions for weather, making a difference by keeping people safe and informed, and giving back by mentoring the next generation of successful meteorologists. Thanks for reading! /EP ]

ORIGINALLY POSTED DECEMBER 14, 2012:

A quarter-century ago, I had been living in the Memphis area for just over a year and was in middle school when an event occurred that I now believe was the first spark that started the fire, igniting a passion that lives in me to this day and likely determined my future career path.

The West Memphis Tornado of 1987

On Monday, December 14, 1987, at 9:40pm, a major twister touched down just southwest of West Memphis, AR and moved rapidly northeast at 60 mph, tearing a path through the city across the Mississippi River from it's namesake, then blew across the Mighty Mississippi (thus disproving the myth that the river and bluffs protect Memphis and Shelby County) and into Meeman-Shelby Forest State Park in northwest Shelby County before lifting just west of Millington, TN.

Track of the F-3 tornado that passed through West Memphis, AR and crossed the river into Shelby County, TN

By the time it was done, F-3 damage was recorded in both Arkansas and Tennessee along a 25-mile path, six people were dead, and 121 others were injured.  Damage estimates were approximately $35 million [1987 dollars], including 235 homes, 35 businesses (many along Broadway street in downtown), and a school in West Memphis and 88 homes in the Northaven development west of Millington that were destroyed or heavily damaged.  In all, 1,500 people, or roughly 5% of the population of West Memphis, were left homeless.

According to Associated Press archives, Arkansas Governor Bill Clinton sent in the National Guard and additional state troopers to put a halt to looting in the central business district following the tornado.

The tornado also struck several high voltage power lines, including two 500,000 volt lines and three 161,000 volt lines, leaving much of Crittenden County, AR without electric power. Those killed included a woman in her mobile home, an elderly man in a boarding house, a teenager in a grocery store parking lot, a one-year-old child in an apartment building, a person in a vehicle that was thrown on I-40, and a person in a truck stop parking lot.

As bad as it was, the destruction could have been much worse.  At the time of the tornado, 7000 spectators were at Southland Greyhound Park dog-racing track in West Memphis, which the twister missed by just one-quarter mile. Video below is courtesy KATV meteorologist Todd Yakoubian (@KATV_Weather on Twitter).


Meteorological setup

From a meteorological perspective, the tornado appeared to form just behind a warm front that lifted through the area.  From observations taken at Memphis International Airport (the closest recording station to the tornado), it was 50 degrees at 7pm with wind from the east at 6 mph and dense fog being reported. An hour later, the temperature had climbed to 66 degrees (after dark) and wind shifted to the southeast at 21 mph with fog lifting. Between 9:00-10:15pm, the temperature was 70 degrees and wind gusted from the southwest at up to 40 mph as pressure bottomed out at 29.38".

Surface map valid at 9pm with the surface low moving by just west of West Memphis.  The map indicates that it was 70 at Memphis Int'l and 40 in Jonesboro, AR with heavy snow falling in the Ozarks.

By 7am the next morning, the temperature had fallen back to 32 degrees following a night of westerly wind that gusted between 35-48 mph.  Weather maps show a potent upper-level disturbance moving by just west of the area and a rapidly-strengthening surface low moving through AR that evening.

Daily weather map for the morning of December 14, 1987. Low pressure over south TX lifted rapidly north and strengthened, reaching Chicago the next morning. The track of  the low through AR put the Mid-South in prime position for wintertime severe weather.

Upper level weather maps from December 14, 1987 at 6pm. Upper left: a strong jet stream over the Mid-South. Upper-right: an upper-level disturbance moving by to the west. Lower-left: low pressure at 5,000' over southern MO. Lower-right: surface low pressure over AR moving rapidly north, placing the Mid-South in the storm's "warm sector."

A triple case of bad luck

Unfortunately, the tornado was just the first event in a series of cases of bad luck dealt by Mother Nature. The town had not recovered from the tornado when parts of it flooded from 12" of rain eleven days later, on Christmas Eve night, leaving 1000 homes flooded and another person dead. Then, 7-10" of snow fell on January 6, another 11 days after the flooding rains. As snow melted, it added to the already existing misery caused by the flood and the destruction caused by the tornado.  Oddly enough,  West Memphis became the first U.S. city to be declared a federal disaster area twice in a two-week period due to this string of events.

A personal note

Many times, when a meteorologist is asked what triggered their interest in weather, it is a singular event that had an impact on their life. For many years, I was unsure of what that event in my life was.  However, I knew that my passion began in the middle school years, shortly after I relocated with my family to the Memphis area. There is no doubt now though, as I now vividly recall the destruction of the city upon driving through it with my parents within a few days of the tornado, that the West Memphis tornado of 1987 was THAT event in my life. I find it hard to believe that it was 25 years ago!  Perhaps that is also why I am so passionate about making sure people are informed and taking precautions when severe weather strikes, which has resulted in the services offered by MemphisWeather.net and our mobile app-based weather alert system - StormWatch+.

Do you have more than a passing interest in weather, even if you're not in the profession?  What event triggered your  interest?  If you've lived in the Mid-South for a quarter century, what do you recall about this event? I'd love to see your comments below!

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info! 
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app 
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder



Saturday, December 10, 2022

November 2022 Climate Report for Memphis, TN

November Climate Recap

Temperatures for the month of November in Memphis averaged just below normal, though about two-thirds of the month was actually above normal. The average was skewed down by a 10-day cold snap mid-month with multiple days 10-16 degrees below average, several of them sporting highs only in the 40s. That also drove up the number of sub-freezing mornings we experienced, with 11 days at or below 32 versus an average for November of about four. 

The temperature anomaly map for the month of November shows slightly below average temperatures across the Mid-South. (PRISM temperature data via WeatherModels)

With slightly below average precipitation recorded, minor drought conditions continued through the month, and actually worsened slightly for Tipton and Fayette Counties (from abnormally dry to moderate drought). East AR remains in severe drought as we head into December. The wettest day of the month was on the 5th when thunderstorms moved through the area. The cold spell mid-month was primarily dry, before multiple wet days occurred in the last week of the month, though not with excessive rainfall. A little over an inch fell with additional storms on the 29th. These storms also brought hail to southern Shelby County and sporadic wind reports south and east of Collierville. Severe Thunderstorm Warnings were issued.

Memphis International Airport, Memphis, TN

Temperature 
Average temperature: 52.1 degrees (0.6 degrees below average) 
Average high temperature: 61.9 degrees (0.7 degrees below average) 
Average low temperature: 42.3 degrees (0.6 degrees below average) 
Warmest temperature: 82 degrees (8th) 
Coolest temperature: 24 degrees (21st) 
Heating Degrees Days: 398 (19 above average)
Cooling Degree Days: 20 (8 above  average) 
Records set or tied: None
Comments: Eleven days dropped to 32 degrees or below this month, which is 6.7 days above the average November. 

Precipitation 
Monthly total: 3.62" (1.07" below average) 
Days with measurable precipitation: 9 (0.0 days below average) 
Wettest 24-hour period: 1.61" (5th) 
Snowfall: 0.0"
Records set or tied: Daily maximum rainfall set on the 5th (1.61")
Comments: None 

Miscellaneous 
Peak wind: South-southeast/45 mph (4th) 
Average wind: 6.7 mph 
Average relative humidity: 69%
Average sky cover: 49%

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

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN

Temperature 
Average temperature: 50.0 degrees 
Average high temperature: 62.2 degrees 
Average low temperature: 39.6 degrees 
Warmest temperature: 81.1 degrees (9th) 
Coolest temperature: 19.8 degrees (21st) 
Comments: None 

Precipitation 
Monthly total: 3.40" (automated rain gauge), 3.35" (manual CoCoRaHS rain gauge) 
Days with measurable precipitation: 9
Wettest date: 1.89" (5th) (via automated gauge) 
Snowfall: 0.0"
Comments: None

Miscellaneous 
Peak wind: Southeast/32 mph (29th)
Average relative humidity: 73% 
Average barometric pressure: 30.17 in. Hg
Comments: None

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

MWN Forecast Accuracy

MWN average temperature error: 2.08 degrees 
MWN forecast temperatures within 2 degrees of actual: 69% 
MWN average dewpoint error: 2.25 degrees 
MWN forecast dewpoints within 2 degrees of actual: 65% 

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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Follow MWN on Facebook and Twitter for routine updates and the latest info! 
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app 
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder