Tuesday, February 28, 2017

March arrives like a lion - details on potential severe weather

As we close out what will likely be the warmest February on record, March appears to be coming in like a lion as severe weather potential exists mainly early on Wednesday morning (March 1).

A strong cold front will plow into a very warm, unstable, and moist airmass that resides across the eastern U.S. A rare (considering time of year and location) Moderate Risk (category 4 of 5) zone across the Midwest and Ohio Valley region, which stretches as far south as southern Missouri. Scattered supercells capable of producing tornadoes, very large hail, and damaging wind will be likely across this region this evening and into the overnight hours:

The severe weather outlook for Tuesday through 6am Wednesday. A Slight Risk (category 2 of 5) is in effect for the metro, primarily for the last few hour of this outlook period (wee hours Wednesday).

Behind those discrete supercells, a squall line will likely form along the front as it moves east overnight into Wednesday. That will lead to additional severe storms, more capable of damaging straight line wind, east of the Mississippi River on Wednesday:

The severe weather outlook for Wednesday, beginning at 6am. A Slight Risk (category 2 of 5) is in effect for the early portion of this outlook period. Storms should be east of the metro by 9-10am.

A preliminary look at hi-res simulated radar from the HRRR model valid at 6am Wednesday showing the approach of what might be the second line of storms to affect the metro early Wednesday morning. An extensive area of thunderstorms extends through the Ohio Valley into western PA. (WxBell)

Memphis-area storms

For the Memphis metro, most of the "discrete" supercells tonight will remain to our north. That is a good thing. A few thunderstorms will likely form in AR late this afternoon/early evening and move northeast, but will likely miss the metro to our northwest. We'll be keeping a close eye on this situation as they could produce large hail, damaging wind, and have the low potential for a tornado. Note that those are most likely in the Enhanced Risk (3 of 5). For at least the first half of the overnight period, we should remain dry, but strong south wind and high dewpoints (mid 60s) will keep the pump primed.

By the wee hours of the morning through rush hour, we will begin to see our severe weather risk ramp up as the cold front draws a little closer to our area. The possibility exists of one or more lines of strong to severe storms moving through between 3am-9am. These lines would bring the possibility of straight-line wind damage, perhaps some hail, and a low-end tornado risk. By mid-morning, the line(s) should be to our east and the threat of storms ends as wind shifts to the northwest and temperatures fall out of the 70° range.


To summarize, a few storms are possible, mainly northwest of the metro, early this evening, followed by a higher risk of storms from the wee hours of Wednesday morning until mid-morning. Damaging wind, hail, and possibly a tornado are all possible. We strongly suggest that you take the time review your severe weather action plan and make sure that you have multiple ways to receive notice of threatening weather while sleeping. These could include NOAA Weather Radio and a smartphone service like StormWatch+ in the MemphisWeather.net mobile app. Do NOT rely on hearing a tornado siren overnight. With wind blowing and potentially rain hitting the roof, you're asking for trouble if you hope that you hear a siren. We also encourage you to follow along on our social media channels for the latest information and nowcasting of any storms that affect the area.

Given that this week is also Severe Weather Awareness Week, it's perhaps ironic that severe storms could occur. However, it's also fortunate that this week is the one week of the year that we discount the StormWatch+ service in the MWN app! If you don't have a weather radio or can't get one, spend $5.99 (one-time upgrade in the app) and set up the locations you want to be alerted for. Here's a video that describes the setup (it's pretty straight-forward) and here's something you should read to make sure you receive severe weather notifications via our "wake-me-up" audio alerts while sleeping. The app only yells at you if a Tornado Warning (or Severe Thunderstorm Warning) is issued for your specific location.

Finally, on our Facebook page, we are giving away a NOAA Weather Radio this week courtesy of our partners at Midland Radio! Just find the pinned post at the top of the page to enter. #TeamMWN also will be presenting a severe weather preparedness video discussion on Thursday night at 8pm. Be sure to mark your calendar to watch, learn, and join in the conversation, as well as have another chance to win a weather radio!

Stay safe,

Erik Proseus
MWN Meteorologist

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, February 25, 2017

Warm February ends wet; TN Severe Weather Awareness Week

With four days left in the month, February is currently ranked as the warmest on record in Memphis (55.1°, which is a full 10° above the monthly average). Despite much cooler weather this weekend, we are projecting that the month will end as the warmest since records began in 1875, as the unusual warmth returns to end the month. We should also end "meteorological winter" (December-February) with as fourth warmest on record. Looking ahead to this week, it also appears that March will come in like a lion! Let's get into the details.

Memphis average temperatures by month for "meteorological winter," ordered by warmest season. This winter currently ranks #4.
A strong cold front that brought scattered severe storms to places that don't usually receive them in the winter (Upper Ohio Valley) also moved through the Memphis metro last evening. Though very little rain fell in the metro, it did usher in MUCH cooler temperatures. Most of us woke up to wind chills in the mid 20s with temperatures in the mid 30s this morning.

24-hour temperature differencefrom 9am yesterday to 9am today. You can clearly see areas that the front passed through in the past day! Purples indicate temperatures more than 30° cooler in 24 hours. (WxBell)
As high pressure moves directly overhead later today, wind dies down and temperatures remain cool despite sunny skies. We'll see highs near 50. With light wind, clear sky, and dry air in place tonight, expect the budded trees and flowers to shiver as the mercury falls below the freezing point - to near 30 in the city and mid to upper 20s in rural and suburban areas. If you need to cover plants to protect them, do so this evening. Outlying areas could see 6-8 hours of sub-freezing temperatures overnight!

Sunday begins the warm-up as high pressure shifts east. For the most part, it will be a sunny day with high clouds moving in by sunset in advance of the next quickly-moving weather system. Look for highs about 10° warmer than today, or near 60°. The month of February has also been dry with officially just over an inch of rain so far. That will change as the next weather-system arrives Sunday night. Low pressure organizes in the southern plains and a warm front approaches from the south. Upper level low pressure will trigger a rain event Sunday night into Monday morning with some rain potentially heavy early Monday morning. No thunder is anticipated from this event, which will move out during the morning hours Monday. Anticipate a wet morning commute.

The North American Model (NAM) prediction for rainfall from 6pm Sunday through 6pm Monday. (PivotalWx)
Monday night, the warm front moves through from south to north, ushering in very humid Gulf air and triggering scattered showers and a few thunderstorms. This puts the Mid-South in the warm sector of the next low pressure and frontal system. Tuesday will see very warm conditions and unstable air, but with little dynamics to trigger precipitation, only a few showers or thunderstorms are anticipated, and it could turn out dry. Highs will be back into the 70s with dewpoints near or above 60° and warm south wind.

The NAM model prediction for high temperatures on Tuesday afternoon, as warm, moist southwesterly breezes push highs well into the 70s. (PivotalWx)

Tuesday night into Wednesday morning, as March arrives, is when we'll feel the effects of that next front. It's too early to predict severe weather chances, but the front will be strong with decent upper level dynamics and will tap into plenty of moisture. The X-factor could be instability, which would peak during the warmest part of the day. If the front arrives as scheduled now (mid-day), sufficient instability will be a question mark. For now, plan on a stormy day Wednesday, particularly early. Behind the front, temperatures cool down again, but sunny skies prevail for the remainder of the week.

The American GFS model prediction for rainfall from 6pm Tuesday through 6pm Wednesday. Most of this falls late overnight into Wednesday morning locally. (PivotalWx)

Next week is also Severe Weather Awareness Week in TN and AR (this past week was awareness week in MS). As usual, we plan to have a full slate of information and education to help prepare you for severe weather season. In addition, we'll have some giveaways throughout the week, including free MWN apps (including our StormWatch+ severe weather alert app upgrade) and free weather radios from our severe weather awareness week partner, Midland Radio!

The week starts tomorrow with a discussion of SKYWARN and social media storm spotting and reporting and continues each day with a different topic. We also will be hosting a live video presentation (most likely Tuesday evening, weather-dependent!) with a panel discussion on multiple severe weather topics and a chance for you to ask questions. You can get all the details of our activities this week on our Severe Weather Awareness page on MWN.

Erik Proseus
MWN Meteorologist

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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, February 21, 2017

Sun and Storms Lead the March Towards Spring

As the close of February draws near, Mother Nature is ready to turn the page from winter to spring. After near record warmth across the region to start the week, the end of this week could bring more of the same, with the possibility of some storms mixed in too.

Heating Up (Again...)

After showers moved through the metro area early on Tuesday, warm temps are coming back for the mid-week. Expect a mostly cloudy sky and highs in the 70s for Wednesday and more of the same for Thursday with a bit more sun. Highs could even reach record warmth by Thursday afternoon. Lows will drop into the 50s to near 60 each night.

The final day of this 70-degree streak comes on Friday, but with that comes the potential for some stormy weather on Friday evening in the region.

Storm Front Coming

A low-pressure system working its way into the intermountain west will continue to propagate east, bringing showers and storms to the Ohio Valley and Midwest. This system could also bring rain and thunderstorms into our area on Friday afternoon or evening, but right now there is only a slight (20 percent) chance. With the cold front set to cross over Memphis to start the weekend, there is the possibility of severe weather across areas north and east of Memphis, although these chances are conditional, meaning that if a few storms can form, they could become severe.

Following that front will be a cool down to seasonal temperatures and conditions for the rest of the weekend, though Saturday could be slightly below average. Highs may only hit the mid-50s, with lows in the lower 40s on Saturday. Sunday looks to gradually warm things up a little more, with highs near 60, after a chilly night with overnight lows in the mid 30s.

Into March We Go!

The final few days of February bring temps back into the 60s and 70s during the day, but also another chance of showers and thunderstorms Monday into Tuesday. We'll know more after the frontal passage on Friday.

Early March is shaping up to be coming in like a lion, with above average temperatures, but also above average precipitation. Perhaps it will help the end of March head out like a lamb?

With Severe Weather Preparedness Week underway in Mississippi, and the next week here in Tennessee, now is a great time to get ready for spring storms. Make sure you have warnings pushed to your phone through our StormWatch+ app, where you can customize the alerts you get for your hometown. Also be sure to regularly check our MWN human-powered forecast through our website, social media feeds, and mobile app.

Alex Herbst, Meteorologist
MWN Social Media Intern

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Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

So... is winter over??

You won't believe (or maybe you would) how many times I've been asked whether winter is actually over. The short answer? I think so.  Let's take a look...

First, if you think this was a "year without a winter," you are only partially right. It's been a while, and the recent heat has probably seered some brain cells, but December had some very cold periods. In fact, this blog spoke of at least three "Arctic blasts. Interspersed between some very warm days were multiple days with highs in the 30s and 40s. In fact there were low temperatures of 15° and 18° on consecutive days mid-month. Overall, December was about 1° above normal, mainly due to a few very warm days offsetting those cold ones.

Moving on, while January was very warm overall, we had 4 consecutive days with highs in the 20s and 30s and snow fell on Friday the 6th with most kids getting a snow day. There are many years when a snow day doesn't happen. Snowfall will end up below normal this year, but we only average about two small snow events a year. We got one. (And yes, I'm predicting we won't see another.)

Remember this snowfall on January 6? We didn't completely skip over winter this year!
After a top 10 warm January, February is likely on track to out-pace the warmth of January. As of the 20th, the average temperature for the month ranks third warmest on record...

Top 10 warmest February 1-20 periods on record, according to NOAA. 2017 ranks #3.

...and the forecast models indicate well above average temperatures to close out the month, with the exception of this weekend behind a Friday cold front.

The American-made GFS model ensemble system forecast temperature anomalies through the end of the month show plenty of warmth, with one "break" of near average temperatures this weekend behind a cold front that moves through Friday. (WeatherBell)
Looking towards March, we have a few products that can give us hints on what's to come. The first is NOAA's Climate Prediction Center outlook for days 8-14, which covers the first full week of March.

NOAA's day 8-14 temperature outlook, covering the first week of  March, expressed as percentage chance of above (below) normal. The Mid-South has a 60% chance of above normal temperatures. (NOAA/CPC)
No signs of any cold blasts there, with a 60% chance that temperatures will average above normal and a less than 10% chance they will be below normal. The week 3-4 outlook, which covers the period through the middle of the month shows a bit more promise, but even slightly below normal temperatures for that time of year would indicate highs near 60 (not winter, but not 80° either).

NOAA's week 3-4 temperature outlook, covering the period March 4-17, expressed as percentage chance of above (below) normal. The Mid-South has a 50% chance of below normal temperatures according to this graphic. (NOAA/CPC)

Finally, the NOAA temperature outlook for the entire month of March (issued last week), shows slightly enhanced odds of above normal temperatures for the month (first image below), while the March-May "spring" outlook indicates a decent chance of temperatures averaging above normal  (second image below).

NOAA's March temperature outlook, expressed as percentage chance of above (below) normal. The Mid-South has a 33-40% chance of above normal temperatures. (NOAA/CPC)

NOAA's March-April-May temperature outlook, expressed as percentage chance of above (below) normal. The Mid-South has a 40-50% chance of above normal temperatures (which according to their methodology means a 33% chance of near normal and a 17-27% chance of below normal temperatures). (NOAA/CPC)

Shifting from NOAA to the European model ensemble (basically the European model produced 50 times with slight variations and averaged), here is the latest temperature anomaly (departure from normal) map for the next 46 days (though April 6), also indicating above average temperatures east of the Rockies.

The European Ensemble model system predicts above average temperatures (overall) for the next 46 days. (WeatherBell)

And just for fun, the precipitation anomaly for the same period, showing the potential for a wet 6 weeks in the southeastern U.S.

The European Ensemble model system predicts a wet 6 weeks ahead for the southeastern U.S. (WeatherBell)

Does all this mean we won't see ANY more cold weather? Not necessarily. In fact, some areas will be back into the 30s again Sunday morning. However, it's POSSIBLE that the last freeze of the year has occurred in the city. The average date of the last freeze at the airport is March 19, which is still nearly a month away. I certainly can't rule out that still occurring. Our last 32° reading was February 16, While that is very early, if there isn't another freeze, it won't be the earliest last freeze on record, which was set 4 days earlier, on February 12, 1878!

The average last frost date is March 29, using 36° as a proxy for frost formation. There's still plenty of time for some 30s to affect the buds and blossoms that are arriving 2-3 weeks ahead of schedule, so if you have an itch to plant something, understand that frost, or maybe a freeze is still possible for some time yet.

The USA-National Phenology Network tracks the start of spring using models based on the Spring Leaf Index. Shown above is the spring anomaly through February 20, indicating that spring arrived in the Mid-South 2-3 weeks ahead of schedule.
So by all indications, spring has sprung and Punxsutawney Phil is #FakeNews! Just don't be surprised by a few chilly mornings mixed in with the occasional 80° day over the next month or so!

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

Thursday, February 16, 2017

Warming weekend kicks off another warmer than average week ahead

Is it spring, winter, summer, or fall? While Mother Nature may still be undecided on the answer to that, the next week will feel more like early April than mid-February. That’s right, the warm weather is back and is shaping up to bring you a pretty good weekend in the metro.

Wide World of Warmth

The warming trend that started on Thursday will continue Friday as a ridge over the center of the country builds east. High pressure will remain over the region to end your work week, with temperatures jumping into the mid to upper 60s.

Temperatures are on the upswing over the next few days, as seen here in this temperature map (oranges/reds are 70s), with winds shifting out of the south to southwest. (PivotalWx)
Sunny skies will make Friday a pleasant way to lead into the weekend. A south to southwest wind will help usher in that warmer air too, leading to a more temperate overnight low in the 50s on Friday night. By comparison, our average high for this time in February is the mid 50s.

Showers on Saturday

The next chance of rain enters the picture Friday night into Saturday. A low pressure system moving across the Gulf of Mexico will throw the chance of showers north into the Mid-South overnight Friday night, though mostly scattered in nature. It will certainly not be a total washout on Saturday, with the best chance of showers coming between midnight and noon. Temps will still stay warm in the mid 60s.

Our next chance of rain will move through Friday night into Saturday. Though this NOAA surface map shows lots of green over the Mid-South, we’re expecting more scattered precipitation over the early part of the weekend
Showers and rain will be more likely the further you head south. If you’re traveling down through the Magnolia State, you could see a few thunderstorms too. These storms will likely not be severe across most of the state, though the Mississippi coast could see some stronger ones.

Overall, Saturday will be the only questionable day weather-wise over the holiday weekend ahead. Sunday will see clearing skies and warmer temperatures. 70+ degrees would not be a surprise over most of the metro area, with lows in the 50s.

70s in Command!

For those of you with extended weekends thanks to the Presidents Day holiday, Monday may be the best day of your weekend. Sunny skies and temperatures into the lower 70s will make you want to be outside soaking up some unseasonably warm rays. Lows in the 50s won’t feel bad either on Monday night.

The next system worth watching enters the picture for Memphis around mid-week. A low pressure center currently off the California coast will work its way across the west this weekend, and could bring rain and thunderstorms into the Mid-South by late Tuesday or Wednesday. Of course, MWN will keep you ahead of any incoming storms all through the next week. Looking further ahead, the temperature outlook indicates a very high likelihood of above average temperatures continuing into the last weekend of February.

The temperature outlook for Feb. 22-26 indicates a greater than 70% chance that above average temperatures continue across the Mid-South. (NOAA/CPC)

Want to get more updates from MWN? Check out our human-powered forecast and don’t forget to download the MWN app for your smartphone and tablet to get your daily dose of MWN in one complete package!

Alex Herbst, Meteorologist
MWN Social Media Intern

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, February 8, 2017

Back to winter, for a minute...

Quickie blog today, mainly to pass on our "Social Media 6-Day" forecast to you. It's a continuation of the roller coaster ride we've been on lately! A cold front stalled over the area last night. As it pulled back to the north this morning right around sunrise, dense fog formed. it honestly was some of the "pea soup-iest" I had seen in a long time!

As I sat at the intersection of Winchester and Plough Boulevard on the northwest corner of the airport about 8:15am, I couldn't see the control tower. And not just the top of it, which happens sometimes, but NONE of it! And yet, there was FedEx, landing planes anyway! I marvel at how those jets and their flight crews can operate in such harrowing circumstances as not seeing the runway until you're over it.

The fog lifted by mid-morning and this afternoon, that front got one more push south, shifting wind back to the north, starting a temperature drop that will continue until tomorrow morning, when it will end up about 40° cooler than this afternoon's high just above 70° with wind chills down in the 20s. If you're heading out this evening, take a coat. Temperatures will be in the 40s with a gusty north wind up to 25-30 mph.

Tomorrow we're back to winter. Sun returns, but the mercury tops out in the mid 40s. A clear night is expected Thursday night with lows near freezing. As wind begins to shift towards the south Thursday night, it picks up Friday, pushing temperatures BACK into the 60s! South wind taps into some Gulf moisture Saturday with highs back above 70°, despite abundant cloud cover and widely scattered light showers or sprinkles dotting the radar.

The next cold front arrives Sunday with plenty of moisture and some instability to work with. Look for showers and thunderstorms, especially the second half of the day, and another warm one on tap as highs again reach near 70. Early next week looks like off and on showers with seasonal temps. More on that as it gets closer. Here's that forecast (and bless you...I know your sinuses love it):

Erik Proseus
MWN Meteorologist

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Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Tuesday, February 7, 2017

January 2017 Climate Data for Memphis, TN

January Recap

After December broke a streak of six consecutive months ranked in the top 10 warmest for their respective months, January returned to the top 10 rankings, tied for eighth warmest January on record.  The warmth lasted nearly all month with just one spell of multiple days that were well below average temperature-wise, which also coincided with the first significant snowfall of 2016-2017 winter on the 6th. That early-month cold spell featured four consecutive days with high temperatures at or below 35 degrees and a couple of morning lows in the lower teens. However, three days later, highs were back above 70 degrees. After the 9th, only two days featured average temperatures below normal, and those were 1-2 degrees below an "average" day.

Warmest Januarys on record in Memphis, per the National Weather Service. 2017 tied for 8th warmest.
Precipitation was just a bit above normal at the airport, but below average at MWN in Bartlett with more than an inch and a half less than the airport recorded. Snowfall officially totaled 2.0" at the airport with reports across the metro varying from just under an inch to about three inches. No severe weather was reported and only one warning was issued, a Flash Flood Warning for far southern Shelby County and far northern DeSoto County on the 10th, which also happened to be the wettest day of the month as storms trained along the TN/MS border.

Memphis International Airport, Memphis, TN

Average temperature: 48.5 degrees (7.3 degrees above average)
Average high temperature: 56.4 degrees (6.6 degrees above average)
Average low temperature: 40.6 degrees (8.0 degrees above average)
Warmest temperature: 76 degrees (12th)
Coolest temperature: 13 degrees (7th, 8th)
Heating Degrees Days: 503 (235 below average)
Cooling Degree Days: 2 (1 above average)
Records set or tied: None
Comments: The average temperature of 48.5 degrees ties for 8th warmest January on record. Seven days recorded sub-freezing low temperatures, which is 7.5 below the long-term average.

Monthly total: 4.26" (0.28" above average)
Days with measurable precipitation: 13 (3.5 days above normal)
Wettest 24-hour period: 1.50" (10th-11th)
Snowfall: 2.0 inches
Records set or tied: None
Comments: All snowfall occurred on a single day, January 6th.

Peak wind: South/47 mph (10th)
Average wind: 8.9 mph
Average relative humidity: 73%
Average sky cover: 70%

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

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN

Average temperature: 47.9 degrees
Average high temperature: 56.0 degrees
Average low temperature: 39.1 degrees
Warmest temperature: 74.8 degrees (12th)
Coolest temperature: 10.8 degrees (8th)
Comments: None

Monthly total: 2.64" (automated rain gauge), 2.73" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 12
Wettest date: 0.82" (2nd) (via automated gauge)
Snowfall: 0.9 inches
Comments: None

Peak wind: Southwest/30 mph (12th)
Average relative humidity: 80%
Average barometric pressure: 30.07 in. Hg

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

MWN Forecast Accuracy

MWN average temperature error: 2.79 degrees
MWN forecast temperatures within 2 degrees of actual: 53%
MWN average dewpoint error: 3.20 degrees
MWN forecast dewpoints within 2 degrees of actual: 53%

MWN's forecasts extend out five periods (2.5 days, or roughly 60 hours). Historical accuracy statistics can be found here.

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

Sunday, February 5, 2017

Another round of spring-like warmth, wind, and storms

Warm weather more suitable for March/April returns early this week as a storm system moves out of the Rockies and across the mid-section of the country into the Mississippi Valley by early Tuesday. Southerly wind has already set up across the region, returning a bit of moisture from the western Gulf as dewpoints climb through the 40s as we end the weekend. A dichotomy in sky conditions exists across the metro with clouds over north MS but sunshine over the northern half of the metro.

Clouds are prevalent over the southern half of the area this afternoon, while sunshine abounds north of the TN/MS line.
As high pressure over the Gulf of Mexico shifts east, clouds increase over the northern metro tonight and by morning we'll see southwest flow bringing in greater amounts of moisture on a strengthening low-level (2000-5000') jet stream. The increasing wind and moisture will trigger the development of scattered showers in the wee hours of the morning as a quasi-warm front moves north through the region. A few cracks of thunder are also possible though severe weather is not expected.

A round of scattered showers and a few thunderstorms is expected early Monday as this model simulation of radar echoes shows. The model depicted is the newest high resolution NAM valid from midnight to noon Monday. (PivotalWx)
By mid-morning, that round of precipitation will lift north and the atmosphere will become "capped" by a layer of warm air aloft throughout much of the rest of the day, putting an effective lid on anything but a few stray showers. With warm Gulf air being pumped into the region Monday on southerly wind of 15-20 mph, a lack of widespread precipitation, and dewpoints climbing towards 60°, high temperatures will likely reach 70°.

Very warm air will be in place Monday afternoon, as shown by the forecast temps at 3pm from the high-resolution NAM model. Highs in Memphis could reach 70° with a warm southerly wind. (PivotalWx)
Late Monday afternoon, the primary upper-level energy will begin moving across the nation's mid-section, resulting in thunderstorms well to our west. On Monday night, those storms continue rolling east with the upper-level shortwave, reaching the Mid-South in the wee hours of the morning Tuesday.

This loop of upper-level energy (yellows/oranges) from the GFS model shows a shortwave trough and its attendant lift moving across the southern Plains Monday and into the Mid-South very early Tuesday. (PivotalWx)
Activity should weaken a bit during those overnight hours due to a lowering of instability under the cover of darkness, but strong south wind pulled north by a low pressure system moving into the midwest, plenty of atmospheric moisture, and the lift generated by the shortwave will result in thunderstorms from very early Tuesday morning through perhaps mid-day. There is currently a Slight Risk (category 2 on the 5-point scale) of severe weather for the metro during that timeframe. Damaging wind and hail are the primary threats, with an isolated tornado not out of the realm of possibility. A greater threat of strong storms will likely exist to our east as areas from the Ohio to Tennessee Valley get more unstable due to storms arriving later in the day.

The early day storms will far out-run a cold front, which means after the storms, a few showers will be possible Tuesday but temperatures should again reach the 70° mark (perhaps warmer than Monday) as wind remains southwesterly and dewpoints still at least in the 50s.

Another warm day is expected Tuesday behind the morning storms and ahead of Wednesday's cold front. The high-res NAM model predicts widespread 70s along and west of the Mississippi River at 3pm. (PivotalWx)
The cold front finally moves through early Wednesday it appears, as weak low pressure forms over the southern U.S. and pulls it south. Previous forecasts had Wednesday dry with moderate temperatures, but it appears that there could be a few more showers, and maybe a thunderstorm, as the low moves quickly by to our south and the front drops through the metro. The end of the week appears much cooler again, but dry, leading to our next chance of rain next weekend.

We encourage everyone to stay tuned to the latest forecast information, particularly with regards to Tuesday morning, in case severe weather chances increase. As it stands, you still need to plan on having a way of getting severe weather information via a wake-me-up source like NOAA Weather Radio or StormWatch+ in the MemphisWeather.net mobile app overnight Monday.

Erik Proseus
MWN Meteorologist

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