Sunday, July 29, 2018

Elevated rain chances, then more pleasant summer weather ahead!

The Mid-South experienced a couple of days of near to slightly below average temperature and humidity days this weekend and now we look ahead to the upcoming week, which had been promising a wet start then more decent weather to end the week. Let's see if that has changed any given the latest computer data and current state of the atmosphere.


We head into Sunday night in-between any major systems as weak high pressure controls much of the eastern U.S., but low pressure is forming to our west. At the upper levels, a disturbance in the force will move across the area through the first half of the night, leading to a chance of a few showers, mainly in northeast AR. A much more moisture-rich airmass sits to our south, but will start to move north tonight as a stationary front lifts into our area by Monday. Temperatures will be near average in the lower 70s.
Late afternoon runs of the HRRR model show the potential for scattered showers and thunderstorms through the evening hours before drying out overnight into Monday morning. (


Monday brings another late day pocket of upper-level energy across the area, so while much of the day should be dry, more scattered showers and thunderstorms are possible by late afternoon and evening. They will tap into a more humid and unsettled airmass with the surface front nearby, so a couple of storms could be strong. The Storm Prediction Center currently has us in a Marginal Risk (level 1/5) for severe weather, though high-resolution models indicate that the prime area of concern for storms could slip by to our south and west. Expect highs to be below normal - in the mid to upper 80s.

The mid-day run of the high-res NAM model forecasts a few evening showers tonight then a lull before more showers and storms moves through late afternoon/evening on Monday. The heaviest storms should swing through southern AR if it is accurate. (
A Marginal Risk (level 1/5) of severe storms is forecast for a broad area from the Ohio Valley southwest into the Arklatex on Monday. A few storms could having strong wind gusts in the PM hours in the Mid-South.

Monday night - Tuesday

On Monday night, expectations are for a wetter pattern with weak low pressure moving along the front draped over the area. That said, the latest model data has been trending a little drier than we had thought late last week. We're still going with "likely" for the rain chances, but it may not be as heavy or prolonged as first thought. By Tuesday, an upper level trough will form over the Midwest and Mississippi Valley, which will begin to shove the cold front to our east. Once again, there is a chance of scattered showers and thunderstorms, but the severe threat appears minimal and rain chances move east with the cold front as the day goes on. We should be dry by Tuesday night. Another "cool" day to end July with highs in the mid 80s.

Forecast rainfall from the National Weather Service through this week's event is generally 1/2"-1", though amounts could vary quite a bit in any given spot. (WeatherBell)

Mid-week and beyond

For the rest of the week, the upper level trough hangs on over the Mississippi Valley region it appears, which should keep most or all of the precipitation to our east. It also means more pleasant weather is likely, especially for mid-week as August begins. We'll certainly take that! The long-range outlooks from last week pointed to a period of below average temperatures to end July and start August and it looks like they were accurate. Look for highs in the 80s to continue!

The setup in the mid levels of the atmosphere by Wednesday morning features a large trough of low pressure controlling our weather with a well-entrenched high over the southwest U.S. and another high off the Atlantic coastline. Showers and thunderstorms are expected ahead (to the east) of the trough over us with cooler weather under the trough. (PivotalWx)
Expect dry weather to continue as well through the end of the week with temperatures moderating and humidity below summer norms with dewpoints in the 60s. Signs point to near-average conditions heading into next weekend and the first full week of August as many Mid-South kids and teachers get ready to head back to school!

Erik Proseus
MWN Meteorologist

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

Wednesday, July 25, 2018

Unbearable summer heat looks to remain at bay

It has felt pretty decent outside recently for mid-July if you ask me. What's been causing all of this nice weather? Well a couple of things. One of the key factors for us lately is we haven't been stuck under a ridge pattern. When we get into these patterns, it keeps out any fronts that would help out our temperatures. This leads to extremely hot temperatures, increases those pesky pop-up afternoon shower chances, and makes dewpoints sore through the roof.

Thankfully, in recent times an upper-level trough has in control for the most part over our area. This allows temps to stay fairly mild for mid-July, holds dewpoints in the 60s, and keeps those afternoon thunderstorms away. Looking at the next few days Mother Nature will try to bring those sticky dewpoints back into the picture, but another cold front will pass through on Friday, which will help to cool things off again.

A little sticky and gross tomorrow

Tomorrow is likely going to be the most summer-like day that we will see this entire week. Highs will reach around 93 by the afternoon with heat index values creeping near the 100 degree mark. Winds will remain out of the northwest, which will keep dewpoints at bay and in the upper 60s.

While it will probably feel a bit more sticky tomorrow, there will not be enough moisture for afternoon pop-up thunderstorms to be a concern. So, lucky for us, we should dodge showers for yet another day.

Cold front Friday sets the stage for a fantastic weekend

Beginning tomorrow night, cloud coverage and our rain chances will begin to increase ahead of Friday's cold front. As the front moves close to the Mid-South, this may provide enough forcing to get some showers and maybe even a thunderstorm or two to develop.

Timing of these showers appears to be between late Thursday night through Friday morning. Different models have different variations on timing of these showers, but since they appear to be moving when temperatures are naturally at their coolest, there are no severe weather concerns.

The NAM model shows a line of showers passing through sometime during the overnight hours on Thursday night and showers moving out of our area rather quickly on Friday. (Tropical Tidbits)
Since these showers do appear to move through in the AM hours, afternoon and evening plans appear to be in the clear, but we'll be closely monitoring that. Additionally, cloud coverage through the day on Friday will keep high temperatures in the mid 80s. That's right, mid 80s. 

Saturday looks fantastic. If you have weekend plans, definitely make sure they include Saturday. Highs near 90, dewpoints in the mid 60s, basically no rain chances - sounds great to me!

Sunday looks to be very similar to Saturday in terms of temperatures; however, some rain chances may try to creep in the afternoon and evening. I am still not completely convinced that showers will arrive Sunday and not Monday, but with that being said Sunday night into Monday do appear to be rather wet compared to recent days. 

Cooler temps are here to stay for now 

The past week has been pretty refreshing with temps remaining slightly below normal. Luckily, this is expected to continue into next week and weekend. While daily high and lows may vary, our 6 to 10 day outlooks give us a high chance of remaining below average for our temperatures and slightly above average for precipitation.

The Climate Prediction Center keeps the Mid-South in below normal temperatures from next Tuesday through next Saturday. (NOAA/CPC)
The Climate Prediction Center keeps the Mid-South on the cusp between normal and slightly above normal in terms of precipitation. (NOAA/CPC)

Caroline MacDonald
MWN Meteorologist Intern

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

Friday, July 20, 2018

Details: excessive heat and severe weather threats for today

A busy day in the weather office today as multiple hazards affect the Mid-South over the next 24 hours. Let's dive in...

Excessive Heat

Morning radar shows an area of light rain moving over the metro. As of earlier this morning, the prediction was for temperatures to reach the 96-98° range this afternoon with sauna-like humidity levels, resulting in heat indices of 110°+. That prompted the issuance of an Excessive Heat Warning for counties along the MS River (dark pink shading on the map below) and a Heat Advisory for Fayette and Marshall Counties in the metro (orange shading).

Excessive Heat Warning in pink. Heat Advisory in orange. 

Given this morning's "fly in the ointment," we may not quite see values as high as predicted, but we're basically quibbling over Grand Champion and Reserve Grand Champion barbecue at Memphis in May here... it's gonna be very hot and very humid this afternoon, to dangerous levels! Practice good heat safety and avoid the outdoors if you can. If you can't take more breaks and drink more water than you think you need. Heat Exhaustion is no laughing matter.

Severe storms

It's not unusual (as we have seen lately) for scattered storms to form in the summertime and pose threats of gusty wind, a bit of hail, lightning and heavy rain in spots. What is more unusual is the atmospheric setup for the Tennessee/Ohio Valleys into the Mid-South today and tonight. The risk of organized, more widespread severe weather is elevated across the region, particularly this evening with all of those threats higher than usual in the summer.

You can thank a digging trough of low pressure at the mid and upper levels of the atmosphere to our northeast, an unusually strong mid-level jet stream moving into the region, and the excessive heat and humidity at the surface for creating ideal conditions for the development of strong to severe storms to our north that will move into the region later today.


As far as threats are concerned, they include large hail (some up to 2"), damaging wind to 60-70 mph, copious lightning, very heavy rain, and an isolated tornado threat. The higher probability of severe weather looks to be to our northeast (northeast of Jackson, TN), but we are still in an Enhanced Risk, or level 3 out of 5. Summertime Enhanced Risk areas in our region are not common, so this is an event to stay tuned in to. If I were you, I would be most concerned about hail and wind.

Probabilities of severe weather within 25 miles of you

  • 1" or larger hail: 30%
  • 2" or larger hail: 10%
  • 60 mph or higher wind: 30%
  • A tornado: 5%


Timing is the bigger question mark for multiple reasons, but primarily because it could be different times for different areas in the metro. The storms should take the form of clusters or mini-lines, which will affect some people and not others. I do NOT expect a massive squall line that affects everyone nearly the same. You should be prepared for the possibility of severe weather starting around rush hour and continuing through at least midnight. The most likely time for the strongest storms appears to be about 7pm-12am, but storms are possible both before and after that time. In addition, showers and rumbles of thunder could continue throughout the night, but the severe weather threat drops significantly after about midnight.

The big question that still lingers is whether the extreme levels of instability forecast by the models is unrealized due to the late morning showers and cloud cover. Even if it doesn't get as unstable as forecast, I still expect that it will be more than sufficient for strong to severe storms this evening.

Be prepared!

Have your severe weather safety plans dusted off. If you are able to garage vehicles this evening and overnight, it would be a good idea. Secure all loose outdoor objects. And of course, have multiple ways to receive severe weather warnings. StormWatch+ in the app is our #1 recommendation, paired with a weather radio and local TV outlets. We'll also bring you the latest on our Facebook and Twitter feeds. Links to all are below.

Remember, a watch issuance means that conditions are favorable for the development of severe storms - and I expect one. It may be a tornado watch if it includes areas that have a slightly higher chance of that (our threat for tornadoes is very low, but not zero). A warning means it is time to take action. Heed them all.

Looking ahead

After a few morning showers move out Saturday morning, conditions improve quite a bit. Rain chances will be gone through at least Tuesday if not longer, and, in the wake of a front early Saturday, dewpoints and temperatures will also start to recede a bit. It will still feel like summer, but heat indices of 100 or less should be much more tolerable this weekend and into early next week as highs top out near 90.

Erik Proseus
MWN Meteorologist

Follow MWN on Facebook and Twitter for routine updates and the latest info!
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Tuesday, July 17, 2018

Brief "cool-downs" expected over the next several days

A couple of frontal passages today and in the coming days have allowed our forecast to have a little bit more variability than a typical summertime pattern. Overall, while temperatures look to stay in the 90s throughout the foreseeable future, we will have periods of both slightly above and slightly below average temperatures, and also reduced humidity, which should really lift our spirits!

GEFS temperature forecast through the beginning of August. *MODEL DATA - SUBJECT TO CHANGE* (WeatherBell)

Even if you look at the next couple weeks, you can see this small roller coaster type feature of some above average temps and some below average temps. It will be nice to have this variability in the coming weeks.


We're still highlighting above average warmth today though as temperatures are expected to reach the mid 90s by this afternoon with dewpoints in the very muggy mid 70s. With temps and dewpoints so high, portions of the Mid-South are currently under a Heat Advisory as heat index values will top off between 105 and 110 this afternoon.

Counties highlighted in orange are under a Heat Advisory until 8 PM this evening. 
The good news is that a "cold" front is expected to pass through the area today. While this won't knock down our temps a whole lot, we will feel some relief in the coming days, particularly a reduction in the dewpoint. 

Current surface analysis shows a surface low pressure system located near the Missouri Bootheel with a frontal boundary draped across Arkansas and northern Tennessee. (NOAA/WPC)
I don't know about you , but I am really looking forward to the somewhat drier airmass!

This front could initiate some shower and thunderstorm activity into this afternoon. Like most summertime thunderstorms, coverage will likely begin to decrease after sunset.  Overnight temps will fall back into the mid 70s.

HRRR model loop shows scattered thunderstorms developing in the afternoon hours and continuing into the early evening.  (WeatherBell)

Wednesday & Thursday

Into tomorrow, we will begin to feel this somewhat cooler and drier weather pattern. An upper-level trough will continue to dig into our area over the next few days. What does this mean for us? Well, it will help to keep our winds out of the north, bringing cooler and drier air into the Mid-South. 

300mb analysis shows a trough digging into the eastern half of the U.S. through the middle and second half of the week. (Pivotal Weather)

Looking at temperatures just above the surface across the U.S., the western half of the U.S. is experiencing some pretty warm temperatures. Luckily for us, our winds will stay out of the north, northeast over the next few days, ushering in the cooler and drier air.

850mb (5000 feet) temperatures and winds show cooler air being brought into the Mid-South, keeping the much warmer temperatures to our west. (Pivotal Weather)

Overall, temps look to hang around near 90 over the next couple days with dewpoints backing off into the upper 60s. These lower dewpoints will keep the extreme mugginess away. However, with the upper levels of the atmosphere exhibiting northwest wind (what we call "northwest flow"), storm complexes moving out of the Plains could affect the Mid-South. This possibility means we'll keep shower and thunderstorm chances in the forecast Wednesday, and a lower chance Thursday.


Good things can only last so long as warmer and muggy air attempts to make a comeback on Friday. 

The predominately northerly winds discussed above will begin to shift to more westerly, allowing all those hot temperatures from the western U.S. to slowly migrate over to our area.

850mb (5000 feet) temperature and winds show westerly winds by Friday afternoon across the Mid-South, allowing warmer temperature to push eastward. (Pivotal Weather)
Highs on Friday will reach back into the mid 90s with dewpoints creeping back into the humid 70s. As for rain chances, we will have to keep an eye on another front that poses to sweep through the Mid-South late Friday into Saturday. Depending the timing of this front, we could see some shower and thunderstorm activity later in the day.

Surface analysis for early Saturday morning shows a closed low pressure located in Michigan with a cold front sweeping across the Ohio River Valley into portions of the Mid-South. (NOAA/WPC)

Weekend and beyond

Our muggy and hot weather pattern will begin to move out following the frontal passage. Temps look to stay in the mid 90s on Saturday before backing off into the low 90s on Sunday.

GFS shows a chance of thunderstorms moving through late Friday into early Saturday, with rain chances clearing through the weekend. (Tropical Tidbits)

Luckily, rain chances will be minimal through the weekend. So if you have any outdoor weekend plans, it looks like you picked a fantastic weekend to have them!

Caroline MacDonald
MWN Meteorologist Intern

Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: 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

Thursday, July 12, 2018

Extreme heat & high pressure continue to dominate the Mid-South

It's summer. It's hot. We know it's coming every year, but somehow it always feels worse when it does arrive. The big weather maker to highlight for the next week is in fact the heat. Heat index values are expected to climb well over 100 degrees for the rest of the week and even into the beginning of next week. For the past couple of days, several of our counties have been included in a Heat Advisory for these dangerous heat indices. A Heat Advisory is issued when heat index values are expect to rise above 105 degrees. While the current Heat Advisory will expire this evening, given the forecast, it will be back before long!

Late afternoon warning map shows the Heat Advisory in orange. A Special Weather Statement, also highlighting heat potential, is shown in tan and also includes the Heat Advisory counties.

As we head into the weekend, be sure to remember some heat safety tips. I would also suggest finding a pool to cool off in!

Tomorrow and this weekend

Hot, muggy, afternoon showers. With any summertime pattern, like we are in right now, those three phrases are the ones to live by. Expect temps to stay a few degrees above average the next few days with dew points hanging in the 70s. This will provide that sticky feeling we all love during the summertime.

I'm sure many are wondering about our precipitation chances. Well, it looks like our afternoon pop-up showers and thunderstorms will hold on for now. Scattered showers and thunderstorms will likely develop each afternoon with coverage decreasing once the sun sets. This translates to a 20 to 30% chance each day. Whether you have plans to head to Levitt Shell or the Memphis Botanic Gardens for concerts or have other outdoor plans this weekend, things will likely stay muggy, but any afternoon showers should be on the downward slope by evening. 

Saturday and Sunday look to have the same old song and dance on the surface, but not necessarily in the middle and upper atmosphere. While temps will stay in the mid 90s during the daytime and "cool" into the upper 70s at night, the high pressure system that has been dominating our weather pattern will begin to lose strength. 

GFS shows a ridge pattern initially that begins to lose strength into Sunday. By Monday and next week, a mid-level trough begins to take its place. (Pivotal Weather)
With any meteorological phenomena, it usually takes some time for things that start aloft to reach the surface. So while the ridge appears like it will break down aloft, it will take some time for the extreme heat to go away. 

Beginning of next week

While we may not begin to feel the implications of the ridge weakening and the trough taking over, we will notice some increased thunderstorm coverage for the first half of the week. Temps will stay mild, muggy, and in the mid 90s Monday and Tuesday with overnight temps coasting in the upper 70s, proving little nighttime relief.

As for our rain chances, each day will likely have a few more showers and thunderstorms than we have seen in recent times. Typically in this pattern, they fizzle out after sunset, so that is good to keep in mind when making evening plans. 

GFS loop from Saturday evening through Tuesday evening shows scattered showers each day. (TropicalTidbits)

Second half of next week

With the mid-level trough digging into the eastern half of the U.S for the second portion of the week, expect things to finally cool off just a tiny bit compared to the above average temperatures and extreme heat we've been having recently. 

The Climate Prediction Center releases daily graphics highlighting the 6 to 10 day temperature and precipitation outlooks for the U.S. They currently span from next Wednesday through the following Sunday. On average over the period, temps will likely stay right around average here in Memphis with precipitation being a little higher than average for summertime. I don't know about you, but I could use some more showers and a little less heat. Stay cool until then!

The Climate Prediction Center's 6 to 10 day outlook shows a near normal temperature outlook over the Mid-South. (NOAA/CPC)

The Climate Prediction Center's 6 to 10 day outlook shows a slightly above average (33%) precipitation outlook over the Mid-South. (NOAA/CPC)

Caroline MacDonald
MWN Meteorologist Intern

Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: 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

Monday, July 9, 2018

June 2018 Climate Data for Memphis, TN

June Climate Recap

Continuing the trend from May (but not quite the anomaly that May was), June temperatures averaged well above normal, to the tune of over 2 degrees, placing the month twelfth warmest on record. Twenty-four of the thirty days in June were above normal (although four of those six that were below normal were within a degree of the normal temperature). No daily records were set during the month. Also as in May, precipitation for the month of June was below average by over one and a half inches at the official observing site at Memphis International Airport, however scattered thunderstorms with heavy downpours on several days resulted in a wide range of precipitation. For example, MWN in Bartlett recorded 6" more rain than the airport in June.

Severe weather reports received during the month were primarily from downed trees due to high wind associated with powerful scattered storms. These include in Marshall County overnight on the 2nd/3rd, in the immediate metro on the afternoons of the 13th and 21st and the morning of the 23rd (when a 65 mph wind gust was measured at a secondary sensor at Memphis International Airport). Hail was recorded in DeSoto County on the 12th and flash flooding occurred in north Bartlett near MWN HQ on the morning of the 24th.  There were multiple Severe Thunderstorm and Flash Flood Warnings during the month in the metro, but no Tornado Warnings. Most Flash Flood Warnings were in Shelby County for urban flooding from localized heavy downpours.

Memphis International Airport, Memphis, TN

Average temperature: 81.9 degrees (2.3 degrees above average)
Average high temperature: 91.6 degrees (2.7 degrees above  average)
Average low temperature: 72.1 degrees (1.8 degrees above average)
Warmest temperature: 96 degrees (15th, 16th)
Coolest temperature: 64 degrees (4th)
Heating Degrees Days: 0 (0 below average)
Cooling Degree Days: 513 (75 above average)
Records set or tied: The month ranked 12th warmest on record.
Comments: Twenty days recorded high temperatures at or above 90 degrees, which is 6 days above average. Only six daily temperatures were below average.

Monthly total: 2.06" (1.57" below average)
Days with measurable precipitation: 9
Wettest 24-hour period: 0.66" (23rd)
Snowfall: 0.0"
Records set or tied: None
Comments: Only a single day recorded more than 0.5".

Peak wind: Southwest/50 mph (23rd)
Average wind: 7.3 mph
Average relative humidity: 69%
Average sky cover: 40%

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

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 80.9 degrees
Average high temperature: 91.2 degrees
Average low temperature: 70.0 degrees
Warmest temperature: 97.2 degrees (28th)
Coolest temperature: 60.0 degrees (4th)
Comments: None

Monthly total: 8.08" (automated rain gauge), 8.62" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 12
Wettest date: 2.56" (21st) (via automated gauge)
Snowfall: None
Comments: In stark contrast to Memphis International Airport, four days recorded precipitation of 0.99" or higher (zero at the airport).

Peak wind: South/33 mph (1st)
Average relative humidity: 76%
Average barometric pressure: 29.94 in. Hg

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

MWN Forecast Accuracy

MWN average temperature error: 1.48 degrees
MWN forecast temperatures within 2 degrees of actual: 84%
MWN average dewpoint error: 1.88 degrees
MWN forecast dewpoints within 2 degrees of actual: 74%

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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Complete MWN Forecast: 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