Thursday, May 24, 2018

The May pattern continues as we cast our gaze towards the Gulf of Mexico

We really haven't caught much of any break over the past few weeks from the above average temperatures. The record average monthly temperature for May is 76.8° which occurred back in 1962. If May were to end today, we would have the second highest average temperature for the month of May at 76.6°. And for the period May 1-23, this year currently is the warmest on record! While we won't be setting any record high temps in the next few days, temps will still be 5 to 10 degrees above average.

End of the work week

Right now our overall weather pattern has been dominated by a weak mid-level ridge that has been hanging out over our area. This ridge has helped keep those afternoon thunderstorm chances down a bit the past day or two. At the surface, a high pressure system is located in the Ohio River Valley, which has also helped to keep our temps above average and afternoon shower chances to a minimum.
The majority of the Eastern U.S. is dominated by a surface high pressure, which has helped to keep our temps well above average this week. A cold front boundary is located nearly over the metro, but will not affect our temps that much unfortunately. (NOAA/WPC)
Overall, today and tomorrow look to be pretty similar. While mid-level features will try to push the already weak ridge out of our area, the trough following behind will not be strong enough to really impact our overall weather conditions, other than perhaps a few more afternoon showers or thunderstorms.

Taking a look at the 500mb (18,000') level, notice the higher heights (what looks like a hill) located over the eastern U.S. into tonight with some lower heights (a "valley") beginning to move into our area tomorrow. This change in mid-level heights shows a very weak trough moving into our area which will bring some more shower chances tomorrow. (Pivotal Weather)
Highs will stay in the upper 80s to finish up the work week with some scattered afternoon showers/thunderstorm chances each day. Given the location of the stationary boundary, this will help keep some cloud coverage around both days as well.

The holiday weekend

As we move into Memorial Day weekend, the previously mentioned mid-level trough will begin to have more of an impact. Overall, temps look to follow the typical summertime vibes with highs reaching the upper 80s on Saturday and Sunday. Dewpoint temperatures look to be pretty uncomfortable both days as well - near 70 degrees - making for a sticky, sweaty airmass. 

As for rain chances, our afternoon rain chances look to increase slightly both days. Showers and thunderstorms will likely still be scattered in nature, so not everyone will see these showers. Hopefully they will hold off in the AM for those running in the Great American River Run on Saturday. By Saturday afternoon, rain chances will increase a bit, but I wouldn't let that discourage you from going downtown for #901Fest to wrap up Memphis in May. Overall, there is no need to cancel any plans this weekend, but having a good rain plan just in case would be beneficial. 

The GFS model shows scattered showers mainly Saturday and Sunday afternoons around our area. This loop runs from late Friday night through late Sunday night. (Pivotal Weather)

Memorial Day

Yes, there is a developing tropical system in the Gulf of Mexico.

In short, the National Hurricane Center is keeping a very close eye on an area of low pressure currently stationed in the Yucatan Peninsula. This system is expected to become more well-defined in the coming days as it moves into the Gulf of Mexico where warm water awaits. The conditions in the Caribbean Sea, where it is currently located, are favorable for this system to develop into a tropical system. 

The image above displays the chance of tropical cyclone formation within the next five days.  The red bubble indicates the area where there is now a 90% chance of formation within the next five days. (NOAA/NHC)
There is a 70% chance of development within the next 48 hours and a 90% chance of formation in the next 5 days. The system will likely continue to develop in the coming days. While this developing system won't necessarily get to hurricane strength, the main threats will be in the form of copious rainfall for the southeast U.S. and rip currents on the coast, which will likely make the waters at many beaches dangerous.

So what exactly does this mean for us? Two things. 

First of all, we could potentially see some rain from this system in our area sometime next week. There are still enough variables at play that the "how much" and "when" questions can't be answered. We are currently expecting our scattered thunderstorm regime of this weekend to continue into Memorial Day and beyond.

Secondly, schools are getting out for the summer, which means a lot of people have beach trip plans. If you are planning to head to the central or Florida Gulf Coasts this weekend or next week, it would be a good idea to keep up with the National Hurricane Center statements and local National Weather Service offices and local media in the area you are planning to go to. Here are the latest key messages from NHC:

We hope that you all have a safe and enjoyable Memorial Day weekend as summer "unofficially" kicks off (despite it starting May 1 in the atmosphere here in the Mid-South)! Remember that you can take your app with StormWatch+ activated with you on vacation for severe instant weather warnings, no matter where you go in the U.S.! And for local forecasts, radar, and current conditions nationwide, we recommend the free StormWatch+ standalone app for iOS devices. No need to pay for severe weather alerts in that app if you already have them in your MWN app!

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

Saturday, May 12, 2018

April 2018 Climate Data for Memphis, TN

April Climate Recap

April will be remembered as much cooler than average with temperatures over six degrees below the climatological average. In fact, the month featured one sub-freezing morning low (30 degrees on the eighth) and a monthly high of only 80 degrees (just four days after the 30-degree reading in fact)! The overall average temperature ended up third coldest on record for April.

Precipitation was above normal as well, totaling nearly eight inches for the month. Again, heavy precipitation was not uncommon as there were only 9 days with rain but a few heavy rain events, including three with more than an inch and one (the 14th) with three inches of rain. Also due to the cool temperatures, the normal start of severe weather season was delayed as there were no severe reports during the month and only two Severe Thunderstorm Warnings in the metro, on the 3rd and 4th in norther MS.

Memphis International Airport, Memphis, TN

Average temperature: 56.3 degrees (6.6 degrees below average)
Average high temperature: 67.0 degrees (6.0 degrees below average)
Average low temperature: 45.7 degrees (7.2 degrees below average)
Warmest temperature: 80 degrees (12th)
Coolest temperature: 30 degrees (8th)
Heating Degrees Days: 266 (129 above average)
Cooling Degree Days: 12 (63 below average)
Records set or tied: The month was the third coolest April on record.
Comments: One day recorded a temperature below freezing (30 degrees on the 8th). The growing season for 2018 commenced on April 9.

Monthly total: 7.86" (2.36" above average)
Days with measurable precipitation: 9
Wettest 24-hour period: 3.02" (14th)
Snowfall: 0.0"
Records set or tied: None
Comments: Three days recorded more than 1.0" and one day saw more than an inch of rain fall.

Peak wind: South/43 mph (13th)
Average wind: 9.7 mph
Average relative humidity: 65%
Average sky cover: 50%

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

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 56.1 degrees
Average high temperature: 67.8 degrees
Average low temperature: 43.9 degrees
Warmest temperature: 82.5 degrees (12th)
Coolest temperature: 28.1 degrees (8th)
Comments: None

Monthly total: 7.22" (automated rain gauge), 6.95" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 8
Wettest date: 2.17" (14th) (via automated gauge)
Snowfall: None
Comments: None

Peak wind: South/29 mph (3rd)
Average relative humidity: 70%
Average barometric pressure: 30.04 in. Hg

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

MWN Forecast Accuracy

MWN average temperature error: 2.35 degrees
MWN forecast temperatures within 2 degrees of actual: 62%
MWN average dewpoint error: 3.05 degrees
MWN forecast dewpoints within 2 degrees of actual: 42%

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