Friday, October 16, 2020

Frosty then mild (typical for fall in the Mid-South), plus an early glance at our Winter Outlook

A couple of fall cold fronts later, and the remnants of Delta that moved through about a week ago are ancient history, as high temperatures today barely reach the threshold where dewpoints stood last weekend! (That means moisture levels last weekend were higher than temperatures are today.) Portions of the Mid-South are now under a Frost Advisory as we anticipate our first readings below 40° Saturday morning with fire pits, hot chocolate, and hoodies on standby!

Early weekend

With clear skies and wind going calm this evening, look for our afternoon temperatures in the 60s to fall quickly through the 50s and 40s overnight. Along and west of the Mississippi River, a whisper of a breeze from the south will halt the temperature plunge just enough to keep frost at bay. But east of the river and outside the confines of the concrete jungle we call the Bluff City, morning lows on Saturday will be in the mid to upper 30s, resulting in areas of frost. 

Thus the NWS has issued a Turn-on-the-Heat Frost Advisory for points east of Memphis, namely Fayette and Marshall Counties in the metro, for the overnight hours. Even cooler locations in eastern Shelby, Tipton, and DeSoto Counties could see patchy frost with lows in the high 30s. The city proper will warm itself, keeping lows above 40. If you have outdoor plants (or even sensitive animals) in these cooler areas that you don't want to be affected by the cold air, bring them inside for the night.

FUN FACT: The first Frost Advisory of the fall has been issued on the same day as the earliest recorded freeze on record at Memphis International Airport - October 16, 1876! Luckily we're not that cold quite yet!

With that southerly wind increasing Saturday, and plenty of sunshine, temperatures will rebound quickly tomorrow. Look for highs back up close to 70° as the Tigers kickoff mid-afternoon at the Liberty Bowl in front of 10,500 lucky folks! A beautiful afternoon for football (or whatever else you may want to to outside) if you ask me!

Late weekend into next week

The return of southerly wind means more moisture arriving, and with another front approaching, a few showers are possible on Sunday under mostly cloudy skies. It'll be mild however as morning lows will be a good 10-15 degrees warmer than Saturday morning (50s) with highs into the lower 70s - not too far from average for mid-October. Southerly wind continues as the front moves into the metro area by Sunday night. 

The National Surface Map for Sunday evening shows a front just to our northwest with precipitation chances near it. This front stalls out near the Mid-South into next week. (NWS)

Early next week, the front stalls near or just north of us, wavering for a few days. This leads to a bit more uncertain forecast with rain chances possible each day early next week, but besides the presence of the front, no strong triggering mechanisms noticed for downpours or thunderstorms. Rainfall amounts should generally be light and showers spotty Monday-Wednesday. Mild conditions continue with lows in the upper 50s to lower half of the 60s and highs in the 70s. 

Rest of the week

By late week the front, or maybe another that approaches and merges with it, will finally get enough upper level support to move through the region. There is model debate about when that actually occurs as the strength of high pressure over the southeast U.S. and eastern Atlantic will ultimately determine when the passage is allowed. Signs point to Friday or Saturday at this time. When that happens, rain chances will increase, and it is possible we could see thunderstorms as well. That's a week out though, so we aren't too excited about it just yet. For the most part, next week looks to be mild with more clouds than sun overall, and low daily rain chances.

Despite a front nearby, total precipitation through next Friday morning is not excessive for our area, generally under one-half inch. (NWS)

NOAA Winter Outlook

NOAA, the parent organization of the National Weather Service, issued their 2020-2021 Winter Outlook yesterday. All signs point to continued La Nina conditions this winter, perhaps moderate to strong. That drives much of the forecasted conditions for the winter outlook, which is shown below. The Mid-South tends to be in the "battleground" of the airmasses in this type of setup, with wetter conditions to our north and dry conditions across the southern U.S. While that means things are a bit inconclusive, know that battleground is code for "not uninteresting" in this case. We'll see how that plays out in terms of timing of precipitation and warm/cold airmasses over the course of the next few months!

This might actually be more appropriate though:

Erik Proseus
MWN Meteorologist

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
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, October 10, 2020

September 2020 Climate Data for Memphis, TN

September Climate Recap

September was a tale of two seasons as far as temperatures were concerned - summer for the first half of the month and fall for the last couple of weeks. From the 1st through the 17th, high temperatures averaged 88 degrees with only four morning lows in the 60s and only one daily average temperature below normal. From the 18th on, high temperatures averaged 76 degrees, morning lows routinely dropped into the 50s, and only one daily average temperature was above normal. Because cool anomalies to end the month were warmer than the warm anomalies to start it, the monthly average temperature ended up just under a degree below normal.

September is typically the second driest month of the year behind August, and September 2020 kept that statistic trending the right direction with just over 1.5" of rain at Memphis International Airport and under 3" in Bartlett. A large pat of that differential occurred on the 12th when Bartlett recorded over an inch of rain and the airport was under 0.10". There were seven days with measurable rain for the month, right at average.

September is not typically a severe weather month and 2020 help serve. There was one severe weather event - scattered strong thunderstorms on the evening of the 2nd. Severe Thunderstorm Warnings were issued for the metro and a Tornado Warning was issued for Crittenden County. Trees were downed in DeSoto County. Flash Flood Warnings were also issued for the eastern MWN coverage area on the 12th.

MWN StormView Radar on September 2 as a rotating cell moved through Crittenden County, AR.

Memphis International Airport, Memphis, TN

Average temperature: 74.5 degrees (0.7 degrees below average) 
Average high temperature: 82.6 degrees (2.5 degrees below average) 
Average low temperature: 66.4 degrees (1.2 degrees above average) 
Warmest temperature: 92 degrees (11th) 
Coolest temperature: 52 degrees (29th) 
Heating Degrees Days: 7 (4 below average)
Cooling Degree Days: 302 (14 below average) 
Records set or tied: None 
Comments: None

Monthly total: 1.58" (1.51" below average) 
Days with measurable precipitation: 7 (0.3 days below average) 
Wettest 24-hour period: 0.62" (23rd) 
Snowfall: None 
Records set or tied: None 
Comments: None

Peak wind: East/32 mph (19th) 
Average wind: 7.6 mph 
Average relative humidity: 71% 
Average sky cover: 50% 

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

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 71.9 degrees 
Average high temperature: 81.8 degrees 
Average low temperature: 63.8 degrees 
Warmest temperature: 93.2 degrees (7th) 
Coolest temperature: 49.6 degrees (29th) 
Comments: None 

Monthly total: 2.88" (automated rain gauge), 2.68"(manual CoCoRaHS rain gauge) 
Days with measurable precipitation: 7
Wettest date: 1.11" (12th) (via automated gauge) 
Snowfall: None 
Comments: None 

Peak wind: Northeast/20 mph (19th)
Average relative humidity: 83% 
Average barometric pressure: 30.00 in. Hg
Comments: None

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

MWN Forecast Accuracy

MWN average temperature error: 2.19 degrees 
MWN forecast temperatures within 2 degrees of actual: 62% 
MWN average dewpoint error: 1.73 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.

Climate Outlook - October 2020

The October climate outlook for the United States from the Climate Prediction Center is shown below. Above average temperatures are forecast for much of the United States, with highest probabilities in the Northeast and Southwest U.S. Odds favor above average temperatures for Memphis, where the average temperature for October is 64.1 degrees.

Precipitation is expected to be below normal in the central U.S., particularly in the Southern Plains with a signal for anomalously wet conditions in portions of the Pacific Northwest and Florida peninsula. For Memphis, odds favor below average rainfall (a 49% chance) versus only an 18% chance of above average rainfall. Precipitation historically averages only 3.98 inches in October. 

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 
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