Saturday, December 4, 2021

Unseasonable warmth departs; severe weather possible early Monday

A warm start to meteorological winter resulted in record-setting warmth on Friday as high temperatures reached the mid 70s, setting a record of 76 degrees at Memphis International. 



It stayed mild overnight as temperatures remained in the 60s ahead of a slow-moving (stalling, actually) cold front that sits over far northern MS this afternoon. We had some patchy fog and areas of drizzle this morning for the St. Jude Memphis Marathon. I'm sure the runners would have preferred cool and dry with lower humidity.

Saturday afternoon through Monday morning 

Conditions are pretty stable for the rest of today and tonight as the front doesn't move, allowing clouds to stick around and temperatures remain to be mild. Low 60s this afternoon and 50s overnight. A stray shower is possible due to the proximity to the front. Overnight the front starts to return to the north with wind switching from north back to south by Sunday morning. 

On Sunday, we'll be back in the "warm sector" ahead of a more significant front that arrives Monday morning. Temperatures will warm once again to 70 degrees or a bit higher with gusty southwest wind. Most of the day will be under cloud cover, but breaks in the clouds are possible and will offer more warming and increasing instability in the air. Scattered showers are possible, and maybe a stray thunderstorm, but overall the lower atmosphere will remain capped to storm development during the day. Don't lose track of the waterproof wind breaker Sunday.

The midday Saturday HRRR model showing "future radar" loop from noon Sunday to noon Monday. Scattered showers Sunday, then quick development of a squall line Sunday night, arriving Monday just before or during rush hour. (WeatherBell)

The cold front lights up to our northwest Sunday overnight as it enters Arkansas from the north. As storms develop, a few may become strong to severe. ETA for a fairly well-developed squall line in the Memphis metro is estimated to be just before sunrise Monday. The main threats will be heavy rain which could produce ponding water in time for rush hour and scattered strong to damaging wind gusts. There is a non-zero chance of a quick spin-up tornado within the line as well, but the threat is fairly low. Overall, the severe weather risk places the Memphis metro in a Level 2 (Slight) Risk. 


Severe weather prep

Because the storms will arrive while most of us are either sleeping or just waking up Monday morning, having a way to get severe weather warnings will be important. Widespread severe weather is not currently anticipated, but having multiple methods of receiving information is necessary. We recommend SW+ Alerts in our MWN app as one such way. 



Also recommended: get those outdoor Christmas decorations and other loose objects secured by Sunday afternoon as the wind starts picking up to 25 mph or higher. Leaves in gutters and storm drains could also contribute to low-lying flooding or other water issues so a quick cleanup would be a good idea as well.

Next week

Cool weather and clearing skies are expected Monday behind departing showers Monday morning. A gusty north wind and prior warm weather will make temperatures near 50 feel even colder Monday. Tuesday morning we wake up to clear skies and cold conditions. Clouds start to return Tuesday with highs only in the upper 40s - another chilly day. Wednesday has trended drier in recent model data as a system moves by to our south and another to our north. Best rain chances will likely be south of Memphis Tuesday night, but for now a low rain chance mid-week is justified. Wednesday will be cool again with highs near 50. Lows look to mostly remain above freezing the first half of the week, though outlying areas could dip to 32 Tuesday morning.

The European model for Monday evening through Wednesday evening shows mainly dry conditions for the Mid-South. A couple of systems split the area Tuesday night with rain and snow passing by well to our north and rain showers likely missing us to the south. (WeatherBell)

By Thursday, another quick-moving front slides through the Mid-South. The front could bring a brief rain chance Thursday as highs climb to the upper 50s. Southerly warm wind arrives again Friday with temperatures back well into the 60s. The next major system looks to arrive next weekend with another chance of heavy rain and thunderstorms. More on that as we get closer. Overall, a very progressive pattern over the next week as one system after another moves through!


Stay tuned to our social media feeds for the latest on Monday's severe weather threat. 

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 1, 2021

"Fall" and hurricane season end, so here's the winter outlook!

Meteorological Fall Comes to an End

As the calendar turns to December and minds collectively turn towards the end-of-year holiday season, meteorologists see a changing of the seasons. While the official start of winter is when the winter solstice occurs (December 21), "meteorological winter" for climate record-keeping purposes starts December 1 and runs through the end of February. That means the record books are closed on autumn. We'll have more detail in the November climate summary in a few days, but preliminary data indicates that the average temperature for fall this year was 65.1 degrees, which is above the long-term average of 64.4 degrees. Rainfall, however, was below normal, totaling 8.92" for September-November versus the average of 11.70". 

Winter 2021-2022 Outlook

So what does the crystal ball look like for winter, perhaps the most anticipated season of the year? Early prognostications are driven primarily by the state of El Nino-Southern Oscillation (ENSO), but there are many other factors that make it pretty unpredictable, especially in the south. What is likely is the current La Nina climate pattern - an oceanic pattern that features cooler than average waters in the central Pacific Ocean - will continue through the winter. In fact, it's a "double dip" La Nina after the pattern dominated last winter, receded this summer, but reappeared in the fall. The typical impacts from a La Nina pattern are shown below. The Mid-South tends to be in the battle zone between wetter conditions to our north and drier to our south, while temperatures tend to be above average.

Typical impacts over North America during a La Nina winter. (NOAA)

The official Winter Outlook from NOAA is very close to what we would expect from a La Nina pattern and is shown below. There is a 40-50% chance of temperatures averaging above normal and odds of wetter than average conditions dip as far south as west TN. 

The temperature outlook for December-February 2021 from NOAA.

The precipitation outlook for December-February 2021 from NOAA

Remember that these are predictions of average conditions over a three-month period. That means there can certainly be cold spells in an overall warm pattern, or rainy periods in a dry month. In fact, you will certainly remember the Arctic outbreak last February that occurred in a very similar overall pattern to this winter. Other factors and atmospheric patterns will dictate the day-to-day conditions.

Atlantic hurricane season also ends

The start of December also means that the Atlantic hurricane season has also come to an end. It also marks the first time that the pre-defined list of 21 storm names has been exhausted in consecutive years. The 2021 season featured exactly 21 named storms (the third most in a year), seven hurricanes (five of which classified as "rapidly intensifying" during their life cycle), four major hurricanes, and eight U.S. landfalls. It was also the sixth consecutive "above normal" season and seventh consecutive season in which a named storm formed before the official start of the season on June 1. (NOAA's outlook published in May called for 13-20 named storms, 6-10 hurricanes, and 3-5 major hurricanes.)


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