Sunday, November 10, 2019

Arctic blast to engulf the Mid-South. Winter weather too?

On an afternoon like we've had today, with high temperatures just a few degrees shy of 70°, it's hard to imagine just how cold a wind chill of 8° feels... but we're about to find out! I hope you've enjoyed this beautiful fall weekend!

It's all about that front

The first half of Monday sets up fairly mild all things considered as pre-frontal southerly wind keeps overnight lows from dropping much below 50°, leading to a decent start to Veteran's Day. However, an increase in clouds will eventually bring scattered showers into the picture during the morning hours with temperatures in the mid 50s.

By lunchtime or shortly thereafter, rain rates pick up and, between about 2-4pm, an Arctic cold front slices through the metro. No severe weather, or even thunder, is likely, but a definitive wind shift is! That northerly wind will force temperatures to fall the rest of the day (and night) as it gusts to 25-30 mph by late afternoon. Look for temperatures to be in the mid to upper 30s by 6pm with rain continuing.

The high-res NAM3 model forecast of wind speeds at 3pm Monday clearly shows the position of the front bisecting the Memphis metro. (WeatherBell)

Monday evening mischief

As the mercury continues to fall through the 30s, colder air aloft will also push in, and we know what that means... the moisture departs! :-) In actuality, there is a narrow window of a few hours, probably between about 8pm and midnight, in which a mix of cold air and moisture could result in a changeover of rain to sleet, snow, or freezing rain. The deepest moisture will indeed be pushed south by the arrival of cold air, but enough could linger to produce very light accumulations of snow or sleet. We're talking potentially a dusting of snow or a thin layer of ice pellets, but likely no more.

The mid-day run of the high-res NAM3 model, showing forecast radar from 6am to midnight Monday, indicates rain chances increase during the day with a possible changeover to wintry mischief on Monday evening. (
With the latest model data today, including the most recent high-resolution data, confidence is increasing to "moderate" that we'll get some form of wintry precipitation falling, but is still "low" on any impactful accumulation. Bread and milk index? Very low.

By midnight, it all is pushing to our south as north wind gusting to 30 mph continues to cause temperatures to fall through the 20s. That wind should be enough to help dry most streets overnight, preventing a major "flash freeze" of lingering precipitation. However, we won't know the exact ramifications of lows in the lower 20s until we see just what, and how much, winter precipitation falls Monday evening.

Forecast snow amounts Monday evening, via NWS. At dusting at most is expected, mainly north of I-40.

Tuesday - brutally cold

As we wake up Tuesday morning to head back to work or school (yes kids - right now you need make sure that homework is done from the long weekend!), the bus stop wind chill will be a #StupidCold 5-10°! With sunrise temperatures in the lower 20s and the wind still kickin' it at 15-25 mph, it truly will feel like a cold day in January! Parents, against their will, layer the children up and grab your winter coat and gloves as well. While it'll be a sunny day, the breeze continues and wind chills never get above the 20s as highs struggle to reach freezing. In fact, Tuesday morning's record low of 23° is in jeopardy and the day's record minimum high temperature of 37° will be broken by a few degrees.

Tuesday morning wind chills, via NWS

Wednesday starts a slow recovery

Tuesday night, the wind dies off as high pressure presses overhead. This is good and bad. Wind chills won't be that much colder than temperatures - good. Temperatures will plummet into the teens - bad. I expect in the city proper it'll be near the record low, once again, of 20°. Outside the concrete jungle? 15-18°. Novembrrrr! However, with sunshine and wind turning southerly, highs recover all the way into the lower 40s! Yes, you'll need the winter coat another day.

As we head into the end of the week, we'll be back near 50° Thursday and the lower to mid 50s Friday through Sunday with dry weather continuing. Morning lows remain in the 30s. Normal highs are in the 60s this week...

How to plan for the week

Take an umbrella and warm coat with you Monday morning. The afternoon drive will be in rain and wind chills in the 30s.

The threat of winter precipitation Monday after 8pm is real, but accumulation looks minimal. Plan to get up early Tuesday to take a peak out the window and check your favorite local news and weather sources for the latest info.

Bundle up in layers Monday night through Wednesday. The cold air isn't messing around.

Make sure pets are warm and outdoor plants are protected during the same period. And, in fact, it'll likely be a good idea to slow-drip faucets on exterior walls Monday and Tuesday nights.

Slowly shed a layer or two by the end of the week!

Erik Proseus
MWN Meteorologist

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