MWN Blog: Another winter storm gone, time to look to the next one!

Winter storm #1 brought a thick glaze of freezing rain to the metro last Wednesday night and also ushered in the first round of sub-freezing air. The prelude to storm #2 arrived yesterday as light snow throughout the day, coated over by a layer of sleet last night. This morning, heavy sleet changed to heavy snow - and my what a sight for an hour or so this morning as blizzard-like conditions reduced visibility and snow literally blew sideways! Generally, snow and sleet totals from this round varied from 3-7" and made for a nice snow day for most.

Snow blowing sideways! Reduced visibility in heavy snow in Bartlett. #memsnow pic.twitter.com/xVvlVh5v7r
— MemphisWeather.net (@memphisweather1) February 15, 2021

Now we turn our eyes to the next system in our triple scoop of #PolarVortex goodness. We'll see a lull for about 36 hours before that round starts early Wednesday and continues into Thursday. With temperatures "warming" about 15 degrees from second round levels in the 10-15 degree range, this storm presents a different set of challenges. Precipitation type appears to not be as straight-forward across the metro.

While Arkansas appears to be cold enough to support straight snow once again, more of north Mississippi could get into a warm sector that supports rain. That leaves the metro in the crosshairs of the dreaded "mixed precipitation" phase for perhaps a lengthy period of time. With significant differences in the models, I'll do my best to let you know what is likely and what is less certain tonight. More information as we are able to provide it will be posted on our social media channels.

What we know

Temperatures will start very cold Tuesday night into Wednesday. Morning lows will be in the mid teens. By afternoon though, the mercury will climb to the upper 20s, perhaps to near 30, but will not quite reach freezing. Despite Arctic air receding a bit, lingering snow cover will keep the air from warming more than if we had bare ground.
Temperatures Wednesday night remain below freezing, but not nearly as cold as we're experiencing currently. In fact, with low pressure moving by over Mississippi and Alabama, they may not drop much at all Wednesday night.
Colder air will again filter in Thursday on the backside of the departing system, with temperatures remaining in the 20s. Once it completely moves out Thursday night, we'll see lows again down in the lower teens to near 10 depending on fresh snow cover.
Precipitation may start as some snow flurries Tuesday night with light snow expected on Wednesday. A of now, it appears totals through Wednesday mid-afternoon will remain light. Potentially an inch or a bit more of snow could fall.
With low level temperatures staying cold and cold air aloft moving in behind the system, precipitation should fall on Thursday as snow as well before ending in the afternoon.

What is less certain

The main problem for this forecast is Wednesday night temperature profiles. With most precipitation falling Wednesday night, that presents a big "what if" scenario! Again, models present different scenarios and determining the most accurate is a challenge. So for now, the course of least resistance and most likely to be accurate is to expect a variety of precipitation types overnight.

With slightly warmer temperatures southeast of the metro, the best chance for higher ice or snow amounts will be northwest of the metro, tapering to the southeast. Thus, the best chance for freezing rain and sleet will be southeast and snow or snow and sleet is northwest. With the precipitation amount (in liquid form) expected to be enough to produce impactful snow or ice amounts, I expect we'll be dealing with more (or continued) travel issues at a minimum, and perhaps even ice that could result in power outages or multiple inches of snow, depending on how it all plays out.

The probability of 0.10" of freezing rain for the period from 6pm Tuesday to 6pm Thursday shows how the metro could be right on the line of receiving significant icing and not. Probabilities range from 30-60% across Shelby County for now. (NWS/WPC)

Probabilities for 4" or more of snow range from 10-50% across Shelby County between 6pm Tuesday and 6pm Thursday. These two graphics demonstrate how uncertain the forecast is for now. (NWS/WPC)

[ UPDATE: As of 8:50pm Monday, a Winter Storm Watch has been issued from Tuesday at midnight through 6pm Thursday. The graphic below depicts the initial forecast amounts from the National Weather Service. Heaviest snow is expected west of the river, while a few inches is possible east of the river, in addition to some freezing rain. ]

For now, plan on an inch or so of snow Wednesday on top of what is left from storm #2 (likely most of it), a variety of precip Wednesday night that could leave us waking up to significant impacts once again, followed by another layer of snow (maybe another inch or two) to top it all off! Any accumulations on top of what we already have will result in potential infrastructure damage and, at a minimum, even more inconvenience. Plan accordingly and keep everyone, including the pets and pipes, warm for the next few days!

The good news is that we will be seeing sunshine return Friday and Saturday with moderating temperatures .We'll rise above freezing by Saturday and end what will likely be the longest stretch of sub-freezing days on record in Memphis! And I think we'll all be extremely grateful as we head towards March and warmer days.

Erik Proseus
MWN Meteorologist

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