Wednesday, February 18, 2015

Winter storm #1 in the books, #2 on the way, but first an Arctic rush!

Monday recap

The President's Day winter storm (#Snobama) officially broke the 1,167-day "snowless" streak,* forcing us to reset the MWN Snow Counter. However, we take partial issue with doing so, which led us to the creation of Official AND Unofficial Counters:


* Per NWS official definition for climate record keeping purposes, "snow" is defined such that it includes snow, sleet and hail. Officially, Memphis International Airport received 1.3" of sleet and 0.3" of ice (freezing rain), but no snow. However, the snowless streak has to be terminated due to the sleet. We didn't like that, so we started our unofficial counter as well!

Here's what fell across the Mid-South Monday according to the NWS:



We're fortunate there wasn't a lot more freezing rain across the heart of the metro. More sleet than freezing rain meant a much lower strain on the overhead power lines and trees, though north MS got their share.

Then last night we had a brief snow-blitz with 1/4" to more than 1/2" falling in about 30 minutes. It came quickly and was even escorted by a few lightning strikes!


So while we woke up to yet another snow day (we love the kids, but it's time they go back to school...) and a dusting of snow on everything, conditions are improving even more today with abundant sunshine and temps near 30. We think most of the kids will be back in school tomorrow, but there's one more little wrinkle to talk about that may be factored in: #StupidCold

Tonight

As Arctic high pressure builds overhead, with clear skies, a little ice still around in pockets, and light wind, temperatures will fall to near 10 in the city and 5-7 in rural areas. That light wind will be enough to push wind chills to 0 or a bit below in the metro. The NWS has issued a Wind Chill Advisory for tonight for these wind chills:


That's a #StupidCold Arctic rush! Tonight is a night that you should throw another log on the fire, drip your faucets, and of course be sure to keep pets warm and have "un-frozen" water for them and check on the elderly.



A very cold day is in store on Thursday as well with highs in the mid 20s and wind chills maxing out in the teens. Clouds move in ahead of our next system with lows falling to near 20 by Friday morning.

Friday/weekend weather system

Speaking of the "next system" - another shot at winter weather arrives Friday. And by Friday, I mean much of the day Friday. We're still fine tuning the forecast and watching models get a better handle on this, but once again the best bet is not snow, but ice.

Cold air will already be in place (like the last system) but this time, the low pressure responsible for the weather will not track to our south (the favored track for winter storms) but to our north. This means, that, though precipitation starts in a wintry state, temperatures will rise as a warm front lifts north of us Friday night, bringing an end to the ice.

Friday's national map showing a large area of potential freezing rain, including the Mid-South
In fact, the system itself will bring quite a bit of atmospheric dynamics with it as it moves through this weekend, so heavy rain and some thunder will be possible. The weekend could be downright soggy with a couple inches of rain expected from Friday night through Saturday night. The main bouts of heavy rain look to come Friday night as the warm front lifts through and Saturday night as the cold front approaches, however Saturday will also have a high chance of rain. Being in the warm sector of the system on Saturday will mean temperatures that climb well into the 50s! Cold air moves back in Sunday behind the front however, ushering in yet another very cold airmass to start next week.

The morning GFS model is predicting 2.5-3" of total precipitation through Sunday evening. Some flooding issues could arise by Saturday night. Shelby County is the gold star. Graphic courtesy WxBell.

More on Friday

Back to Friday - it looks like light precipitation starts early (around sunrise we're guessing right now) as a snow/sleet mix, then transitions to freezing rain, possibly mixed with sleet, during the morning, finally changing to rain by late afternoon or early evening as the surface temperature finally reaches 32°. In other words, we'll be devouring the whole cake!


As for how much and the what the impacts will be, total sleet/freezing rain amounts look to stay at or below 1/4", but that is enough to mess up the already fragile transportation infrastructure that has been very cold all week. Expect icing of bridges and overpasses at the least and some droopy trees and power lines on Friday, though power outages should again be minimal if the forecast pans out. The factor working against power lines on Friday that wasn't a problem Monday is wind, which will be southeasterly at 10-15 mph. Schools COULD be out again, though we'll leave that up to the superintendents and staff - we have a hard enough time with the forecast!  A Winter Storm Watch has been issued for the entire metro from 6am through midnight Friday. As temperatures rise above freezing (and keep climbing) Friday night, hopefully any ice will melt/be washed away by Saturday morning.

In sum, a #StupidCold night is in store tonight, another wintry weather day is on tap Friday, very heavy rain and some thunder is expected this weekend, then we get cold again. Oh yeah, March is just over a week away!  So much for Severe Weather Awareness Week! :-)

Speaking of which, check out our SWAW webpage for safety tips and a contest giveaway schedule that features a free local storm chase prize tomorrow night from Mid-South Storm Chasers and a free storm shelter from Take Cover Storm Shelters on Friday!

Erik Proseus
MWN Meteorologist

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4 comments:

Glenna Gonzales said...

Our "1,167-day "snowless" streak"? Am I missing something? It snowed last March, and we had a significant ice event in February. I live in south Tipton County, but I thought both of those events spread into Memphis, too.

MWN/Erik said...

Glenna - the airport (where the official observations are taken) did not receive an inch of snow or sleet. Freezing rain is separate but it's rare to get an inch of that too. Tipton Co was MUCH worse than southern Shelby Co a couple of times last year!

Anonymous said...

#Snobama That made me laugh. I could see him trying to take that hashtag for his own personal gain and say he came up with it!

MWN/Erik said...

In case there is any question, the #Snomaba reference is because the event occurred on President's Day. No political statements are being made... :-)