Wednesday, December 4, 2013

Details on Friday's expected ice storm in the Mid-South

As most people in the Memphis metro know by now, unless they haven't had TV or radio on and haven't looked at a forecast in the past few days, winter weather is taking aim on Friday.  This is hard for many to fathom given that it's 75 degrees today, thus there are plenty of doubters.  However, if you follow us, you know this is not a test, and if you were here in 1994 you will remember that it was 70 degrees a day before the big Ice Storm of '94 hit.  This blog will provide a little more detail on what to expect and when to expect it, but we invite you to tune in to YouTube or Google+ tonight at 9pm for a live G+ Hangout (video chat) as a panel of experts weather geeks, lead by MWN, talk about the upcoming storm in greater detail.

We'll start with what the weather will do:
A Winter Storm Watch is in effect Friday, beginning at 3am for Tipton and Crittenden Counties in the metro and at 9am for Shelby and Fayette Counties in TN and DeSoto and Tunica Counties in MS.

An arctic cold front will move through early Thursday morning , dropping temps from the 60s overnight to the lower 40s by Thursday PM rush hour with showers around the area most of the day. Rain continues overnight Thursday night as temperatures fall into the mid 30s. By Friday morning, with rain continuing, temperatures will hit 32 degrees.  The timing of this will vary

  • early morning, possibly by 6am, for the northern metro (Tipton Co)
  • mid-morning (8-10am) for the I-40 corridor, including Shelby & Crittenden Co
  • late morning (10am-noon) for Fayette Co and our MS counties (DeSoto, Tunica, Tate, Marshall)
Freezing rain will continue throughout the morning and afternoon hours, mixing with or changing to light sleet and possibly some light snow by late afternoon.  All precip will come to an end by the evening hours (for round 1) as temperatures fall into the upper 20s.  Ice accumulations will likely average 1/4" to 1/2", though northern areas that transition earlier could see higher amounts.

NWS-Memphis graphic summarizing impacts and timing
By Saturday morning, conditions will be dry as far as falling precipitation, but it will be very cold with lows in the lower 20s and wind chill readings near 10 with a north wind at 10-15 mph.  Highs Saturday will only rise to near freezing under extensive cloud cover, so we don't expect a lot of melting to take place as we head into round 2... another round of freezing rain Saturday night that could drop another 1/4" to 1/2" before changing to rain on Sunday morning!

Potential impacts:
We expect the Winter Storm Watch to be upgraded to a Winter Storm Warning or Ice Storm Warning no later than tonight, while areas outside the current watch (including Tate and Marshall in the metro) should get a Winter Weather Advisory by Thursday morning.

With 1/4" to 1/2" of ice, accumulation could be enough to cause some damage to trees and power lines, resulting in power outages.  In fact, the Weather Service's experimental Ice Storm Index (which is being tested locally for the first time this winter), places the I-40 corridor in a level 3 ice storm based on accumulation and wind speed, which could result in "numerous utility interruptions, lasting up to 5 days" and "damage to some main feeder lines possible."

NWS experimental ice storm index forecast, depicting a category 3 storm for most of the metro.
In addition to power outages and downed tree limbs, secondary roads could be slippery, bridges and overpasses will likely be iced over and perhaps impassable, and multiple events could be forced to postpone or cancel this weekend.  Air travel into Memphis could also be affected by delays or cancellations Friday with aircraft having to deice prior to departure. Schools could also be affected Friday, but we know better than to venture into guessing what their operation plan will be!

You have basically just over 24 hours to prepare for the above impacts.  Be sure you consider what you'll do if power is out for multiple days, roads are slick, and ice covers unpaved surfaces and exposed objects. Also don't forget to consider elderly and sick relatives and friends, especially those who might require power for oxygen, etc., and your pets!

As mentioned above, we'll have a very detailed discussion, including comparison to previous ice storms and more preparedness information on our Google+ Hangout tonight.  You'll have an opportunity to ask questions via chat or the Twitter hashtag #wxchat. You can watch live and chat via this MWN webpage and we'll also post a direct link around 9pm tonight on our Facebook and Twitter accounts listed below.

You can also get the latest information, including current conditions, our metro forecast, and StormView Radar with precip typing, via our mobile apps for iPhone and Android. In addition, within the mobile app, be sure to upgrade and add StormWatch+ for a very affordable one-time charge. StormWatch+ allows you to receive severe and winter weather warnings via push notification for just those locations YOU select. A link to the apps can also be found below.

Stay tuned for the latest!
Erik Proseus
MWN Meteorologist

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DanTheCigarMan said...

Thanks as always Erik!

Christina said...

Thank you! Finally I found someone talking about the weather -- the traditional TV station Web sites were no help! Out of town and trying to decide whether to keep plans or change them. Leaning towards staying away from the Memphis drivers -- bad enough when the roads are clear and dry! That's the wise decision, right?

Meteorologist Erik Proseus said...

Christina, I would say if your travel is not necessary, it should be avoided. Yes, especialyl around Memphis drivers! :-)