Monday, January 14, 2013

Winter Weather Advisory issued - MWN's forecast for possible wintry precip Monday

Winter Weather Advisory area in purple - see text for details
A Winter Weather Advisory has been issued for the metro from 10am today until noon Tuesday.  For more details on the atmospheric setup regarding this event, please refer to last evening's blog post.  Our general thought process has changed little since then.

I've pasted the text of the Advisory from the NWS below. However, in our estimation, we feel that this is a very conservative forecast based on continuing disagreement among the computer models and issued for an area larger than the metro where conditions could be worse than they are locally.

In the metro (from Crittenden to Fayette County east to west, and from Tipton to Tate County north to south), these are the impacts:

Period of chief concern: noon-6pm today
Main precipitation types: freezing rain or sleet
Intensity of the precipitation: very light to light (0.01-0.05")
Chance of precipitation: 40%.
Temperature during potential precip: 31-33 degrees
Expected impacts: minimal, mainly on elevated roadways and exposed surfaces, such as power lines, due to a potential light glazing of ice. Ground temperatures from recent warmth should keep (non-elevated) roadways from becoming hazardous

Plan ahead, especially for your afternoon commute.  Have an ice scraper in your vehicle today. Allow extra time for travel and, if precipitation has fallen or is falling, leave plenty of distance between you and other vehicles and do not make sudden lane changes or brake quickly.  Icy spots can come up quickly and with little warning.

There will be a lull in the precipitation this evening and most of the overnight hours.  Another round of  precipitation will be possible Tuesday, with most of that falling from mid-morning to afternoon when temperatures are expected to be above freezing. Some of this precipitation could also start off as very light freezing rain early Tuesday morning.

Stay with MemphisWeather.net for the latest on this developing winter weather scenario, including nowcasting on Twitter and Facebook during inclement weather.  Links to our services are at the end of this post.

Winter Weather Advisory  text from the National Weather Service for the entire region:

...WINTER WEATHER ADVISORY IN EFFECT FROM 10 AM THIS MORNING TO
NOON CST TUESDAY...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A WINTER
WEATHER ADVISORY FOR FREEZING RAIN...WHICH IS IN EFFECT FROM 10
AM THIS MORNING TO NOON CST TUESDAY. 
* ICE ACCUMULATIONS...FREEZING RAIN ACCUMULATIONS OF LESS THAN ONE QUARTER OF AN INCH ARE EXPECTED...MAINLY ON TREES...POWER LINES AND ELEVATED ROAD SURFACES.
* TIMING...10 AM THIS MORNING TO NOON CST TUESDAY WITH THE
GREATEST POTENTIAL FOR ICING LATE LATE MONDAY EVENING THROUGH
SUNRISE TUESDAY.
* IMPACTS...SOME DAMAGE TO TREES AND POWER LINES WILL BE POSSIBLE.
ALTHOUGH GROUND TEMPERATURES REMAIN WARM AT THIS TIME... SLICK
AND HAZARDOUS ROAD CONDITIONS WILL DEVELOP ON BRIDGES AND OTHER ELEVATED ROAD SURFACES. WIDESPREAD HAZARDOUS ROAD CONDITIONS MAY DEVELOP IF PRECIPITATION IS MORE INTENSE THAN CURRENTLY ANTICIPATED.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF FREEZING RAIN
WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS AND
LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.

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2 comments:

Anonymous said...

I've read a few blogs/pages linking to this post and it seems like there is some confusion about the line "However, in our estimation, we feel that this is a very conservative forecast...."

Some folks seem to read this as "things may be worse in Memphis" and "conservative" means the forecast is reporting the least possible accumulation. I read it as "things may be better in Memphis" because the forecast covers a wide area where conditions may vary and "conservative" means the NWS is covering all of their bases.

Just wanted to share in case you use similar language in the future - it seems to be a little unclear.

Thanks for all of your great reporting!

MWN/Erik said...

Thanks for your constructive comment. Yes, I realize I should have been more clear. What I mean was your second thought - I felt the NWS was covering all their bases. I'll be sure to state that more definitively in the future.

Thanks for reading!
--Erik