Tuesday, January 19, 2016

Winter Gone Wild

9PM Tuesday Update... This still looks like a light event, quick moving, and there will be travel issues north.  How far south the freezing line gets is the big question.  I have sat at 34.7 in west Little Rock for hours.  New data even warms the metro overnight.  It's going to be a close call for us in the Little Rock metro and I urge you to watch Channel 7 Daybreak for the newest information.  Once again, it will be light and quick moving and the focus will be northern Arkansas.

Now onto the comment section.  I mentioned below some of the data points to the precip staying frozen for portions of northern Arkansas most of Thursday with the next system .  Here's the data showing that.  Not saying that's what will happen, but some of the models indicate it.

Noon Thursday.
6PM Thursday.

Midnight Friday.
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Well the chorus of voices has already changed from "where's winter" to "I want the warm weather back".  LOL.  I told you to be careful with what you asked for!

We have only had one minor event so far, but there's at least two more on the table.  I'll address the Tuesday night/Wednesday morning system first.

I was taught to always look at the data and ask, what could go wrong with your forecast?  In my opinion, where does the freezing line end up is a key question.  Remember, arctic air is dense and does not move easily.  I'm writing this early Tuesday afternoon and the temperature in west Little Rock is only 35 degrees with a dew point of 12 degrees.  There's plenty of room to drop.  The European model takes that freezing line a little further south tonight and that's my concern.  The models are not doing a great job with the cold air and that's to be expected.  By far, the best chance for sleet and freezing rain will be northern Arkansas and the cold air will be deep enough close to the Missouri border for mostly snow.  Also, very important, amounts will not be heavy.  That's why a winter weather advisory is in effect instead of a winter storm watch/warning.  But we all know it does not take much ice to cause problems on the roads.  As far as the biggest impacts are concerned, I think that's roads and school closings.  I'm not too worried about power outages at all.  

At this time, I think the freezing line (32 degrees) may be a little further south than what most models are predicting.  This may put portions of central Arkansas in the winter weather advisory.   We'll see how that plays out.  Southern Arkansas, just plain rain.

Now onto the next system Thursday.  There's a good chance, the precipitation stays mostly frozen over northern Arkansas for the majority of the event.  It's not until the surface low passes, we get air cold enough in central Arkansas for a transition to snow.  Accumulations?  It's too early to pin point at this time, but I don't think it will be too heavy for central Arkansas, BUT it does have potential to bring enough to satisfy some snow lovers!  We're NOT talking about a huge storm here!  The favored locations at this time are across northern and eastern Arkansas.  

By the way, if you're traveling to the east coast later this week, expect major delays and a major winter storm there.

BELOW IS THE EUROPEAN MODEL.  IT IS NOT A FORECAST!  THIS IS A TOOL USED TO MAKE OUR FORECAST.  IT WILL NOT VERIFY EXACTLY, BUT IT'S GOOD GUIDANCE AND SHOWS OUR CONCERN.  I PROMISE YOU, THESE MAPS WILL NOT VERIFY EXACTLY.


Below are model maps from EuroWx.com.


The Tuesday morning run of the European favors ice amounts a little further south than some of the other models I have seen.  That's my worry.  Notice all amounts are under .2''.  That's advisory criteria and not warning criteria.  Warning criteria is .25'' or more.  While amounts will be light, it will cause problems on the roads and I expect school closings north.  If the European is correct, some of that wintry weather could make it as far south as Conway or northern Pulaski county.  It's a tough call for sure!!!!!!!!
Snow amounts Tuesday night and Wednesday morning could be around 1-2 inches close to the Missouri border.  This is where the cold air is deep enough to support mostly snow.
Now onto round #2.  This arrives Thursday with a mix across northern Arkansas and rain across central and south Arkansas.
By Thursday night, cold air pours south and a transition may occur to wintry weather across much of the northern 1/2 of the state.  Southern Arkansas MIGHT see a LITTLE too.
THIS IS NOT A FORECAST.  IT'S ONLY MODEL GUIDANCE AND THIS WILL CHANGE... I PROMISE!  On the back side of the system there may be a couple inches of snow and maybe a bit more further north and east.  This depends on how much moisture there is and the track of the low.  I promise this will NOT verify exactly, but you see my concern.

4 comments:

Anonymous said...

On Thursday: "There's a good chance, the precipitation stays mostly frozen over northern Arkansas for the majority of the event." No. Data does not show this at all. There will be more warm air in play aloft than with the Tuesday/Wednesday system. There may be a changeover to snow in the north later on Thursday, but this will not be an all snow event. No way. Just keeping you honest, my man.

Todd Yakoubian said...

Not true. the 18Z GFS and new NAM both show northern Arkansas with frozen precip most of the time.

Todd Yakoubian said...

From the NWS Little Rock AFD "SYSTEM WILL SPREAD MOSTLY RAIN ACROSS CENTRAL AND SOUTHERN ARKANSAS ON THURSDAY BUT ENOUGH COLDER AIR MAY HOLD ON ACROSS THE NORTH THAT
A PERIOD OF FREEZING PRECIPITATION IS POSSIBLE AT THE ONSET OF THE
STORM. IF THE COLDER AIR DOES NOT GET SCOURED OUT AS THE CURRENT
THINKING INDICATES...THE FREEZING RAIN COULD HOLD ON LONGER THAN
EXPECTED."

Temperatures aloft don't mean much if cold air gets trapped at the surface. Again, not saying that's going to happen, but it's possible according to the data.

Anonymous said...

Winter has definitely not gone wild, not even close here in little rock.

NOAA Winter Guidance