Winter Storm — Still Waiting on More Certainty

FINAL UPDATE:  Thursday, December 19, 2013, 4:12 p.m.

First off, the “Freezing Rain Advisory” has been push back to midnight tonight through 9 a.m. Friday.

There is now a “Winter Storm Watch” (blue on the map) in effect from Saturday evening through Sunday afternoon.  This means significant snow is becoming more likely across eastern Iowa and western and northwestern Illinois.

Winter Storm Watch

Let me get this out of the way now.  If you live in Knox or Stark counties in Illinois, you are under a different weather service office that hasn’t issued a “Winter Storm Watch” yet for their forecast area.  YOU WILL STILL GET ACCUMULATING SNOW!

Here is the available moisture being generated from this storm by the Hydrometeorological Prediction Center.

HPC

It shows a solid 0.5″-1″ of available moisture.  If this was a perfect 10:1 snow, that would translate to  5-10″ of snow.

The afternoon models are continuing the trend from earlier today that the storm will be tracking more to the east and not to the north.  This would keep eastern Iowa and northern Illinois in the colder air with less icing and more snow.

Here is the new 3 a.m. Sunday map from the GFS.

SUNDAY 3AM GFS

And, this is 9 a.m. Sunday.

Sunday 9 AM GFS

The bottom line, as it looks right now, is that we could have 6-12 hours of moderate snow in and around the Quad Cities.

Early indications for planning purposes 48 hours out, AND THIS IS SUBJECT TO CHANGE AS WE GET CLOSER TO SATURDAY, is that 6-9″ of snow may fall from Freeport, Illinois, to the Quad Cities, to Burlington, Iowa, to the northwest to Dubuque and Cedar Rapids, Iowa.

Southeast of the Quad Cities, 3-6″ of snow could accumulate.

Remember, this is still two days out and there will be deviations to this forecast as better data and a more concrete storm path is established.

I’ll have another update Friday morning!

Anthony

UPDATE:  Thursday, December 19, 2013, 11:03 a.m.

The new American models (NOAA’s GFS) is out now and it now has the storm on a more southerly track.  If this continues to verify, it would indicate more cold air to work with and more snow, possibly heavy.

NEW SUNDAY 6AM GFS

It would also cut back on the icing threat in the Quad Cities.

As I’ve stated all along, there is not much consistency, so let’s see what the late afternoon runs show.  I’ll update this again by evening.

Anthony

ORIGINAL POST:  Thursday, December 19, 2013, 7:37 a.m.

Happy Thursday!

I have to admit that I’m getting old or the rigors of getting little sleep and waking up at 1:30 a.m. five days a week for work are getting to me.  I dozed through the two episodes of “The X-Files” we watched last night and I saw part of the Michael Buble Christmas special between dozing!

michael-buble-mary-j-blige-3rd-annual-christmas-special

I loved Mary J. Blige and Mariah Carey was less robotic and seemed to have a good time.  But, we’re here to talk about weather on my day off.  Yes, I slept until 6:45 a.m.!

Freezing Rain Advisory

Before we even talk weekend snow, remember that it will be very slippery out there Thursday night and Friday with freezing rain and temperatures back below freezing.

The counties you see painted in fuchsia on this map are under a “Freezing Rain Advisory” from 6 p.m. tonight until 6 a.m. Friday.  It’s going to get slick with more snow melting today and 40° highs.  That will freeze later overnight.

Snow's a comin'

Now let’s talk about getting prepared for the weekend.  We’re now more than 48 hours away from the onset of a winter storm Saturday and there is still little certainty in the forecast.

What I do know is that we’ll see snow, we’ll likely see freezing rain and sleet, and some rain.  The problem is how much.

As I mentioned last night and I’ll re-post the link, it all depends on the path the storm takes.

https://anthonypeoples.wordpress.com/2013/12/18/possible-ice-before-the-weekend-snow/

The latest American models are still hinting at a more northwesterly track.  For the Quad Cities, that would mean more warm air to work with and more ice threat and less heavy snow.  That heavy snow would be northwest of the Quad Cities.

This is midnight Saturday on the GFS.  It shows us in the cold air and moderate snow falling in the darker green.

SATURDAY MIDNIGHT  GFS

This is six hours later at 6 a.m. Sunday.

SUNDAY 6 AM GFS

The storm is pulling off to the northeast, but snow will still be moderately falling.

The big change that I noticed is that by noon Sunday, the snow may be over.

Now, here’s another big piece of the winter storm puzzle other than the storm track.  This storm will have plenty of Gulf of Mexico moisture to work with.  This map shows available moisture from Saturday evening through Monday evening.

Sat PM- Mon PM

It shows the Quad Cities with 0.50″-0.75″ of available moisture.  For simplicity sake, a 10:1 ratio of snow and rain would show 5-8″ of snow for the Quad Cities.  However, any rain or freezing rain falling Saturday and Saturday night would significantly cut back on those totals.

So, until a more definite path is known, we’re still waiting.

The bottom line is that if you have travel plans, expect messy weather.

I’ll update you again this afternoon.

Anthony

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2 responses to this post.

  1. Thanks Anthony. Hey are you on vacation? & where to? Missed you on the news this morning. I am sharing all of your reports acting as your personal assistant. lol! Have a lovely time wherever you may be. Merry Christmas!

    Reply

    • Deb,

      I’m only using up the last two days of vacation this year. I’m at home. A stay-cation.

      Definitely get the word out and for people not to panic — yet.

      Have a great day!

      AP

      Reply

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