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Warm to Winter Mess... Rain, Snow and Ice

by Monty Webb

WHAS11.com

Posted on December 4, 2013 at 1:42 AM

Updated Wednesday, Dec 4 at 8:26 PM

Warm to Wintry Mess

The front out to our west will stall out somewhere south of the Ohio River late Thursday.  Setting the stage for the cold air to our north and warm air south to battle it out over Kentuckiana Friday.  A warm front moves through Wednesday with scattered showers and highs climbing to the mid and maybe the upper 60s. 

Temperatures will then plummet 30 degrees by  Friday!

 

Forecasting winter weather in the Ohio Valley is always challenging.  We are quite often the transition line between liquid, freezing, and frozen precipitation or a combination of all.  Forecasting what type of winter precipitation is more complicated than whether or not we will be below freezing at the surface. 

What's really important is determining the temperature profile of the lowest few thousand feet above the surface of the ground.  A difference of a couple of degrees or in the height of the freezing level can change a wet commute into one of slipping and sliding to work in freezing rain or snow!

Below is a Skew-T that gives us a vertical cross of the atmosphere.  What makes this Friday so complicated is that many of the weather models we use have very different solutions in the temperature profile.  The NAM is the warmest showing rain; GFS - coldest with a mix to snow; ECMWF is in the middle forecasting freezing rain or sleet changing to snow.

As you can see weather is never easy to forecast in Kentuckiana.

Image courtesy of NWS Louisville

 

Futurecast (note the time stamp in the banner)

Lets try to time things out with Futurecast...  With the warm front moving through the area on Wednesday we will be dodging scattered showers, but temps will warm well into the 60s.  A good 15 degrees warmer than average!

Late Wednesday the cold front pushes into the region for more showers and a very slight chance for a stray thunderstorm.

By Thursday morning the front stalls somewhere south of the Ohio river and the rain will increase throughout the day.

The rain will be heavy at times Thursday evening-night along and south of the Ohio River.  Rainfall totals by early Friday morning could be between 1-3".  We will need to watch out of some local flooding issues. 

Notice by 8pm Thursday the cold air is working into our NW Indiana counties and we see a change-over the a wintry mix.

These times and precipitation types are not set in stone and we will be fine tuning the forecast as we get closer to Friday!

That spreads south of the Ohio River (Metro) by early Friday morning and our northern IN counties see a change over to snow

The Metro sees the mix to snow Friday afternoon

While our southern KY counties have to what until Friday evening.  Right now it appears the wintry weather will be leaving the area Friday night at the front sags south.

Looks like we will have some slick roads Friday night-Early Saturday morning.

Everyone wants to know how much snow...  I'll be honest and tell you that this is extremely difficult this far out!  The models are all over the place with no accumulation to over 7 inches!

Below is my best guess right now.  Again, this is not set in stone and will likely change between now and Friday.

Icy Sunday

We get a little break Saturday with a cold and dry day.  But, Saturday night the front starts drifting north with warm moist air overrunning cold air at the surface.  The perfect set-up for a little freezing rain.

Right now it looks like the freezing rain will start overnight Saturday into Sunday morning, then change to cold rain during the day.  Possibly ending as a little snow or mix late Sunday evening/night. 

We will need to watch out for icy roads Sunday morning.

Remember a lot could change before Friday and Sunday.  Stay tuned!

 

 

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