Thursday 10:30am

With one storm behind us, it looks like there is the chance for some more in front of us. This coming weekend will see two systems. The first looks unimpressive and will bring rain to us on Friday night and into Saturday. Some light snow might mix in with it, but accumulations will be next to nothing.

Later in the weekend looks to be tricky. Sunday and Monday will bring a rather impressive storm system into play. However the models are all over the place and go back and forth from snow to rain.

Here is the latest GFS for Sunday at 7pm. A nice band of heavy precip over the Ohio Valley area, but there are two problems with this. First, notice that the 540 thickness line is well to our north (the first blue line north of the Ohio River). This would essentially be the rain/snow changeover line. That 540 line doesn't go south of us until 95% or more of the precip is gone on Monday! So if that turns out to be the case, this will be an all rain event. This will definitely be something we'll need to watch closely.

Here's what the Louisville NWS says about this system:

BEST PRECIPITATION CHANCES SEEM TO BE ON TAP FOR SUNDAY AFTERNOON THROUGH
MONDAY.  GOING CLOSER TO THE 18/00Z EURO SOLUTION HERE...WOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF RAIN DURING THE DAY ON
SUNDAY.  TEMPS LOOK TO STAY JUST WARM ENOUGH FOR MOSTLY RAIN ON
SUNDAY NIGHT ACROSS THE NORTH...BUT SOME SNOW COULD MIX IN AT
TIMES...WHILE THE SOUTH LOOKS TO STAY ALL RAIN.  PRECIPITATION WILL
CONTINUE INTO MONDAY WITH TEMPS COOLING FROM WEST TO EAST.  WE
TRENDED TEMPS HERE CLOSE TO THE RAW 2M TEMPS FROM THE 17/12Z AND
18/00Z EURO SOLNS.  LOWS SAT NIGHT SHOULD DROP INTO THE LOWER 30S
WITH HIGHS ON SUNDAY WARMING INTO THE UPPER 30S IN THE NORTH AND
LOWER 40S IN THE SOUTH.  LOWS SUNDAY NIGHT LOOK TO COOL BACK INTO
THE LOWER 30S IN THE NORTH AND MID-UPPER 30S IN THE SOUTH.  HIGHS
MONDAY WILL LIKELY TOP OUT EARLY IN THE DAY IN THE UPPER 30S TO THE
LOWER 40S BEFORE FALLING DURING THE AFTERNOON.

One other thing looks really good for this to be an almost all rain event. At left is the 850mb temps and you can see that the top red line goes over our area. That indicates 3 degrees celcius above freezing. The purple line is freezing and that is well north of us. This is also supportive of rain. The 850 temps really need to be below freezing for this to even be a wet snow because the 700-850mb region is typically where the snow forms. With this model run it looks like temps will be just too warm to support snow in our area.

Now this won't be the same for Indy. If you are heading toward Indy you will definitely see some snow accumulations. The latest QPF's from the HPC suggest over 0.5" liquid in the Indy area and with that being a more wet snow, they could get around 5" snow. Certainly a 3-5" forecast of snow for that area is not out of the question at this point. Now what if the Low decides to go further south? It is certainly possible and if it does that snow will be pulled down into our area. I'll update more on this system as the models come in again.