First Snowfall of the Season?

Tuesday High Temperatures

If you have been following our updates the past few days, you have been reading about us keeping our eyes closely tuned to Monday, as there is a storm system that will bring very cold temperatures and potentially some snow. We haven’t talked about any snowfall accumulations due to the fact that we are still several days away, and the models continue to flip flop back and forth. Because of this, we will still be refraining from talking about snowfall projections, however, we will show the latest model trends. This article is simply about the latest trends that the models are showing, so the following information is NOT a forecast, as the data will continue to change.

Tuesday High Temperatures

Tuesday 11/11/2014 High Temperatures

We will first start out talking about the colder weather as that will be the bigger story. If you think temperatures today are cold, just wait until mid week next week. Temperatures will continue to be in the 4o’s and 50’s for the remainder of the week and on into the weekend, before the arctic blast moves though the state Monday afternoon. Temperatures on Tuesday will be will be 15 to 20 degrees cooler than where they are today. Highs on Tuesday will be in the 30’s and potentially in the 20’s across northern Iowa, and we won’t get much relief on into next week. The wind will also be strong, and this will add an extra bite into the air.

Now onto what everyone wants to know about… the snow. All of the models have been showing an area of snow somewhere across the upper Midwest starting Sunday night, through the day on Monday, and on into Tuesday. Yesterday, it appeared that the boundary that will bring this snow chance would stay up into Minnesota and Wisconsin. Last night the 00z model runs shifted this boundary further to the south where snow would be affecting northern Iowa. Below is this latest two GFS model runs, with the first one being the 06z run and the second one being the current 12z run.

06z GFS Snowfall

06z GFS Snowfall

12z GFS Snowfall

12z GFS Snowfall

As you can see above, the GFS model runs have been focusing on northern Iowa for potential snowfall. The latest 12z model run has colder temperatures arriving earlier, and this is why we are seeing more widespread snowfall compared to the 06z run. Now we will compare the GFS to the European model which tends to be the more accurate model. Below is last nights 00z model run and this mornings 12z model run.

 

00z ECMWF Snowfall

00z ECMWF Snowfall

12z ECMWF Snowfall

12z ECMWF Snowfall

As you can see from the very latest European runs, the very latest 12z run has shifted the boundary back north and has kept the snowfall confined up into Minnesota and Wisconsin.

Because of all the flip flopping and differences in model runs, this system will need to be closely monitored. If the boundary makes its way far enough south, like the models have been trying to depict, then snow will be possible across the central and northern parts of Iowa. If the boundary does not make it far enough south, then the snow will stay to the north across southern Minnesota/northern Iowa. What should also be noted is even if temperatures near the surface are above freezing, temperatures in the upper levels of the atmosphere are far below freezing during this event. So any precipitation will begin to fall as snow and will quickly transition back to a very cold rain, possibly mixing in with a few snow flakes that do not melt at the surface. However, we are expecting temperatures to quickly fall across northern Iowa first, and this would transition any rain to snow rather quickly. Temperatures across central and southern Iowa will take a bit longer to fall below freezing, but will eventually fall below freezing in the evening hours Monday.

4" Iowa Soil Temperatures

4″ Iowa Soil Temperatures

Now another thing to remember, is the current ground temperatures. The very latest 4″ soil temperatures as of yesterday were in the mid to upper 40’s as shown above.  This will make for a hard time for the snow to accumulate as snow will melt on contact. Some accumulation will eventually be possible, but not as much as if our soil temperatures were near freezing. The best potential for accumulating snow will be across northern Iowa. The question will be just how much will that be?

There is still plenty of time for all of this to change, so continue to check back here for all the very latest details.

Zach Sharpe

My name is Zach Sharpe. I am the president and forecaster for the Iowa Storm Chasing Network. You can find me on Twitter @Stormchaserzach and on Facebook at: https://www.facebook.com/stormchaserzach/

Leave a Reply

%d bloggers like this: