A LATE-WEEK STORM TO WATCH

Overall in the short term the weather will be defined by warm and calm weather, but later this week a strengthening storm system will likely bring rain and snow to the region. Confidence in the actual strength of the storm system is limited, but the likelihood of a system continues to increase. The 24-hour European Ensemble precipitation output shows a rather large area of rain/snow, but this will continue to shrink as the exact path of the system comes into better agreement.

On the warm side of the system, Thursday/Friday could see a heavy rain threat develop near the region as unseasonably high moisture content of the atmosphere will lead to showers, and potential thunderstorms as well. A Level 1 of 4 risk, a Marginal Risk for potentially flooding rains, is closing in on the region.

The current precipitation forecast through the weekend has a rather broad area of 0.5"+ of moisture to the southeast, with lighter totals locally. To the north, some of this would be on the colder side of the system and would pose a snow threat. There is additionally increasing confidence in an accumulating snow threat which could be impactful to travel.

An area of accumulating snowfall is being indicated by the Weather Prediction Center which matches some of the model trends. Right now it is lower probabilities, just in the 10-30% range with some increasing probabilities in northeast Iowa and southern Minnesota near 30-50%. The snow threat would be more focused on Friday.

The GFS

The EURO

Compared to last night the GFS has more in line with the Euro with a stronger, more organized system, in our area. Both systems continue to indicate a mainly cold rain affair for the Quad Cities region with a less than ideal storm track for accumulating snow. The lack of cold air in place ahead of this system additionally limits the snow potential. Farther north and northwest, however, the snow threat is higher. This would include northwest Iowa and much of Minnesota.

The European Ensemble mean covers areas to the west and northwest with accumulating snow. I really agree with the placement of the axis of accumulating snow. For the time being this does not look like a major snow storm as there is some question in the "phasing," or combining of pieces of upper-air support that could lead to a stronger system. With that said trends will need to be monitored for a stronger storm.

Above you can see the spread in the individual 50 members of the European Ensemble. There are a few low centers pushing 990mb which could be more problematic. Notice the lower centers are farther west as a stronger storm would have a tendency to trend that way. So, even if we were to see a stronger storm capable of heavier snow the likelihood of it affecting us is limited as it would likely trend farther west. Overall the Euro suite of models seem to have a pretty good handle on this system thus far.

Of the 50 members of the European Ensemble, quite a few do indicate at least some light snow Saturday. The ensemble mean is about a half inch for the Quad Cities. Only one of the 50 members is impactful (6"+) with snow, which further affirms what I mentioned earlier about a stronger storm likely being more west/northwest than in our area.

Enjoy the warmth over the next few days with highs in the 50s as the storm system late this week will bring the cooler temperatures and some snow threat Saturday into Sunday. Have a great week, friends!

-Meteorologist Nick Stewart