HELLO DARKNESS MY OLD FRIEND...
A potent spring storm will take sweep across the central Midwest Wednesday bringing wind, rain, severe weather, and in some areas a bit of late season snow. Overall, another dark deary day.
With regards to snow, the past couple days I've seen a wide range in model solutions. And while there is still some possibility of seeing wet snow in my local area Wednesday, it appears it would be a quick mix or brief changeover. Any accumulations would be minimal and confined to grassy or elevated surfaces.
The critical layer we usually look to for snow formation is 850mb, (5,000 ft). If temperatures at that level are at or below freezing it usually is a go for snow. However, in this case surface temperatures are just so warm that the snowflakes will have a tough time reaching the ground before melting. One way it could happen is if precipitation rates are high enough to cause dynamic cooling which in turn pulls cold air to the ground. That's looking like a tough sell and one that would be confined to a very narrow region near and north of the upper air features.
At this point the only model that depicts snow in eastern Iowa and my local area is the NAM. It shows the transition in blue late Wednesday morning or early afternoon. Take a look.
It has this for snow accumulations.
Once again the NAM is the outlier and most other models show a limited or snow free scenario over my local area. You can see below the GFS and EURO are lighter and further east with their snowfall forecasts.
Again, I have seen these dynamic spring storms do some crazy things so I can't write off a band of accumulating slushy snow in some part of eastern Iowa or NW Illinois but it's beyond my ability to see or pinpoint. We'll need to watch the situation as the event unfolds during the day.
One thing is for sure, this will be a windy wet system for much of my local area. Wind gusts of 30 to perhaps 40 mph are likely out of the N/NE. Rains of as much as an inch could fall southeast of a line that runs from near Dubuque back to Cedar Rapids and on to Des Moines.
The NAM has this for total precipitation.
The high-res NAM WRF has this for total precip.
On a positive note, warmer weather makes a quick return to the Midwest just in time for the weekend. The EURO meteogram for Cedar Rapids has highs of 70 Saturday, 75 Sunday, and 71 Monday.
Brothers and sisters, I am all in with the warm weekend. Things are really going to pop! Roll weather...TS