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WINTER STORM UPDATE, WHO SHOVELS THE MOST...

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WHO'S IN AND WHO'S OUT...THE LATEST ON THE IMPENDING WINTER STORM...

Lot's of new data has come in since my last post and the screaming message is that models have trended further east with the impending winter storm. The shift is minimal (roughly 30-40 miles), but if correct would have significant impacts for my area which was previously on the eastern fringes of the storm. The greatest impacts are still expected over my western counties (and much of Iowa ). However, higher snow totals are now anticipated in my central counties and even the east, (which previously looked unscathed), could see up to two inches of accumulation. More on that below.


Here's the latest warnings and advisories which have been issued recently by the National Weather Service. Most of the region west of the Quad Cites is under a winter winter advisory. Further west than that, winter storm warnings are flying to the left of a line from Waterloo to Cedar Rapids, Iowa City, and on to Ft. Madison.

The Weather Prediction Center has issued these odds of at least and inch of snow.

Below are the odds of 6 or more inches.

Traveling is likely to become difficult in most areas by Friday evening. However, the region west of a line from Waterloo to Cedar Rapids and Ft. Madison lies within the region of moderate impacts as indicated by the Winter Storm Severity Index. Major impacts are likely further west in central Iowa where major disruptions are expected with regards to travel and daily life.

Below is the official NWS snowfall forecast. Notice amounts rapidly decrease east of the Mississippi. The further west you go into central Iowa, the heavier the amounts are expected to be. These numbers could still be revised based on new data Friday before snow begins to fly.

Now the snowfall output from the 0Z runs late Thursday night. Again, these are not specific forecasts but we are now within the range of the storm where this output is being integrated into the official NWS snowfall forecasts. I will show you the raw data and comment below.


The EURO

The GFS

The 12K NAM

The 3k NAM

The GEM

The 6Z HRRR (a late addition)

To me the most important change was the EURO. For 3 days its maintained a drier solution for my central and eastern counties but Thursday night made the shift east that finally brings a consistent look to all model solutions. This brings much higher confidence to how much snow will fall, something you would expect within 24 hours of the actual event. If the current trends hold, I could see the NWS extending both the warnings and advisories about a county east at some point Friday. That's not my call but something I'm sure the NWS is considering.


AMOUNTS

While some minor tweaks are still possible, my interpretation of the data Thursday night would now "roughly" have the 6"+ line near and west of a line from Waterloo to Cedar Rapids, Iowa City, and on to Ft. Madison. The 4" line is near and west of a line from Dubuque to the Quad Cities and a little east of Galesburg. The 2" line runs from near Freeport to Dixon and east of Princeton. In essence, all of my area is in line for 6 to 2 inch totals from west to east. In the far west some areas could exceed 6 inches. Again, some adjustments are possible Friday as we get a couple more model runs before the event. Just a small shift east would mean higher totals and greater impacts east of the Mississippi.


TIMING

The snow begins in my northwest counties mid-morning and spreads southeast to the Quad Cities around noon and the rest of the SE by 2:00PM. It gradually ends in the NW shortly after midnight and is out of the southeast around daybreak Saturday.


WINDS

The system is tight and compact with the potential to generate east/northeast winds between 20 and 30 mph Friday night. As temperatures fall after sunset blowing and drifting is likely in the open country. Travel could be quite difficult for a time, especially west of the Quad Cities. Winds will quickly diminishing Saturday morning.


I do plan on doing a live Facebook briefing sometime around 1:00 Friday when all the new data from the morning runs are in. Make sure you are set to get a notification that the briefing is underway. With that, I will call it a day and catch a few hours of sleep. Until then, roll weather...TS

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