Keeping a very close eye on late week storm in midwest!!!

[Gothpunk-IL-WX]

Major arctic high pressure about to make a two day gateway, before slowly retrograding back westward with a possible, but becoming more likely winter storm just in time for late week and most of if not all of the weekend. This will all be followed up by yet another warm trend, but this warming trend should not be nearly as bad as the one last week. Finally another big storm will cool us off by the very end of the extended.

All of these top stories, are what this discussion is about. Brng the snack and something to drink, because this is gonna be a very, very, very long discussion. O.K. here we go. First off is the arctic high pressure which currently dominates the eastern half of the nation. This arctic high has brought to us the coldest air we have yet to see this winter, with even a few record low high temperatures broken! This high will bring us a very cold Martin Luther King Jr. Day. After that it will push to the east and allow some more seasonable to even some above average temperatures to work in for one to 3 days depending on where you live. The western half of the midwest will stay warmer the longest, while the eastern midwest stays colder the longest. What all this means is that for several days there will be a tight temperature gradiant between the cold and warmer places making temperature forecasting a living nightmare. Based on trends I have decided in the 1-10 day outlook to take a cross of all the models and blended them together to make the temperature forecast. By Thursday the Arctic High begins to retrograde back west towards us and will lower our temperatures again. No big deal right??? Well not exactly. For as this cool down begins again, a developing storm will ride under this shallow to somewhat high cold dome, and pull up some gulf moisture to create a wintry mess for the eastern and central portions of the midwest. Temperatures will be key to what precipation type will fall. If temperatures are even slightly colder then currently expected, then a major snow storm with up to a foot of snow will be possible, But should the temperatures be slightly higher then expected, then a nasty major ice storm will occur for the corn belt region with rain to the south and moderate to heavy snowfall amounts of up to 4-8 inches possible. Temperatures are too warm then it will stay liquid for the most part with ice and snow for the far north. I decided to go with a blend of the 1st and 2nd situations for now which seem the most likely to occur at this point. The forecast for this time period will need lots of adjustments as we approach the days of Thursday through Sunday morning. After all that mess there won't be an arctic blast behind this winter storm, in fact it will accually get more warmer as a warm front and pacific high pressure build in. This will cause temperatures to go sky high again, but it shouldn't be as warm as it was a week ago, but 40s and 50s will be very common during this warm up. Haven't mentioned any 50s yet in the forecast in case the models contiune to lessen the warm spell like they are currently doing. Either way wouldn't be surprised to see these kind of temperatures. By day 10-12 another storm will come through, this time in the liquid variety thanks to warmer temperatures, but there could still be some snow troubles especially north and behind the storm system as it should bring seasonably cold to possibly a minor arctic shot behind it. After then it cools off till day 16 with below average temperatures an light snowfall from any clipper type storm systems that come through at that time.

So will watch the late week storm, again temperatures and storm track will be very important in determining precipation type with the possible winter storm. Any snowfall accumulations with this storm could be very heavy due to strong gulf moisture associated with this storm as it rapidly develops thursday night and pulls out by Sunday. If it's an ice storm the ice amounts could be damaging. But there still remains many questions, so will keep a very close eye on it. and the temperatures throughout the forecast period.

Another shorter discussion to be issued tuesday night to discuss current forecast trends on the winter storm, if it is still likely to occur, and if so what the situation will be like and issuing the first guess weather type map and accumulation maps at that time. Stay tuned. That's all for now.

[sertorius]

Excellent discussion-I have been talking about this storm next week for a couple of days. The gem was on it starting last Friday. I think most of it will be liquid for me, but if the gfs and euro are to be believed I will have below normal temps. Saturday and Sunday. If there is enoug mositure (gfs on both the 12z and 18z today says there will be) I could get some lite snow on the back of it. The euro and gem really want to take this storm south thru southern Kansas and Missouri and the gfs further north. With the size of the ridge over the Rockies late this week, the gfs solution makes sense, but the euro is such a better model and has tracked almost every strom right this year. Also, the 12z euro is not nearly as warm as it was yesterday for my area behind this storm all the way thru next Wednesday. The other interesting thing about that run was the breaking down of the Western ridge and how much further west it pushes it. By the looks of things right now, my two warmest days will be Thursday/Friday of this week. I also think the gfs is onto something by the 13 day period-not specifics, just trend wise-it really brings a colder pattern back to this area and that coincides with the pna going back to negative. We shall see-but for sure, the next two weeks are not going to be as boring as December and are not going to be the zonal blow torch that it appeared just 5 days ago. I post my thoughts, as bad as they are, in the Lawrence/Kansas City thread and will continue to do so. But again, excellent discussion.