Feb 5th-6th Ice Storm Update #5- Ice Storm Warnings Go Into Effect Later Today/This Evening As Tricky Forecast Remains
As you have probably seen on previous posts, Ice Storm Warnings have been issued by several National Weather Service offices across the state of Illinois and these will go into effect later this afternoon and evening across the area. The locations of the warnings are shown below.
The main point to get across regarding this system and potential ice storm across some areas is that it continues to remain a very tricky forecast and the difference of a degree or two will make all the difference between potentially significant freezing rain/ice accumulations and just plain rain if temperatures end up just a tad warmer, which is definitely a possibility. Warmer temperatures would the axis further northwest across northern Illinois and we have adjusted our thinking slightly due to this as you'll see below.
Taking a look at a current visible satellite imagery below across the region along with radar and surface plots, we can see that there is precipitation developing off to our west and southwest early this afternoon, across portions of Missouri and Iowa and this will continue to blossom and mature over the next few hours off in that direction. Temperatures are already in the low 30's across portions of northern Illinois at this time, all the way up to the I-80 corridor. This is leading to a good amount of uncertainty to our going forecast, which could mean more rain instead of freezing rain. Further northwest, away from the Chicago metro area from about Dekalb to Rockford, temperatures are still in the mid to upper 20's and the most significant icing could end up further northwest of where it is currently forecast to be.
Even with still plenty of uncertainty to this forecast regarding the finicky surface temperatures, the overall evolution of this system still looks to remain on track with precipitation blossoming to our west and southwest later this afternoon, before continuing northeast and east into all of northern Illinois by the late afternoon and evening. The loop below runs from noon today till 2am early tomorrow morning and is one models take on the overall precipitation type.
Due to the slightly warmer temperatures so far this morning and early afternoon compared against model guidance last night and what we see so far today, we have changed our thinking slightly with regard to the axis of the highest freezing rain and ice accumulations. This change has led shifting the axis slightly to the northwest as you can see below.