Yet another snowstorm, maybe some TSSN??

Another winter storm is on its way into northern IL for sunday night into monday with a good possibility of it dumping significant amounts of snow across the chicagoland area. unlike like the last snow event that went on for over 30 hours, this one will not be as long-lived but will pack quite a punch when it does get here. this storm will also be wetter and our southern counties could have to worry about possible mixing issues down along and south of I-80. It is still a bit early to say where the rain/snow line will set up. snow ratios will be lower which will mean a heavier snow to shovel aka "heart attack snow" but given the dynamics of this sucker and possible convection, they could be higher maybe nearing 12:1 or so.

as usual, I will start with the WV loop to get a quick look at whats currently going on. we had the weak wave move through overnight dumping near an inch in places across the area. our attention now turns the trof coing down the western U.S and the big guy at the base of that trof spinning off the southern CA coast and moving onshore into CA and the baja.

http://weather.cod.edu/loops/US-WV24.loop.html

WAA snow is already breaking out in KS in association with the upper level low over baja and will continue to develop. this is just the beginning of this major storm.

as the ULL kicks out and moves into the southern plains this will create a surface refletion and an area of low pressure will develop and begin to move ENE and deepen slowly. the progs are coming into better agreement on the track but there is still some uncertainty on the exact track but it looks to head into MO and then through central IL and into IN with an area of heavy snowfall to the north and west of the surface low.

here the where the vort is located at 36 hours as it moves NE into MO by early monday morning.



and then by monday morning at 12z its over IL/IN.



here is where the sfc low is progged to be early monday morning at 6z, looks to be over the st. louis area



and then by 12z monday morning its in east central IL now down to 999mb moving NE.



this storm is going to have a good amount of moisture with it and tons of lift to help produce some hefty snowfall rates and wouldn't suprise me if we were to see some TSSN reports as this thing really gets going given the amount of the omega in the DGZ. here is a map showing the amount of lift at 700mb



what is going to be a problem for the soutern counties and down towards the kankakee area is going to be the warm nose at 925mb and 850mb with strong WAA that is going to create mixing issues down there but up here will should remain all snow. here is the winds at 850mb showing the impressive wind fields.



so as all this is going on, the storm will be strengthening and heavy snow will begin to break out in MO and streak into western IL and eventually our area by late sunday night and the deformation begins to take shape which will produce heavy snow rates overnight sunday and through the morning and afternoon hours on monday.

here is where the defo band is located overnight sunday, really starting to ramp up.



and then by rush hour monday morning, we are getting blasted.



The chicago office has a Winter Storm Watch in effect for the area north of I-80 from sunday evening to monday evening for 6-10". I think there will be some areas that hit a foot or more when all is said and done, heaviest being the further north and west you go. with the heavier rates, the snow should stack up pretty quick, even more if there can be some thundersnow. some models are spitting out near 1.25" QPF for ORD and even with 10:1 ratios, that would yield 12" of snow.

here is a image I just took off the LSX hi-res WRF, this is for overnight sunday as the heavy snow is now over the area.



and just took this off the new 12z hi-res NMM showing the impressive omega as this thing ramps up tomorrow evening



I will probably do an update later tonight after the 0z runs come out but there will most likely not be many changes. some other notes, the hi-res NMM takes the surface low down to 996mb along the IL/IN border sw of INDY by monday morning, and im really impressed with the omega showing up throughout the storm as well.

hopefully in a few months I will be able to see a few of these if we ever get out of this pattern