Snow: Little For Some-More For Others

ScreenHunter_02 Dec. 11 12.16

+++4PM Weather Update with additional warnings/advisories.

As expected the NWS in Pleasant Hill has issued a Winter Weather Advisory for the KC metro area for later tomorrow night into THU AM. Here is the outline of the new Winter Storm Warnings in pink and Winter Weather Advisories in blue.

ScreenHunter_02 Dec. 18 15.26

The model data this afternoon is slightly delaying the storms true impact to sometime around or after midnight through about daybreak THU AM. The “worst” of the snow is slated for sometime between 1AM and 5AM or so. This is where the bulk of the wind blown accumulation should occur. Here is the latest snowfall forecast off the 18Z NAM model...

I really at this point don’t have any significant changes to my thoughts from earlier this AM…aside from the timing and warnings update all else from the AM update continues. Now that the storm’s energy is coming onshore, my suspicion is that tonight’s model runs should be very telling and provide a bit more confidence in the outcome of the storm. Concerning Christmas…the EURO giveith (yesterday) and the EURO taketh away (today). We’ll worry about that over the weekend though.

Now back to the previous blog++++++++

I could also tack on to that title wind for all!  At the bottom of the blog is a revised KC White Christmas graphic as well.

There hasn’t been a lot of change in the modelling concerning the evolution of our 1st real winter weather maker moving into the western part of the country today. This storm will move through the SW and eventually move right through our region over the next 36 hours. Our precipitation will run the gambit from rain showers to a brief mixture to the potential for a very wind driven snow that may come down at a decent clip for awhile before rapidly shutting off. As all this is evolving strong gusty NW winds will be cranking up and during/after the transition the winds will be howling from the NW at close to 35-40 MPH…so regardless of who picks up the most snow and who gets the least, everybody will be dealing with the wind. When the winds crank up the temperatures will be falling fast.

I’m actually concerned about the potential for some light glazing on the roads etc, especially for those areas that will be untreated. Temperatures will quickly tank from the upper 30s to the upper 20s in a matter of a couple of hours between 8PM and midnight later Wednesday night. So assuming we get at least some rain ahead of the main storm (it should be light), this moisture would then tend to freeze up fast as the colder air plunges in.

My feeling as far as the metro snow goes, is that this is going to be an issue for us for about 4-6 hours or so…the timing seems to be for a transition from 10PM-12AM then some decent snowfall from then through about 3-4AM then the whole thing winds down rather fast towards daybreak Thursday. Skies should rapidly clear off before lunch on Thursday and then it will just be blustery for the rest of the day.

The worst snowfall accumulations appear to be, not surprisingly towards N MO and then farther north into NE and IA. Amounts in parts of NE/IA may be in the 4-8″ range, which will be impossible to measure with the blowing and drifting going on through the area. This will complicate the issues for the various road crews from 36 highway in N MO up towards the I-80 corridor. So IF you’re traveling on Thursday to the north, odds are you should think about postponing that trip till Friday. Here is where the storms worst should be…this map represents the highest likelihood of 4″ or more of snow.

So barring any major track changes the worst, again is in the area outlined and centered well to the north of the KC area.

So how far south does this get to KC? Well with the 4-6 hour snow window of potential snow accumulation, the plunging temperatures and the current forecast of the storm’s track…it seems for the most of the metro we’re looking at a windswept 1-2″ or so. There is some potential that the NW side of the KC area…think KCI to Leavenworth to Lawrence could sneak in a bit more but on average that’s where my mind is at this point. Areas farther to the SE would be more in the dusting to 2″ range I think. Areas farther towards the IA border are looking at perhaps 3-5″ or so. Again with that snow and the wind, it’ll be impossible to measure accurately. Even in the metro the snow may blow around enough so that some areas are almost bare while other areas, where the snow will “pile” up may have 2-3″.

At this point there is no weather advisories in effect for the KC region. My suspicion is that at a minimum, and considering the lack of winter weather last winter and through the late fall around these parts, is that a Winter Weather Advisory will be issued for most of the region later today or tonight for not only the snow fall but for the blowing and drifting part of the storm as well.

The storm is still a bit weird looking to me and while the surface low is taking a very nice track for us to get some decent snow in KC, the features aloft still seem a bit “off” to me and with the storm getting it’s act together (through the atmosphere) across NC and NE MO and our snow “window” being pretty small, at this point I’m comfortable with my ideas for the region. So let’s show you a map, off the latest NAM model run that is finishing while I type this blog…click on this image to make it larger. I could see areas of far N MO getting a bit more than the model indicated 3″.

ScreenHunter_01 Dec. 18 08.35

Obviously things can change, should the system be able to generate more precipitation and that precipitation wrap farther back into the cold air and turn to snow, there is some upside to this. Should it intensify a little faster through the atmosphere, perhaps the wrap-around is a bit more impressive, but I think the ideas outlines about serve as a good starting point.

Finally I should mention Christmas. For the last few days the models have been hinting at the potential for a snow, perhaps a prolonged snow to affect the area around Christmas. Last night the EURO went a little overboard suggesting a 2-3 day onslaught of snow that would pile up in excess of 12″. The GFS has a storm for that time period (around Christmas) but we’d initially be too warm for snow, although we would have the opportunity for some backside snowfall when colder air comes into the future system. so something is going on for next week and it really needs to be watched because I think somebody in the Plains is going to have some real travel issues either on Christmas Day or on the day afterwards. So with that said…here is my latest “Chance of a White Christmas” for KC graphic.

white xmas

Joe

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