Support Salvation Army Wildfire Relief

Joe’s Weather Blog: Snow Likely … How Much In KC? (5P Update WED-12/17)

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Good afternoon…we’re tracking an expanding area of precipitation that is developing across S KS and N OK…this area will move NEwards this evening and should arrive towards 10PM or so. Snow will then fall, at times on the moderate side. Accumulations will be increased to 1-4″ through the region (on average). Some may get a dusting and a few (should some heavier and persistent bands set up will get near 4″ or so. Odds favor that band to be SE and or NW of KC (but rather close for comfort).

Forecast:

Tonight: Patches of snow move in later overnight…odds favor near or after 10PM. There may be a brief period of sleet mixed in, but overall we should be mostly snow. Amounts will be discussed in in the latter part of the blog. On average anywhere from 1-4″ is expected however there are some signals that the south side of the area, from Paola to Harrisonville to Sedalia, along the US 50 corridor and southwards do have some upside potential in the amounts and perhaps some areas to the NW of KC could get some higher totals…

Tomorrow: Snow should taper significantly around or before rush hour. Rush hour may still be very messy depending on the amount of treatments etc. Tough to predict road conditions in the area but they may be highly variable. Highs tomorrow should be near 32° with light NE winds.

Discussion:

5PM Update: We’ve decided to open up the accumulation numbers to 1-4″ on average through the area just to be on the safe side. There is this lingering concern that while it may take a bit for the air to saturate there are still signals that some decent, but probably somewhat narrow bands of snow may set up in parts of the area…hence the higher side numbers that we opened up. The issue is exactly where those bands set up…and the problem is that where the bands don’t set up well…some are not going to have 1″ of snow. That could be in KC…it could be in Sedalia…or it could be in St Joe.

The folks from the College Of DuPage have this for the precip totals off the RAP model…notice how there is widespread .3″ totals…even cutting that back a bit but then going with a 10-12:1 ratio would get you nearly 2-3″ or so. Also notice the drier totals just SE of the metro…it’s the model trying to pick out these weird bands that may try to set up. At this point though we expect one of these bands to set up just barely to the SE of KC (heavier not lighter). It’s the model trying to tell us something.

 

The latest HRRR model suggests this evolution…

More at around 10PM tonight as the snow is moving into the area…I want to stress that it appears that some of us will wake up to a coating tomorrow and not a lot more than that…while others may need to do some light shoveling…just the nature of this weak system.

______________________________________

1PM Update: Not a lot of new thinking as far as the suite of models that have come in. I think that we’re more or less going to forecast 1-3″ as an average through the region. This means some will get less and there is the potential (as mentioned this AM) that the south part of the area get a bit more. Heaviest seems to be from 12AM-6AM or so. Could there be a 4″ bullseye somewhere SE of KC…yes. Odds favor areas farther north getting closer to a dusting to 1″ or so…namely St Joe northwards.

We’ll keep watching and updating.

____________________________________

Well things, at least in my opinion, are not any more clear now than they were yesterday and that to me is NOT surprising because of the nature of this potential snowmaker. Everything I was concerned about yesterday is still much in play. The model data has been at times more bullish than I’d like. At one point last night the lower res NAM was actually trying to crank out close to 6″ of snow in parts of the area just south of the metro (and not by much). This still seems excessive to me at this point. The higher res NAM model though has gotten a little more bullish with the “liquid equivalent” of the storm…giving areas south of KC (really from I-70 southwards) close to 1/4-1/3+” of moisture which even at a 10:1 ratio would yield 1-3+” of snow. Some areas though were were modeled to get considerably less snow.

Here are a couple of model totals maps showing the “liquid equivalent” which then you’d have to figure out the roughly 10-12:1 snow ratio to calculate how much snow would then fall.

Notice how the models are trying to portray these SW to NE bands of snow…that’s what is making this system a bit more complicated. It’s the models way of trying to tell us…”be alert for locally higher totals that may vary significantly across counties” or something like that.

1st here is the early TUE evening model total…then the 2nd map is the overnight model run. There has certainly been an uptick in the totals on the south side especially.

hires_t_precip_kc_16 hires_t_precip_kc_14

 

The GFS showed to bands of higher snow totals with one band towards the I-44 corridor and another to the NW of KC. So the models are trying to sniff out some higher totals. The placement though is still an issue I think.

The EURO model had overall .2-.3″ totals (yielding a solid 2-3″ snow) with the 3″ totals in E JACO through Cass and into Miami County through southern Franklin Co, KS

The next map shows a combination of 700 mb (or about 10,000′ in the atmosphere) of relative humidity and also the smaller black numbers show the extent of the “lift”.

nam_w700_rh_mc_10

So the lift is coincident to the higher values of RH, especially from KC southwards. The lift (vertical velocity) though of 5-10 is not huge by any stretch. Notice the higher values in N MS

Hey, if it was better looking from a model standpoint and a meteorological standpoint I’d be thrilled because I’ve got a 32″ snow forecast twisting in the wind right now…and it’s twisting. Low snow totals in DEC will not be of much help to me from a huge bust potential with that prediction.

I continue to feel the best forecast, in my opinion, is anywhere from a 1/2″ of snow (dusting) to about 2″ of snow. There may be some 3+” totals somewhere in the area…I’m just not confident that those totals will be in KC.

The morning run of the NAM is not exactly bullish for a lot snow for KC at this point. With all that said, again between the timing of things and the potential of a rush hour mess tomorrow AM…please follow the blog/forecasts carefully through the late shows tonight for the latest information/updates. In the end, some may need to shovel while others may not need to do much of anything (except be careful on the roads).

Joe

 

 

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

5 comments