Joe’s Weather Blog: Hello Winter (Weekend Issues in KC) (THU-1/29)

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Well we promised you a significant change….and Mother Nature delivered…sadly for many of us. Temperatures as I type this are about 30° colder than yesterday at this time (2PM) and it “feels” 40° colder…ahhh the power of a cold front. in reality though today is just a typical late JAN day in KC. We actually had a midnight high of 51° so when we stick the numbers in the book for the day…it will be another well above average day for temperatures.

Forecast:

Tonight: Clearing skies and colder but still seasonable with lows near 20°

Tomorrow: Sunny and seasonable again with highs in the lower 40s.

Saturday: Cloudy with rain developing. We may get a good soaking on Saturday. It will be a cold rain though with readings in the 30s (above freezing). There may be some areas that briefly start as some freezing drizzle/rain…odds favor that happening to the north of KC. During the rain on SAT…should it come down hard enough, it’s possible that there could be a few snowflakes mixed in.

Saturday night into Sunday: This get’s trickier as the atmosphere a couple of thousand feet up would certainly support snow. The issue is the bottom 2000′ of the atmosphere. A wintry mix developing changing to snow. More on this in the discussion part of the blog. Temperatures dropping to near 32°

Discussion:

Well I guess we should start with the temperature change that has occurred in the region. The front blew though and the 70s from yesterday are history. Not to be seen again for over a week (probably much longer).

 

All those blue colors in the Plains (and some pinks) are indicative of 20-30°+ changes in the past 24 hours. This map will auto-update.

It’s really not that cold of a air mass (relative to late JAN) but since we warmed up and have been warm for awhile…it’s a jolt for sure.

Tomorrow looks fine.

Then we get to the weekend. There is no doubt that moisture has been lacking this winter…certainly since mid December…so we need rain or snow or whatever to help us out. The latest drought monitor that came out today also shows conditions becoming “abnormally dry” in the region as well…

 

It’s not a big concern at this point for most…but it’s something to watch…now IF we can get a good 1/2-1″ of moisture…we’d be in much better shape.

It just may happen this weekend.

There is a storm across the SW part of the country and a piece of that + a piece dropping down from the NW will be the main weather makers for the Plains on SAT/SUN. How they play with one another will go a long way in determining the amount of rain and the amount of snow that we could see.

Here is the SW storm system…

 

Quite a bit of moisture associated with that and a lot of subtropical moisture as well.

 

Some of that rain is evaporating…but AZ should get more rain over the next 24+ hours. That system will not wholly move this way…but the moisture will and that will essentially be the rainmaker for Saturday. The latest data would support some decent rainfall with this…1/4″-1″ which would solve some of our moisture ills around these parts. In a sense the warm weather of the last couple of weeks will allow that moisture to seep into the ground more readily than IF this happened in mid JAN. The ground has thawed quite a bit lately…so instead of being somewhat frozen and the rain running off the rain should soak in easier.

So that takes care of Saturday (daytime) and with temperatures in the 35°+ range…it will be a cold rain and a great day to be inside!

From there things get a bit more dicey. While temperatures during the day here on the ground will be 35°+ aloft things are going to be cooling down and in reality once you get about 2500-3500′ above the ground the atmosphere will be below freezing. Basically what’s saving our bacon from having a significant snow storm on Saturday is the bottom few thousand feet of the atmosphere!

Now the issue becomes when does that bottom few thousand feet of the atmosphere cool down to 32° or less? Timing on that potential looks to be somewhere between 9PM Saturday-12AM Sunday (subject to change). As we switchover the surface temperatures will be around 31°-34° or so. Typically accumulations are tough to come by on the pavement at least when that is the case…although it’s somewhat easier with it being at night as opposed to during the day. Then the issue is how hard the snow falls SUN AM…because with those surface temperatures in that range…it really needs to come down hard. Model data right now supports a period of some pretty heavy precipitation so it’s something to watch. The big question is will this heavier precipitation be in the form of rain or snow later SAT night. In other words will the lower part of the atmosphere be supportive of sticking snow before 3AM SUN.

The other feature that will be watched, because it too is a big player in this weekend’s scenario..is a disturbance that will be moving through SW Canada tomorrow and diving into the northern Rockies on SAT night then into the Plains on Sunday. As it does it should be intensifying. The whole thing actually “looks” more like a real storm by later Sunday in the OH Valley and this will eventually turn into another rather impressive snow-maker along the east coast early next week. So we have a few things happening that will be monitored.

Overall I hate these types of forecasts. Too many pieces and nothing really organized till things are too far east of KC.

Caveat time: 1) Should the heaviest precip be shutting down SUN AM with temperatures around 32° it may be tough to get any accums in KC. 2) Should the bottom 2000′ of the atmosphere be colder than what we’re thinking…then this turns into a bigger snow-maker for the area.

I think at this point it’s best to just mention the potential of accumulating snow without throwing out too many numbers. With that said it’s tough to imagine more than a few inches out of this potential and the roads may have somewhat less than that due to melting processes. It appears most likely that this will NOT be a big snowstorm for the area. Odds favor the areas south of KC metro to get little to no accumulations from this set-up. The accums would probably be from here northwards to the IA border. Odds favor areas in N MO and NE MO to have a better chance of seeing over 3″ of snow.

So with a lot of “inside baseball” talk within the meteorological community involving probabilities and communicating confidence (or lack thereof) let’s try this. we’ve done this before…a while back so we’re re-visiting an old idea here…the following refers to snowfall accumulations only…not total rainfall.


 

South of KC from Ottawa-Paola-Harrisonville and Sedalia southwards:

Nothing -1″: 80% Chance

1-2″: 15% Chance

2″+: 5% Chance

The KC metro area:

Nothing to 1″: 30% chance

1″-2″: 45% Chance

2″+: 25% Chance

Holton, KS-Atchison, KS-St Joseph-Chillicothe northwards to IA Border

Nothing to 1″: 20% Chance

1″-4″: 60% Chance

4″+: 20% Chance


 

What do you think?

Joe

 

 

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2 comments

  • Rockdoc

    Hi Joe. Nice discussion and breakdown about what is going on. Always amazes me the phasing or merging of systems and how the timing has to be just right. We are dealing in 3D, and all the ingredients such as moisture, pressure gradients and temps that determine/impact the outcome. Thanks for your thoughts, very much appreciated.

  • Anthony rudder

    Hello joe, my name is Anthony rudder and I loved this discussion! I have some points in this storm that is dropping out of Canada later on. For instance I know for a fact that there is plenty of moisture in the atmosphere for this system. There are a lot of ifs still but I’d like to say one or two points. If the arctic blast were to be scheduled to come a few hours earlier, then the entire forecast would be increased for the snowfall part of the system, am I wrong? Another factor is if the arctic air were to be scheduled to move in later than anticipated the snowfall part of the system would be much less. I’ve been taking some thought into the models I’ve seen with this storm and I’ve done something strange. I looked over the NAM model for our area and it was cranking out numbers between 3-6″ for the kansas city metro area. Then on the other hand, the GFS model only gave us a dusting-2″. What I did with both models was I combined the GFS and the NAM the some what average was about 2-4″ with isolated higher amounts possible. But in the short term there are too many ifs like you said and I am looking forward to seeing what this snow can bring to the Kansas city metropolitan area!
    Sincerely, Anthony rudder