Joe’s Weather World: Rare accumulating snows possible in area this week (MON-10/28)

Oh my…here we go…a 4 days of crazy weather…although tomorrow should be OK…beyond that the cold…rain…wintry mix and snow potential will all be notable items through Thursday morning. To put into perspective how unusual the cold weather will be…I did some calculations about the average temperatures based off my forecast and it appears these last 4 days of October will be the coldest last 4 days of October since 1925. That is pretty impressive…

Most, if not all of you though are more attuned to the risk of snow…and with good reason. There are two main chances…later this evening, fleeting for KC…better for northern MO…and later Wednesday into Thursday morning…better for KC and northwards. one opportunity for snow in the later part of October is noteworthy in and of itself…two though is really rare…if not unique. There have only been 4 measurable snows during the last 4 days of October in KC weather history going back to the late 1880s.

These last few years though have been more interesting for whatever reason in October…we had snow on 10/31/2017 and we had our earliest accumulating snow last year (10/14/2018). October is the new November.



  • Forecast:

Today: Cloudy and cold…temperatures going nowhere with readings only around 40° (if that). Light rain may develop later today but is more likely tonight and that will be a cold rain locally.

Tonight: Rain may mix with or change to some snow in parts of the Metro…especially north of Downtown. Some moderate sticking snow is possible towards and north of St Joseph into Maryville and Bethany…up to 2″ on grassy surfaces especially is possible.

Tomorrow: Not a terrible day with clouds and sun and chilly weather by late October standards…highs in the 40-45° range. Some rain is possible later Tuesday night especially on the MO side from around the Metro east and south

Wednesday: Clouds/light rain/drizzle/sleet at times…then the potential of a wintry mix to snow later in the day into Wednesday night. It is not out of the question to get accumulations into KC with this, especially at night after sunset. High only around 35°

Halloween: Brief morning flurries/clouds then clearing out and cold with highs in the upper 30s.



  • Discussion:

Well this is going to be a unique weather week in the area.

Strange nationwide as well. Denver is going to be digging out…here is a live blog from our sister station out there with the situation…jsut miserable and this is their 3rd snow this month…

Denver snow blog

That system will be lifting through the Plains states today and tonight.

As it does so…rain will develop later today…and there ay be some sleet mixed in as well at times.

Here is one of our short term models showing this potential…for timing purposes 21Z is 4PM…0Z is 7PM…3Z is 10PM and 6Z is 1AM. This model should auto-update automatically as the day moves along.

 

Locally the snow window is pretty short and seems mostly confined towards the north side of the Metro into north-central MO.

I don’t want to seem like I’m glossing over this…because again pretty unusual stuff…and there could be a coating overnight, especially on the grassy surfaces.

One thing to remember is that if we clear out quick enough…temperatures may head down quickly towards daybreak tomorrow, perhaps even into the mid 20s. Some slick roads are possible to likely in N MO especially IF this occurs…something to think about…odds are IF this even happens it would be more of a bridge/overpass thing but the road temperatures may not get cold enough.

Tomorrow is a lull day with sun and clouds…

The tomorrow night into Wednesday more rain will develop ahead of our stronger system and cold system that will move into the Plains.

That is connected to this system dropping into southern Canada today and will come into the Rockies tonight and tomorrow.

So let’s track that…because where it goes will determine what happens to our accumulating or not snow potential locally in the Metro.

To do this more efficiently we’ll go up to about 18,000 feet or so and track the various dips in the flow at that level. Each dip represents a cold pocket of air in the mid>upper part of the atmosphere…those are disturbances. You can see the one moving this way today and passing more towards the north of the Metro…sort of giving us a glancing blow…and the stronger one dropping into the Rockies and coming out of the Rockies and into the Plains tomorrow night.

Fro timing purposes…00Z is 7PM…06Z is 1AM…12Z is 7AM and 18Z is 1PM. These times revert back 1 hour starting Sunday when the time changes.

Since the disturbance is stronger it should have a somewhat easier time bringing up enough moisture to get things going on Wednesday. The issue is does it track more towards I-70 or southwards…or does it go towards SE NE into IA.

Why is that an issue..because with a storm like this, a lot of dry air in the middle part of the atmosphere will move towards the area. A track of the storm farther north brings that drier into the region where the snowflakes need to form above us that would mean perhaps some freezing rain/sleet as an issue for Wednesday night. IF the track goes a bit farther south that drier slot of air would be shoved farther south and that means a better chance of some potential accumulations even into KC with this scenario. IF you want snow…that’s your option. IF you don’t want snow to accumulate you want the storm to be farther north.

So that will be a somewhat work in progress. FWIW the new NAM model does indeed show a pretty impressive dry slot streaking in from the SW later Wednesday…that would definitely cut down any snow accumulation risk into the Metro. Let me show you what I just looked at…this is the 700 mb map…basically life up at around 10,000 feet or so…and it shows the humidity at that level…see all that brown color…that’s dry air. Snow won’t form well with that. The map is for 10PM Wednesday night

IF you want snow you want those darker greens and blues (showing higher moisture in the clouds where better snowflakes form) to be more towards KC.

Something like that would mean more of a freezing drizzle/drizzle/sleet type thing with a few snowflakes mixed in.

Then by 4AM Thursday we sort of briefly get into some better snow producing moisture above us…especially from the Metro northwards. You can see areas father south are not in good shape for flakes. Trends farther north or south can really make a big difference here, and we’re talking a few counties.

We’ll be cold enough for snow…at the surface and above…the issue is will be have moisture where snowflakes try and form in the clouds.

OK that is a lot for today…which is par for the course when snow becomes an issue locally…so many ins and outs. Again watch for the dry slot!

Our feature photo comes from Sheldon Proell

Joe

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