Joe’s Weather Blog: Changes in wind…changes in temperatures (SUN-10/22)

Good afternoon…it’s not quite as sunny as I was hoping today, at least not in the KC Metro area…there are clouds streaming up from the SW that are still influencing our immediate area. NW MO and NE KS are faring better this afternoon. Regardless, we were expecting temperatures today to be considerably cooler (really just back to seasonable) than yesterday and that has proved correct. The forecast this week will be mainly influenced by wind shifts that will change the temperatures (positive and negative). We also really don’t have any rain in the forecast in the near future, so the 2-3″ of rain from last night will have to do us for awhile.



Forecast:

Tonight: Clearing skies and cool with lows near 40°

Monday: Sunny with a few clouds in the afternoon. Not a lot of wind in the AM but turning windy in the afternoon. Highs in the mid 60s

Tuesday: Breezy and cooler with highs in the mid 50s

Wednesday: Breezy and milder with highs well into the 60s and mostly sunny skies



Discussion:

Last night some rather heavy rains fell in the region. Amounts were in excess of 2″ for many areas…and some even had over 3″ of rain overnight.

KCI ended up with a whooping 2.93″ of rain from the system, including 2.65″ on Saturday…the record for yesterday was over 4″ so it was well short of that…but a very healthy October rain for sure.

Our monthly averages are also well above normal for temperatures…over 5° through yesterday for KC. This is the 26th warmest start to the month through the 1st 3 weeks or so. We won’t end up there however…strong signals continue for a rather significant dump of cold Canadian air towards the end of next week. More on that this week.

Over the next few days however, a series of typical for late October wind shifts will be moving through the region. I briefly touched on this during some blogs a few days ago…because the timing of these shifts will lead to some potential forecast conundrums. Not as bad as what can happen in the winter season…but here’s an idea of what we’ll be fighting through Thursday.

One of the features of the Plains region is when the winds turn towards the west of west-north-west. This brings air to us that was in the western Plains…and comes down the elevation towards the State Line. The elevations out west…are closer to about 4000 feet in western KS and closer to about 1000 feet along the State Line. Take a look at the change in elvation just along the I-70 corridor region…from the west to the east.

Here is a look at KS…via KU Geography

 

So why is this important? Well as the wind brings the air from the west to the east or from the WNW to the ESE…the air comes DOWN the slope of the Plains. When that occurs the air warms by compression. Think about it…all the air molecules out there flows and get’s “compressed” coming into our area because it’s sinking. The air molecules are being forced to collide with each other because their being forced together. This allows those air parcels to increase in temperature. Given the same conditions from one side of the Plains to another (about the same amount of sunshine…apprx. the same amount of moisture present in the air)…this will lead to warming temperatures the farther east you go…hence what we call “downslope” warming.

This phenomena happens often in mountainous areas as well…except at a faster rate…when the winds blow from the top of the mountains down the slopes. This is common in the Rockies and other mountain chains.

This is a long way to go about to explain our weather for the next few days…on Monday AM we’ll be in an area getting some of this downslope warming…notice this tomorrow AM around 10AM…

The air above us is close to 63°…not bad for that time…but notice towards 4PM…it’s cooler just above the surface…

The air above us has dropped about 11°. This is thanks to a cold front coming through…hence more wind in the afternoon…and a wind shift towards the north…that removes the downslope warmth that moved in during the morning hours…

That more north trajectory allows cooler air to spill through the region into Tuesday…and Tuesday night. The next key is how fast the next “warm” bubble of air comes into the area on Wednesday. Should it be slower…we could easily dip to about 35° Wednesday AM with frost…IF faster we won’t get that cold WED AM…the NAM model is chillier than the GFS model because of this difference in the speed of the next milder air mass spreading eastwards. Right now I’m leaning to a faster transition…and a “not as cold” start on Wednesday morning.

Then we do this again…we warm up WED and THU before turning MUCH chillier on Friday…downsloping won’t help us for the end of the week as highs on Friday may only be in the 45° range…and the chances of a freeze (32°) or a hard freeze (28°) come into play next SAT and SUN AM.

Normally I’d be concerned about some rain or something with this next big change later in the week…but the air is going to be so dry ahead of the strong cold front later Thursday into FRI AM…that I don’t think, aside from some clouds and maybe a few sprinkles, that we’ll generate much of anything with this change.

I will mention that there well may be an accumulating snow across the far northern Midwest up towards northern MN and MI…and as I mentioned a few days ago…the Lake Effect machine may start up in western MI…I’m talking about you Marquette, MI. They average about 1″ of snow in OCT…so this may be their chance.

Back home…after a cold morning next Sunday…we should warm up for a couple of days…Halloween though is still sort of tricky…it looks dry…but I’m not sure where we’ll be with temperatures at this point.

That’s it for today…our feature photo comes from our own Karli Ritter who was out in Lawrence yesterday evening watching the storms come through…

Joe

 

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