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Joe’s Weather Blog: Wavering front and more rain chances (THU-10/5)

Good morning…a pretty gray day on tap for the region today but there should NOT be an all day rain…so you’ll be able to do a couple of things outside for awhile…the problem is that there could be some showers almost at any time today…so it’s tough to make any concrete outdoor plans for today…and perhaps for part of Friday too…it is what it is…at least the temperatures are rather reasonable…and the weekend will be better!


Forecast:

Today: Cloudy with an occasional sprinkle/showers moving through the area. Temperatures should end the day around 75°

Tonight: Scattered showers/storms, perhaps heavier up to the north of KC. Lows in the 60s

Friday: Variable clouds with more off/on rain and storms. Highs in the 70s…it may be warmer towards the south of KC…perhaps into the 80s.

Saturday: Clearing AM skies then a nice afternoon…highs 70-75°

Sunday: Even nicer with highs around 80°


Discussion:

What struck me this morning, when looking at the model data is that you can really see how the jet stream is starting to strengthen. It does this EVERY year during the fall season and is driven by increasing temperature contrasts between the poles and the equator in the northern hemisphere. With darkness becoming more and more of a factor across the northern latitudes…for example in Barrow, AK they are now down to 10 hours of daylight and are losing almost 10 minutes PER DAY of daylight…it’s getting colder and colder. AS a matter of fact their average high there is down to 28° today..so you can see how the temperatures are really dropping in the far northern latitudes (at the surface). This strengthening of the jet stream continues into the winter then starts to weaken as the temperature contrasts diminish as the northern latitudes start warming up again as the sunshine increases up there.

During this time of the year the storms (in the big picture) start to strengthen, driven by these temperature contrasts as colder air dumps into the backside of the storms and warmer air surges ahead of the storm. These storms can cover hundreds to 1000s of miles from north to south or east to west and move across the hemisphere with some regularity.. Typically the stronger the surface storm…the stronger the area of HIGHer pressure building in behind the storm. Sometimes those HIGHS will be more of Pacific origin…flooding the region with cooler Pacific air that quickly modifies…sometimes the areas of HIGH pressure come from the northern latitudes…these are the ones that drive the colder weather down through the Plains. This may occur early next week.

I bring this up because we’re starting to come into the time of the year where gardener’s especially want to start paying attention to the weather forecast. Even though we’re only in early October the risk of frost, on average, gradually increases over the next few weeks. Northern MO especially is more vulnerable than the KC area for the next couple of weeks…so for folks farther north…watch Tuesday morning (10th) for the potential of some scattered frost.

Now let’s talk about the rain…

So far the amounts of rain haven’t been overly heavy. Roughly 1/4″-1″ of rain has been the average in the KC metro area. I’m still expecting more over the next 42+ hours though…

Today we’re sort of in “no mans land” when it comes to the rain situation. The front that come through the region yesterday is now retreating more towards the north of KC…so that area will have “some” focus for additional rains today. Here is a look at the radar from the NWS in Pleasant Hill.

As of the time of this writing…not so impressive.

In reality there may not be a LOT of action around the immediate KC Metro area for awhile. Here is the short range (out to 15 hours) HRRR model run showing what it THINKS radar will look like through the day.

Keep an eye on any developing rain towards central KS moving towards the east this afternoon and this evening.

Overnight there will be a low level jet stream developing that will ride up and over whatever boundary to the north of KC exists…this should help enhance the thunderstorm chances up there especially tonight…then there could be a bit of a southwards drift in that activity Friday morning putting the KC area more in the region for getting some heavier downpours…especially the northside. Let’s see how things play out overnight.

Then on Friday we’re sort of waiting for the main part of a rather strong upper level wave to come through the Plains. I wrote about that yesterday and the cold front attached to a surface storm will move through towards daybreak Saturday. So the risk of the heaviest rains may wait till Friday night into early Saturday. We may see 1-2″ of rain from that batch…

Whatever rain is left over Saturday morning should be clearing the region by 8AM or so…then we should start seeing more sunshine as the day moves along. Sunday looks nice.

Our next rain chance will come later on Monday as a somewhat stronger cold front comes through the region.

Our feature photo comes from Jerry Urton…

Joe

 

 

 

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