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Joe’s Weather Blog: Yes to rain…but very iffy timing (MON-5/15)

One of the things I absolutely hate seeing/doing is seeing/watching meteorologists slap rain chances every single day on a 7 day forecast. I see it way too often for no good reason. Have some gumption and figure things out a bit more than doing a big CYA. Then I did my longranger last night and realized that, sure enough, I was sticking in rain chances for almost every day. The reality is, in my opinion at least, it won’t be raining every day this week and the vast majority of the week overall will be dry. There are chances though but I’m not trusting the model data in terms of the timing of those chances right now. More on all this in the discussion.


Forecast:

Today: Mostly sunny and warm-hot Highs well into the 80s. It won’t be overly humid for this type of heat though…NOT summer type humid at least. Windy as well with gusts to 30 MPH possible.

Tonight: Fair and mild with lows in the 60s

Tuesday: Partly sunny and warm with highs well into the 80s again. Slightly more humid

Wednesday: Morning storm chances linger through lunch. There is a chance that there could be some strong winds with those storms, possible 60+ mph in some areas. Worth monitoring at this point. Highs should rebound in the afternoon to near 80° (depending on how quickly things move along).


Discussion:

I started the blog the way I did this today, because sometimes, when a temporary weather pattern set’s up like this one is doing for the next 5-6 days it’s tricky to have a very accurate forecast. So perhaps I should elaborate a bit more.

Here is what I’m more confident in about the week…1) Monday and Tuesday should be dry. I can’t rule out something isolated after sunset on Tuesday. 2) It will be about 10-15° above average as well these next two days 3) It WILL rain this week 4) Some areas should see over 1-2″ this week 5) there will be a day in there that it doesn’t rain (at least during the daytime hours)

What I’m not confident in is 1) the timing of the rain each day this week 2) when the rain is finally done (I think THU is dry but then rain chances come back FRI>SAT and I’m not sure about SUN. 3) who gets the heaviest rains this week. NW MO certainly would like to win this one I think since it’s been quite a bit drier up there compared to areas from KC southwards. Finally the overall severe weather risk each day with the storms in the forecast. I’m thinking there will be at least one and maybe 2 days with use talking about the risk locally (probably winds/hail) but I’m NOT confident when those days are right now…I think WED AM…beyond that…not confident.

With ALL that said…the heat will grab your attention today. The highest we’ve been so far this year was back in mid MARCH with highs of 87°. Since then we haven’t had a spike in warmth. Today we’re going to make a run towards 85°+. There will be some clouds out there for awhile though and that has me somewhat leery about getting warmer than 87°. There will be decent wind though to stir up the air…so that is a positive. The record today is 91° set in 1941. I don’t think we have a chance of getting there at KCI (official thermometer for KC). There is also the green terrain that isn’t as conducive (just yet) to get us really popping in the temperature department. Dew points should be around 60° which is bearable with highs in the 85-90°. The heat index won’t be too bad today, compared to a more typical July set-up.

Tomorrow will be a bit more humid, with some extra clouds around knocking highs down a notch or two.

Then the fun begins.

Let’s start this mess by showing you the 500 mb map…which gives us an idea on what is happening above the ground and away from the frictional effects of the terrain. MB is short for millibar. It’s a unit of pressure. This particular map gives us a good idea of what’s happening concerning the weather pattern. Since the average air pressure on the ground is around 1000 mbs…as we go up and the pressure decreases…the 500 mb level is roughly around 18,000 feet.

This is the forecast 500 mb map for 7PM tonight off the GFS model.

We look for dips [U shapes] (troughs in weather jargon) and ridges [upside down U’s) (ridges in weather jargon). On the map above there are troughs extending from CA southwards and also off the coast of Main and another from British Columbia southwestwards. This is a basic interpretation of the map above. Where the height lines (black lines) are more concentrated or tighter, there are stronger winds at around 18,000 feet. Where the lines spread apart the winds are lighter. Near troughs they’re stronger…around ridges they’re weaker.

Anyway you get the idea of the “waviness” of the pattern at that level at least. The air ahead of troughs typically has vertical motion, while the air behind a trough is typically sinking, and the air under ridges typically has sinking motion. I’m getting too far into the weeds with this. Here is more information for all the weather junkies out there IF you want to take a deeper dive into this map

Now take a look at the same map with the expected movement of the various waves this week. Tracking this movement is important for helping try and figure out the various rain chances.

The feature near Las Vegas this morning will move towards NE and the upper mid-west. The feature off the coast of NW Canada will move towards Salt Lake and do some loops and then move towards the northern MN area. All this, while the storms themselves are spitting out pieces of “lift” that don’t exist and won’t for a few more days.

You can just see how convoluted this is and that’s why predicting rain this week isn’t the easiest thing to do with any real confidence. What we’re trying to do is predict where storms will form, even IF they don’t form near the KC area. Perhaps they form out towards the western Plains or down towards the TX …well with the winds aloft carrying that activity to this region…that would need to be monitored as well. Again I write all this so you can understand the “herding cats” approach to all this and the whys and “whatfors” of the forecast for the week.

This is now over 1000 words of weather confusion I realize.

Again re-read my confidence and less confidence ideas earlier in the blog.

Wednesday’s issue is that IF there is some sort of wave coming towards us in morning…the winds in above the surface will be going at around 55-65 mph. So IF there is convection it could bring down those stronger winds and create some isolated wind gusts of 50-60 mph+. By the same token the storms would be weakening as they come our way probably…so again we’ll have to see how healthy they are overnight into the morning hours.

Then there is decent potential that behind that wave we’re stabilized for some time…so later WED into THU may be OK…but there will be a front in the area as well on THU complicating issues. Then that storm off the coast of Canada will be doing loops in the central Rockies before finally coming out into the Plains…hence again rain chances later int eh week.

This is overall a good severe weather set-up for the western and southern Plains states. It’s not clear cut about how much severe weather we get locally right now.

If this sounds confusing it is. I’m not going to post model rainfall maps today just because I have little confidence in the overall playout of things right now. I will add that I’m expecting some areas to see over 2″ of rain this week as a whole. again NOT confident of the location of the heavier rains.

Interesting feature photo today from Andy Wisdom…I asked how he took it…this was his response. “This is 190 individual pictures then put into a software program that Stacks them on top of each other to create the star trails. The contrails you see are actually just cloud movement over the period of the two hours that it took me to take these pictures”

Cool stuff!

Joe

 

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