Wind in Kansas City Wednesday, potential severe weather in area

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I’m leaving for the rest of the week but couldn’t write anything about the craziness of today’s weather in this part of the country and elsewhere. Things are happening / can happen today (in December) that we have never seen before. For this reason alone, we dive into a blog with a big volume of statistics to show the uniqueness of what is going on. So let’s dive in.

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Provide:

Today: Variable clouds with extreme wind. Strong wind warning in effect. Gusts to 60 MPH are possible. Extremely hot and “heavy” by winter standards. Maximums 73-76 °. The daily record will be broken by the time you read this (68 ° set in 2002) and the monthly December record is also attainable at 74 °, set on December 3, 2012, December 5, 2001 and December 6, 1939. Storms / rapid it is likely to rain between 5 p.m. and 7 p.m. in KC. Earlier in the NW and a little later in the SE.

Tonight: Windy and becoming seasonal with dawn troughs in the lower 1930s (still above average)

Tomorrow: Sunny and pleasant with lighter winds. Highs close to 50

Friday: Variable clouds with highs in the lower 50s

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Discussion:

I don’t even know where to start …

Records the heat … record dew points … record winds … tornado risk … the end (hopefully) of almost a month’s dry spell for KC … and the list goes on and on. So let’s start with the winds… because a strong wind warning is in effect. This is quite rare for winter in KC. There have only been about 18 issued by our local NWS office since 2005.

All counties shown in orange / dark brown are warned counties… areas southeast of KC are subject to a wind advisory. The gusts in KC can be 50 to 60 MPH +.

So why?

A strong developing surface storm over the Western Plains will move through NE / IA / WI as the day progresses. Here is the current pressure model. The black lines are isobars… lines of equal pressure.

Notice ALL the isobars along the I-35 corridor. When they are closely spaced like this it shows a big change in air pressure from one part of MO to the other. The same goes for almost all of the Plains and the upper Midwest. These tight lines of equal pressure represent a strong pressure gradient.

Strong winds cause significant pressure gradient forces. So ! The air also changes from a higher pressure to a lower pressure. It will be an intense storm that will pass through… in fact, it could break records for the lowest air pressure in December for the states north of here. you have to go back to the late 1940s to find something comparable.

The area most vulnerable to this potential is Minnesota.

All southerly winds bring very unusual high dew points to the region. Dew points this morning are approaching 60 °.

Here are the highest dew points reported during the winter season (DJF)

The magic number seems to be the dew points of 63 ° at the end of December 84.

How about stronger winds… the highest reported wind gust at KC during the winter season (DJF) is 55 MPH. It can break.

and in December… back to the opening of KCI…

and looking back at the downtown airport records, I can’t find anything before this timeframe that exceeds KCI. So IF we hit 50 MPH or more… we get a record.

So concerning temperatures … a daily record is a guarantee. The 2nd of this month in fact. Also on the 2nd day with highs in the 70s this month… it’s happened before but it would also equal a record.

Here are the highest temperatures of December …

In number of days 70 ° or more … for December

So today we tied for 2. Again the scarce air we breathe for this stat.

Elsewhere, these recordings are now vulnerable.

The squared cities are the ones in play this afternoon

Basically from MI to TX …

Peak forecast… around 50 cities have a chance of record heat today

So let’s watch this storm as it intensifies on the surface as it exits the Rockies and turns in the northern plains.

From 7 a.m. to 9 a.m. tomorrow

All the dynamics AND the intense winds at altitude… create the risk of violent thunderstorms… even in December above all.

Let’s look at the strong winds this thing is going to generate… at 5,000 / 10,000 / 18,000 feet (approximately).

5,000 feet. The winds are in knots
10,000 feet. The winds are in knots
18,000 feet. The winds are in knots

One node equals 1.15 MPH. So 25 knots = ~ 28 MPH. 50 knots = ~ 58 mph, 100 knots = 115 mph. It’s impressive to see the cards above.

This brings us to this …

The risk of bad weather.

Seeing red in IA and MN… that’s a moderate risk of severe storms. In December. It has never been issued in the North before. What’s also fascinating is that this region was hit by a 12-18 inch snowstorm last Friday. 5 days later… a night tornado is likely to develop. This is the 1st time that SPC has issued a moderate risk of severe weather in IA / MN / WI in December!

There has never been a tornado in meteorological history recorded at MN during the winter months (DJF).

Courtesy TornadoArchive

December blackout.

Just for laughs here is a breakdown closer to home

and a close up of the KC area

That Ray County tornado was back in 1960… an F2 and the Platte Co one was back in 1975

The risk of a tornado up there is related to those strong winds aloft and the change in wind direction as you go up in the atmosphere. This is a scenario where the instability is somewhat limited, but whatever shapes may “spin” so it could bring down tornadoes. IF that happened, they would move at an incredible speed of 60-80 MPH! At night no less. It’s crazy to see this again as investigations continue in the southern part of the region for what happened last Friday night.

For KC… the main risk of rain / thunderstorm will only last about 30 minutes at a given location and seems to be roughly between 5 and 7 p.m. Here is the evolution of the HRRR model. For the timing, 21Z corresponds to 3:00 p.m.… 0Z corresponds to 6:00 p.m. and 3Z corresponds to 9:00 p.m.

Whatever happens it will be fast… and while the winds before storms / showers can gust to 55 MPH +, winds with storms can be close to 60 MPH… you really shouldn’t be able to tell the difference.

The risk of hail is low, but I also cannot rule out something ‘turning’ in northern MO. Again, a lot is happening so quickly.

Oh and for the prospect of snow… well… that’s not a good sign. GFS total snow until 30

Joe

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