Joe’s Wx Blog: Tornado Watch In Effect

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6:30 Update:

This may be my last chance to update the blog for a bit as things will get very active in our viewing area over the next few hours. I’ve been tracking a complex of storms coming from the Wichita area, that earlier produced a tornado in the city limits of Wichita. These storms are moving towards the NE at about 40 MPH. There is a history of at least 1″ hail and also 50-60 MPH winds. As the storms moves our way into an unstable atmosphere, they should maintain their strength and perhaps strengthen even a bit more since our atmosphere hasn’t been worked over yet.

The main threat from the storms continues to be strong straight line winds. It’s not out of the question that there could be some very brief tornado spin-ups with the line moving our way. This happened last night. The spin-ups will be next to impossible to detect, even if your close to them in most cases and usually they last for only seconds. Damage whether from them or the straight line winds is difficult to separate. The bottom line is not to be concerned whether or not there is a tornado. Be aware and stay safe from the strong straight line winds which will affect a broad area through the region. Again I can’t totally rule out what we call these VERY small scale meso-vorticies.

Our Tornado Watch continues for most of the area through 10PM and areas SE and E of KC are under a new Tornado Watch till 1AM.

Stay safe and stay away from the windows as the storms barrel through the region.

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The SPC has issued a Tornado Watch till 10PM for most of our viewing area. There are exceptions as you can see from the map below.

This WATCH includes KC and St Joseph. It does not include Sedalia or Warrensburg. At this point (2:30PM) there are no storms threatening the immediate area. Storms that do form should move towards the NE or NNE…so let’s keep an eye towards Emporia and Wichita for development which is starting now.

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1PM Update: As expected skies have rapidly cleared of during the late AM hours and now the atmosphere is starting to become more unstable. The latest hi res satellite image from the Nexlab website shows a pocket of more stable and clear air from I-70 northwards moving away, while additional moisture in the form of some cloud cover and somewhat higher dewpoints are moving towards the region thanks to strong south winds at the surface and aloft. Click on this image to make it larger…

ScreenHunter_04 May

Aloft I’m watching several features 1) is the area towards the TX Panhandle where some weak areas of atmospheric spin (at about 18,000′ or 500 mbs) are located, these are called areas of vorticity and represent areas of lift in the atmosphere as they move closer to a location. The waves are/will be curling towards the NE during the afternoon. The waves though are more subtle compared to the larger X’s which are stronger, like the waves that moved through last night and this AM with the storms/rainfall.

ScreenHunter_05 May

The other thing that I’m watching is actually farther up into the atmosphere, more towards the jetstream level or closer to about 300 mbs or about 30,000 feet or so. It’s there that a jetstream is also in same area and curling towards the NE as well.

300

This jetstream is promoting “diffluence” which also creates rising air…and with the winds at that level and below out of the WSW and SW, combined with the surface winds and just above the surface winds more from the SSE and S, this creates wind shear or the change of winds with height. When the winds change with height going in a clockwise manner (think of a compass) we call that veering (important for severe weather). When the winds do the opposite, for example aloft the winds are west and the winds at the surface are from the north, the winds “back” with height or turn counter clockwise which typically means sinking air (bad for severe weather). So today the winds as you go up in the atmosphere are veering. It’s not as classic/strong though for us because the amount of veering isn’t as great here as it will be towards the OK/KS border later today.

That’s important because that area, to the S and SW of the KC area represents where there is a higher chance of tornadic storms later today/tonight in my opinion. Specifically in an area outlined from the Emporia area towards Wichita to Oklahoma City then to Muskogee then towards Springfield, MO. NOT to say we’re off the hook…there are still some ingredients out there for tornadoes, but the higher risk seems to be to the SW and S of the metro. This could certainly change but right now IF I was chasing the soon-to-be storms that’s my first stopping region to sit and wait.

Our main risks continue to be hail (larger than golfballs) and strong winds from the storms. As I’m writing this clouds are now quickly moving back in, so temperatures should start to level off this afternoon. I’m more concerned though about the potential of storms to fire to the W/SW of KC and roll our way as explained in the blog from this AM. Our latest hi-res NAM model shows exactly that…

Here is the forecast radar for 6PM tonight showing the beginnings of the storms (also these explode rapidly over the course of about 1 hr.)

ScreenHunter_06 May. 19 12.53

and 2 hours later…storms moving through the metro…

ScreenHunter_07 May. 19 12.54

So the bottom line is that the highest risk of severe weather will be from 6PM-10PM or so for the KC area.

Here is a look at future radar for 12AM Monday…

ScreenHunter_08 May. 19 12.55

As this line moves through the entire region…at times you can get brief spin-up vorticies along the leading edge of the straight line winds from the t/storms…this is something that is very difficult to warn for ahead of time.

Also I should note and this is important. Do not use the forecast radar products above as gospel. They are from a model. Remember almost everything that we’ve been predicting for tonight doesn’t even exist, or at least the clouds that will turn to storms don’t exist yet. Think about that this afternoon as you see the clouds start to bubble up later on.

Also let’s see how much instability is really there later today with skies now turning cloudy fast. There are still some unknowns about how all this will play out this evening…so my advise is just to be “weather aware” and I’ll do my best to keep you updated through the blog/twitter and of course on the air as well starting at 5PM.

One last note…tonight are the season finales to many of our FOX shows in the evening. I’m aware of that and will do my best to limit my cut-ins to covering national commercial breaks. I won’t promise perfection and should a tornado threaten an area all bets are off but I want you to know that I’m aware of the situation and will keep our viewers in mind.

Joe

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Well some impressive thunderstorms rumbled through the area earlier this AM and we’re starting the day with some more rain that should last for another 1-2 hours or so before it moves away this morning. Things will be drying off considerably towards lunchtime.

Now the question is how much cloud cover will hang around, and connected to that, how much sunshine and potential instability we’ll achieve this afternoon and tonight. I do feel the clouds will thin out considerably today allowing the instability to build during the afternoon. This instability will eventually get released through the atmosphere later this afternoon and turn into big t/storms over on the KS side which then will move our way in the evening hours.

These storms represent our severe weather threat and are likely to contain some VERY large hail and potentially as the evening moves along some strong straight line winds. The origination of these storms to the west, hopefully well west of KC should preclude much in the way of tornadic activity near KC. The higher risk of tornadoes will be as the storms form and within 1-2 hours after they form. I’m hoping that by the time they get close to KC they will be a more clustered area…and not individual cells. This will need to be watched though as the evening wears on.

The SPC is still highlighting our area for the potential of severe weather…

A lot still needs to be figured out about the whole evolution about this evening…I’ll work on that aspect this afternoon with another update before 2PM or so here on the blog.

Here is an updated timeline for the day and tomorrow:

Through Lunch: Skies dry out from the SW to the NE with sunshine warming things up. We should be well into the 70s by lunch

Lunch through 5PM: Clouds clear rapidly and we warm up fast  to 80-85 degrees. Dewpoints should also increase to very muggy levels allowing the atmosphere to destabilize rapidly from KC westwards. A Tornado Watch will more than likely be issued before 5PM for the region.

5PM-11PM: Storms develop rapidly farther to the west of the KC area and start moving towards the east into the region. For the 1-3 hour period after the storms 1st form the tornadic threat will exist (again hopefully all to the W/SW of the KC area) then all the storms will cluster together into a line that moves our way this evening. Large hail/damaging winds will be the biggest threats I think for the KC area.

11PM-3AM: Storms move away and start to weaken.

Tomorrow: Additional strong to severe storms possible after 3PM in the afternoon from the KC area southwards and eastwards. This will be somewhat dependent on what happens tonight it the area

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