Weather Blog: Severe weather risks tonight

KANSAS CITY, Mo. – Good morning bloggers,

We’ve gone almost three full years without a tornado watch over parts of our region. Could tonight end that streak, or will the big risk miss us again? Thunderstorms have been trying to miss us this morning despite a scary-looking sky:

Storm Dog

There was an outflow boundary tracking the northern Kansas City metro area, as you can see in that dark cloud above. Rainbow and Sunny The Weather Dogs weren’t that concerned as this boundary weakened as it moved in. Thunderstorms were forming all around Kansas City and, as of 7 am when I was writing this blog, they were missing the metro area. This morning but we are still running out of time. The “cap” may be about to build in and this will end the risk of thunderstorms soon. Our attention will then focus on tonight’s risk of severe thunderstorms.

Potential of Supercell

Potential of Supercell

KSHB 41 Meteorologist Lindsey Anderson showed this forecast map valid at 11 pm tonight. She is pointing at a cell that is forecast by this model to be ahead of the developing line. These isolated cells ahead of the main line have more energy to work with and severe weather is more likely. Hopefully one of these won’t form in our area, but it is very large hail and damaging winds and a risk of a tornado will be watched closely.

The “cap”

Some warmer on aloft will be building during the day and this will shut off thunderstorms for a while. We have had this “capping” layer protect Kansas City this season already. This time, the upper level storm is strong enough to finally overcome the cap, and the cap will break later today or early this evening close to sunset. And, the triple point, the low pressure center, it looks like it will be in Kansas. This will be the target for storm chasers today.

The “triple point” is where the cold front, warm front and dry line all meet. It is wound together that strong surface low pressure area. The low is forecast to deepen to around 988 millibars, which is equivalent to a pressure of 29.17 inches.

The Triple Point

The Triple Point

This HRRR model shows the “cap” holding as of 6 pm with the thunderstorms forming the northwest of the surface low, or triple point. The cap may break earlier. The earlier it breaks the more likely cells will be tornado producing cells, and this risk is better to the west of Kansas City. If they form later, the risk of significant tornadoes will be lower.

Here is this same model just three hours later. This is a very interesting model. It shows the thunderstorms forming behind the front. Thunderstorms behind the front are likely to be severe, but the potential for tornadoes would be much lower. However, they could produce some very strong winds. Again, if they form behind the front they will not be as severe.

Surface Forecast Valid At 9 PM Tonight

Surface Forecast Valid At 9 PM Tonight

The thunderstorms are forecast to finally be right on the front by around midnight:

Midnight Forecast

Midnight Forecast

The line of thunderstorms is forecast to develop all along the front between 9 pm and midnight. This will be approaching Kansas City. Again, if they form earlier, they are likely to become stronger and get here sooner. So, these are a few of the things we will be monitoring tonight.

There is a large level 3 out of 5 risk west of Kansas City. The metro is in the level 2 out of 5 risk area as you can see here:

Severe Risk Later Today & Tonight

Severe Risk Later Today & Tonight

The hashed 10% area shows that there is a 10% chance of a violent tornado within 25 miles of each spot. This enhanced tornado risk is west of our viewing area. And, again, it is highly dependent on the earlier breaking cap, which is a possibility.

7:55 am update from the Storm Prediction Center:

Updated Outlook

Updated Outlook

The SPC just updated the triple point. Kansas City has gone into the Level 3 out of 5 risks. There is nothing new that has changed, but I’m not shocked at this upgrade. This is a powerful storm system and we will be monitoring it roughly tonight.

Tornado risk from the Storm Prediction Center

Tornado Risks

Tornado Risks

Let’s see how this evolves today! We are still monitoring a few thunderstorms this morning. By noon, these will be far to the north and east and then we will begin concentrating on the breaking cap and the timing and strength of the thunderstorms.

Thank you for sharing this weather experience and spending a few minutes of your day reading the weather blog. We will be monitoring any serious risks very closely, so you are aware tonight of any thunderstorms moving our way. Watch KSHB 41 for live updates as necessary.

Have a great Friday,

Gary

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