Severe Storms Sunday

The threat for severe weather Sunday continues for parts of the Mississippi River Valley and the Ohio River Valley.

The Storm Prediction Center has placed parts of Illinois, Indiana, Kentucky, Michigan and Ohio in a "Moderate Risk" for severe storms.  They have also placed parts of Arkansas, Illinois, Iowa, Kentucky, Missouri and Tennessee in a "Slight Risk".  The outlook covers the time from 7am ET Sunday through 7am ET Monday.

The population bases within the different risks are pretty high.  Seventy-six and a half million people live within the risk area.  A little over 39-million people live within the "Moderate Risk" and another 37-million live within the "Slight Risk".

Hopefully, people aren't taken by surprise with the potential for severe weather.  November is not an unusual time for severe weather.  In fact, it is the height of the secondary severe weather season for Ohio River/Mississippi River Valleys.

Here is a look at the latest information from the RPM 4km high resolution computer model.

It suggests a line of storms begins to develop and quickly strengthen around 11am Sunday in northwest Illinois.  If this holds true, this could start to bring the line in to the St. Louis metro area shortly before noon.  It would also bring a line of storms near the Chicago metro area around noon.  The model also suggests the line of storms reaching central Indiana between 5pm and 8pm.

IF a line develops further south in to Missouri, the model is suggesting it could start to arrive in southeast Missouri around 12pm-1pm.  The line would continue to move east arriving at the Mississippi River (in southeast Missouri) around 2pm-3pm.

The line mentioned above is likely a secondary line that will develop ahead of a cold front.  Well ahead of the front there could be isolated to scattered thunderstorms later Saturday night through early Sunday morning (pre-dawn) in Missouri, Illinois, Indiana and Kentucky.  There is enough instability to generate a few strong thunderstorms but I think the "main show" will be the secondary line.

There appears to be plenty of instability within the atmosphere to get thunderstorms going.  Here is a look at the CAPE's (a form of instability forecasters look at) from this morning's run of the North American Model at 12pm CT.

CAPES are anywhere between 500 and 1000+ joules/kg for anywhere from Michigan down through Arkansas.

Also, if you step up to around 30,000 feet, there will be tremendous amounts of lift taking place due to divergence in the jet stream starting Sunday morning for areas west and southwest of St. Louis.  Then by late morning a powerhouse jet streak will start to nose in to central Illinois and western Indiana.  Winds will be moving along at 145mph out of the west at 30,000 feet.

Further down the atmospheric column winds will be coming out of the southwest at 55-70 mph just 5,000 feet above the ground.  This being the case, there will be lots of dynamic energy along with turning of the winds throughout the column.  Any thunderstorms that get going can start turning quickly.

I want you to note the probabilities put out by the Storm Prediction Center.

Notice the large 45% probability through the Midwest.  That doesn't mean there is a 45% chance of severe storms for that entire area, however it means that there is a 45% probability of severe weather occurring within 25 miles of any point within that area.

You may also notice the hatched area.  That indicates an area where there is a 10% or greater probability
of significant severe weather within 25 miles of a point.

So what are the main threats?  Right now, it appears that the biggest threat from thunderstorms will be strong, damaging winds.  Also, I think there is a decent tornado threat with this setup.  Especially the further north you go.  For right now, lets say north of I-64 in Illinois in to Indiana.  That means there will be a threat for tornadoes in central/northern Illinois, most of Indiana, southern Michigan and perhaps Ohio.

Since this is a time of year when people aren't thinking about severe weather, make sure you have fresh batteries in your NOAA Weather Radio.  Go over your action place with your family.  What are you going to do/where are you going to go if a Tornado Warning or a Severe Thunderstorm Warning is issued?

FREAK-OUT-METER

Finally, a lot of you ask about my "Freak-Out-Meter".  What is the meter?  It is basically a way for me to try to indicate how much I am concerned about the storm.  Hopefully, for some of you that get freaked out easily from weather it is a way to calm your nerves but also a way for you to see how big of a deal this is.  Keep in mind, this is on a scale from 0-10 with zero meaning I'm not concerned to a 10 meaning I'm beyond concerned.

Central Indiana: 6
Southern Indiana: 5
Northern Illinois: 6
Central Illinois: 5
Southern Illinois: 4
Northern Kentucky: 4
Western Kentucky: 4
Southeast Missouri: 4
St. Louis Metro: 4

Outdoor Warning Sirens

I have been having an interesting discussion about outdoor warning sirens on Facebook and wanted to move it/include my blog readers.

What is sparking this conversation?  I have had a strong opinion about outdoor weather warning sirens for many years.  I feel they are dangerous to people in a community.  They give people a false sense of security and rely on them too much.

Tragically, a tornado hit the village of Diehlstadt in southeast Missouri Monday, June 4.  Three people were killed when their mobile home was overturned.  Because of the event, several people in Diehlstadt are working to have an outdoor warning siren installed.  KFVS/Heartland News reported on the story of a woman in Diehlstadt working to have a warning siren installed.

Since the tornado occurred in the KFVS viewing area, where I used to work, there has been a lot of good conversation going on my Facebook page.

Something many people don't know about outdoor weather warning sirens. Warning sirens are only designed to cover 1-square mile. A typical warning siren costs approximately $30,000 to install. That does not include annual maintenance fees, $2,500 (total) for 5 years.

Weather warning sirens are an antiquated technology dating back to the civil defense system of the 1940's.  The system was initially designed to warn of air raids during World War II.  They were then adapted to warn of nuclear attack and eventually used for warning of storms.

Lets look at a couple of examples...

• The city of Cape Girardeau has approximately 24 square miles. That would take 24 warning sirens to cover the city. Keep in mind, that is to cover the city outdoor.s Sirens are not designed or meant to be heard if you are indoors. If you break down the number of people in Cape Girardeau (37,941 according to 2010 Census) that equates to 1,580 people per square mile. I would propose a city purchase weather radios for each household within that square mile. A Midland Weather radio would cost approx $26 wholesale (I imagine they could get a bulk rate discount and I know there are cheaper alternatives available). Electric companies say they figured 3-4 people per "customer". That means approximately 530 radios would need to be purchased per square mile. That would cost $13,780 (high end) and warn people indoors and in a much more timely manner. Plus, it would save the city $16,220 (54%).

• In the case of Diehlstadt, according to the 2000 Census there were 61 households within the village. To provide every household with a weather radio would cost approximately $1,600. If you install an outdoor warning siren, it will cost approximately $30,000. Weather radios would provide savings of 94% to the village/county.

I contend that with weather radios, you can be notified several minutes ahead of warning sirens. The process of a warning siren being sounded is the NWS sends a warning. The warning is read by the dispatcher (if they aren't on the phone/radio). The warning is read over the radio. The dispatcher presses the button to sound the siren. That can take several minutes and the siren doesn't tell you why it is being sounded.

The information you get via weather radio, is the exact same information the tv station, radio station and dispatcher is getting and at the same time. Along with the alert, the radio also speaks the text of the warning so you know why it is going off.

I should probably add that I am not being compensated by Midland Radio or any other manufacturer of NOAA weather radios for the above comments.

What are your thoughts?  Join in the conversation by leaving comments to this post.