Today is a SEVERE WEATHER ALERT DAY, a day to stay updated on the latest weather conditions and to be ready to react quickly if severe weather threatens. The Storm Prediction Center has placed areas along and south of I-64 in a MODERATE risk (see map) for severe weather later tonight and early Wednesday. Strong damaging straight-line thunderstorm winds will be the primary threat, although brief tornadoes will also be possible. A very strong cold front will move through the tri-state overnight and the transition from today's high temperatures in the upper 60's to Wednesday's high temps in the 30's may be a rough one. The following is taken from the SPC Outlook issued at 2:00 p.m. January 29th, "Widespread and significant damaging winds will also be possible as far NE as the lower Ohio Valley ..." 

Remember to make EvansvilleWatch a PART of your personal severe weather alert system. We feature INSTANT weather alerts via ReadyWarn on Facebook and Twitter! However, do not rely on just one source for all your weather warnings. Technology fails and it's possible you may not receive an alert if you do this do this. 

Be sure you follow our local broadcast media and have your NOAA weather radio close by and ready to alert. Utilizing these and other weather sources ensures you receive the latest watches/warnings/advisories so you can keep your family safe from the storm.

FROM THE NATIONAL WEATHER SERVICE - PADUCAH
Tornados can occur during any month of the year here in the Lower Ohio Valley. This chart below shows the number of tornadoes by month from 1996 to 2011. Although there is a peak in the spring and fall, the most important point is that we have had tornadoes every month. You need to be aware of this fact.

Plus a lot of our tornadoes that occur in the winter happen at night.

This is also evident by looking at tornadoes by the time of day.

Yes, most tornadoes happen in the late afternoon and evening, but notice that we have had almost 40 tornadoes between midnight and 6AM when most people are asleep.

Tornadoes in the winter act a bit differently than they do in the spring. One of the most important features of tornadoes in the winter is that they move extremely fast and develop extremely fast. It is not uncommon for tornadoes in the winter to move at speeds of 60 to 70 mph! That means that your time to react and to get to safety is shorter than during other parts of the year. Make sure you have plans for home, at work, and at your place of worship.

We issue warnings for tornadoes based upon three things:
1) The environment: Tornadoes are most likely in the winter when the winds are very strong throughout the atmosphere and when there is a very small amount of instability (warm, moist air near the ground). This information can help you too. Whenever you notice it is unusually warm and humid outside, you need to be on alert. More than likely thunderstorms, and possibly severe weather, will be in the area within 48 hours. One of the ways you can keep ahead of this is by looking at our Outlooks page.  That page will show you what we expect to happen for the next few days.

2) Spotter Reports: Each year we train hundreds of volunteers to contact us when they see certain cloud formations or experience strong, damaging winds, hail, or if they see a funnel cloud or tornado. Storm spotting in the winter can be very difficult as the storms are moving and developing rapidly, and often it is dark, so it is difficult to see the cloud formations. We now also use Facebook (https://www.facebook.com/US.NationalWeatherService.Paducah.gov) and Twitter to gather reports. We send tweets as #NWSPaducah and we monitor the following streams: #nwspah and #tristatewx for weather reports.

3) Radar: Doppler radar cannot see the actual tornado. However, the circulation associated with tornadoes extend well into the cloud in most cases. We look for this larger circulation, and once we see the circulation intensify, a tornado warning is issued. Almost all storms have some rotation, but the strength of the rotation is one of the things we look for on radar. When we go back and research past cool season tornadoes, some of them go from little or no rotation in the cloud to producing a tornado on the ground in just 10 minutes! There is still a lot of research to be done on these tornadoes to better understand them.

In an ideal world, we would like to have all 3 of the above items available to us before we issue warnings, but that is not always possible. Sometimes there are no spotter reports, and sometimes the atmosphere is marginally favorable for tornadoes to form. So, we often have 2 out of the 3 and we then issue warnings based upon the information we have. We, as meteorologists, know that there is still much to learn about the atmosphere and how it works, but we make decisions based upon the information we have.

If you think about it, this is very similar to how a doctor might think when you go into an emergency room. They do not have all the information, but they look for symptoms, listen to you, and then make decisions based upon that information.

Safety is key and part of being safe is having a plan. If a tornado moves through your neighborhood at 2 AM, how are you going to know? If we issue a tornado warning at 2AM, will you know about it? How are you going to know about tornado warnings when you are asleep.

There are several ways to make sure you are awake.
1) Purchase and program a NOAA Weather Radio. We can help you program them.

2) Appoint a family member to stay up and watch the weather, then have them call some friends and relatives before the storms move into your neighborhood and make sure people are awake.

3) Subscribe to receive warnings via your cell phone. Several local media outlets provide this service for free or a nominal fee. In addition, tornado and flash flood warnings are received for free on smart phones with WEA technology.

In addition, have a plan to know where to go. Again, there is little time to react during the winter when severe weather arrives. You have to have a safe location in your home, office, place of worship, before severe weather starts. If you have a basement or a storm shelter, great, that is likely the safest location. If not, try to find a room or a hallway that is near the center of the building on the lowest floor. Try to put as many walls as possible between you and the outside of the building. Schools have tornado drills, you need to make sure everyone in your home or business knows where to go when severe weather strikes. It is not if severe weather will occur, it is when.

Fall often marks an increase in severe weather. The months of October and November, particularly from about mid-October through mid-November, usually brings an increase in severe thunderstorms activity including tornadoes, large hail and damaging thunderstorm winds across southeast Missouri, southern Illinois, southwest Indiana and western Kentucky. Recent years proved several examples of this annual increase in severe thunderstorms  From October 14 to October 26, 2004, a total of 11 tornadoes occurred across southern Illinois, southeast Missouri and western Kentucky. On October 18, 2007, 16 tornadoes ravaged our region causing 20 injuries and 20 million dollars damage. A total of 26 tornadoes occurred across our region in November of 2005 including the November 6th Evansville, Indiana tornado which caused 25 fatalities. We also had the November 15, 2005 Madisonville, Kentucky area violent EF4 tornado.

The cause of the increase in tornadoes and other sever thunderstorm activity is usually a result of the jet stream dipping south. This causes an increase in the wind field aloft  These wind fields are often enhanced by storm systems approaching from the Plain states. This coupled with sometimes favorable instability and moisture levels can produce the necessary conditions for severe thunderstorms, including tornadoes.  

Preparation and response are the keys to ensure you and those close to you stay safe this fall. First, ensure you have a plan that includes a safe sheltering location when severe weather threatens. Secondly, ensure you have a means to receive weather warnings, particularly of overnight storms which are more than twice as likely to be killers. A weather radio is a perfect solution for being alerted of dangerous weather  Thirdly, go to your predetermined safe location promptly when a warning is issued for your area or severe weather is observed. 

For additional information on severe weather, see:
HTTP://WWW.STORMREADY.NOAA.GOV/LINKS.HTM and HTTP://WWW.NWS.NOAA.GOV/OS/SEVEREWEATHER/INDEX.SHTML


SOURCE: National Weather Service - Paducah Public Information Statement 7:28 a.m. Thursday, October 11, 2012

UPDATE FROM BEAU DODSON WEATHER AT 2:00PM CDT - FRIDAY, SEPTEMBER 7TH:
The coming hours...Expect a few thunderstorms to form (scattered) between 3 PM and 5 PM. Expect a widespread squall line to move into southeast Missouri and southern Illinois between 5 PM and 9 PM - this squall line will push east into southwest Indiana, northeast Arkansas, western Kentucky, and northwest Tennessee between 8 PM and 11 PM. 

There are timing issues with this system - the first problem is whether or not a complex of storms will form over parts of southern and central Missouri (ahead of the main line). If this does form then it will move east/southeast through the 3 PM - 5 PM time frame - perhaps approaching parts of IL and KY. 

The second concern is the timing of the front itself. Obviously the further west/northwest you are in the region (St Louis/Mt Vernon/Perryville, MO/Poplar Bluff) the earlier the line will move through. The further southeast you are in the region - Kentucky Lake region - Hopkinsville - the later at night it will be. 

Plenty of sunshine is causing the atmosphere to heat up and that means it is becoming unstable. 

Current soundings indicate that CAPE values (potential energy) are in the 1500-3000 range over the region. Lift index values are in the -4 to -10 range across our region. Wind fields are so-so. 

I suspect that the main concern with the storms today with be high winds. Hail will likely occur with some storms - thinking right now that dime size to perhaps quarter size hail will be possible in the most intense storms (especially true of isolated storms that form ahead of the line). Tornado risk will be enhanced if a bow echo forms or line segments - same as Thursday. 

Tornadoes are expected to be short lived (if they occur at all). Short lived doesn't mean damaging - keep that in mind. 

I am expecting a severe thunderstorm and/or a tornado watch to be issued for parts of Illinois and Missouri at some point after 3 PM - I am expecting watches for Indiana/Kentucky/Tennessee to be issued at some point between 3 pm and 7 PM. 

Watches mean that conditions are favorable for severe weather. Warnings mean to take action/shelter. 

Football games this evening will need to closely monitor radars and watches/warnings. Again - there is some "debate" over what time storms are going to pop ahead of the front. Monitor for updates. 

Rainfall totals of 1-2" will be possible in the most intense downpours (that is between this afternoon and Saturday morning). Most of the rain will fall within a 2-3 hour period of time (with the main line of storms). 


ORIGINAL POST:According to our local weather folks, a fairly significant severe weather event is possible this afternoon and evening across the tri-state area. A cold front approaching the area will trigger storms that could become severe from early afternoon into the late evening. Therefore, we are calling today a SEVERE WEATHER ALERT DAY. We do this when a severe weather event appears likely and may be widespread. Stay alert to rapidly changing weather conditiions, monitor your local weather closely, be sure your NOAA Weather Radio is in alert mode and be ready to react if a warning is issued for your community. You can use the links and features under our WEATHER tab above to closely follow this developing weather situation. 

Below is a great synopsis of today's possible severe weather from Beau Dodson Weather. Beau is a meteorologist for the McCracken County Emergency Management Agency and an adviser for the Kentucky Transportation Cabinet. His insights are usually accurate and they are very easy to understand. He talks to you, not above you. Anyway, here is his outlook for today posted at 7:15am CDT - September 7th:

Severe Weather Event Possible Later Today:
... Severe thunderstorms are likely today in our region. A cold front will approach from the west and northwest this afternoon. Storms will first form in a scattered nature in the region. The primary show will be the squall line itself. This line should become a solid line that will extend for several hundred miles over Indiana, Illinois, Missouri, and into Arkansas. The line will sweep east at speeds of 40-50 mph (perhaps faster in bows and line segments).

The main concern will be damaging wind, lightning, heavy downpours, hail, and perhaps a few tornadoes. The tornado threat today could be embedded in the squall line itself. We call these QLCS tornadoes. They can be brief and difficult to warn on (same as what happened on Thursday). QLCS tornadoes can occur in the rain or just ahead of the rain. They don't last long but can cause damage. We will be monitoring for these if the squall line fully matures.

Best guess on timing today - some isolated cells could occur as early as late morning and early afternoon. The main squall line will prob push through the area from 2 or 3 pm right on through the evening hours. Moving from west to east (perhaps northwest to southeast) over our local counties.

Wind shear and instability today are favorable for a few supercell storms, as well.

Today is a severe weather "heads up" day - that means to monitor watches and warnings if and when they are issued.

Football games and sporting events should be aware of rapidly changing weather conditions later today. Schools should have their severe weather safety plans readily available. School bus drivers may have to deal with the line of storms - depending on timing. Heavy downpours could cause low visibility in the most intense storms - along with gusty winds. ... 


We will post updates as needed as we go through the day, so check back often.