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.