Joe’s Weather Blog: Monitoring later PM severe threat in region (WED-8/16)
Good afternoon…storms, rain, and sun have already greeted us this morning…now we’re seeing marked clearing in the area that should set the stage for renewed convection later this afternoon into tonight in the region. As I mentioned yesterday…this secondary batch of potential storms will be the stronger one…and with it comes the risk of a variety of severe weather including damaging winds and hail. Heavy rains as well may lead to localized flooding. There is a smaller risk of tornadoes as well…especially for areas more south of KC and SE of the metro…something to pay attention too as well.
Forecast: (5PM update)
This evening: T/storms are most likely around and towards the SE of the I-35 corridor…radar posted at the bottom of this blog is sort of illustrating this. The main threats appear to be locally heavy rain…perhaps some 1″ hail and an isolated wind gust to 60 MPH. The highest risk appears more towards the south side of KC.
Tonight: Evening storms with possible severe weather in area. Lows in the 60s
Thursday: Not as oppressive and overall pleasant with highs around 85° with lower dew points
Friday: Partly cloudy and seasonable with highs in the mid 80s
The atmosphere is in the process of undergoing “recovery” right now. We’ve stabilized after the morning storms (some of which produced over 2″ of rain already) and now the sunshine is doing it’s work and making things hotter and hotter. Also of note are the dew points that are around 75° which is pretty oppressive.
The latest hi-res satellite picture (shown every 5 minutes) shows the area clearing out…but there appears to be a stream of mid level clouds that may come in this afternoon as well. The picture below should auto-update during the day today…
Depending on when you read this blog…you may notice different things…but the instability is building once again. Typically we would be done for the day after the AM convection BUT there is a cold front approaching the region as well and this will be the needed trigger to get new storms forming later on.
The 12PM surface map shows a cold front towards the west of the area…the front will be moving into the region overnight but ahead of the front new storms should try and form later today and this evening.
So as the instability builds and with a front near serving as a trigger storms should fire up…the instability that is building should create strong updrafts to the storms…and hence the severe weather risk has to be brought up.
Here is a map that shows the instability building towards 4PM today…
The map shows CAPE values which I’ve written about before quite a bit. CAPE stands for Convective Available Potential Energy. The higher the values…in this case near 3000+…the stronger the instability that can be tapped by the storms as they try and form.
In addition to this parameter…the amount of moisture in the atmosphere is pretty strong too! This next map will auto-update and shows the Precipitable Water values (PW). Anything above 1 1/4″ during this time of year…shows pretty juicy air in place. Values early this afternoon are 2+”!
That signifies heavy rain potential…there was one area that had over 3.5″ of rain already this morning towards the north of Liberty!
In terms of tornadic potential…it’s something for us to watch..especially at the start of storm formation (within the 1st 2 hours or so) but I’m not convinced at this point that threat in KC is that high at this point. I want to watch the winds in the lower part of the atmosphere this afternoon to see what changes they may undergo.
So there are several parameters coming together this afternoon indicating the threat of severe storms. The main window appears to be roughly from 5-9PM…and areas from KC and southwards will want to be Weather Aware as the later afternoon moves along. These storms may impact the latter part of rush hour as well.
Storm movement should be towards the ENE and NE at 25-35 MPH or so…which will be helpful to prevent the ridiculous rain totals that have been characterizing the month of August thus far…BUT the storms will produced some real heavy rains…so localized flooding for short periods of time is certainly on the table today.
The folks at the SPC (Storm Prediction Center) are watching the area…and I would expect some sort of WATCH to be issued this afternoon for parts of the area. Remember a WATCH means conditions are favorable for severe storms…a WARNING means something has been spotted or indicated on radar (i.e. winds over 60 MPH…hail 1″+…rotation that could or is producing a tornado). When a WARNING is issued for your area…you TAKE ACTION.
Finally here is a look at radar…we should be fine for the next few hours…through 4-5PM…after that all bets are off from the KC area and southwards…
Our feature photo comes from @mikkilicious on Twitter…from this morning.