Based on latest radar trends we’ve adjusted the forecast to account for spotty showers that will impact some areas midday into afternoon. Temperatures are slow to warm due to thicker cloud cover on the western half of Indiana… where midday readings are mainly in the upper 60s and lower 70s. Farther east, and in a brighter sky, temperatures are already nearing 80 degrees.
We’re also monitoring a little storm cluster near Champaign, IL. It should weaken as it moves away from better atmospheric lift in Central/Western Illinois… but its remnant cloud cover and showers likely sneak across the state line.
Don’t let this discourage you from attending the many concert events around Indianapolis this evening. From the Concert On The Canal to Animals And All That Jazz at the zoo… dress for warm air and expect only a slight shower chance.
Preceding our hottest stretch of days in nearly two years will be a round of locally heavy rain and storms tonight. Some locations may see 1-2″ rainfall between midnight and sunrise Friday. Early morning storms diminish and high heat and muggy air build into Central Indiana.
Air conditioners will be working overtime as highs tomorrow near 90 degrees area wide. This heat combined with jungle-like dewpoints in the upper 70s produces some of the most uncomfortable conditions we’ve felt in a few years.
If our forecast high of 90 degrees and heat index of 100 degrees and highers verifies, this would mark the highest heat indices in Indianapolis since August 31st of 2013. During daytime heating new scattered storms develop and with more locally heavy rain. But we need to stress there will be a lot of dry time to enjoy tomorrow, Saturday and Sunday… though additional storms are part of the weekend forecast.
Dave Matthews Band tailgaters and concert-goers need to dress for very muggy conditions with the scattered storms around Klipsch tomorrow afternoon. But we need to stress there will be a lot of dry time to enjoy tomorrow, Saturday and Sunday… though additional storms are part of the weekend forecast.
So is rather uncomfortable heat and humidity. Highs in the 90s this weekend team up with dew points in the 70s to produce heat index values of 100 to 105 each day! We’re also targeting Sunday evening into Monday morning for organized storms that could reach severe levels. I’ll have more on the forecast today at noon and 5:30pm on WTHR – Sean Ash
Unfortunately, but as advertised, the first of a few rounds of storms proved damaging over a good chunk of Central Indiana.
Below are just a few pictures of the wind damage caused by severe wind and saturated ground that made it easier to topple trees. You can view the severe weather slide show here: http://www.wthr.com/story/29534236/july-13-severe-weather-blog
Zionsville appears to be one of the harder hit areas and where radar velocities measured wind nearing 80mph just prior to noon. Folks will need to clean up quickly as the sun begins to thin and the atmosphere reloads for more severe weather. This storm complex originated in near the North Dakota-Minnesota state line Sunday evening and has traveled some 1,100 miles since then.
We’ll need to monitor an outflow boundary currently in western Indiana back to Illinois. This may serve as a focal point for storms to initiate as the atmosphere becomes extremely unstable.
Wind shear around this boundary will make it easier for storms to rotate, and the extreme instability allows rapid intensification and large hail production. Though storms may only be isolated to widely scattered in the 5pm to 9pm time frame… they’ll have a high chance to deliver severe weather.
Eventually supercelluar storms in Illinois and Indiana converge into a line or multiple lines of storms that have a probability to produces severe wind, flash flooding, and embedded tornadoes. Wind gusts with these complexes may be significant with gusts at or above 75mph possible.
The threat of severe weather ends after by 5am but flash flooding likely continues well into Tuesday morning. We continue to urge that you remain weather aware, have a way to get warnings and know your safety plan at work or home. More to come so check back for updates – Sean Ash
Much of Central Indiana is under a Severe Thunderstorm Watch until 4pm as we monitor a line of strong to severe storms diving east-southeast at 40mph. These storm will impact Central Indiana & Indy? metro heading into midday with severe wind gusts, flash flooding rainfall and possible embedded tornadoes along the leading of the line.
Embedded supercells along the line and isolated supercells potentially later today will have tornado potential. We’ll need to monitor where the outflow boundary from this complex sets up… which could serve as a storm initiator during peak heating. We still expect multiple rounds of storms today. I’ve attached the latest HRRR model output which backs up that theory.
It will only take around 1.5″ of rainfall in an hour to produce flash flooding… and rain rates today will be in the 1-3″ per hour range. Storms will impacting the area during the the WTHR midday show and we’ll be tracking the first line. Stay safe and weather aware today friends.
Hazy and humid conditions for most of the night as we monitor a severe storm complex over Minnesota and Wisconsin. This features dives southeastward overnight and arrives in Indiana by 10am. These storms likely intensify by midday to pose a severe weather risk for much of the viewing area into Monday afternoon.
On a scale of 1 (low risk) to 4 (extreme risk) for severe weather… all of Central Indiana is in a Zone of 3 or what we label “high” risk. This essentially means there’s a 45% probability, which is uncommon, of severe weather within any storm on radar tomorrow. Have a way to get watches, warnings, radar and updated weather information.
After the initial complex it’s uncertain whether or not isolated storms develop during peak heating late day heating… but if they do they’ll likely be supercells capable of producing large hail and tornadoes.
A second complex develops late evening over northern Illinois and looks to impact the region between 10pm Monday and 4am Tuesday with severe wind and flash flooding rainfall. Due to saturated ground trees are more susceptible to being blown over which ups the ante for power outages. We’re recommending you charge up phones, weather radios, and generators in the event this verifies.
Unfortunately the threshold for flash flooding is rather due to highly saturated ground. In fact latest Flash Flood Guidance suggests just 1″ in an hour or 1.5-2″ in 3 hours will be enough to cause flash flooding. Those numbers are easily achievable given the highly moist atmosphere and potential for multiple storm clusters. Rainfall in the 2″ to locally 5″+ range within 24 hours will result in more flash flooding by Tuesday morning.
*** Severe Weather Likely Monday***
After the early morning storms that produced flash flooding for many areas, and high end EF-0 tornado damage in southern Johnson County, it’s been a quiet afternoon. Though isolated showers or storms are possible this evening… many locations will remain dry until mid-morning Monday.
The first storm cluster arrives after 8am but before midday tomorrow and lingers into the afternoon. It’s uncertain whether or not isolated storms develop after this complex… but if they do they’ll likely be supercells capable of producing large hail and tornadoes.
There’s higher confidence on a second, and stronger complext to impact the region between 10pm Monday and 4am Tuesday with severe wind and flash flooding rainfall. Due to saturated ground trees are more susceptible to being blown over which ups the ante for power outages. We’re recommending you charge up phones, weather radios, and generators in the event this verifies.
Rainfall in the 2″ to locally 5″+ range within 24 hours will result in more flash flooding by Tuesday morning.
On a scale of 1 (low risk) to 4 (extreme risk) for severe weather… all of Central Indiana is in a 3 or what we label “high” risk. This essentially means there’s a 45% probability, which is uncommon, of severe weather within any storm on radar tomorrow within 25 miles of a point. There’s also a 10% or greater chance of seeing either significant hail (>=2″ diameter), damaging wind (>=75mph) or an EF-2 or greater tornado.
It’s a good idea to review the safety tips below and go over them with your family and place of employment. Have a plan in place to save time when severe weather strikes. Also have a way to get warnings, radar and an updated forecast.
– Download the free Skytrak13 Weather App here: http://www.wthr.com/category/225686/wthr-skytrak-weather-app
– Live Doppler 13 Radar: http://www.wthr.com/category/200638/live-video
– Skytrak13 Weather Blog: http://blog.wthr.com/category/skytrak-weather/
Anyway you slice it you need to be weather aware until further notice – Sean Ash
Due to thick cloud cover, showers/mist, and an easterly wind make it feel more like late spring than mid-summer in Central Indiana. Temperatures today will be closer to the record low maximum for July 8th (69 set 1891) than the average for this date which is 85.
Adding insult to injury will be damp conditions with a good chance of showers and areas of mist. It should be noted that the heaviest rain will not occur until much later today… more likely after 8pm. Unfortunately highly tropical air continues to blanket central Indiana and the Precipitable Water (PWAT) map below shows values in excess of 1.5″ of normal values. This type of air mass leads to efficient rain-makers.
As an approaching mesolow from Missouri interacts with this air we up the ante for more super soaking rainfall. Anything precipitation on radar overnight into early Thursday morning will be highly efficient at rain production… with rain rates of 1″+ per hour.
For a good reason much of the area remains under a Flash Flood Watch until Thursday 2pm. The flash flood threat is high overnight, but at this point it’s to be determined which area will see the heaviest rain axis.
Stay weather aware and use caution traveling overnight. Rain becomes more scattered but will still be locally heavy Thursday afternoon into the weekend. Some storms Saturday and Sunday more be severe as the temperatures warm into the upper 80s and lower 90s – Sean Ash
Heavy rain through Central Indiana has led to wide spread flooding and the issuance of a Flash Flood Warning. This warning is in effect until 8pm this evening. Use caution when travelling on roadways today, as there have already been many reports of flooding on the streets.
Rain will continue into the early evening as this system continues to push southeast. Heavy rain will continue to impact Central Indiana for the next several hours and rain rates will continue to be near 1-2″ per hours in the heaviest pockets.
Viewer photos of the flooding have begun to come in:
Photo above courtesy of Shelley Young in Indianapolis
Nearly 3″ of rain has fallen in some spots of Central Indiana and areas of heavy rain continue this afternoon.
From now until 4pm, the heaviest rain will be concentrated along the I-70 corridor, where flooding will be likely. Rain rates of 1-2″ per hour could cause significant street flooding. Please use caution when travelling around the Indy metro area. The rain will taper off in Central Indiana from 5-7 PM.
Wednesday will provide us with a break from the humidity as dew points drop out of the oppressive range and into the 50s. This break doesn’t last long as very humid air will return by Thursday.