AFTERNOON – TONIGHT: An area of low pressure continues to develop off to the regions west today. Across northern Illinois a stationary front is in place. This front will allow for strong southerly winds to continue across the region.
While most places across zone 1 have started off with sunshine, farther south across zone 5 clouds are starting to build in. These will continue to thicken and spread across the region through the afternoon and evening hours today.
While clouds will continue to build across the zones today I am not anticipating much, if anything, in the way of rainfall. While I won’t totally rule out a stray shower, anything that does develop will be light and brief in nature.
Overnight isolated chances of rain will continue. However, better rain and storm chances will get going around 4-6 AM.
By 8 – 9 AM scattered rain and t’storms will be moving across zones 1 and 5 in Indiana.
Through the morning the rain and storms will continue to work to the northeast across the forecast zones. By 12-1 PM scattered rain and storms will be ongoing across Indiana and western Ohio. It does look like there will be some pretty decent rain coverage across Indiana at this time.
Through mid-afternoon the first round of storms will move off into eastern Indiana and Ohio. However, the cold front will still be in western Indiana and Illinois. As this progresses to the east a second round of rain and storms will develop along the sharp cold front.
The latest 12 km NAM model does raise the concern that there could be the threat for a few strong to severe thunderstorms across zones 1 and 5 tomorrow afternoon. The latest NAM does show a dry slot developing between the first and second wave of rain/storms.
If this verifies it would allow for afternoon instability to build into the forecast area. The latest models show 500-1000 J/Kg of CAPE across western and central Indiana.
With a low-level 850 mb jet of 50-60 mph blowing in from the southwest combined with a southwesterly 500 mb jet at 70-80 mph, it would create enough speed shear to allow some strong to severe storms to develop.
While there is the potential for strong to severe storms Thursday afternoon, I am not expecting a significant severe weather event. Right now main risks with any severe storm would be damaging winds, hail, and perhaps a tornado. The better severe weather risk looks to be from I-70 south where there is a higher probability for more instability. We will continue to watch this over the next 12-24 hours and bring you updates as needed.
Regarding timing, the cold front will start to enter western Indiana by 3-4 PM Thursday. Along this cold front rain and storms will likely have already developed to the zone forecast areas west.
Rain and storms will continue off to the east through the evening. By 5-6 PM the line of rain and storms, along with the cold front will be arriving across central Indiana and the Indianapolis area.
By 8-9 PM the cold front will be in place across eastern Indiana and western Ohio, along with most of the rain and storms. By this time, I think any severe weather threat will be rapidly diminishing as we lose daytime heating.
Highs on Thursday will top out in the upper 50’s to mid 60’s across the forecast area. If sunshine can be achieved for any length of time Thursday afternoon, then even warmer temperatures are not out of the question. Winds will be very strong through the day, wind gusts of 40-50 mph will be possible!
Once the front moves through winds will shift and temperatures will fall rapidly. The Hi-Res NAM illustrates this well with a temperature of 61° in Indianapolis at 5 PM. By 1-2 AM temperatures will be in the upper 30’s!
Through the evening into the early overnight some isolated to widely scattered rain showers will remain. If cold air can surge in quick enough some of these could chance over to some wet snowflakes, but no accumulation is expected.
Regarding rainfall, a pretty widespread soaking looks likely across zones 1 and 5. The latest NAM models show .50-.80” of an inch of new rainfall on average across Indiana and Ohio. However, places that get under some of the more intense storms could see 1-1.50” locally. The NAM 12 km is a little more aggressive with 1.5-1.8” possible in locations, but I feel the broad area of heavy rain may be a bit overdone.
FRIDAY: Behind the cold front Thursday night into Friday an area of high pressure will build into the forecast area. This will allow for sunny to mostly sunny skies to end the week.
However, it will also keep temperatures cool with highs topping out in the mid 40’s to mid 50’s.
WEEKEND: Saturday we will be in between weather systems. This as the area of high pressure slips off to the east and another area of low pressure develops to our west across the Great Plains.
Regardless, Saturday does look to be a nice day with mostly sunny skies and temperatures warming into the upper 50’s north to upper 60s south.
Beyond Saturday models are in major disagreement how things will work out to end the weekend and for next week.
The Euro solution would favor rain chances Sunday, possibly turning into a heavy, wet snow for areas Sunday night. Then beyond that gives us a cooler start to the week as high pressure builds in for Monday.
The GFS would favor dry conditions on Sunday with rain chances not entering the forecast until late Sunday night into Monday. It would also support a warmer look to start the week.
The CMC would support rain through the day on Sunday like the EURO. However, there is no support for snow Sunday night into early Monday.
Overall, I would tend to favor the GFS more as it seems to match the pattern better. With that said, we will continue to watch the latest data and trends over the next few days.
7 DAY FORECAST
THURSDAY: MOSTLY CLOUDY WITH SOME SUNSHINE, A 50% CHANCE OF RAIN & T’STORMS, A FEW STRONG/SEVERE POSS. WEST. HIGHS IN THE MID 50’S WEST TO THE MID 60’S EAST. WINDS FROM THE SOUTH TO WEST AT 10-20 MPH, GUSTING TO 40-50 MPH.
THURSDAY NIGHT: TEMPERATURES FALL, PARTLY TO MOSTLY CLOUDY WITH A 20% CHANCE OF RAIN TO SNOW SHOWERS. LOWS IN THE UPPER 20’S NORTH TO MID 30’S SOUTH.
FRIDAY: MOSTLY SUNNY, COOLER. HIGHS IN THE MID 40’S NORTH TO MID 50’S SOUTH. WINDS FROM THE NORTHWEST AT 6-12 MPH, GUSTS TO 20 MPH.
FRIDAY NIGHT: CLEAR TO MOSTLY CLEAR WITH LOWS IN THE MID 30’S EAST TO LOW 40’S WEST.
SATURDAY: SUNNY TO MOSTLY SUNNY. HIGHS IN THE UPPER 50’S NORTH TO UPPER 60’S SOUTH. WINDS FROM THE SOUTHEAST AT 5-15 MPH.
SATURDAY NIGHT: MOSTLY CLEAR TO PARTLY CLOUDY WITH A 10% CHANCE OF A SHOWER WEST. LOWS IN THE UPPER 30’S NORTHWEST TO UPPER 40’S SOUTH.
SUNDAY: PARTLY TO MOSTLY CLOUDY WITH A 30-40% CHANCE OF RAIN & T’STORMS. HIGHS IN THE MID 50’S TO MID 60’S. WINDS FROM THE SOUTHEAST TO SOUTHWEST AT 5-15 MPH, GUSTING TO 30 MPH.
SUNDAY NIGHT: MOSTLY CLOUDY WITH A 30% CHANCE OF RAIN, POSSIBLE SNOW NORTH? LOWS IN THE UPPER 30’S NORTH TO MID 40’S SOUTH.
MONDAY: PARTLY CLOUDY AND COOL, CLOUDS DECREASING WEST TO EAST. 30% CHANCE OF RAIN & STORMS. HIGHS IN THE UPPER 50’S TO UPPER 60’S.
MONDAY NIGHT: PARTLY TO MOSTLY CLOUDY WITH A 20-30% CHANCE OF STORMS. LOWS IN THE LOW 40’S NORTH TO MID 50’S SOUTH.
TUESDAY: PARTLY CLOUDY, RAIN ENDS. HIGHS IN THE UPPER 40’S TO UPPER 50’S.
TUESDAY NIGHT: PARTLY CLOUDY WITH LOWS IN THE UPPER 30’S TO MID 40’S.
WEDNESDAY: MOSTLY SUNNY WITH HIGHS IN THE UPPER 50’S TO MID 60’S.
WEDNESDAY NIGHT: INCREASING CLOUDS, CHANCE OF RAIN WEST. LOWS IN THE 50’S.