AFTERNOON-OVERNIGHT: Mostly sunny to partly cloudy skies are in place across zones 1 and 5, even as a stationary front remains in the vicinity.
Through the afternoon clouds will be on the increase and rain chances will rise across the area. As instability increases through the afternoon scattered areas of rain and storms will develop across zones 1 and 5 around the front. By 1-2 PM isolated to scattered storms will be developing.
By 5-6 PM a larger cluster of storms will be developing across zone 5 in southern Indiana. This while a larger area of rain and possibly severe storms move across Illinois.
By 8-9 PM a pretty widespread area of rain and storms will be occurring from the I-70 area southward across Indiana into the Cincinnati area.
By 12-1 AM the rain and storms will be moving to the east and southeast. While rain and some storms will continue across southeastern Indiana and southern Ohio, rain will be ending across central/western Indiana.
Through the overnight the rain and storms will come to an end in many places. However, some isolated to scattered storms may stick around across southern zone 5 where the stationary front remains in place.
I do think heavy rain will be a concern this evening through the overnight from I-70 south across Indiana. The latest Hi-Res models are pretty impressive with rainfall. The RAP model shows a pretty good swath of 1-1.5” totals across zone 5, with .50-1” of rain across southern zone 1.
The latest HRRR model is equally as impressive with localized 2-3” reports possible through 12-1 AM. If rain totals are to verify, places that do receive heavier amounts could see some localized flooding problems.
With afternoon CAPE values increasing across Indiana, some strong to low-end severe storms can’t be ruled out across southern zone 1 and zone 5. However, overall potential will be limited because of the extremely weak upper-level winds. Main risk from any strong to severe storms would be strong winds and small hail.
Lows overnight will be in the low 50’s north to mid 60’s south.
WEDNESDAY: Overnight into 8-9 AM Wednesday morning some isolated to scattered rain/storms may be ongoing across very southern zone 5 in Indiana. These will be strongly associated with the stationary front.
Through the morning the low to the west will start to get closer to the forecast area. As it does, the stationary front will start to slowly lift northward. By 12 PM the front will still be in southern Indiana. Any rain or storms will also be closely tied to the front, therefore in southern Indiana as well.
Wednesday afternoon and evening there will be some isolated to widely scattered storms possible. However, it really looks like these will be hit and miss, so I don’t expect a wash out by any means.
Better chances of rain and storms start to develop around 6-8 PM across Indiana.
Highs on Wednesday will be dependent on the placement of the front. Right now it looks like highs across northern zone 1 will be in the low to mid 60’s. However, farther south highs will top out in the upper 60’s to possibly upper 70’s. Winds will be strong at times on Wednesday with gusts of 20-30 mph.
Through the overnight rain and t’storm chances will increase across all of Indiana and likely western Ohio as a frontal boundary moves into the forecast area. By 1-2 AM Thursday scattered storms will be in place across zones 1 and 5 in Indiana.
Through the overnight the rain and storms will move off into eastern Indiana and into Ohio.
Regarding severe weather, I am not expecting a widespread event Wednesday night into Thursday. However, models are looking a little better later in the evening for severe storm development, mainly across southwestern Indiana.
The latest NAM does have some decent low-level winds of 35-45 knots moving into southern Indiana briefly after midnight. This coupled with leftover instability may be enough to generate some strong to severe storms overnight. Main threats would be damaging winds and perhaps some hail.
THURSDAY: The storms will move off to the east of the forecast zones by early Thursday morning. This will allow for drier conditions to persist through at least early afternoon.
By 4-5 PM Thursday afternoon a low pressure system and a surface boundary will move through the region. This boundary will allow for some isolated to scattered rain and storms to develop across Indiana.
By 8-9 PM This will be moving across northern/eastern Indiana and into Ohio. Any precipitation associated with the boundary will move with it.
Through the late evening the system will move out and it will set up a calm end to the weak. Highs on Thursday will be in the upper 60’s north to upper 70’s south. Winds will be breezy at times with gusts of 20-25 mph possible.
New rainfall totals through Thursday evening will be rather impressive. The NAM 12 km does show most locations getting 1-1.5″ of new rainfall.
The NAM 4 km is much more aggressive with 8-10″ of new rainfall. With that said, I do not want you to think this is a forecast, it is too aggressive. However, I wanted to show you this to emphasize that there could be locations that see higher amounts. Perhaps some localized areas of 3-5″ of new rainfall will be possible through Thursday afternoon. It’s something we will be keeping a close eye on as that would cause some serious concerns regarding flooding.
FRIDAY: We will be between two weather systems during the daytime hours on Friday. The first low will be exiting to the east of the region, while the second low continues to develop across the southern Plains.
At the upper-levels a ridge will build in briefly helping keep the weather calm Friday.
Friday will be a cooler day with highs topping out in the mid 60’s north to mid 70’s south.
WEEKEND: The area of low pressure across the Great Plains will move closer to the forecast area on Saturday. As it does, rain and t’storm chances will be on the increase throughout the day.
While I don’t think Saturday will be a totals washout, those precipitation chances will exist.
Highs on Saturday look to remain cooler than they have been. Temperatures on Saturday will warm into the mid 60’s to around 70.
Sunday the area of low pressure will move across the Illinois area. Along with the low pressure system and attendant warm front and cold front will be moving across the forecast area. Along the fronts rain and thunderstorms will develop.
While it is still in the longer-range, at least the potential exists for severe weather in portions of the region Sunday afternoon through Sunday night. We are still several days out so timing/location/impacts still need ironed out.