Though rain showers will end this evening, a moisture-laden atmosphere will be spawn areas of locally dense fog overnight/early Monday morning.  This may reduce visibility enough to cause school delays in the morning…so it’s a good idea to make alternate plans for your kids just in case.  Fog and low cloud overcast should thin after 10-11am.

Though most areas remain dry Monday, there is enough weakness in the atmosphere to allow a few showers to “pop” during daytime heating.  If anything develops it will be short in nature.

The brighter finish will allow temperatures to quickly shoot into the mid 70s… marking the beginning of four day stretch of unseasonably warm days!

Highs Tuesday make a serious charge at 80° and temps should be well into the 80s Wednesday.

While I’m pumped about the impending warm up… consider me less than thrilled about pollen levels that are poised to shoot through the roof this week!  This is an unfortunate byproduct of the recent rain and rapid warm up.

We’re still monitoring trends for a potential wet set-up late week into next weekend.  Computer models continue to suggest a “cutoff” low impacting the midwest…though exact location is still uncertain and plays a major role in the outcome.  Underneath this low will be unseasonably cold air (30s/40s) and even potential for snow.  ”Right now” it appears Central Indiana will be on the eastern edge of the coldest air Friday/Saturday…but possibly underneath a train of rain/storms that will be wrapping around the storm center.  If model projections verify, it could be a rather wet Saturday for the Indianapolis Mini-Marathon.  Stay tuned to a very changeable forecast being this far out. Due to this uncertainty don’t be surprised to see rather large changes made to days 5-7 in the 7 day forecast.  We’ll continue to monitor trends and make adjustments accordingly.  Have a great evening and thanks for reading the blog – Sean Ash

As of 5:40pm monthly rainfall at Indianapolis is 8.55″…which ties April 2013 and 1922 for the 2nd wettest April on record in Indianapolis.  Rain continues to fall at the airport, and only .06″ is needed for the top spot.  Stay tuned for updates this evening and a detailed look into the week ahead.

That is a possibility with the return of rainfall the next 24 hours.  As of now, this month is the 3rd wettest April on record… trailing only 1893 and 1922 for top honors.

“If” computer model rainfall projections of .25″ to a .50″+ between now and Monday 7am verify… this could be wettest April on record by the end of the weekend.  Stay tuned!

Showers are increasing across Central Indiana as I type this forecast blog, and become likely area wide overnight into Sunday morning.  This is in response to a slow-moving low pressure system that will turtle along the I-70 corridor the next 36 hours.  The eastern side of the low center has better lift, and provides higher rain chances… contrasted by descending air on the northwestern/western side where rain becomes more scattered.  This positioning plays a role in our Sunday forecast.  Notice below the coverage of rain “scattering” out later Sunday.

Less rain/cloud cover also plays a big role in the latest temperature forecast.  Overcast tonight, despite the rain, serves as a blanket and keeps lows from dropping much below 52°-54°.

But the “blanket” of clouds blocks sunshine on Sunday, and temperatures will only be roughly 10° warmer than overnight lows.

A brighter sky allows Monday temps to quickly soar into the mid 70s!  This marks the beginning of a prolonged stretch of above normal temps that will send us to near 80°+ during mid-week!

The late week/next weekend forecast gets more difficult, and ultimately hinges on the precise location of a cold-core low… something that is not unanimous in current forecast modeling.  Below is a comparison of placement for Friday 2pm (CLICK IMAGE TO ENLARGE).  Notice the Euro model is farther west than the GFS (the GFS has been trending westward to the Euro’s solution).  This is a drier, warmer solution for Central Indiana (noted by star) for Friday… and why I’ve opted to go mid-70s in my latest forecast.  Also note the channel of precipitation on the eastward side of the low.  Impossible to say how wide this will actually be.  Areas outside of the rain axis will have considerably warmer (50s vs 70s) temperatures than areas parked under rain/storms.

There is some agreement, for now) that the rain axis may have a higher impact locally on Saturday.  Still plenty of time to change, but “if” the scenario below verifies it would be wet for the Indianapolis Mini-Marathon.  Nothing set in stone, but something we’re monitoring for changes.

With all that said… know the 7 day below is highly changeable.  The potential narrow nature of rain on east side of the system makes for a highly bustable forecast even within 24 hours.  Could be a feast or famine situation next weekend.

Thanks for reading the blog and be sure to check back for updates.

The shelf life on our dry weather is set to expire this afternoon.  Before the rain arrives highs will near 70° in Indianapolis, and should eclipse that mark in eastern Indiana where clouds are thinner.

Rain in western Indiana will push east into the Indianapolis metro by 3pm, and become likely area wide for the evening.

Rain amounts will range from .50″ to 1.5″, with the heaviest amounts possibly falling along the Wabash and White River basins.  This is not good news with portions of both rivers still at moderate to major flooding levels… and remain under Flood Warnings until further notice.

The forecast focus quickly shifts to a temperature tumble that occurs behind the passage of cold front overnight.  Temperatures Wednesday afternoon will be stuck in the 40s… a good 20° colder than today!

High pressure settling overhead provides the ingredients for patchy frost potential Thursday morning: clear sky, light wind and cool/dry air.

This will allow maximum raditional cooling, and aid in temperatures plummeting into the lower 30s.  I expect Frost Advisories and/or Freeze Watches/Warnings to be issued in future forecasts for damage potential to tender vegetation.

Thursday morning will be the coldest temperature in the 7 day forecast, with a decent warm up this weekend.  Long-range models continue to suggest a little weakness in the atmosphere over the Ohio Valley Saturday/Sunday… and it’s enough to warrant a chance of precipitation.  Stay tuned for updates.

Thanks for reading the blog and have a great afternoon – Sean Ash

Another chilly night on tap, with temperatures quickly dropping after sunset this evening.  Lows Monday morning will again be in the 30s, and some areas may see frost develop just prior to sunrise.  It’s a good idea to either cover-up or bring in tender vegetation tonight for protection.

Due to air mass modification, and a bright sky, temperatures Monday will warm quicker than this weekend and eventually finish in the mid/upper 60s… in what will be one of the better days of the week!

We’re still targeting the time frame of late Tuesday through midday Wednesday for our next round of rain/storms.  For the moment we don’t anticipate severe weather, but heavy downpours are fair game during that time.  Below is a series of FutureTrak 13 images that show the progression of precipitation the next 24-36 hours.

This rain event will not be as heavy as last week, but this is still unwanted due to swollen rivers/creeks across Central Indiana.  Rain amounts will be in the half-inch to one-inch range on average… though locally higher amounts are possible.

Another bout of unseasonably cold air follows the rainfall, with temperatures parked in the 40s Wednesday afternoon.  This will be a quick-hitting shot of chilly air… with highs quickly returning to the 60s by next weekend.

Have a great evening and thanks for visiting the blog – Sean Ash

Temperature departures of 15-20° in Central Indiana provide the back drop for a chilly weekend.  Clouds clearing this evening will allow the minimal heating from this afternoon to quickly escape due to raditional cooling.  The end result will be a period of sub-freezing temperatures.

For good reason a Freeze Warning is in place overnight/predawn Sunday.  I highly recommend you bring in any plants you don’t want to lose, and cover up tender vegetation outside.

Sunday highs will be warmer than Saturday, but still well below normal for April 21st.

The temperature timeline below shows sub-40° readings into the 9am hour.

For now Monday is my pick-of-the-week in the 7 day forecast… with a good dose of sun and spring-like highs in the mid 60s.  Thankfully the next 60 hours will be dry, which will allow most river levels to drop below flood stage.  Our next chance of rain will during the second-half of Tuesday into Wednesday morning.

Enjoy the rest of your weekend and thanks for visiting the blog – Sean Ash

Complex set-up this afternoon in Central Indiana due to rain-cooled outflow from northern segment of a broken line of storms that extends southwestward to Arkansas.  The outflow has stabilized the air mass north of I-70…where heavy rain/thunder are the main storm threats.

Along and south of this outflow boundary is where better sunshine/heating exists, and where wind shear/instability has a better chance to produce severe storms.  I expect a new tornado watch to be issued at some point this afternoon for this area.

The southern segment of the broken line will pivot northeastward out of southern Illinois this evening and keeps severe weather in play well past 5pm central/southern viewing area.  Still a long way to go for the all clear.

For good reason, much of the focus has been on damaging wind/tornado potential.  Due to recent heavy rain, and additional heavy rain this evening… flash flooding is real concern.  1-3″+ rain amounts will make roads flood quickly.  (CLICK ON IMAGE BELOW TO ENLARGE)

Scattered, strong storms are possible later tonight in western/northwestern Indiana…and the heavy rain from downstream leftovers may dampen the Thursday morning commute for some.

Based on latest computer model data, the Storm Prediction Center decided to upgrade western Indiana to a Moderate Risk of severe storms for Thursday.  This is an area where atmospherice wind shear/instability will be maximized…and offers the greatest threat to produce damaging wind/tornadoes.  However, all of Central Indiana is under a Slight Risk for severe storms late Thursday/predawn Friday.

All modes of severe weather are possible with an elevated risk of damaging wind, flooding rain and tornadoes along the leading edge of the squall line.

By Friday 7am rain amounts may approach/exceed 3″ in locations where storms “train” from southwest to northeast.  So river flooding and street flooding are likely.

It appears the main timing of severe storms for the WTHR viewing area will be between 6pm Thursday and 2am Friday.  Below is a series of hi-res FutureTrak 13 images…don’t focus on exact time of arrival yet (which is subject to change in any given area), but the idea is that this will be a late event for the squall-line.

By 7am Friday morning a cold front will push the severe threat, and warm air out of the state.   Thursday highs near 80° will be contrasted by temps tumbling into the 40s Friday afternoon!

The chilly air lingers into the first half of the weekend, with Saturday morning lows dipping into the 30s for the Race For Cure.  But the weekend will also be bright, as the cool air is dry.