Numerous strong (but not quite severe) thunderstorms are developing over northern Indiana and southwestern lower Michigan. These storms, while below severe criteria, might contain hail of up to one half inch diameter, winds of up to 50 mph, frequent lightning and brief heavy downpours. It’s also possible that a couple of the storms might strengthen just above severe criteria and produce wind gusts to 60 mph and hail of up to an inch diameter. Expect small branches to fall and loose objects to blow around. And be alert to the possibility of severe thunderstorm warnings this evening, even though the area is currently not under any kind of watch. For more, see a Special Weather Statement issued by the National Weather Service northern Indiana office.

Update: The Day 2 Convective Outlook that SPC issued at 1:44 p.m. EDT continues the slight risk of severe weather in Indiana tomorrow. The outlook indicates that conditions will support all modes of severe storms, including supercells and bowing line segments. Also, the system will be capable of a few tornadoes, damaging straight-line winds and large hail. The next outlook for tomorrow will be the Day 1 Convective Outlook due at 2 a.m. EDT tomorrow.

Original Post: Almost all of Indiana remains at slight risk for severe weather tomorrow, according to the Day 2 Convective Outlook at that the Storm Prediction Center issued at 1:57 am. EDT today. As you can see on the map at right, the slight risk area excludes only a tiny corner of southeastern Indiana. All Indiana, Ohio and Michigan counties covered by the northern Indiana National Weather Service office are in the slight risk area.

The outlook indicates that several rounds of storms are possible in the slight risk area. Conditions are forecast to support organized clusters of strong to severe storms in the forms of supercells and bowing line segments. If substantial destabilization of the atmosphere happens tomorrow, there could be an appreciable tornado threat in the slight risk area, especially in the Missouri River Valley. The next look at tomorrow’s risk will come in a new Day 2 Convective Outlook by 1:30 p.m. EDT today.

In addition to a slight risk tomorrow, there is now a slight risk of severe weather in Indiana on Saturday, according to the latest Day 3 Convective Outlook. The slight risk area in that outlook covers all of Indiana and again, all of the Indiana, Michigan and Ohio counties covered by the northern Indiana weather forecast office.

Check out the infographic below from the National Weather Service northern Indiana weather forecast office. It shows that in May, 2013, the office issued only three warnings. That’s the lowest number for any May in the past 15 years.

The Fort Wayne area got off easy yesterday. The National Weather Service canceled an evening severe thunderstorm watch early, because storms that blew down some trees and caused other damage in northwestern Indiana weakened by the time they got to northeastern Indiana.

According the the Storm Prediction Centers convective outlooks, the next chance of severe weather in Indiana is from 8 a.m. EDT Friday, May 31 to 8 a.m. EDT Saturday, June 1. The Day 3 Convective Outlook that the SPC issued at 3:41 a.m. EDT today puts all but a tiny part of Indiana in a slight risk area. All of the counties covered by the northern Indiana NWS weather forecast office are included in the slight risk area. The outlook indicates that severe storms could develop by late afternoon Friday, with high winds and hail being the main threats.

The Storm Prediction Center has issued Severe Thunderstorm Watch number 236 in effect until 2 a.m. EDT.

The Storm Prediction Center issued a mesoscale discussion at 9:20 p.m. EDT that indicates a weather watch might be needed within the following hour or two. The mesoscale discssion indicates an increasing risk for severe wind gusts across parts of northern Indiana, southern Michigan and northwestern Ohio between 9:20 p.m. and 1 a.m.

Probability of damaging thunderstorm winds or wind gusts of 58 mph or higher within 25 miles of a point.

1:30 p.m. EDT update: The SPC issued an updated convective outlook at 12:25 p.m. EDT. The area outlines remain pretty much the same as they were in the earlier outlook. The 12:25 p.m. outlook contains the following language:

“Storms may increase in coverage and intensity this afternoon as lift is enhanced by existing outflow boundaries. Hail and damaging winds will be the primary hazards with these storms into this evening.”

Original post: There’s a slight risk of severe weather over the northern half of Indiana and Ohio and the southern half of Michigan between 9 a.m. EDT today and 8 a.m. EDT tomorrow. The main risk is damaging wind and hail but a tornado is possible. Casual weather observers should be alert for watches and warning through this afternoon and tonight. Make sure your weather alert radios work!

If you are interested in weather details, here’s a summary of relevant products from the National Weather Service (NWS):

At 8:47 a.m. EDT, the NWS Storm Prediction Center issued a Day One Convective Outlook that indicates a slight risk of severe weather over all of the county warning area (CWA) of the northern Indiana weather forecast office (WFO), including, of course, Fort Wayne. The outlook indicates a five percent risk of a tornado within 25 miles of any point in the risk area, a 15 percent risk of hail of one inch or greater diameter, and a 15 to 30 percent risk of thunderstorm winds or wind gusts of 50 knots (58 mph) or higher. As you can see in the map above, the area of enhanced (30 percent) wind damage risk includes Allen, DeKalb and Steuben Counties of Indiana and much of northwestern Ohio. The text of the outlook discusses the possibility of bands or small clusters of sustained storms and/or weak supercells with bowing segments capable of locally damaging wind and possibly a tornado.

At 4:59 a.m. EDT the Northern Indiana NWS WFO issued a Hazardous Weather Outlook that reads, “Scattered thunderstorms are expected across the area today and tonight. Locally heavy rainfall is possible during this period. Also, some of the storms may be severe with large hail and damaging winds this afternoon and this evening. The outlook also indicates that spotter activation might be needed this afternoon and this evening.

In an Area Forecast Discussion issued at 6:43 a.m. EDT, the northern Indiana WFO wrote, “A warm front over northern portions of Illinois Indiana and Ohio early this morning will lift north into Wisconsin and Michigan today. Thunderstorms are expected in the vicinity of the front.”

The discussion also indicates that a shortwave impulse is forecast to move across the WFO’s CWA this afternoon through an air mass that will be moderately unstable by that time. The combination of 30 to 40 knot 0 to 6 kilometer shear and moderate instability suggests that some of the storms could be severe. In addition, another shortwave impulse tonight could combine with some lingering instability and convective outflow boundaries, resulting in thunderstorms again tonight. The best chances for those storms will be in the northern portion of the CWA, closer to the warm front.

Click the image for a full-size version.

Update: The convective outlook issued at 9:05 p.m. EDT indicates that there is no longer any risk of severe weather in Indiana or Ohio.

Once again today, the Storm Prediction Center (SPC) has determined that a slight risk of severe weather exists in a large part of Indiana. According to the Day One Convective Outlook the SPC issued at 8:44 a.m. EDT, a slight risk exists in the eastern half of Indiana and all of Ohio from 9 a.m. EDT today until 8 a.m. EDT tomorrow, May 23. This includes all of IMO SKYWARN quadrants one and two. The outlook forecasts isolated thunderstorms this afternoon, with the primary risk being wind and hail damage (15 percent probability of either). Things look a bit more intense in eastern Ohio and parts of Pennsylvania and New York, where the probability of damaging winds and hail is 30 percent.

The northern Indiana national weather service weather forecast office issues a Hazardous Weather Outlook (HWO) at 5:01 a.m .EDT in which wrote that thunderstorms are likely, mainly this afternoon. The HWO also indicates that a few storms could be severe with large hail and damaging winds, mainly east of U.S. 31. The HWO indicates that the office does not expect to activate storm spotters today.

It will be interesting to see what the SPC has to say in their updated convective outlook at around 12:30 p.m. EDT.