SEVERE THUNDERSTORM WATCH 264 IS IN EFFECT UNTIL 1200 AM EDT FOR THE FOLLOWING LOCATIONS:

INDIANA COUNTIES INCLUDED ARE:
     
     ADAMS                ALLEN               BLACKFORD           
     CASS                 DE KALB             ELKHART             
     FULTON               GRANT               HUNTINGTON          
     JAY                  KOSCIUSKO           LAGRANGE            
     LA PORTE             MARSHALL            MIAMI               
     NOBLE                PULASKI             ST. JOSEPH          
     STARKE               STEUBEN             WABASH              
     WELLS                WHITE               WHITLEY 

There’s a new chance for severe thunderstorms in north central and northeastern Indiana this evening. The Storm Prediction Center issued Mesoscale Disucssion #912, which indicates a 40 percent probability that SPC will issue a severe thunderstorm watch in Kosciusko and surrounding counties, possibly including Whitley and Huntington Counties. According to the mesoscale discussion, a cluster of storms over northeastern Illinois has evolved into a small bow echo along the eastern fringe of an environment where vertical shear and instability support organized storm structures. While the atmosphere downstream is not quite as favorable, it might support a threat for isolated damaging wind and hail in the next few hours.

Stay alert for a possible watch and then for possible warnings, especially in and near Kosciusko and Marshall Counties.

Visible satellite image showing cloud cover over most of Indiana at 4:01 p.m. EDT

The northern Indiana National Weather Service office does not anticipate severe storms into this evening, according to an updated Area Forecast Discussion the office issued at 3:19 p.m. EDT. The discussion credits a lack of sunshine over the area, which prevented the atmosphere from becoming unstable enough to support severe weather.

In a revised Hazardous Weather Outlook (HWO) issued at 3:26 p.m. EDT, the office indicated that locally heavy rainfall in excess of an inch will be possible tonight, which could cause localized flooding of streets and streams. But the new outlook makes no mention of severe weather today or tonight and indicates that SKYWARN spotter activation is no longer anticipated this afternoon into tonight. For tomorrow and tomorrow night, the HWO suggests that additional rain and thunderstorms might lead to additional localized street and stream flooding. There’s also a slight risk of severe storms tomorrow afternoon into tomorrow evening.

The infographic below from the northern Indiana office of the National Weather Service shows why there’s some question about how much severe weather our area will see and/or when. Click on the image to view a full-size version.

Almost all of Indiana — along with the Indiana, Michigan and Ohio counties served by the northern Indiana National Weather Service Office — are at slight risk for severe weather between 9 a.m. EDT today and 8 a.m. EDT tomorrow, according to the Day 1 Convective Outlook issued at 8:45 a.m. EDT by the Storm Prediction Center. The outlook indicates a 15 percent probability of damaging thunderstorm winds or wind gusts of 58 mph or higher within 25 miles of any point in the counties covered by the northern Indiana NWS office. It provides the same probability of one inch diameter or larger hail. The probability of a tornado, however, is two percent or less in northeastern Indiana, southern Michigan and northwestern Ohio.

Severe weather in these areas is most likely late this evening, according to a Area Forecast Discussion issued by the northern Indiana NWS office at 5:17 a.m. EDT. At that time, meteorologists were uncertain of the exact timing but wrote that a severe squall line could pass through the region this evening and/or overnight. In its Hazardous Weather Outlook at 6 a.m., the office indicated that SKYWARN storm spotter activation might be needed this evening and tonight.

Meanwhile, the latest Day 2 Convective Outlook continues to indicate a slight risk for more severe weather between 8 a.m. Saturday and 8 a.m. Sunday.

So spotters, make sure all your gear is ready for possible action tonight and then try to get some rest, because it could be a late night for us!

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.