Surprise! Slight risk of severe weather today in much of Indiana

1300Z Day 1 convective outlook map
Risk of severe weather between 9 a.m. EDT today and 8 a.m. EDT Wednesday. Yellow area: Slight risk of severe thunderstorms. Green: Thunderstorms but no severe storms expected. Source: NWS SPC “Day 1 Convective Outlook,” 8:35 a.m. EDT.

I wrote yesterday that the National Weather Service (NWS) Storm Prediction Center (SPC) had issued convective outlooks for the following eight days that indicated no expectation of severe weather in Indiana.

Conditions changed since then.

As of 8:35 a.m. EDT, approximately the northern three fourths of Indiana and large parts of nearby states have a slight risk of severe weather between 9 a.m. EDT today and 8 a.m. EDT tomorrow, according to a “Day 1 Convective Outlook” that the SPC issued.

The entire slight risk area has a 15 percent probability of either of the following types of severe weather within 25 miles of a point:

  • Damaging straight-line thunderstorm winds of 58 mph or greater.
  • Large hail of one inch or more in diameter.
1300Z Day 1 Convective Outlook tornado probability map
Probability of a tornado within 25 miles of a point between 9 a.m. EDT today and 8 a.m. EDT tomorrow.

In addition, a large part of Indiana — primarily in the northwestern and north central regions — have a 2 percent probability of a tornado within 25 miles of a point.

If these probability numbers (15 percent and 2 percent) seem insignificant, have a look at the SPC’s explanation of what they mean.

Any severe weather that does occur is most likely this afternoon and evening. Showers and thunderstorms are forecast in the area this morning, but a second round of storms later today is mostly likely to contain severe weather.

SKYWARN storm spotter activation might be needed this afternoon and evening, according to the “Hazardous Weather Outlook” that the northern Indiana NWS office issued at 4:39 a.m. The slight risk area includes all of IMO SKYWARN quadrants two, three and four and nearly all of quadrant 1, with only the northeastern halves of Hillsdale and Fulton Counties excluded.

Anyone in the slight risk area — especially anyone involved in outdoor activities — should be sure they have a way of knowing about any weather watches or warnings that NWS might issue today.

As always, as time permits, I’ll update this blog with more information as it becomes available. Any updates will appear on the blog’s home page.

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