Meteorologists at the National Weather Service Storm Prediction Center (SPC) are keeping their eyes on a possibly growing risk of severe weather in northern Indiana, according to the updated “Day 1 Convective Outlook” the SPC issued at 12:28 p.m. EDT.

A north-northeast- to south-southwest-oriented band of thunderstorms moving through the Chicagoland area as of 12 p.m. EDT exhibited some forward-propagating characteristics with isolated wind damage reported along its track. By afternoon, a subset of these storms will likely merge with a down-shear cluster of slower-moving thunderstorms ongoing over Indiana, according to the 12:28 p.m. outlook.

Daytime heating, coupled with the presence of a very moist boundary layer, will once again yield a strongly unstable air mass ahead of these storm clusters, with mixed-layer convective available potential energy (MLCAPE) approaching 3,500 to 4,500 joules per kilogram. And similar to yesterday, meteorologists expect storm motions to become more southerly with time, as activity is drawn into the backside of a mid-level high pressure system centered over the Ozarks. Vertical wind shear will once again remain weak, which should inhibit severe storm development. But the presence of the strong instability and high moisture content will foster intense water-loaded downdrafts capable of damaging surface winds.

The 12:28 p.m. “Day 1 Convective Outlook” does not indicate any risk of severe weather in this area (or any other part of the country), but meteorologist might upgrade the area to a “slight risk” in the 4 p.m. EDT convective outlook update, if by then it is more apparent that an organized cold pool and associated greater severe threat will materialize.

Meteorologists expect scattered thunderstorms today in northern Indiana, southern Lower Michigan and northwestern Ohio, but they do not anticipate widespread severe weather, according to the “Hazardous Weather Outlook” that the northern Indiana National Weather Service office issued at 5:42 a.m.

Some storms, however, might contain strong, gusty winds, especially those that form this afternoon south of a line from Defiance, Ohio to Winamac, Indiana (below the yellow line in the map above).

Another hot/humid day expected, hwvr, sct tstms may again provide some relief from the heat! pic.twitter.com/ny6L1crlXJ

— NWS Northern Indiana (@NWSIWX) August 26, 2014

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 476
   NWS STORM PREDICTION CENTER NORMAN OK
   335 PM CDT MON AUG 25 2014

   THE NWS STORM PREDICTION CENTER HAS ISSUED A

   * SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
     NORTHERN ILLINOIS
     NORTHERN AND CENTRAL INDIANA

   * EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 335 PM UNTIL
     1100 PM CDT.

   * PRIMARY THREATS INCLUDE...
     ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
     ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50
   STATUTE MILES EITHER SIDE OF A LINE FROM 35 MILES WEST NORTHWEST
   OF MARSEILLES ILLINOIS TO 35 MILES NORTHEAST OF INDIANAPOLIS
   INDIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
   ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.

.    INDIANA COUNTIES INCLUDED ARE

BENTON           BOONE               CARROLL
CASS             CLINTON             FOUNTAIN
FULTON           GRANT               HAMILTON
HANCOCK          HENDRICKS           HOWARD
HUNTINGTON       JASPER              KOSCIUSKO
MADISON          MARION              MARSHALL
MIAMI            MONTGOMERY          NEWTON
PARKE            PULASKI             PUTNAM
STARKE           TIPPECANOE          TIPTON
VERMILLION       WABASH              WARREN
WHITE            WHITLEY

Isolated instances of damaging straight-line winds and some hail are possible this afternoon across northern Illinois, northern Indiana and possibly portions of southern Lower Michigan, according to a “Mesoscale Discussion” that the National Weather Service Storm Prediction Center issued at 2:10 p.m. EDT.

Meteorologists at the time did not anticipate issuing a watch for the area, but they planned to monitor thunderstorm trends this afternoon to determine if a watch will become warranted.

Damage from a flash flood this morning forced the Allen County Highway Department to the close Smith Road between Lower Huntington Road and Yohne Road, just southwest of Fort Wayne. The flash flood washed away soil on the west side of the road, creating a hole approximately 40 feet wide and 25 feet deep. Workers will fill the hole with gravel.

The National Weather Service issued a flash flood warning for the area at 4:17 a.m. EDT. It was in effect until 8:15 a.m.

SKYWARN storm spotter activation might still be needed tonight, according to an updated “Hazardous Weather Outlook” that the northern Indiana National Weather Service office issued at 5:40 p.m. EDT.

The outlook indicated that thunderstorms are likely tonight, with locally heavy rainfall and minor flooding possible. Some storms might be strong to severe along and south of the U.S. 30 corridor, with damaging straight-line winds being the primary threat.

Much of Indiana — including all of IMO SKYWARN quadrant two — continues to have a slight risk of severe weather between 4 p.m. EDT today and 8 a.m. EDT tomorrow, according to an updated “Day 1 Convective Outlook” that the National Weather Service Storm Prediction Center issued at 4:05 p.m. EDT.

The highest probabilities remain at 15 percent for either damaging straight-line thunderstorm winds of 58 mph or greater or large hail of one inch or more in diameter. The 15 percent hail probability, however, no longer includes an Ohio counties.

Factors that are limiting atmospheric instability should mitigate the potential for severe weather this afternoon and early evening, according to an “Area Forecast Discussion” that the northern Indiana office of the National Weather Service issued at 3:10 p.m. EDT. Meteorologists indicated, however, that coverage of showers and non-severe thunderstorms will increase over the next few hours.