Short Term Forecast

Over the last few hours, the atmosphere has destabilized over the last few hours, with rather high instability building over parts of the area.  Current RUC analysis images from 3 p.m., show the axis of highest instability located in Northeast Indiana, along with parts of extreme western Ohio. (note: areas west of Defiance are relatively stable, and not near as warm as areas east of Defiance, due to morning rain and thunderstorms.)  CAPE values or instability values are over 3000 J/kg which indicates a strongly unstable environment, conducive for thunderstorms.  According to the latest satellite imagery, convection was developing over western Indiana, with a large cumulus field also located over the area.  Farther south, large areas of widespread severe thunderstorms were occurring in southern Indiana and along the Ohio River.  I expect over the next few hours that thunderstorms will begin to develop especially east of a line from South Bend to Indianapolis.  More organized thunderstorms will be present east of Defiance, due to stronger deep layer wind shear present, even though instability is not as high as around here.  With the rather moist environment that is also present, I expect that these thunderstorms will be capable of producing heavy rainfall, especially in areas where thunderstorms train (meaning that they move over the same areas over and over).  According to the Storm Prediction Center, large hail is the primary threat from any isolated severe thunderstorm, but it is possible that they also produce gusty winds.  The thunderstorm threat will gradually die out by about 11 or 12 tonight.  Tomorrow, a similar situation will occur, but with more available moisture.  In fact, according to computer models, these situations will be very similar each day until Sunday, when the ridge will be too strong to allow thunderstorms to develop.  The ridge will amplify considerably by Tuesday, with even warmer temperatures than what we've been seeing.  As for right now, we are not sure when this warmth will end, primarily due to the fact that computer models keep changing the story.  I will keep you informed about this record-breaking heat over the next several days.