At 12:20 this afternoon, the National Hurricane Center upgraded Issac from a Tropical Storm to a Category 1 Hurricane with maximum sustained winds of 75 mph. The storm is likely to remain at Category 1 strength as it pushes toward an overnight landfall on the Louisiana coast. For the latest updates on Isaac: http://www.nhc.noaa.gov/#ISAAC
Isaac will weaken once it pushes inland, but could still bring heavy rain in a swath from the Southern Gulf Coast into the Midwest. Indiana is in the National Hurricane Center’s official forecast track as of its 11am update. By this weekend, we could get heavy rain plus gusty winds and possibly the threat of isolated tornadoes.
One of the ways of assessing the likelihood of getting the effects of Isaac is looking at a plot like this, known as a “spaghetti plot.” Each line (which looks like a strand of spaghetti) corresponds to a computer model. When you compare multiple computer models, if most of them follow the same path, the confidence in that track becomes high. If the models have paths that don’t agree, that leads to lower confidence. Since most of the paths head through Indiana this weekend, my confidence at this point in heavy rain threat for Indiana is becoming increasingly high.
So, what does this mean for Hoosiers? Plan on rain this weekend. How much could still change, but based on the information today, we could get between 2 to 6″ of rain along with sustained winds of 15 mph and gusts of 20-30 mph. Because of the circulation of Isaac, we might also have severe storms with the possibility of isolated tornadoes. Timing looks like Friday for our first impacts (some computer models bring us rain by Friday morning, others wait until Saturday). My forecast for rain Friday: 30%, Saturday and Sunday: 60%, Monday 30% in the morning.
If we get the high end of the possible rain this weekend (around 6″), then that could nearly erase our precipitation deficit. That could make a huge dent in the drought. We’ll have to wait and see.
In the meantime, we’ll have sunny, warm and pleasant weather for the next 3 days. Increasing humidity and increasing rain threat arrive this weekend.
Finally, our Hoosier Pic at noon courtesy of Gary Paschke, Sr. who snapped this pic of his rain gauge after yesterday’s heavy rain. He measured 3.45″ in Clermont! Submit your pic here: https://www.facebook.com/ChikageWindlerFanPage or here: https://www.facebook.com/WTHR13.
Have a good one!