Dangerous Heat Today……..Lower Atmosphere a Boiling Pot On the Stove (With a Lid)June 29th, 2012 at 12:21 pm by Chad Evans under Chad's WLFI Weather Blog
It is incredibly hot today. It is 96.1 at WLFI as of 12:38 p.m. with a dew point of 78, bringing our heat index to Heat index is 112 in places! How is it this incredibly humid with dry soils? Wind blowing over wet Iowa & Minnesota soils ahead of a front has pooled & concentrated just ahead of it, really increasing the amount of low-level moisture.
SEVERE T’STORM WATCH VIEWING AREA-WIDE UNTIL 7 P.M. EASTERN…………..
It does appear a cluster of storms will begin to pop pretty much overhead this afternoon in the viewing area, then organize into a bowing MCS with damaging straight-line winds. BUT THE STRONG CAP MUST BE OVERCOME FIRST! The trigger for storms popping through it? Subtle shortwave, weak, weak front, outflow boundary from last night & lake breeze. All of these will work with EXTREME instability to pop cap & get severe storms going. These would tend to pop early to mid afternoon.
It appears a microburst/macroburst & large hail threat will exist as the storms pop directly over the area. Then, as they tend to congeal more in our far eastern counties, more of a widespread damaging straight-line wind threat will evolve. This bowing MCS will likely continue through Indiana, Ohio, western Pennsylvania & West Virginia, before reaching Washington D.C. by early Saturday morning. Since these will pop literally overhead, coverage will run 50% & NOT everyone will necessarily get rain. The more widespread rains will occur east of here, to possibly our far eastern counties.
Given the fact that dew points are near 80 in places, extremely heavy downpours may accompany the storms as they will behave like a loaded sponge.