August's infamy as Chicago's wettest month will be on full display Thursday. The area remains precariously positioned at the heart of a region from Iowa east to Indiana that was swept Wednesday by waves of soil-saturating rainfall. Additional downpours, some of them thundery, are to continue into Friday. Rainfall hit 3.50 inches about 3 miles southwest of Rockford on Wednesday and 2.42 inches in Rockford itself while the near 1-inch tally (0.87 inches) at Chicago's O'Hare International Airport marked that site's heaviest one day rainfall in more than two months. The flash flood watch hoisted late Wednesday continues through at least 7 p.m. Thursday and rainfall estimates off 23 computer projections Wednesday suggest coming downpours by week's end may produce totals approaching 4 inches. One forecast off the European Center's global model places potential 5-day totals in parts of northwest Illinois in excess of 8 inches. That area's August rain tallies are already at 6 to 8 inches--more than 3 inches above normal at a number of locations including Dubuque, Cedar Rapids and Burlington, Iowa.
The heavy rain threat comes into being as air piles up in the midst of converging winds along a stalled front. The process forces moisture-laden air to rise and cool. Upper atmospheric conditions encourage the air to keep rising. As winds accelerate into the jet stream, air from below is drawn aloft. Moisture levels near 2 inches make the situation especially dicey since thunderstorms form when this happens and produce uniquely heavy downpours.
TROPICAL UPDATE
Poorly organized, northwest-bound Tropical Storm Danny was churning the Atlantic northeast of Haiti and the Dominican Republic with 45 m.p.h. winds late Wednesday. The storm is to turn north in coming days---but perhaps not soon enough to avoid flirting sections of the East Coast. North Carolina and New England residents have every reason to be cautious. The storm is predicted by some hurricane models to possibly come ashore in New England after brushing North Carolina's Outer Banks.
The heavy rain threat comes into being as air piles up in the midst of converging winds along a stalled front. The process forces moisture-laden air to rise and cool. Upper atmospheric conditions encourage the air to keep rising. As winds accelerate into the jet stream, air from below is drawn aloft. Moisture levels near 2 inches make the situation especially dicey since thunderstorms form when this happens and produce uniquely heavy downpours.
TROPICAL UPDATE
Poorly organized, northwest-bound Tropical Storm Danny was churning the Atlantic northeast of Haiti and the Dominican Republic with 45 m.p.h. winds late Wednesday. The storm is to turn north in coming days---but perhaps not soon enough to avoid flirting sections of the East Coast. North Carolina and New England residents have every reason to be cautious. The storm is predicted by some hurricane models to possibly come ashore in New England after brushing North Carolina's Outer Banks.
