Barometric Pressure Forecast for Morris, Illinois
Barometric pressure forecast for Morris, Illinois — the Grundy County seat on the Illinois River, about sixty miles southwest of Chicago on the prairie. See current barometric pressure and what it means for weather-sensitive people.
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Pressure and weather in Morris
Morris sits at roughly 510 feet on the north bank of the Illinois River where the valley cuts through flat glacial prairie, far enough from Lake Michigan that the lake exerts almost no moderating influence on its weather. Northern Illinois sits beneath one of the busiest storm corridors in North America, and the annual barometric range here is among the widest in the country. Three storm types account for most of it. Alberta clippers dive southeast out of Canada in midwinter, fast and moisture-starved, with modest falls of ten to fifteen hPa and very quick recoveries behind a hard cold push. Colorado lows track northeast out of the Rockies and deepen as they cross the Mississippi valley, delivering the big winter storms and pressure falls of twenty-five hPa or more. And Panhandle systems curl up from the southern Plains, often producing the region's heaviest snow. Spring adds a fourth: strong low pressure over the Plains pulls Gulf moisture north into Illinois and organises severe convection, including squall lines and the occasional derecho, whose arrival produces a sudden pressure jump of several hPa as the gust front crosses. Between systems, sprawling Canadian high pressure can push the reading well above 1030 hPa.
What this means for you
Few places swing further or more often than the northern Illinois prairie in winter. A migraine tracker app with continuous logging is the practical way to keep up with a barometer that moves several times a week.