SWOP Weekly Weather Discussion

HEADLINE

A southwesterly flow pattern will bring above normal temperatures and precipitation to central Illinois over the next week.

DISCUSSION

A short-wave trough currently tracking eastward out of the Rockies will flatten a prominent upper-level ridge of high pressure anchored over the southeast U.S. over the next 24 hours. As the wave approaches, it will push a cold front through central Illinois late tonight into the morning of October 31st...bringing showers and a few thunderstorms. Once the wave departs and the upper flow becomes more zonal in its wake, a brief cool-down into the 50s is anticipated for Friday, November 1st.

After that, computer models are in good agreement that a big pattern change will take place by early next week as the southeast U.S. upper ridge shifts slightly further southeast and a short-wave digs a significant trough over the Great Basin/Rockies. In between these two features, deep-layer southwesterly flow will develop from the Southern Plains into the Great Lakes...bringing a return to warmer temperatures and a high probability of significant rainfall across central Illinois. After a chilly day on Friday, temperatures will gradually climb back into the middle and perhaps upper 70s by Monday, November 4th. At the same time, a slow-moving cold front will interact with increasing amounts of moisture throughout the entire atmospheric column to trigger occasional showers and thunderstorms from Sunday through Tuesday. Early projections suggest widespread rainfall of 2-3 inches across central Illinois...with the highest amounts focused across the Illinois River Valley. Stay tuned to later forecasts as these totals will be adjusted as more data becomes available. The western U.S. wave will eventually shift eastward, bringing cooler and drier weather back to the region by the middle and end of next week.

The latest 6-10 day outlooks (Nov 5-9) from the Climate Prediction Center (CPC) suggest ABOVE normal temperatures and ABOVE normal precipitation across central Illinois.

Issued: 10/30/24