This page displays different GFS maps (Global Forecast System). These forecasts
are generated and uploaded 3-4 times per day when data is availible. Please note that the forecast maps are shown in UTC or Zulu time.
New forecast maps are availible!
Note: These calculated forecast maps can depart significantly from actual weather.
WEATHER TRIVIA -
Weather TermsFlash Flood Warning - Flash flooding is occurring, imminent or highly likely. A flash flood is a flood that occurs within 6 hours of excessive rainfall and that poses a threat to life and/or property. Ice jams and dam failures can also cause flash floods. These warnings are issued on a county by county basis by the local Weather Forecast Office in Chicago/Romeoville and are generally in effect for up to 6 hours.