CHICAGO — A major winter storm is headed towards the Chicago area and expected Thursday into Friday, just before the holiday weekend.

Here’s what you need to know:

WINTER HAZARD TIMELINE

Expected impact level of winter weather

Including snow, wind, freezing precipitation, low temperatures

TUESDAY

  • Trace amounts of snow or freezing drizzle possible
  • NIGHT: Low temps dip to teens

WEDNESDAY

  • No hazards expected
  • NIGHT: No hazards expected

THURSDAY

  • Snow becomes increasingly likely, especially late afternoon
  • NIGHT: Blizzard conditions expected; Rapid drop in temps makes accumulating snow powdery; Conditions deteriorate very quickly during early evening; COLD. Wind chills drop to -20 to -30°

FRIDAY

  • Heavy snow into midday; White-out continues; Winds gusts to 50+MPH, causing damage and possible power outages; Wind chills to -30°
  • NIGHT: Falling snow abates, but considerable blowing snow continues. Temps dip below zero with wind chills to -30°

SATURDAY

  • Visibility improves. Continued very windy and dangerously cold
  • NIGHT: Sub-zero temperatures at night with wind chills near -30°

SUNDAY

  • Low temps and winds keep wind chills well below zero
  • NIGHT: Winds diminish, but temps dip below zero

MONDAY

  • COLD. Chance of light now and flurries

FLASH FREEZE-UP MAY CAUSE ICE JAMS ON SOME AREA RIVERS

With the cold temperatures of the past several days water temps in many local rivers, especially smaller, shallower streams hover just above freezing. Ice will likely form as temps plummet below zero this weekend.


HEAVY SNOW EXPECTED ACROSS METRO AREA

European model forecast of total snowfall ending 6 PM Friday

Considering the powdery nature of the expected snowfall, and forecast wind speeds, it will likely be difficult to measure snowfall even for trained observers. Depths will likely range from bare ground to 5 feet within a few yards. Model forecasts are in reasonable agreement in producing snowfall amounts of 10 to 14” across the metro area.


MAP SHOWING FORECAST STORM TRACK AND TIMING, AS WELL AS FORECAST CENTRAL PRESSURE

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Note that the expected time of most rapid cyclone intensification is to occur as the low center passes just east of Chicago. Dynamic rising motion during this stage of storm development, combined with relatively mild, moist air circulating into a much colder environment will likely produce heavy snowfall rates across the metro area Thursday night into Friday.


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