Major Storm Hits Midwest Tonight

A strong low pressure area now over the Northern Plains is forecast to deepen to 959 mb over International Falls by 0Z Wed (7PM Tuesday CDT), possibly producing a derecho which will start across Iowa/Illinois tonight, and blizzard conditions in North Dakota.This storm has already prompted high wind watches and warnings (brown) from the Dakotas to Ohio, storm warnings (purple) for Lakes Superior and Michigan, winter storm warnings (pink) for most of western Colorado, and freeze warnings for the northwest Texas Panhandle:Temperatures across eastern Iowa and Northern Illinois may actually rise overnight tonight. The NAM forecast sounding for Davenport shows very strong low level unidirectional wind shear, and surface-based instability even at 12Z, suggesting a high potential for damaging wind.

Hurricane Otto and Northeast Cold

Otto was named a tropical storm at 15Z (10:00 AM) on October 7th. Visible satellite imagery for that time shows very little convection:It did have a more tropical appearance later that night:A cold spell prompted frost (blue) and freeze (light blue) advisories for New England on October 9th:

Subtropical Storm Otto and Midwest Freeze

Subtropical Storm Otto was named in the Atlantic today at 21Z (4PM CDT). Otto, seen here just east of the Bahamas, clearly has non-tropical characteristics especially in water vapor imagery:
Freezing temperatures have already been observed near the Ohio River:
Although not shown on the above chart, even Carbondale, IL had a low of 30F on the morning of October 4th (Monday), and 32F on the 5th. Mount Vernon, IL had a low of 28F on October 5th. Frost advisories for tonight include Cattanooga, TN and Knoxville, TN.A severe thunderstorm watch is active for western Colorado and a hurricane warning east of Florida.

North Atlantic Storm and Midwest Frost

A storm south of Iceland is now at 952 mb:Buoy 62095, west of Ireland, has reported 31.8 foot waves.

Frost advisories for tonight now include: Mena, AR; St. Louis, MO; Paducah, KY; Evansville, IN; Indianapolis, IN; Flint, MI.

Extensive Frost Tonight

Frost advisories tonight include: Oklahoma City, OK; Fort Smith, AR; Decatur, IL; Terre Haute, IN; Marion, IN; Nashville, TN.

East Coast Rain and Midwest Frost

The East Coast received flooding rains from September 26th-October 1st:Storm totals were as high as 23.36" in coastal North Carolina. The 22.54" at Wilmington, NC was the heaviest 5-day total since records began in 1850.

A widespread frost/freeze event is expected across the Midwest tonight. Freeze warnings extend to La Crosse, Wisconsin, and frost advisories to two counties south of Kansas City.
Last night, snow was reported from the station at Sawyer International Airport near Marquette, Michigan: