National Weather Service United States Department of Commerce

Cold Front Moving Through the Northeast U.S. Monday; Atmospheric River to Impact the Pacific Northwest Midweek

A cold front will cross the Great Lakes and Northeast U.S. through Monday with gusty winds and areas of rain showers. A strong atmospheric river is expected to move into the Pacific Northwest by midweek bringing a threat for moderate to heavy rainfall, gusty winds, and mountain snows for parts of Washington, Oregon, northern California, and the Sierra Nevada. Read More >

Overview

Sunday, January 7 saw persistent light freezing rain and drizzle over the area over a span of six to nine hours. At brief times this was mixed with sleet and snow, but was mainly an icing event during the afternoon. After dark, the precipitation gradually transitioned to snow by mid-evening.

This event came on the heels of a significant cold weather period from Dec 26-Jan 6, which meant ground and pavement temperatures were below freezing.  This furthered the icing on roads and created very hazardous travel conditions. 

A Winter Weather Advisory was issued for generally south of Interstate 80 in the early morning of January 7, and this was expanded northward early in the afternoon.

 

Radar Loop
January 7 13-hour radar loop from 10:30 a.m.-11:30 p.m.  Overlaid in yellow are mPing observations.  Symbols are drops (rain), drops with a horizontal "S" (freezing rain), S with a circle (sleet), and asterisk shape (snow).

Meteorology

Precip Types Sounding
An explanation of different precipitation types. A look at the observed atmosphere over central Illinois on January 7 that was  representative of much of the local area.

 

 

 


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