National Weather Service United States Department of Commerce

Cold Front Dropping South Across the Western U.S.; Watching Threat for Tornadoes and Flooding in the South

A cold front will push south across the Western U.S. into Tuesday with mountain snow and areas of gusty to high winds. An area of low pressure will form along this front on Tuesday and bring a potential for severe thunderstorms with tornadoes and excessive rainfall in the lower to mid Mississippi River Valley. To the north, heavy snow is possible in parts of the upper Midwest. Read More >

December 2015 went down as one of the wettest and warmest on record for both Chicago and Rockford.

graphic of top 10 warmest decembers

 

The wet pattern in December was a continuation of the abnormally wet weather in November. The combination of the 2 resulted in the Nov-Dec period being one of the wettest on record.

map of nov + dec precip and top 10 wettest dec and nov lists

 

After an unusually cold start to the year, 2015 finished much warmer than average. The end of the year warmth actually was able to cancel out the early year temperature deficit and 2015 ended up averaging close to normal.

chicago 2015 monthly temperature departure from average graph rockford 2015 monthly temperature departure from average graph

 

The record to near record wet end to 2015 helped make up for the drier than average months earlier in the year and both Rockford and Chicago ended up slightly above average for precipitation in 2015. Here is a month by month break down of precipitation for both locations in 2015.

chicago monthly precip 2015 rockford monthly precip 2015

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1150 AM CDT FRI JAN 1 2016

...A LOOK BACK AT THE CLIMATE FOR THE MONTH OF DECEMBER 2015 FOR
CHICAGO AND ROCKFORD...

AT CHICAGO...THE AVERAGE HIGH TEMPERATURE WAS 44.5 DEGREES WHICH IS
9.7 DEGREES ABOVE NORMAL. THE AVERAGE LOW TEMPERATURE WAS 33.5
DEGREES WHICH IS 12.8 DEGREES ABOVE NORMAL. THE AVERAGE TEMPERATURE
FOR THE MONTH WAS 39 DEGREES WHICH IS 11.3 DEGREES ABOVE NORMAL.
DURING THE MONTH OF DECEMBER...4.87 INCHES OF PRECIPITATION WAS
RECORDED WHICH IS 2.62 OF INCHES ABOVE NORMAL. 4.5 INCHES OF SNOW
WAS RECORDED WHICH IS 4 INCHES BELOW NORMAL.

TWO RECORDS WERE SET FOR CHICAGO FOR THE MONTH OF DECEMBER 2015...
* RECORD DAILY WARMEST MINIMUM TEMPERATURE OF 48 DEGREES ON THE 13TH.
* RECORD DAILY PRECIPITATION OF 1.47 INCHES ON THE 28TH

TWO TOP TEN MONTHLY RECORDS
**4TH WARMEST DECEMBER ON RECORD SINCE 1872 WITH 39.0 DEGREES
**6TH WETTEST DECEMBER ON RECORD SINCE 1871 WITH 4.87 INCHES


AT ROCKFORD...THE AVERAGE HIGH TEMPERATURE WAS 43.4 DEGREES WHICH IS
10.2 DEGREES ABOVE NORMAL. THE AVERAGE LOW TEMPERATURE WAS 32.1
DEGREES WHICH IS 14.4 DEGREES ABOVE NORMAL. THE AVERAGE TEMPERATURE
FOR THE MONTH WAS 37.7 DEGREES WHICH IS 12.3 DEGREES ABOVE NORMAL.
DURING THE MONTH OF DECEMBER...4.65 INCHES OF PRECIPITATION WAS
RECORDED WHICH IS 2.67 INCHES ABOVE NORMAL. 5.2 INCHES OF SNOW
WAS RECORDED WHICH IS 6.1 INCHES BELOW NORMAL.

THERE WERE 10 RECORDS FOR ROCKFORD FOR THE MONTH OF DECEMBER 2015...
* TIED DAILY MAXIMUM TEMPERATURE OF 57 DEGREES ON THE 10TH
* RECORD DAILY HIGHEST MINIMUM TEMPERATURE OF 46 DEGREES ON THE 12TH
* RECORD DAILY MAXIMUM TEMPERATURE OF 62 DEGREES ON THE 13TH
* RECORD DAILY PRECIPITATION OF 1.41 INCHES ON THE 13TH
* RECORD DAILY MAXIMUM TEMPERATURE OF 61 DEGREES ON THE 14TH
* RECORD DAILY HIGHEST MINIMUM TEMPERATURE OF 41 DEGREES ON THE 14TH
* RECORD DAILY PRECIPITATION OF 0.63 INCHES ON THE 21ST
* RECORD DAILY MAXIMUM TEMPERATURE OF 59 DEGREES ON THE 23RD
* RECORD DAILY PRECIPITATION OF 0.70 INCHES ON THE 23RD
* RECORD DAILY PRECIPITATION OF 1.25 INCHES ON THE 28TH

TWO TOP TEN MONTHLY RECORDS
**WARMEST DECEMBER ON RECORD SINCE 1905 WITH 37.7 DEGREES
**SECOND WETTEST DECEMBER ON RECORD SINCE 1905 WITH 4.65 INCHES