December 2016 Climate Summary

 Central Indiana

December 2016

Climate Summary

50^th Coolest on record at Indianapolis

25^th Driest on record at Indianapolis

Tied for 58^th Snowiest on record at Indianapolis

Temperatures

Temperatures started out December relatively close to normal as highs in the upper 30s and lower 40s were common with lows predominantly in the 30s. The initial shot of colder air for the month arrived late on the 7^th, with multiple days with highs mainly in the 20s through the 10^th. Temperatures recovered back close to normal from the 11^th through the 13^th as highs recovered largely into the mid and upper 30s.

The bottom fell out beginning late on the 13^th as very cold arctic air overspread the region in the wake of a frontal passage. With a few inches of fresh snow on the ground for most as well, temperatures tumbled into the single digits and low teens by the morning of the 14^th. This started a week long stretch where temperatures largely remained subfreezing across central Indiana, highlighted by highs only from 10 to 15 degrees on the 15th. The only exception took place on the 17^th as a frontal boundary became nearly stationary over south central Indiana. While temperatures remained in the 30s to the north, highs briefly surged into the 50s from Washington to Seymour and North Vernon. Subzero lows were common across much of central Indiana on the 18^th and 19^th as well.  For Indianapolis, the low of -1° on the 19^th marked the first subzero low in December since Christmas Day 2004.

Beginning on the 20^th, a warmer airmass overspread the Ohio Valley, with above normal conditions continuing for the rest of the month. Highs were largely above 40° through the period, with a very warm Boxing Day as highs surged into the 60s ahead of a cold front on the afternoon of the 26^th. The month and year ended on a mild note as highs rose into the middle and upper 40s on the last day of 2016.

Temperatures averaged up to 2° below normal across central Indiana for the month. For many locations, this was the first month with below normal temperature averages since May. Even more impressive, average temperatures this December were 12 to 14 degrees colder than December 2015.

At Indianapolis, there were 16 days with above normal average temperatures, 14 days with below normal average temperatures and 1 day with normal average temperatures.

December 2016 was the 50^th coolest in the Indianapolis area since weather records began in 1871.

Precipitation

December melted precipitation was near normal to below normal for almost all of Indiana.  Only areas near the Ohio River in extreme south central and southeast Indiana received above normal precipitation during the month.

Melted precipitation ranged from less than 1 inch in a few areas of west central and north central Indiana to more than 6 inches on the Ohio River in south central Indiana.  Much of the state received 1 to 3 inches.

River flooding returned to portions of central Indiana for the first time since September.  Brief lowland flooding occurred near the end of the month along portions of the Wabash River in the Lafayette, Covington and Montezuma areas of west central Indiana

Drought conditions improved during the month.  The percentage of the state in drought decreased from 75% at the beginning of December to 25% at the end of the year. Portions of west central, north central, eastern and southern Indiana remained abnormally dry.

December 2016 was the 25^th driest in the Indianapolis area since weather records began in 1871.

Snowfall

The first significant snow of the winter season fell in central and northern Indiana during December.  Monthly snowfall ranged from a trace in southern Indiana to over 28 inches near Lake Michigan in northern Indiana.  Much of central Indiana received between 2 and 6 inches while northern Indiana totaled 6 to 24 inches, with some of the highest amounts downwind of Lake Michigan and courtesy of heavy lake effect snow. Southern Indiana received a trace to less than 2 inches.  Monthly snowfall was normal to above normal in northern Indiana, near normal in central Indiana and below normal in southern Indiana. Indianapolis received 4.9” of snow in December, 2” below the average for the month. Most of the snow fell on the morning of the 13^th as a quick moving storm system deposited 3 to 4 inches of snow along the Interstate 70 corridor.

Severe Weather

No severe weather occurred over central Indiana during the month of December.

For information on severe weather in other areas during December, visit the Storm Prediction Center “Severe Weather Event Summaries” website at http://www.spc.noaa.gov/climo/online/.

Miscellaneous

The maximum wind gust at Indianapolis International Airport was 42 mph out of the west on the evening of the 29^th as scattered snow squalls affected the area.. Fog or haze was reported at Indianapolis on 16 days during the month, with dense fog reported on three days. Freezing rain or drizzle was reported on three days during December.

January 2017 Outlook

The official outlook for January 2017 from the Climate Prediction Center indicates an equal chance of near, above or below normal temperatures and precipitation across central Indiana. At Indianapolis, the average temperature for the month is 28.1 degrees. The average precipitation for January at Indianapolis is 2.66 inches, with 8.6 inches of snowfall.

Data prepared by the Indianapolis Forecast Office.