January Climate Summary

Central Indiana

January 2010 Climate Summary

 

 42nd Coolest on record at Indianapolis

22nd Driest on record at Indianapolis

44th Snowiest on record at Indianapolis

2010 began on a very cold note for central Indiana, with warmer temperatures arriving during the middle of the month. A colder weather pattern returned for most of the last week of the month.  Upper level low pressure tracking through the Ohio Valley on the 7th brought widespread snow to central Indiana, with accumulations between three and seven inches.  This was the only significant storm system to impact the region through the month of January, as the presence of an arctic air mass for much of the month kept the main storm track across the country well south of central Indiana.  Several small systems impacted the region throughout the month producing light precipitation.   The snow cover from the storm on the 7th slowly melted as warmer temperatures arrived during the middle of the month, contributing to an extended period of low clouds and fog that plagued much of the area for several days.

 

Temperatures

Temperatures were very cold to start out the month, with many locations not rising above 20 degrees until the 6th, and above the freezing mark until the 13th.   The extended period of cold was largely due to a persistent upper trough over the eastern part of the country, allowing a continued push of polar air south from Canada.  Many locations across central Indiana began the morning of the 3rd with below zero readings while under the influence of arctic high pressure.  The addition of several inches of snow on the 7th enabled low temperatures to fall below zero once again in localized areas on the morning of the 10th. 

 

The trough finally relaxed by mid month, with daytime temperatures remaining above freezing from the 13th through the 24th.  Highs climbed above 40 degrees on the 14th and 15th, and then again from the 22nd through the 24th as southerly winds brought milder air into the Ohio Valley.  Ahead of a cold front, temperatures on the 24th warmed into the lower and mid 50s.  Colder air returned behind the front, with temperatures generally remaining below freezing for the last week of the month.

 

 

Site

January 2010 Avg Temp

January 2010 Difference from normal

Highest

Temperature

Lowest Temperature

Indianapolis

24.6

 -1.9

55 on 24

1 on 3

Lafayette

23.5

  0.2

54 on 24

-2 on 3

Muncie

22.5

 -2.0

53 on 24

-2 on 3

Terre Haute

23.8

 -2.7

55 on 24

-8 on 10

Bloomington

25.2

 -2.7

53 on 24

0 on 3

Shelbyville

24.9

 -1.9

54 on 24

2 on 3

Indy – Eagle Crk.

24.1

 -2.4

55 on 24

1 on 3

 

At Indianapolis, there were 18 days with below normal average temperatures and 13 days with above normal average temperatures.

 

January 2010 was the 42nd coolest in the Indianapolis area since 1871.

 

 

Precipitation

 

Much of the precipitation during the month fell between the 20th and the 24th.  A frontal boundary oscillated near the Ohio River and weak areas of low pressure moved along it from the 20th to the 22nd, with many locations in central Indiana receiving upwards of a half inch. A more significant low pressure tracked through the region late on the 23rd and early on the 24th.  The quick movement to the low kept rainfall totals less than a half inch across much of the region. However, heavier rainfall with embedded thunderstorms across southwest Indiana and eastern Illinois produced around an inch, causing rises on the Wabash River.  Additional heavier rainfall took place throughout the 24th across eastern Indiana as a cold front moved across the region.   

 

The combination of the two rain events and the warm temperatures on the 24th caused low land river flooding and high river levels in portions of central and southern Indiana.  Low land flooding and bank full conditions occurred along the Wabash River, East Fork White, Muscatatuck, White, and Mississinewa Rivers.   The prolonged period of below freezing temperatures from the 26th through the 31st limited the duration of the flooding.    All river flooding ended by the evening of the 31st.

 

Additional precipitation throughout the month was light and mainly in the form of snow.  Monthly totals throughout central Indiana were generally one to two inches, better than an inch below normal for many areas.

 

Site

January 2010 Precipitation

January 2010 Difference from Normal

Wettest Day

Longest Dry Stretch

Indianapolis

1.22

-1.26

0.64” on 21

3 days 29-31

Lafayette

0.99

-0.80

0.55” on 20-21

7 days 13-19

Muncie

0.77

-1.29

0.40” on 20-21

7 days 13-19

Terre Haute

0.87

-1.26

0.45” on 21

7 days 13-19

Bloomington

1.46

-1.20

0.50” on 20-21

7 days 13-19

Shelbyville

1.29

-1.09

0.65” on 21

7 days 13-19

Indy – Eagle Crk.

1.24

-1.24

0.58” on 21-22

8 days 12-19

 

January 2010 was the 22nd driest in the Indianapolis area since 1871.

 

Snowfall

 

The month was highlighted by one significant storm and several smaller accumulations of snow. The biggest storm of the month tracked across central Indiana on the 7th, producing 3 to 7 inches across the region.  Additional light accumulations followed, most notably on the 25th and 27th as a result of weak upper level disturbances passing through the Ohio Valley.  The atmosphere was unstable enough to generate scattered snow squalls across much of central Indiana on the 25th.  Visibilities dropping to just a few hundred feet within a short period of time and near whiteout conditions were common as the squalls passed through the region.  At Indianapolis, snowfall for the month ended up at 7.8” or about an inch and a half below normal.

 

Severe Weather


No severe weather occurred in central Indiana in January.

 

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

 

 

Miscellaneous

 

At the Indianapolis International Airport, the peak wind gust this month was 38 mph from the southwest on January 25.  Fog or haze was observed on 22 days, including 16 straight days from the 13th to the 28th.  6 days of dense fog were observed, including four straight days from the 16th to the 19th.  The extended period of fog or haze coincided with a prolonged period of cloudy skies that began on the 15th and remained nearly continuous through the 26th.

 

 

February 2010 Outlook

 

The official outlook for February 2010 from the Climate Prediction Center indicates an equal chance of above, near, or below normal temperatures across central Indiana.  At Indianapolis, the average temperature for the month is 31.2 degrees.  A greater chance of below normal precipitation exists across central Indiana in February.   At Indianapolis, the average precipitation for February is 2.41” and the average snowfall is 6.1”.

 

Data prepared by the Indianapolis Forecast Office.



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