Fall 2010 Central Indiana Climate Summary


Fall 2010 Summary
As we begin the month of December, we mark the conclusion of meteorological fall and the beginning of meteorological winter. The fall was highlighted by abnormally dry conditions with all of central Indiana experiencing drought conditions.  The following is a summary of weather conditions experienced at Indianapolis and the remainder of central Indiana during the months of September, October, and November in 2010.
Overall, temperatures during the fall of 2010 were slightly above normal, with an average temperature of 57.8 degrees at Indianapolis.  The normal fall average temperature is 54.6 degrees, making 2010 above normal by 3.2 degrees. The average temperature was slightly higher (~2 degrees) than the last several fall seasons.
High temperatures warmed above 90 degrees on several days in September. Record highs of 96 degrees on September 21st and 94 degrees on September 23rd at Indianapolis were the warmest temperatures recorded so late in the year since a 97 degree reading on September 29, 1953.  High temperatures once again climbed to much above normal levels in early October, culminating with a string of days over the Columbus Day weekend where highs warmed into the mid and upper 80s. Temperatures cooled during the second half of October, with most locations across central Indiana experiencing their first sub-freezing temperatures during the last ten days of the month.
After cooler weather during late October and early November, one last major warmup courtesy of a large ridge of high pressure brought high temperatures back into the lower and mid 70s for several days during the second week of November. Temperatures remained near to above normal into the week of Thanksgiving. A transition to wetter and more unsettled weather during the last several days of November ushered in more seasonable temperatures for late fall as highs fell back into the 40s and 50s with lows in the 20s.
Temperature Data across Central Indiana
Fall 2010 Average Temperature
Normal Average Temperature
Difference from Normal
Indianapolis Int’l Arpt
Terre Haute
Indianapolis – Eagle Creek
Fall Extremes across Central Indiana
Highest Temperature
Lowest Temperature
Indianapolis Int’l Airport
96 on 9/21
21 on 11/26
94 on 9/21
21 on 11/19 and 11/28
92 on 9/21 and 9/23
21 on 11/28
Terre Haute
94 on 9/21 and 9/23
20 on 11/19, 11/26, and 11/28
94 on 9/21 and 9/23
19 on 11/6 and 11/28
95 on 9/23
20 on 11/27 and 11/28
Indianapolis –
Eagle Creek
93 on 9/21
20 on 11/28
Overall, this was the 33rd driest fall on record at Indianapolis, but much of the fall season experienced some of the driest weather in recent memory.  The total rainfall for Indianapolis this fall was 6.34 inches, but over half of the fall total precipitation fell during the last eight days of the month of November. The normal rainfall total for fall is 9.25 inches, which made this fall below normal by 2.91 inches.  
The very dry weather continued from the summer into the fall across central Indiana, with severe to extreme drought conditions developing across the southern half of Indiana by late October and early November. Indianapolis officially recorded the 4th driest September on record with just 0.56 inches of rain fall during the month. Rainfall was only marginally more appreciable during October, with many locations seeing less than 1.50 inches for the entire month. Drought conditions were eliminated in southern Indiana following three to eight inches of rainfall along and south of Interstate 70 from the 22nd through the 30th.  Up to 10 inches of precipitation occurred across portions of south central Indiana in November.
Because of the continued low rainfall since late June in many areas of Indiana, numerous small watersheds in the state were at or near record low daily flow by late October and early November.  Consequently the White, East Fork White, and Wabash Rivers were below normal with the lower portions of the East Fork White and White Rivers the lowest when compared to daily normal flows.  Streamflow increased greatly following the rains during the last week of November.  On the last day of November, streamflow was above normal in most areas.  Geist and Morse reservoirs returned to normal levels, but Monroe Lake and Eagle Creek reservoir remained two and four feet below normal, respectively.
The wet weather over the last week of November helped diminish the annual precipitation deficit, but many locations remain below normal for 2010 through the end of November. At Indianapolis, the total for the year through the end of November is currently at 31.99”, or 5.93” below normal. 
Rainfall Data across Central Indiana
Fall 2010 Rainfall
Normal Rainfall
Difference From Normal
Indianapolis Int’l Airport
Terre Haute
Indianapolis – Eagle Creek
This year, only a trace of snow was recorded during the fall season at Indianapolis.  Although snowfall occurred on several days during the month of November, only a trace was recorded during each of these events. A normal fall season at Indianapolis would bring 1.7 inches of snowfall.
Major Weather Events
The drought and resultant high fire danger present across central Indiana were the main story throughout the fall. There were however a few notable severe thunderstorm events.
The drought conditions that plagued central Indiana for much of the fall season did lead to numerous field fires across the region in September and October. One fire in Rush County on September 23 charred nearly 1,000 acres and threatened a small town. According to Indiana Forestry, some of these field fires approached extreme fire behavior.  The fires during September and October coincided on days when temperatures were very warm combined with low relative humidity values, and moderate to strong winds.
A line of severe thunderstorms impacted central Indiana on the morning of October 26th. One tornado was confirmed over Howard County, briefly touching down just to the east of Kokomo. One home had significant damage and 6 other structures had minor roof or fence damage.   The tornado was rated an EF0. The line produced widespread wind damage across the area, with the most extensive wind damage taking place in Greenfield and Wilkinson in Hancock County and near Parker City in Randolph County. Subsequent storms surveys determined straight line winds of 80 mph were responsible for the damage in these areas.
A widespread line of storms associated with a strong cold front tracked eastward across central Indiana during the late night of November 22nd and early morning of November 23rd. Only one report of wind damage resulted from these storms in the southern portion of the area. A second round of storms produced some spotty wind damage early on Thanksgiving morning across south-central Indiana. These storms developed along a warm front and were ahead of a cold front, which slowly passed through the area later in the day.

Winter 2010-11 Outlook for Central Indiana
The official outlook for the 2010-2011 winter season (December-February) from the Climate Prediction Center (CPC) indicates a slight chance for higher than normal temperatures across central Indiana. At Indianapolis, the average temperature for the winter season is 29.8 degrees. The CPC is also forecasting a greater chance of above normal precipitation across central Indiana through the winter. At Indianapolis, the average precipitation for the winter season is 7.92 inches and the average snowfall is 21.8 inches.
Data prepared by the NWS Indianapolis Climate Team
Questions should be referred to w-ind.webmaster@noaa.gov

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