Central Indiana Fall 2012 Climate Summary

Central Indiana
Fall 2012 Summary




As we begin the month of December, we mark the conclusion of meteorological fall and welcome meteorological winter. The fall of 2012 saw average temperatures generally near to below normal. The wet pattern that developed during August across much of central Indiana continued into September, with Indianapolis experiencing the 5th wettest September on record. October provided generally cool and wet conditions before a much drier pattern set in throughout the month of November. The following is a summary of weather conditions experienced in Central Indiana during the months of September, October, and November 2012.




The fall of 2012 was tied for the 26th coolest fall ever at Indianapolis, with an average temperature of 53.1 degrees. This is 2.1 degrees below the normal fall average temperature of 55.2 degrees. 

The warmest temperatures of the month occurred over the first week as high temperatures routinely climbed into the 80s. The presence of the remnants of Hurricane Isaac over the region contributed to a humid tropical airmass over central Indiana as well. The passage of a strong cold front on the 7th ushered in cooler and drier air with highs mainly in the 70s and lows in the 50s through the 11th. High temperatures returned to the 80s for the 12th and 13th before another frontal passage knocked highs back into the 70s. For most of central Indiana, the 13th was the last day with highs in the 80s for the month.
The pattern across the lower Great Lakes and Ohio Valley transitioned to an upper level trough during the middle of the month, allowing cold fronts and cooler air to overspread much of the region during the second half of September. High temperatures across central Indiana after the 16th were rarely any higher than 75 degrees and on several days, remained in the 60s. Low temperatures from the 18th through the 22nd dropped into the 40s, culminating with several locations bottoming out in the 30s on the mornings of the 23rd and 24th as cold high pressure set up over the region. Many locations in central Indiana received their first frost on the 24th, making for one of the earliest occurrences on frost on record. Lows at Lafayette and Terre Haute approached the freezing mark on the 24th.
October started off near average early in the month, but the month quickly turned cold and remained that way most of the time. Much of the period from October 6-10 saw temperatures of 10 to 20 degrees below average. Many locations saw temperatures at freezing or below on October 8.
Much of the remainder of the month continued to see below average temperatures. The exception was the period from the 22nd through the 25th, where readings ended up 10 to 20 degrees above average. Most locations saw their warmest temperatures for the month during that period, with highest readings in the upper 70s to around 80.
The remnants of Hurricane Sandy brought cold air from Canada down into the area for the end of the month. These cold temperatures allowed a little sleet or snow to fall at some locations in central Indiana on the 30th. Halloween was cold with highs temperatures only in the 40s at most locations.
November started out cool as a trough of low pressure persisted across much of the eastern U.S. in the wake of Sandy. An upper level ridge expanded into the Ohio Valley during the second week of the month, with much warmer temperatures across central Indiana. From the 9th through the 11th, highs rose to 60 degrees or better across much of the region, highlighted by temperatures reaching the lower 70s in most locations on the 10th. The passage of a strong cold front early in the morning of the 12th brought an abrupt end to the warm weather. Highs in the upper 50s and lower 60s were reached shortly after midnight, with temperatures quickly falling 15 to 20 degrees within a couple hours after the frontal passage. Temperatures fell into the upper 30s after daybreak on the 12th, with precipitation changing over to a brief period of snow for most of central Indiana.
Temperatures remained slightly below normal through the 15th, before temperatures warmed. The arrival of a broad area of high pressure with ridging aloft brought an eight day stretch of daytime temperatures exceeding 50 degrees. The warmest temperatures were experienced on the 21st and 22nd as much of central Indiana warmed into the lower and middle 60s. Yet another strong cold front passed through the region early on the 23rd, bringing much colder air back into the Hoosier state. Temperatures on the 24th under cloudy skies were only able to warm into the lower 30s, making for the coldest daytime highs experienced across the region since mid-February. Temperatures slowly warmed through the end of the month, with central Indiana returning into the 50s by the 30th. Lows in the 20s and 30s were typical throughout much of the month.


Temperature Data for Other Sites in Central Indiana


Fall 2012 Temperature
Normal Temperature
Diff. From Normal
Indianapolis Int’l Arpt
Terre Haute
Indianapolis – Eagle Creek

Fall Extremes Across Central Indiana

Warmest Temperature
Coldest Temperature
Indianapolis Int’l Airport
 88 on 9/4
23 on 11/24 and 11/28
88 on 9/4
20 on 11/27
86 on 9/4 and 9/6
23 on 11/14 and 11/15
Terre Haute
90 on 9/4
23 on 11/28
89 on 9/4 and 9/7
20 on 11/29
89 on 9/4
24 on 11/24 and 11/28
Indianapolis-Eagle Creek
86 on 9/4 and 9/6
23 on 11/29



Overall this was the 24th wettest fall on record at Indianapolis. The total rainfall for Indianapolis this fall was 12.93 inches. This was 2.99 inches above the normal fall rainfall total of 9.94 inches.  


The wet weather pattern of August continued in much of Indiana during September.   Monthly rainfall was normal to much above normal in central and southern Indiana and generally below normal in northern Indiana. Precipitation totals ranged from 4 to more than 12 inches in central and southern Indiana, while totals in northern Indiana measured only 1 to 3 inches. Much of southwest, central and east central sections of Indiana were the wettest areas in September. Many locations in these areas received 5 to more than 8 inches of rainfall. As during August, much of northern Indiana missed any significant rainfall and received around 2 inches during the month. Normal rainfall for September is between 2 and 4 inches.
There were two widespread rainfall events during September that covered much of central and southern Indiana. The remnants and moisture from Hurricane Isaac produced rainfall of 1 to more than 4 inches from the 1st through the 8th. The last rainfall event of the month was a result of a series of low pressure areas that moved along a stationary front located in central Indiana. These systems dumped 1 to more than 6 inches from the 25th through the 27th
Between these two widespread rainfall events, there were three lesser events. Rainfall of 1 to 4 inches occurred on the 14th, 17th -18th and the 21st in portions of the state. The storms during the evening of the 21st produced significant hail in parts of central Indiana. Several locations in Hendricks, Marion and Hancock Counties measured hailstones with a diameter of one-half to slightly more than an inch. In a few areas the hail storm lasted for at least 10 minutes and deposited 1 to 2 inches of hail.
Drought conditions were greatly diminished over much of central and southwest Indiana by the end of September. Drought conditions continued to improve in south central and southeast Indiana, but remained largely unchanged in northern Indiana.   At the end of the month, stream flow was above seasonal levels in much of central and southern Indiana, while below normal in northern Indiana and along the Wabash River from Terre Haute to near Vincennes.   Except for Cecil Hardin Reservoir in west central Indiana, local area reservoirs ranged from normal to less than 3 feet below capacity.


October was a rather wet month for much of Indiana. Monthly precipitation totals ranged from 2 to nearly 8 inches with many areas receiving between 3 and 6 inches. The greatest rainfall totals were confined to central and northern Indiana north of Interstate 70 and south of U.S. Highway 30. South central and southeast Indiana near the Ohio River were the driest areas.
There were two widespread rainfall events during October. Much of the state received one-half to 3 inches of rain in early October. Prior to the passage of a strong cold front, significant rain occurred on the 2nd-3rd and the 5th.   The second event occurred from the 17th-23rd.   Rainfall of one-half to 4 inches occurred from significant precipitation on the 17th-20th and the 22nd-23rd.   Less significant rains occurred on the 14th, 26th and 30th. The longest dry spell during the month was an 8-day period from the 6th-13th.
On the 30th Hurricane Sandy brought the season’s first wintry precipitation. Snow accumulated to one-tenth of an inch in portions of northeast and eastern Indiana. Snow flurries and trace amounts of sleet fell in portions of central Indiana during the day of the 30th.
Remaining drought conditions in northern and southern Indiana showed a slight improvement by the end of October. Less than 10% of Indiana remained in moderate drought according to the U.S. Drought Monitor. At the end of the month, stream flow was at or above seasonal levels in all of central and southern Indiana. Local area reservoirs were near or at capacity.
November was a dry month across Indiana. Monthly precipitation totals ranged from a record low amount of one-quarter of an inch in portions of northern Indiana to nearly 3 inches in southeast Owen County in southwest Indiana. Most areas received between one-half and one and one-half inches of precipitation during the month. November was the first drier than normal month for central Indiana since July.
The only widespread precipitation event during November occurred late on the 11th and the morning of the 12th. Much of central Indiana received one-half to one and one-half inches of precipitation while northern Indiana received less than one-half of an inch. Rain changed to snow in central Indiana during the late morning of the 12th. This resulted in the first measurable snowfall of the season for much of central Indiana. Snowfall accumulations were less than one-half of an inch. The snow quickly melted from the sunshine in the early afternoon.
Wintry precipitation fell on two other occasions during November. Sleet fell in portions of central Indiana on the 3rd. Late on the 26th and early on the 27th, light snow accumulated up to an inch in a 20-mile wide area from Lafayette to Winchester north of Indianapolis. All wintry precipitation melted within a few hours. Wintry precipitation totals for the month ranged from a trace to one and one-half inches.
Drought conditions did not improve in northern Indiana during November. The U.S. Drought Monitor indicated about 15% of Indiana remained in a moderate drought at the end of November. Stream flow ranged from seasonal levels in much of central Indiana to below normal in northern and southern Indiana. Local area reservoirs remained near or at capacity.


Rainfall Data for Other Sites in Central Indiana

Fall 2012 Rainfall
Normal Rainfall
Diff. From Normal
Indianapolis Int’l Arpt.
Terre Haute*
Indianapolis – Eagle Creek

* Total at Terre Haute is likely too low from November due to missing data on November 11 and 12.


Major Weather Events
Strong thunderstorms impacted central Indiana on September 1st and 2nd as the remnants of Hurricane Isaac moved into the Ohio Valley. A weak tornado dropped down briefly near 16th Street and the White River just to the northwest of downtown Indianapolis on the evening of the 2nd. No damage was observed. Two thunderstorm complexes impacted central Indiana on the afternoon and evening of September 7th ahead of a cold front. The first complex moved across northern portions of central Indiana, producing pockets of wind damage and small hail. The second and larger thunderstorm complex moved across much of the area during the evening, producing damaging winds and torrential rainfall producing localized flooding. Wind gusts in excess of 60 mph were reported in Lebanon in Boone County and Hayden in Jennings County as the storms arrived. Several locations received in excess of 3 inches of rainfall from the storms on the evening of the 7th.
A mini-supercell developed over eastern Illinois on the afternoon of September 21st, intensifying and moving across central Indiana during the evening. The storm produced large hail throughout much of its track across the region, including some reports of hail covering the ground. The storm was at its most intense across Hendricks County and especially from near Danville through Brownsburg. Golf ball size hail along with wind gusts of 65 to 70 mph.
In October, strong thunderstorms moved across the Hoosier state during the afternoon and evening of the 14th in association with an intense cold front, producing wind gusts near 50 to 55 mph along with brief heavy rainfall. A few stronger thunderstorms moved across far northern sections of central Indiana during the early morning of the 23rd as an upper level disturbance passed through the region.
For information on severe weather in other areas throughout the fall, visit the Storm Prediction Center “Severe Weather Event Summaries” website at http://www.spc.noaa.gov/climo/online/.


Winter 2012-2013 Outlook for Central Indiana

The official outlook for the 2012-13 winter season (December-February) from the Climate Prediction Center, indicates a better chance of near to slightly below normal temperatures across central Indiana. At Indianapolis, the average temperature for the winter season is 30.5 degrees. An equal chance of above, near and below normal precipitation exists across central Indiana throughout the upcoming winter. At Indianapolis, the average precipitation for the winter season is 8.15” with 22.0” of snowfall.
Data prepared by the NWS Indianapolis Climate Team
Questions should be referred to w-ind.webmaster@noaa.gov

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