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Northern Indiana

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November 21st, 2015 Heavy Snowfall

Weather.gov > Northern Indiana > November 21st, 2015 Heavy Snowfall

 

Updated 11/22/2015 11:15 pm EST

Overview

Snowfall Map and Reports

What Caused this Event? 

Radar Loop 

Pictures

Other Useful Links

 

 

Overview

A strong low pressure system tracked northeast across the area November 20th through 21st, bringing widespread moderate to heavy precipitation to the area. Cold air on the northwest side of this sytem allowed for the precipitation to begin as snow across the northwestern half of the forecast area, while precipitation transitioned from rain to snow throughout the event across the southeastern half of the area. Widespread snowfall amounts of 4 to 8 inches were observed, with some areas receiving between 8 to 12 inches of snow accumulation. Snow accumulations fell sharply toward a Portland, IN to Lima, Ohio line, where warmer temperatures kept precipitation in the form of rain or a rain/snow mix for most of the event.

 

Snowfall Map and Reports

Below is a map of general snowfall reports across the area. The heaviest amounts were observed in southewest lower Michigan/Michiana region and along the I-69 corridor in south central lower Michigan southward toward Angola. Immediately below this image is a list of selected snowfall reports from across the area.

Click here for Snowfall Reports

The image below is a GOES-East Visible Satellite image from the morning after the event, Sunday November 22nd. This satellie image shows a sharp cutoff in snow cover between Fort Wayne and Lima.

What Caused This Event?

A strong upper level jet streak with winds in excess of 140 knots entered the southern Ohio Valley. Our area was in the left exit region of the jet streak which is favorable for rising motion.

In the mid-levels of the atmosphere, a strong, negatively tilted trough was moving into the region. Strong cyclonic vorticity advection ahead of this trough aided in the rising motion across the area during the day on November 21st. In the lower levels, strong isentropic ascent, moisture, good moisture, and strong 700mb frontogenesis caused several bands of moderate to heavy snow to develop. The surface low deepened quickly during the afternoon of the 21st from 1013mb that morning to 1005mb by 5pm. 

Surface temperatures along and east of US-24 were at or above freezing which led to mostly rain with some snow mixing in. Once temperatures dropped cool enough for snow, most of the precipitation had already lifted out of the area. 

Radar Loop of Event

Note: The KIWX radar was not operating from the beginning of the loop through 1 PM EST, so the images shown in this radar loop from the beginning of the loop until 2 PM EST only contain radar data from surrounding radars.

 

Pictures

                 

Other Useful Links

 

Updated 11/23/2015 10:00 PM EST

 

NG/Bentley

 

 

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