Wet Start to October No Surprise

Wet Start to October No Surprise:

Normal October precipitation around Minnesota ranges from 2 to 2.5 inches most places. Already over the first few days of the month many of our climate observers in the state report 1.5 to 3.0 inches of rainfall, topped by Grand Meadow (Mower County) with 3.91 inches. Portions of Itasca and St Louis County (Orr) have reported 1 to 1.5 inches of snow already this month, while other places in northeastern Minnesota have reported a trace. Temperatures over the first few days are running about 3 to 7 degrees F cooler than normal.

For the year to date, over 30 climate stations have reported more than 40 inches of precipitation. The community of Rochester (Olmsted County) has recorded their wettest year in history (over 19 inches wetter than normal so far), while many other climate stations are on a pace to do so. Some of the cause for all the surplus precipitation this year stems from a larger number of intense thunderstorms that delivered 2 or more inches in one day. However, some of the cause of surplus precipitation is also due to overall increased frequency of precipitation. For example, Rochester has reported measurable precipitation on 150 days so far this year, that is about 50 percent more than average (fully half of the days in the year have brought precipitation). Similarly, Lamberton (Redwood County) which is 10 inches above normal for the year so far has recorded precipitation on 135 days, which is 44 percent more frequent than their historical average.

The NOAA outlook for October favored a continuation of above normal precipitation across Minnesota during October, so we may not see much relief from this wetness trend.

New Dew Point Record for September 30:

On September 30th this week it felt more like the tropics around Minnesota with dew points in the 60s and low 70s F and temperatures in the 80s F. MSP set a new dew point record Monday afternoon with a reading of 72°F, and a new Heat Index record with a reading of 92°F. The 72°F dew point at MSP was also the highest measured for so late on the calendar. The Minnesota State Climate Office provided a report on this weather.

Weekly Weather Potpourri:

NOAA scientists featured a new video this week describing how the increased melting in the Arctic and associated release of fresh water is affecting the ocean circulation there. Changes in ocean circulation historically have affected the climate patterns over both North America and Western Europe.

There is also an interesting article by NOAA’s Tom Di Liberto about the relationship between Arctic Sea Ice and high latitude atmospheric circulation patterns that affect the winter season. This is a complex relationship that many scientists are trying to figure out.

“A 664-year record of grape harvest dates from Burgundy, France, reveals significantly warmer temperatures since 1988.” This is a line from this week’s AGU-EOS newsletter article about climate change showing an impact in the wine industry of France. By mining archival records of grape harvest dates going back to 1354, scientists have reconstructed a 664-year record of temperature traced by fruit ripening. The records, from the Burgundy region of France, represent the longest series of grape harvest dates assembled up until now and reveal strong evidence of climate change in the past few decades.

MPR listener question:

Is Minnesota's large rainfall this week an effect of the weather system that caused large snowfall in Montana? If so, what happened in Montana?

Answer:

Somewhat. The same weather pattern that favored heavy snowfall across Montana last weekend, also favored the trajectory of rainstorms across Minnesota this week. Whereas we saw some portions of the state receive 1 to 3 inches of rain this week, many of the higher elevations of Montana saw 15 to 30 inches of snowfall last weekend, with over 40 inches in Toole and Glacier Counties. Dozens of new daily snowfall records were set across Montana, including 36 inches at Galata (elevation 3100 ft) on September 29th.

Twin Cities Almanac for October 4th:

The average MSP high temperature for this date is 64 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 44 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for October 4th:

MSP weather records for this date include: highest daily maximum temperature of 89 degrees F in 1922: lowest daily maximum temperature of 41 degrees F in 1885; lowest daily minimum temperature is 24 degrees F in 1935; highest daily minimum temperature of 68 degrees F in 1922; record precipitation of 4.61 inches in 2005; and there was a trace of snowfall on this date in 1935.

Average dew point for October 4th 42 degrees F, with a maximum of 69 degrees F in 2005 and a minimum of 13 degrees F in 1952.

All-time state records for October 4th:

The state record high temperature for this date is 94 degrees F at Albert Lea (Freeborn County) in 1997. The state record low temperature for this date is 10 degrees F at Ada (Norman County) in 1935. State record precipitation for this date is 4.61 inches at MSP Airport in 2005; and record snowfall of 3.2 inches at Ada (Norman County) in 2012.

Past Weather Features:

The coldest October 4th in state history was in 1935 when over 30 climate stations reported a morning low of less than 20°F. As far south as Zumbrota a minimum of 20 degrees F was reported. The daytime high reached only 35°F at Babbitt.

October 4, 1997 was the warmest in state history with over 20 climate stations reporting an afternoon high of 90°F or greater.

October 4-5, 2005 brought heavy rains and rare flash flooding to east central Minnesota. Many parts of Chisago and Washington Counties saw 4 to 7 inches of rainfall, with a rain gage report from Rush City Airport of 9.59 inches. There were widespread road closures and flooded basements.

Outlook:

Cool and cloudy over the weekend with chances for rain. Drying out later in the day on Sunday, then a warming trend will start later on Monday and carry over into Wednesday. Another chance for rain or even snow showers by late Wednesday and Thursday of next week, with much cooler temperatures to follow.