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Extension > Mark Seeley's WeatherTalk

Friday, October 20, 2017

Weather Pattern Reversal in October

Weather Pattern Reversal in October:


After a very wet first half of October, it appears that the 2nd half will be quite dry. During the first two weeks of the month 62 daily rainfall records were set or tied within the Minnesota state climate network, and over three dozen communities reported rainfall totals ranging from 5 to 8 inches, with nearly half the days of the month bringing rain. That pattern has completely reversed itself for the second half of the month, with little precipitation in the forecast out to Halloween. Though dry, the month will continue to be warmer than normal as it was this week.

A Dry Week Helps Farmers:


After a very wet first half of October, this week's sunny, warm, and dry weather has been very helpful for farmers who have resumed harvesting corn and soybean fields. Daily temperatures have been averaging 8-12 degrees F above normal this week. Over 90 climate stations have reported daytime high temperatures in the 70s F this week. The high temperatures, bright sun, strong winds (20-30 mph), and low dew points and humidity provoked the National Weather Service to issue some Red Flag Warnings (ideal conditions for wildfires to break out) for many parts of the state this week. Some of the dew point and relative humidity readings were close to record low values at many locations, including:

On the afternoon of October 18th Roseau had a dew point of 3°F and RH of 10%; Fosston had a dew point of 9°F and RH of 15%; Baudette had a dew point of 9°F and RH of 14%; International Falls had a dew point of 12°F and RH of 16%; Moorhead had a dew point of 13°F and RH of 14%; and Appleton had a dew point of 17F and RH of 16%. For comparison on the same afternoon Phoenix, AZ reported a dew point of 30°F with an RH of 15%.

Although these conditions provoke a higher risk for wildfires, there are also favorable for field corn kernel moisture to dry down by 1 to 2 percent per day, saving farmers on drying costs before storage.

Weekly Weather Potpourri:


NOAA scientists released new season outlooks this week. The outlooks favor a somewhat wetter than normal winter (Dec-Feb) over much of Minnesota and perhaps a cooler than normal winter over northern portions of the state. The Winter Outlook is conditioned on the formation of a short-lived La Nina episode (cooler than normal temperatures in the equatorial Pacific Ocean). I might add that Minnesota has recorded only two cooler than normal winters in the last 8 years, the most recent being 2013-1014. Further over the last 20 years only 5 years have brought cooler than normal winters. The NOAA Climate Prediction Center produced a video to explain the Winter Outlook.


NOAA scientists are teaming up with leaders from the construction trades to see if some of the seasonal outlook models can provide useful tools for the timing and deployment of people and equipment doing large-scale construction projects, especially those undertaken in the winter season. One goal is to see whether or not the risk of a damaging rain, win, or Heat Wave can be priced and factored into the time-table for construction contracts in a better way. A more detailed description of this effort can be found on the NOAA Climate.Gov web site.


In the Western Pacific Ocean this week Typhoon Lan was spinning and growing in strength south of Japan. It was producing winds over 115 mph and sea wave heights of 35-40 feet. It may affect southern Japan over the weekend with high winds and heavy rains. More information can be found at the Joint Typhoon Warning Center web site.

http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/satshots/25W_201200sair.jpg

A recent study from Canada published in EnvironmentInternational shows the risk of heart failure increases in the elderly during cold weather. The study showed that a significant drop in temperature over a 3-7 day period can raise the risk of heart failure among the elderly. This study was based on over 100,000 elderly people studied over the period from 2001-2011.

MPR listener question:


I see many parts of the state are forecast to reach 80 degrees F on Friday (Oct 20). How often does the daytime temperature get that high in October?

Answer:


In the Twin Cities climate record (back to 1872) a reading of at least 80 degrees F or greater has occurred with a frequency of about every two years, not all that uncommon. The last such reading in the Twin Cities record was October 11, 2015 when 85 degrees F was recorded. Readings of 85°F or higher during October are far less common in the Twin Cities climate record, occurring about once every 5 years. At Grand Rapids, MN an 80°F temperature reading in October occurs about once every three years, while at International Falls this happens about once every six years.

Twin Cities Almanac for October 20th:


The average MSP high temperature for this date is 56 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 38 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for October 20th:

MSP records for this date include: highest daily maximum temperature of 83 degrees F in 1953; lowest daily maximum temperature of 32 degrees F in 1930; lowest daily minimum temperature of 18 degrees F in 1960; highest daily minimum temperature of 61 degrees F in 1920; record precipitation of 2.64 inches in 1934. Record snowfall on this date is 3.0 inches in 1916.

Average dew point for October 20th is 37°F; the maximum dew point on this date is 66°F in 1920; and the minimum dew point on this date is 8°F in 1952.

All-time state records for October 20th:


The all-time state high temperature for today's date is 91 degrees F at Canby (Yellow Medicine County) in 1947; the all-time state low for today's date is -1 degrees F at Argyle (Marshall County) in 1916. The all-time state record precipitation for this date is 3.95 inches at Chaska (Carver County) in 1934. Record snowfall is 10.0 inches at Detroit Lakes (Becker County) in 1906.

Past Weather Features:


October 19-21, 1906 brought a winter storm to northern Minnesota where 4 to 10 inches of snow fell. This was one of the earliest heavy snows in state history.

A strong winter storm brought snow to most parts of the state over October 18-19, 1916. Following the storm the coldest temperatures ever reported in the state on October 20th and the earliest seasonal reading of subzero occurred. Argyle (Marshall County) reported a low of -1°F, whiel Angus (Polk County) and Roseau reported a reading of zero degrees F. Several other locations reported lows in the single digits. It was the start of a long, cold, and snowy season.

October 20-21 brought heavy rain to portions of Minnesota. Many climate stations reported 2 to 4 inches of rain which brought an abrupt halt to farmers field work. The rain was one of the heaviest of the Dust Bowl decade.

By far the warmest October 20th in state history was in 1947 when over 30 communities reported an afternoon high temperature of 80 degrees F or greater. Five climate stations reached the 90°F mark. In the Twin Cities even the overnight low temperature never fell below 55 degrees F that day.

October 20-21, 2002 brought some heavy snows to many parts of the state. Many observers reported 4 to 8 inches of heavy wet snow.

Outlook:


Moderating temperatures over the weekend, still above normal but not as warm as earlier in the week. There will be a chance for showers and thunderstorms Saturday, then drier, cooler, and sunnier on Sunday with some strong winds. Temperatures will continue a little above normal next week with the occasional chance for showers.






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