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Extension > Mark Seeley's WeatherTalk > Rare 90 F days emerge this week

Thursday, August 13, 2015

Rare 90 F days emerge this week

Rare 90 F days emerge this week:



August 12 brought record-setting high temperatures to portions of North Dakota with Williston and Dickinson reported a new record high of 102 degrees F.  August 12 and 13 also brought some daytime temperatures of 90 degrees F or greater to western parts of Minnesota.  This is not that unusual historically for this time of year, but in the context of this summer 90 F days have been somewhat rare.  Daytime highs of 91 degrees F were reported from Crookston, Moorhead, and Browns Valley this week, while Park Rapids, Wadena, Fosston, Hallock and Appleton all reported highs of 90 F. 

For the summer of 2015 temperature readings in the 90s F have indeed been infrequent.  I have already commented about this feature in the Twin Cities urban heat island where there have been only two days with 90 F or higher temperatures this summer, compared to a historical average of 14 days.  In other portions of Minnesota the same temperature pattern has prevailed.  Historically Crookston and Moorhead show an average of 10 days with 90 F or greater temperatures by this date, but they have only reported one such day so far.  Even at Montevideo, one of the warmest places in the state, the daytime high has only reached 90 degrees F or greater 5 times this summer, while the historical average is 17 days.  So you can clearly say that farm crops have benefited from the relative lack of heat stress this summer (so far).

Weekly Weather Potpourri:


This week brought a number of heat advisories and excessive heat warnings to portions of western states, the southern plains, and southeastern states as temperatures soared above 100 degrees F in many areas.  Energy demand for air conditioning climbed to record levels for two consecutive days in the Atlanta, GA area.  In Washington state the temperature climbed to 106 degrees F at Ellensburg and 103 degrees F at Kennewick.  Daytime temperatures climbed to 105 degrees F in parts of Arkansas and Louisiana, and up to 106 degrees F in parts of Mississippi and Oklahoma. 

NOAA scientists offered an El Nino Update this week.  The forecast calls for continued El Nino conditions through the autumn and into the early winter season when it is expected to peak.  It is likely to be one of the strongest El Nino episodes since 1950. As such this El Nino will be utilized as a forecast tool for the autumn and winter seasonal climate outlooks across the USA.

Portions of southern Italy reported very damaging flash floods this week as severe thunderstorms brought 6 to 8 inches of rain over a very short period of time to Calabria.  Especially hard hit was the city of Rossano where roads were washed out and cars swept away.

MPR Listener Question:

I am a weather observer in Mankato and I have noticed that the average daily temperature reading has been higher so far in August than it was during July, normally my hottest month of the year.  How often does it happen that August is a warmer month than July?

Answer:

This is perhaps more common than you think.  Examining the climate records for Mankato back to 1955 (past 60 years), August has been warmer than July 14 times, or about 23 percent of all years.  In the Twin Cities, which has a longer climate record (over 140 years) August has been warmer than July nearly 25 percent of all years, most recently in 2014.

Twin Cities Almanac for August 14th:


The average MSP high temperature for this date is 81 degrees F (plus or minus 7 degrees F standard deviation), while the average low is 62 degrees F (plus or minus 5 degrees F standard deviation).

MSP Local Records for August 14th:

MSP weather records for this date include: highest daily maximum temperature of 96 degrees F in 1978; lowest daily maximum temperature of 65 degrees F in 1887: lowest daily minimum temperature is 43 degrees F in 1964; highest daily minimum temperature of 72 F in 1938, 1970, and 1978; record precipitation of 1.00 inches 1981; and no snowfall has been recorded on this date.

Average dew point for August 14th is 60 degrees F, with a maximum of 76 degrees F in 1978 and a minimum of 32 degrees F in 1933.

All-Time State Records for August 14th:

The state record high temperature for this date is 105 degrees F at Hawley (Clay County) in 1984. The state record low temperature for this date is 25 degrees F at Tower (St Louis County) in 1977.  State record precipitation for this date is 5.29 inches at Gaylord (Sibley County) in 1981; and there has not been any snowfall on this date.

Past Weather Features:

Between 5pm and 6pm on August 14, 1914 an F-2 tornado (winds 113-157 mph) was on the ground for 20 miles between Morris and Hancock in western Minnesota.  It damaged or destroyed 30 farms and killed one farmer.  In addition many grazing animals, including cattle were killed. 

August 14, 1964 brought damaging frost to many parts of northern Minnesota.  Bigfork reported a morning low of 27 degrees F while Cook reported 28 degrees F.  In southeastern Minnesota frost was reported in Theilman (Wabasha County) and at Preston (Fillmore) where the corn crop was damaged and had to be harvested for silage.

One year later brought the hottest August 14th of all-time.  In 1965 over 30 Minnesota communities reported an afternoon temperature of 95 degrees F or greater, and at 8 communities the thermometer broke 100 degrees F.  The August Heat Wave of 1965 ran from the 11th to the 15th, ending abruptly with thunderstorms that dropped temperatures into the 60s and 70s F around the state late on August 15th.

Over August 14-15, 1981 strong thunderstorms crossed over southern Minnesota counties bringing hail, high winds, and heavy rainfall to many areas.  Numerous observers reported between 2 and 3 inches of rainfall, while New Ulm received over 4 inches and Gaylord reported over 5 inches.

Outlook:

Warm over the weekend with temperatures in the 80s and 90s F.  A chance for showers and thunderstorms Sunday and into Monday.  Near normal temperatures with a chance for more showers and thunderstorms by Wednesday and Thursday next week.


 

 


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