Windy then cool

Windy then cool:

For many parts of Minnesota last Saturday through Monday (August 22-24) was the windiest 3-day period this summer, as well as the windiest period since mid-April.  Average wind speeds for all hours ranged from 15-20 mph, and peak gusts each day ranged from 35 to 45 mph around the state.  From the stand point of normal climate conditions for August, this was a highly unusual period fueled by the passage of a strong low pressure system across the state and into Canada, a pattern more commonly seen in the late autumn period.

In the Twin Cities area from noon on August 22nd to 5pm on August 24th over half of all hours MSP reported a mean wind speed over 20 mph, with peak wind gusts over 45 mph.  Other stations reporting wind gusts over 45 mph included Rochester, Ely, Crookston, and Hallock.  Both Elbow Lake (Grand County) and Flag Island (Lake of the Woods County) reported wind gusts over 50 mph, not good for those fishermen out on Lake of the Woods. 

One positive dimension to this unusual windy period was that persistent smoke from Canada's summer wildfire season was temporarily flushed out of the state.  Also following the passage of the low pressure system cooler air from Canada with much lower dew points brought some morning low temperatures in the 30s F to International Falls, Cass Lake, Grand Rapids, Thorhult, Brimson, Cotton, Floodwood, Kabetogama, Orr, Tower, and of course Embarrass (just 33°F).  The cool air mass also brought some record cold maximum temperatures to a few Minnesota communities including 58°F at Cotton and Cass Lake on the 24th, and even more on August 25th which included a very chilly 49°F at Isabella, 51°F at Ely, Cook, and Tower, 56°F at Bruno (Pine County), and 58°F at Isle (Mille Lacs County).

State Fair Weather:

The 12-day run of the Minnesota State Fair has begun at the Fairgrounds in St Paul.  For those who are interested I will be there at noon on Friday, August 28th for the broadcast of TPT's Almanac program, live from the Minnesota Public Radio Booth (corner of Judson and Nelson), and again at 11am on Friday, September 4th at Carousel Park for an MPR broadcast of the Minnesota Weather Quiz with host Tom Weber.  I will also be doing a book signing (for 2nd Edition of Minnesota Weather Almanac) from noon to 1pm that day.

As for weather during the State Fair:  the historical average daytime temperatures are in the upper 70s to lower 80s F, with nights ranging from the upper 50s to low 60s F.  It typically rains on 3-4 days during the fair.  Current modeled forecasts favor near normal temperatures this weekend, warming to above normal conditions most of next week, with a cool down and chance of showers and thunderstorms for the Labor Day weekend.

Record climate values for the State Fair include:  a high temperature of 104°F on September 10, 1931; a low of 33°F on September 13, 1890; and rainfall of 4.06 inches on August 30, 1977.  Much more on the weather history of the Minnesota State Fair can be found at the DNR-State Climatology Office.

Twin Cities Dew Point Climatology:

Pete Boulay of the DNR-State Climatology Office has recently updated the dew point climatology for the Twin Cities.  There have been some days with dew points above 70°F this summer, and a maximum dew point of 76°F in the Twin Cities, but conditions have been far short of the oppressive summers of  2002, 2010, and 2011.

Weekly Weather Potpourri:

Hurricane Ignacio was heading for Hawaii this week, producing winds over 90 mph and sea wave heights of 25-35 feet.  It may bring heavy rains and high seas to the islands by early next week.  Right behind it is Hurricane Jimena which is expected to strengthen considerably next week, and hopefully track north of the Hawaiian Islands.   In the Atlantic Ocean Tropical Storm Erika was bringing heavy rains to the Bahamas and heading toward Puerto Rico.  It appears that this storm will bring heavy rains to south Florida by Monday, moving north through the state from there.

For school science teachers and others who might be interested there is a new educational video available on "Climate Change in the Arctic Region" and how it is affecting the indigenous Inuit population. The video runs for about 6 minutes and tells the story of the people there and the changes going on. 

Earlier this week, NOAA reviewed a recent study on “climate change implications for wildfires” across the USA.  Climate change is likely to increase the frequency of very large fires according to recent study of the output of 17 climate models.  Those regions which may see the most increase include the Mountain West, the northern Great Lakes, and some of the coastal southeastern state.

A new study from Columbia University has documented that warming temperatures have worsened the prolonged drought in California.  The warming temperatures have increased the water use demand from both the state's vegetation and its infrastructure.  Average temperatures have generally increased in California since 1901 by about 2.5F and this has contributed to the increased water demand. 

MPR Listener Question:

What do you think has been the most significant weather event in Minnesota this summer?

Answer:

This is difficult, so difficult I have decided to voice a tie for most significant in my opinion.  (1) The weather pattern of May and early June was a blessing in that it completely wiped out the drought in Minnesota, going from 94 percent of the landscape in drought to start May, and finishing with zero percent of the landscape in drought for early June. This pattern helped set up an ideal growing season for Minnesota farmers.  (2) The other most significant weather feature was the Heat Wave followed by the Derecho storm on Sunday, July 12.  Afternoon dew points spiked in the 70s and even 80F sending Heat Index Values above 100°F in many places (111F at St James) that day.  Then severe thunderstorms formed a cluster in west-central counties and began to move across the state. There were reports of brief tornadoes in Wilkin, Grant, and Otter Tail Counties, but much more widespread damage was inflicted by Derecho straight-line winds which were estimated to range from 60 to 100 mph.  The central lakes region around Brainerd, Baxter and Pelican Lake saw widespread tree damage and power outages.  Pillsbury State Forest was hit especially hard.  Insured and uninsured losses, along with infrastructure repair and lost tourism revenues total well into the millions of dollars.  This was a storm that will be long remembered.

Twin Cities Almanac for August 28th:

The average MSP high temperature for this date is 78 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 60 degrees F (plus or minus 7 degrees F standard deviation).

MSP Local Records for August 28th:
MSP weather records for this date include: highest daily maximum temperature of 94 degrees F in 1899 and 1955; lowest daily maximum temperature of 61 degrees F in 1935: lowest daily minimum temperature is 42 degrees F in 1934; highest daily minimum temperature of 75 F in 1969; record precipitation of 1.11 inches 1950; and no snowfall has been recorded on this date.

Average dew point for August 28th is 59 degrees F, with a maximum of 77 degrees F in 1955 and a minimum of 34 degrees F in 1946.

All-Time State Records for August 28th:

The state record high temperature for this date is 104 degrees F at Canby (Yellow Medicine County) in 1937. The state record low temperature for this date is 21 degrees F at Tower (St Louis County) in 1986.  State record precipitation for this date is 6.00 inches at Litchfield (Meeker County) in 1960; and there has not been any snowfall on this date.

Past Weather Features:

The terrible growing season of 1934 (Heat Wave and Drought) brought an early frost to many areas on August 28th.  Many northern Minnesota communities reported morning low temperatures in the 20s F, and frost was observed as far south as New Ulm.  For many farmers this concluded what was already a disastrous growing season.

Strong and widespread thunderstorms brought heavy rainfall to the state over August 28-29, 1960.  Many observers reported 2 to 4 inches of rainfall from these storms, including over 6 inches at Litchfield, with some local flash flooding.

Over August 27-28, 1984 many Minnesota weather observers reported record-setting high temperatures.  Several climate stations in the Red River Valley reached 100°F, and even Gunflint Lake reported 96°F.  Thunderstorms and an associated cold front dropped the temperatures back into the 70s F by the end of the month.

Baseball size hail fell at Pequot Lakes on August 28, 1989, causing some damage to cars and buildings in the area.

Outlook:

Warming over the weekend to above normal temperatures with plenty of sunshine.  Continued warm for much of next week as well with a chance for showers late Tuesday and into Wednesday.  Chance for showers and thunderstorms over the Labor Day Weekend with cooler temperatures by Labor Day.