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Up and Down Temperatures Start August

Up and Down Temperatures Start August:


Temperatures the first few days of August were highly variable, especially from south to north. Both Redwood Falls (100°F) and Marshall (101°F) reached the century mark on the thermometer on August 2nd, while later that day when so many citizens were out gathering for “National Night Out” an influx of dew points above 70°F raised the Heat Index Values from 102°F to 115°F. Over 50 Minnesota communities reported such high Heat Index Values. The Minnesota DNR State Climatology Office provides a good summary of the temperatures and Heat Index Values for August 2nd.

Then two days later, Kabetogama, Brimson, Tower, and Embarrass were just 44°F on the morning of August 4th. Overall temperatures have been average warmer than normal for the first five days of the month.

In terms of rainfall, most places in the state have reported little so far this month. But both August 1 and August 3 brought widely scattered, but strong thunderstorms to some parts of the state. For those areas affected by these storms, some record or near record daily rainfall amounts were reported, including:
2.56 inches at Chisholm 0.4 WSW
1,74 inches at Two Harbors 9.7 NNE
1.67 inches at Iron Junction 3.4 NNW
1.26 inches at Brimson 2S
1.28 inches at Knife River 1.2 N

Then August 3 brought some heavy rainfalls to a few, including:
1.44 inches at Tower 3S
1.22 inches at Babbitt
1.15 inches at Embarrass
1.06 inches at Wolf Ridge ELC

According to the US Drought Monitor portions of 13 central Minnesota Counties (including the Twin Cities Metro Area0 are in Severe Drought now, while over 25 southern and central counties are in Moderate Drought. Further, according to the National Agricultural Statistics Service, just over a third of the Minnesota corn and soybean crops are rated in poor to just fair condition, mostly as a result of the dryness.

The NOAA Climate Prediction Center models continue to show a likelihood of warmer than normal temperatures and less than normal rainfall prevailing across Minnesota through the first half of August.

Weekly Weather Potpourri:

This week NOAA features an interesting article about the effects of El Nino on salmon in the Northwest Pacific Ocean. There are several significant effects that impact the fishing industry.

The United Kingdom Met Office reported this week that the month of July was the driest across England since 1935. Average rainfall across the country was less than one inch. Some parts of southern England reported less than 0.20 inches for the month. As a result watering restrictions were being applied to many areas this month.

According to the Midwest Climate Center the July rainfall totals for portions of eastern Missouri were staggering, and record-setting in many cases. Several climate stations reported monthly total rainfall ranging from 10 inches to over 16 inches. According to NOAA 37 new daily record rainfall amounts were reported form the Missouri climate station network, including 9.20 inches at Elm Point (northwest of St Louis) on July 26th. In addition many climate stations in Kentucky reported record or near-record rainfall totals for July, ranging from 12 to 18 inches. Kentucky remained under a National Weather Service Flood Watch and Flood Advisory through the first week of August, as rains continue there.

An interesting email discussion took place among State Climatologists this week, commenting on the association of high dew point measurements in the Midwestern States during the months of July and August. A research paper in 2007 published by the National Weather Association documented that evapotranspiration of corn and soybean crops can indeed affect local atmospheric moisture conditions, especially when these crops are at full canopy cover and healthy with plenty of rootzone moisture to take up through the roots. High dew points can often occur during this period of time as a result, as peak water use by these crops exceeds the peak water use of native prairie grasses and small grains that used to dominate the Midwestern landscape.

MPR listener question:

After hearing you talk about historical rainfall in Itasca County last week, we wondered about August rainfall in the Twin Cities. Can you tell us what years brought the fewest and the most rainy days in August, and what is the average number of rainy days during the month?

Answer:

Sure. The most ever rainy days in August for the Twin Cities occurred in 1980 when 18 days brought rain (all light amounts as the monthly total was only 3.26 inches). The wettest August in Twin Cities history was in 2007 with a monthly total of 9.32 inches (10 rainy days, some with heavy rainfall). The fewest number of rainy days in August came in 1925 when only two days brought rain (a meager total of 0.20 inches). August of 1920 was the driest in Twin Cities history. The average number of days that bring rain in August for the Twin Cities is 10.

Twin Cities Almanac for August 5th:

The average MSP high temperature for this date is 82 degrees F (plus or minus 6 degrees F standard deviation), while the average low is 64 degrees F (plus or minus 6 degrees F standard deviation).

MSP Local Records for August 5th:

MSP records for this date: highest daily maximum temperature of 100 degrees F in 1947; lowest daily maximum temperature of 67 degrees F in 1912; lowest daily minimum temperature of 48 degrees F in 1994; highest daily minimum temperature of 78 degrees F in 1947; record precipitation of 1.88 inches in 1898. No snow has been reported on this date.

Average dew point for August 5th is 60°F; the maximum dew point on this date is 79°F in 2001; and the minimum dew point on this date is 33 degrees F in 1910.

All-time state records for August 5th:


The state record high temperature for this date is 105 degrees F at New Ulm 2SE (Brown County) in 1947. The state record low temperature for this date is 31 degrees F at Brimson (St Louis County) in 1994. The state record precipitation for this date is 4.75 inches at Albert Lea (Freeborn County) in 1945. No measurable snowfall has occurred on this date.

Past Weather Features:


Strong thunderstorms brought heavy rains to southern Minnesota on August 5-6, 1898. Climate observers in Rice, Renville, Cottonwood, Kandiyohi, and Brown Counties reported 3 to 5 inches of rainfall. Some farm fields were washed out.

On a statewide basis, August 5, 1947 was the warmest in history for Minnesota. Most places saw afternoon temperatures reach the 90s F, but 9 counties reported a maximum temperature of 100°F or greater. The coolest spot in the state was Grand Marais Harbor with a reading of 62°F.

The morning of August 5, 1994 brought the coolest temperatures ever measured on the date in Minnesota. Many northern communities reported temperatures in the 30s F. Both Tower and Brimson reported just 31°F. The afternoon high temperature at Lutsen only reached 61°F.

Outlook: 

Chance for significant showers and thunderstorms this weekend, especially Saturday and Saturday night. Continued chance for showers on Sunday, but with cooler temperatures. Temperatures will generally be a bit below normal for Monday and Tuesday of next week, then warming up to above normal values by Wednesday and Thursday, as well as going into next weekend.


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