July 2011 Saint Cloud Weather Summary

No July Hotter in St. Cloud Since 1936

Loads of Wind Damage and Heavy Rain, But No Tornado Record This Year

Tied for 8th Warmest July in St. Cloud Records

After a July that disappointed fans of summer weather (21 consecutive days without a high of at least 80°F), July lived up to the hot summer reputation, something that has been missing from many recent summers. The average July temperature at the St. Cloud Regional Airport was 75.1°F, 3.9°F warmer than the new 1981-2010 normal. That tied July 2006 for the 8th hottest July in St. Cloud records. Before 2006, there hasn't been a July that warm since 1936, the hottest July in the 118 years of St. Cloud temperature records.

Finally, A Heat Wave After 4 Years Without One

St. Cloud began July with a 96°F high, which would have been the hottest temperature of the previous three years, but we did have a 101°F high on June 7, still the hottest temperature of the summer. However, the key heat was during July 16-20. St. Cloud had 4 straight days with a high of at least 90°F during this time, both the first and the longest St. Cloud heat wave (three consecutive days with a high of at least 90°F) since September 3-6, 2007. Recently, however, St. Cloud did have a 9-day heat wave on July 23-31, 2006, topped off with the previous 100°F high before this June on the 31st. The record heat wave in St. Cloud was set on July 5-18, 1936, with 14 consecutive highs of at least 90 degrees.

There were a total of 8 July days with a high of at least 90°F, nearly double the average number of 4.7 and the most since July 2006 when there were 15 days with such warm highs. So far in the summer of 2011, St. Cloud has had 11 days with a a high of at least 90°F, which is the normal amount for the entire summer. In St. Cloud's recent past, the summer of 2006 had 20 days with a 90-degree high and the extremely hot summer of 1986 had 33 days, the third highest total in St. Cloud records.

Record Moisture in Parts of Minnesota

However, what made this July's heat more difficult to overcome was the high humidity throughout. The Minneapolis-St. Paul International Airport set a record with an 82°F dew point on July 19. Statewide, the amount of moisture was incredible with several long-term cooperative stations setting dew point records. The dew point was actually higher in Moorhead, hitting a greenhouse like 88°F, which combined with a 93°F temperature to produce an incredible heat index of 130°F. That dew point, however, didn't agree with other area dew points. Local sources, such as a very heavy rainfall earlier in the morning and having the sensor close to soybean and corn crops, which put out moisture due to the food-making process. However, oppressive dew points ruled several times through that period, producing heat indices as high as 117°F in St. Cloud on July 19.

Dew point is the best measure of moisture in the air, since it only changes as the amount of moisture changes. Relative humidity cannot directly determine the amount of water vapor in the air since it changes with both moisture and temperature. So, the relative humidity during a blizzard (near 100%) can be higher than our most humid day (our worst heat index was produced by a temperature of 94°F and a dew point of 82°F, which produces a relative humidity of only 68%, even though there was nearly 16 times more moisture in the air in the July heat wave).

Historic Streak of Warm Lows

Unfortunately, St. Cloud does not have an extensive history of dew point readings because the station did not report between 9 PM and 5 AM when the observation required a human to read it. As a proxy for high dew point events, I have researched the history of low temperatures exceeding 70°F in St. Cloud. During July 16-20 of this year, St. Cloud had 5 straight days with a low of at least 70°F. There have been only 21 streaks of at least 3 straight days since St. Cloud temperature records began in 1893. That tied for the third longest streak of such warm lows with June 1931 and July-Aug. 1955. Once again, the longest streak happened during the July 1936 heat wave with 8 straight lows of at least 70 degrees. In total, there have been 6 July days with a low of at least 70 degrees, the most since July 1941. For the summer so far, St. Cloud has had 7 lows of 70 or higher, which ties 2005.

On July 17, the low temperature was a sultry 75 degrees. This marked only the 53rd time in St. Cloud history that there was a 75 degree or warmer low. That's more rare than 100 degree highs (this June 7 was the 59th occurrence).

Even though there were only two more 90-degree highs and no more 70 degree lows after July 20, St. Cloud did not have a high below 80 degrees for the final 17 days of July and only two lows below 60 degrees in the last 18 days of the month. Still, this was only a small taste of the heat and humidity that has stayed in the Southern Plains during most of the summer. For example, Oklahoma City has had 38 days with a high of at least 100 and two straight months (61 days) with a high of at least 90 degrees.

Overall, the average July low in St. Cloud was 64.0°F. That's the 6th warmest average July low out of 115 years. The only 5 years that had a warmer July low were 1936 and earlier. On the other hand, the average high temperature of 86.2°F ranked only tied for 14th warmest. There were hottest high July temperatures in 1974, 1975, 1988, and 2006 within the past 40 years. The last 17 days of this July had highs of at least 80 degrees, but that came on the heels of a record cold high on July 14. Thanks to persistent clouds from thunderstorms, the high was only 68°F.

You Want a Hotter July? Ask Grandma

July of 1936 in St. Cloud was the hottest month in St. Cloud records with an average temperature of 78.9°F more than a degree higher than the second place July. That was nearly four degrees hotter than this July. Included in July 1936 was arguably the worst heat wave in St. Cloud records. Between July 5-18, there were 14 straight days with a high of at least 90 degrees. Nine of those highs, none cooler than 98 degrees, still stand as record highs. That includes the 107°F high on July 13, 1936, tied with two other days for St. Cloud's hottest temperature on record.

In addition, the heat wave produced 8 straight days with lows of at least 70 degrees, still the record for consecutive 70-degree highs. The lows during July 8-14 each set the record for the daily warm low.

Rainfall Deluge Continued in July

While St. Cloud more frequently got into the very warm and humid air during July, we spent most of the month near the border between the edge of the searing air mass to the south and slightly cooler air to the north. That put the Dakotas, Minnesota, Nebraska, Wisconsin, and Iowa frequently in the path of large thunderstorm complexes. There was a total of 5.63 inches of rain in July at the St. Cloud Airport, more than two inches over the 1981-2010 average July rainfall of 3.31 inches. That made July 2011 the 12th wettest July on record, just a quarter inch short of cracking the 10 wettest Julys. It was the wettest July in St. Cloud since 1997 when 6.89 inches fell.

Since the growing season began on April 1, the St. Cloud Airport has picked up 16.16 inches of rain, 3 inches more than normal. However, given the localized nature of the heavy rainfall, some areas nearby have picked up far more. (St. Cloud managed to dode the thunderstorms for most of the last two weeks of the month, picking up "only" 1.05 inch. Nearly all of central Minnesota has at least 25% more rainfall than average with southeastern Stearns County, northern Wright and Meeker Counties in the wettest 5% of growing seasons so far. Becker, in particular, has been more than 4 inches above average during the past 4 weeks and 7.31 inches above normal for the growing season.

The frequent rainfall produced another 11 days with measurable rainfall in July. So far in 2011, 5 of the 8 months, including the last 4, have had at least 10 days with measurable rainfall. Through 7 months, there have been 80 days with measurable rain, the third most in St. Cloud records behind only 1979 and 1963. There have been 44 days with at least 0.10 inch of rain, the 6th most in St. Cloud records.

The summer of 2011 has not had the record number of Minnesota tornadoes that last summer produced, including the 45 tornadoes, 4 of them being EF-4, on June 17. However, July 2011 had several days with prolific severe weather, mostly dominated by strong straight-line winds and flooding rainfall.

July 1 - Waite Park Tornado and Derecho in N. St. Cloud and east

St. Cloud and Waite Park were hard hit by the combination of a weak tornado and a long-lived straight line wind damage event. The tornado which was on the ground from the I-94/Hwy. 23 interchange to Division Street west of the Parkwood 18 Theater, ended up being rated EF-0 (got to do some scrolling from there) with top winds estimated at 65 MPH. The north side of St. Cloud into Sauk Rapids and northern Benton County had widespread straight line wind damage with winds estimated at 65-70 MPH. This was one of several tree downings associated with the derecho described below.

The thunderstorms took the form of a pair of lines of thunderstorms that moved from central South Dakota across central and southern Minnesota. The northern one, that took on the shape of a comma, became a "bow echo," a typical radar signature for a line of storms producing widespread wind damage. Damaging winds were reported as high as 80 MPH in Marshall, 78 MPH in Redwood Falls, and 71 MPH in the Big Lake area. A lot of damage has been reported in Redwood Falls, Sacred Heart, Danube, and many other locations, but the general path of wind damage was in two large lines. The northern one from eastern South Dakota through central Minnesota to the Ashland, Wisconsin, area was long enough to be considered a derecho, a long-lived line of straight line wind damage. Other long-lived straight line. Heavy rain, as much as 2.75 inches in 2 hours in Sartell, and large hail were also reported (baseball sized near Dassel and Monticello, one stone 4 1/4 inches in diameter (softball-sized). There have been no confirmed tornado touchdowns, since this type of storm tends to produce mostly straight-line wind damage.

Other longer-lived examples of straight-line wind damage in Minnesota include the July 4, 1999 storm that cut a swath of wind damage from Fargo through the Boundary Waters and a July 1, 1997 that produced wind damage from central Minnesota to Michigan, including major damage in Big Lake and $10 million damage in Monticello.

The St. Cloud Airport picked up 1.00 inch of rain and wind gusts up to 54 MPH. The temperature also plunged from 88 degrees just in advance of the storm to 68 degrees in 36 minutes between 5:27 and 6:03 PM. At SCSU, there was 1.44 inches of rain. There were 2.83 inches of rain on the west side of St. Cloud, leading to flooding.

There was also a lot of tree damage in St. Croix State Park.

July 10 - Sauk Centre Straight Line Wind Damage

Sauk Centre had winds estimated of up to 90 MPH with about 200 trees knocked over. There was scattered wind damage in a path from Ortonville through Columbia Heights and Forest Lake, although the swath of damage wasn't as wide or as consistent as in the July 1 storm. One small tornado was found along the Kandiyohi-Meeker county line. It was only on the ground for about 20 seconds.

July 19 - Straight Line Wind Damage On the Edge of Record Dew Points In Milaca, Foreston, Ronneby

A particularly nasty complex of thunderstorms blew up just before sunrise in the Red River Valley and pushed east southeastward during the morning hours . Areas affected by this storm complex have seen heavy rainfall with 2-3 1/2 inches in 30-60 minutes reported in Fargo-Moorhead, Detroit Lakes, and Sabin. There were wind gusts up to 64 MPH in Casselton, ND, and large hail. There was also heavy tree damage in parts of Morrison, Benton (Ronneby), Sherburne (Zimmerman), Mille Lacs (Milaca, Foreston) and Anoka counties. Top winds were clocked at 58 MPH in Princeton and 59 MPH in Anola. and northern Morrison Counties. Even the St. Cloud Airport had a gust of up to 36 MPH, despite the storm missing here. Note the gust front (light blue appendage to the southwest of the storm just to the south of Buffalo).

The storm in northeastern Minnesota also dropped some large hail in Carlton County and produced wind gusts up to 45 MPH in Duluth.

July 30 - Wind Damage in Milaca, Bock; Tornado near Dalbo

Two large complexes of severe thunderstorms moved through central Minnesota near sunset on Saturday. The western system produced some large hail near Donnelly and Eagle Bend to the northwest of Stearns County, and in Sauk Centre. However, a large swath of damaging winds hit from southern Mille Lacs County into Isanti County. This included a tornado from southeastern Mille Lacs County to west of Dalbo. Winds were estimated as strong as 70-80 MPH from this EF-0 tornado. There were also straight line damaging winds at about the same time which was the worst around Bock. Winds clocked up to 60 MPH in Milaca.

In St. Cloud proper, the storms left a gap right over the city, so only a trace of rain fell at the Airport and nothing at SCSU, marking a continuation of the Thursday through Saturday weather which saw storms all around us, but little more than a sprinkle hitting us. The St. Cloud deflector lives!

Effect on Area Agriculture

The heavy rain has continued to slow the agricultural progress, although the heat at times in July helped growers. The latest Minnesota Crop Weather Report shows only 22% of the topsoil with surplus moisture. That's down considerably from the 50% seen on June 27. Basically, the heat of the second half of the month allowed many crops to catch up for earlier time, if the fields hadn't been damaged by earlier flooding. Corn silking is now up to 83%, just short of the 85% average. There are many puddles still standing on farm fields.

August Starting Off Hot and Drenchy

Persistent thunderstorms have caused a bunch of problems with flash flooding and wind damage on August 1 with storms producing a wind gust of 63 MPH on August 2. Then the weather will calm down and dry out for the bulk of this week. Still, it's hard to go more than 3 days in this pattern without a decent chance of thunderstorms.

Still, the searing heat in the southern Plains will likely continue for much of this month, barring the landfall of a hurricane on the Texas or Mexico coast.

New 30-Year Normals Announced

July 2011 also marked the release of the new 30-year averages, encompassing the years 1981-2010. The result is that the decade of the 1970's were dropped and the decade of the 2000's were added to produced the new normals. The new averages show a large increase in temperatures with the biggest gains in our part of the country, especially for low temperatures and cool season temperatures. This is due, in large part, to the very warm cold season temperatures of the late 1990's and early 2000's, while very cold winters like 1977-78 and 1978-79 dropped out of the averages.

While data from a single station cannot be considered proof of global warming, it is consistent with the globally observed temperature trend, featuring a sharp rise from the late 1970's to the early 2000's. This warming is larger than the accepted 20th century warming during 1900-1940.

The St. Cloud averages actually show increases in average temperature in every month but May with the biggest increases in the winter months. That is consistent with the computer forecasts of global warming; warming will be largest during the cold season and near the poles. There has also been an increase of precipitation by about half an inch, most notably in the spring and fall. This is also consistent with the forecasts of increased precipitation at high latitudes in a globally warmed atmosphere. However, the snowfall did fall, especially in January, but during all winter months in general.

    July 2011 Statistics