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Continued warm and dry pattern

Continued warm and dry pattern

Despite the recent cool down temperatures so far this month are averaging from 3 to 6 degrees warmer than normal in most places. A brief respite occurred on Thursday and Friday this week (Sept 12-13) as a cool, dry Canadian air mass brought many overnight lows in the 30s F with much lower dewpoints. Perhaps we have seen the last of the 90 F temperatures, though it looks like next week daytime highs in the 80s F could return briefly with higher dewpoints and chances for thunderstorms.

Most of the state has seen drier than normal weather continue to prevail this month, especially in southern counties where rainfall totals are mostly less than a quarter of an inch. A few scattered spots in the north report above normal rainfall thanks to heavy, but widely scattered thunderstorms, including 3.64 inches at Fergus Falls, 3.08 inches at Long Prairie, 3.00 inches at Kabetogama, 2.83 inches at Ottertail, 2.32 inches at Grand Portage, and 2.30 inches at Brainerd.

The dry pattern has amplified and extended drought on the Minnesota landscape. Moderate or severe drought now extends over 55 percent of the state, and severe drought has been extended down along the bluff country in the Mississippi River Valley from Lake City to Winona. Some southern and central Minnesota communities have seen rainfall totals that are 6-7 inches below normal since July 15th. Further, according to the NOAA-Climate Prediction Center the extent of drought is expected to expand across southern parts of Minnesota over the remainder of September.

A salute to Coop observers Steve and Nancy Potter of Long Prairie, MN

The "Senior Perspective" a monthly news publication serving 35 counties in west-central Minnesota recently highlighted the activities and contributions of Steve and Nancy Potter, Cooperative weather observers for the National Weather Service near Long Prairie, MN (Todd County). Not only do they make daily weather observations on their farm, but they also contribute to the National Phenology Network, taking observations of lilacs, maples, and basswoods to assess seasonal variability as it might relate to climate change. Congratulations to Steve and Nancy on this recognition. The article can be found here.

Lyle Schaller retires

A long time colleague, Lyle Schaller of the National Weather Service in Chanhassen, MN retired this month after 51 years of federal service, most of which was with NOAA. He was a hydrometeorological technician responsible for measurement systems and data management, including instrumented balloon launches (radiosondes). He was especially generous with his time when I took groups of teachers through the National Weather Service and asked him to explain their operations. Lyle transferred from Sault St-Marie, MI to MSP National Weather Service Forecast Office in 1975, and later made the move to Chanhassen with the rest of the NWS staff. He has probably launched more weather balloons than anybody in the history of the National Weather Service. I am sure he will be missed and wish him all the best in his retirement. Thanks for your service Lyle.

Climate Change Adaptation Conference at the Science Museum on November 7, 2013

Several organizations are partnering to host the first statewide conference on Climate Change Adaptation, Planning and Practice. It will take place at the Science Museum of Minnesota in downtown St Paul on November 7, 2013. Registration for the all day program is only $50. Sessions will be devoted to city planning, agriculture, transportation, natural resources (including watershed management), and public health.

Weekly Weather potpourri

From Brad Rippey of the USD World Agricultural Outlook Board: Highlights for the drought-monitoring period ending 7 am EDT on September 10 include:
-Overall U.S. moderate to exceptional (D1 to D4) drought coverage increased (up 0.60 percentage point) to 50.69%. Exceptional drought (D4) was affecting 1.25% of the continental U.S., unchanged from week ago.
-Hot, mostly dry weather in the Corn Belt led to further increases in drought overage. Drought coverage in the nine-state Midwestern region increased from 8 to 32% during the 3-week period ending September 10. Drought currently covers 72% of Iowa, 55% of Minnesota, 43% of Wisconsin, 40% of Illinois, and 31% of Missouri.
- In the 3-week period ending September 10, corn in drought more than doubled from 25 to 55%. During the same period, soybeans in drought nearly tripled from 16 to 45%, hay in drought increased from 33 to 41%, and cattle in drought rose from 46 to 55%. With winter wheat planting underway (5% complete nationally by September 8), it’s useful to note that nearly half (45%) of the production area was in drought on September 10.

Humberto, the 8th named Tropical Storm of the Atlantic Hurricane Season became the first real hurricane of 2013 this week when its wind speeds increased to 85 mph. It remains far to the east of any islands or mainland areas. The NOAA NHC is also monitoring a low pressure area in the Gulf of Mexico which may become a tropical storm this weekend and bring heavy rains to Mexico. In the Western Pacific Ocean Tropical Storm Man-yi is expected to bring some heavy rain to portions of Japan early next week.

Thunderstorms late Wednesday night (Sept 11th) and early Thursday (Sept 12) brought heavy rains and flash flooding to parts of Colorado. The NWS had to issue numerous flash flood warnings as observers scattered from Fort Collins to Colorado Springs reported rainfall totals ranging from 4 inches to over 10 inches by Friday morning. Many creeks and rivers were overflowing and causing damages to roads and residences. The University of Colorado campus in Boulder was closed down. Scattered showers and thunderstorms were expected to prevail throughout the weekend as well.

Disparities in the climate change signals of Western Europe are documented in a paper published in Environmental Research Letters this week. Researchers from the London School of Economics and the University of Warwick analyzed temperature data sets from 1950 to the present and found regional differences in the rates of warming. The hottest part of the year, summer, has warmed the fastest in southern England, northern France, and Denmark. Conversely, there has been little warming detected in daytime summer temperatures in Norway and Sweden. The authors attempt to show regional differences in the temperature trends by season as well. You can read more here.

MPR listener question

How many hours was the dewpoint at 70 degrees F or higher this year in the Twin Cities? I have heard you talk about this and how it often leads the National Weather Service to issue a Heat Advisory.

Answer: So far, and this is likely to be close to the final number, MSP has reported 246 hours in 2013 with a dewpoint of 70 degrees F or higher. This is well above the historical average and over the past 68 years (since 1945) ranks as the 15th highest annual value (the highest being 512 hours in 2002). What is unusual about this year is that the majority of hours with such high dewpoints (including a record setting value of 77 degrees F on August 27th) occurred later in the year (late August and early September), and not in late June to early August as normally happens.

Twin Cities Almanac for September 13th

The average MSP high temperature for this date is 70 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 53 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 13th

MSP weather records for this date include: highest daily maximum temperature of 95 degrees F in 1939; lowest daily maximum temperature of 51 degrees F in 1873; lowest daily minimum temperature is 33 degrees F in 1890; highest daily minimum temperature of 72 F in 1939; and record precipitation of 1.29 inches in 1921; No snow has been recorded on this date.

Average dew point for September 13th is 49 degrees F, with a maximum of 71 degrees F in 1939 and a minimum of 22 degrees F in 1923.

All-time state records for September 13th

The state record high temperature for this date is 100 degrees F at Redwood Falls (Redwood County) in 1939. The state record low temperature for this date is 17 degrees F at Roseau (Roseau County) in 1975. State record precipitation for this date is 4.10 inches at Theilman (Wabasha County) in 1978; and no snow has fallen on this date.

Past Weather Features:

Frost on September 13, 1923 brought an end to the growing season in many agricultural areas of the state. Many observers reported overnight lows in the 20s F, even in southern counties of the state. Red River Valley areas fell into the teens. Some crops were damaged by the early frost.

A 3-day Heat Wave prevailed from September 13-15, 1939, producing the some of the hottest mid-September temperatures in state history. The vast majority of observers reported record-setting highs in the 90s F, and at least 10 Minnesota cities reported daytime highs of 100 degrees F or greater. Even Two Harbors along the shores of Lake Superior reached a high of 94 degrees F.

September 14, 1964 is the earliest fall date when a measurable amount of snowfall was reported in the state. This happened at International Falls, though it was very short-lived as the daytime high rose to 59 degrees F the next day.

Thunderstorms brought record-setting rainfalls to many parts of the state over September 12-13, 1978. Rainfall totals ranged from 3 to 6 inches, with the heavier amounts in southeastern counties, where the Zumbro River went beyond flood stage. Many roads were flooded. It was the 8th and last major flash flood of the year 1978. Golf ball size hail fell in some areas and lightning started a large fire in Alexandria, MN.


Near normal temperatures over the weekend with a chance for scattered showers, especially on Saturday night. Generally unsettled weather next week with frequent chances for showers (Tue-Thu) and a warming trend in temperatures by Wednesday. Cooler again by next weekend.
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