Wet Start to July Continues a Trend

Wet Start to July Continues a Trend:

Through the first six days of July thunderstorms have brought 1 to 3 inches of rain to many parts of the state. On July 3-4 heavy thunderstorms occurred causing some flash flooding, road closures, and ponded crop fields, as well as cancellation or postpone of some 4th of July events. Southwestern Minnesota was especially hard hit with many observers reporting rainfall totals of 3 to 7 inches. A couple of places in Redwood County reported over 7 inches. For many southwestern counties all of this recent rain came on top of getting 8 to 12 inches just last month (June). As a consequence many rivers there are running above flood stage and some roads and bridges remain closed.

On July 3rd Marshall received a new record daily amount of rain with 4.71 inches, while Redwood Falls receive a new record amount of 5.25 inches. Renville also had a record 4.32 inches.

Many areas have also reported strong thunderstorm winds, ranging from 50 to 70 mph. You can read more about these storms at the Minnesota State Climatology Office.

Weekly Weather Potpourri:

NOAA reports this week that a water shut-off policy threatened to occur in Cape Town, South Africa earlier this year due to prolonged drought, has been postponed. Thanks to water conservation practices and above normal precipitation during the March-May period, officials there have delayed the implementation of the water shut-off policy.

Typhoon Maria is being monitored in the Western Pacific Ocean. It has winds of well over 140 mph and is producing sea waves of 30-35 feet or greater as it slowly makes its way toward China, where it may arrive early next week with heavy rain and wind near Shanghai.

The American Geophysical Union EOS newsletter features an article this week about how climate model data sets are becoming more standardized to allow for more intercomparisons and to better understand the forcing and mitigating parameters that govern climate change.

The United Kingdom Met Office reported this week that many parts of England, Scotland, Wales, and Ireland reported a near historical warm and dry month of June. Some areas barely recorded any rainfall at all, with parts of southern England reporting less than a half inch for the month.

MPR listener question:

Murray County is a mess with so much water. Something I’ve noticed with these storms is that they have been moving north, or even back building like they are moving east to west. Is this a common feature of heavy rain events? What’s the record for 30 day rainfall in the state? We have to be getting close to yearly rainfall totals in some areas in a matter of 3 or 4 weeks.

Answer:

It is not uncommon for some of the heaviest rains to occur associated with a stalled or slow moving warm front that is draped across southern Minnesota from west to east. This type of system delivered record rainfalls across southern Minnesota in July and August of 1978, June and July of 1993, August of 2007, and September of 2010. As for setting records, many climate stations in southern Minnesota have reported 23 to 27 inches of precipitation so far this year (a little over half way through the year), and indeed this is a record-setting pace if it keeps up. Normal amounts for a whole year range from 28 to 34 inches. The maximum one-month rainfall in Minnesota history was 23.86 inches at Hokah (Houston County) in August of 2007.

Twin Cities Almanac for July 6th

The average MSP high temperature for this date is 84 degrees F (plus or minus 8 degrees F standard deviation), while the average low is 64 degrees F (plus or minus 6 degrees F standard deviation).

MSP Local Records for July 6th:

MSP records for this date include: highest daily maximum temperature of 104 degrees F in 1936; lowest daily maximum temperature of 60 degree F in 1972; lowest daily minimum temperature of 49 degrees F in 1942; highest daily minimum temperature of 77 degrees F in 1988; record precipitation of 2.83 inches in 2015. No snowfall has occurred on this date.

Average dew point for July 6th is 60°F; the maximum dew point on this date is 77°F in 1928; and the minimum dew point on this date is 36°F in 1934.

All-time state records for July 6th:

The all-time state high temperature for today's date is 114 degrees F at Moorhead (Clay County) in 1936; the all-time state low for today's date is 30 degrees F at Cotton (St Louis County) in 1969. The all-time state record precipitation for this date is 5.30 inches at Minnesota City (Winona County) in 1978. No snowfall has been reported on this date.

Past Weather Features:

By far the hottest July 6th in state history was in 1936 with 114 degrees F at Moorhead. The temperature that morning started out at 68 degrees F, so it climbed 46 degrees F during the day.
Over 60 climate stations across the Minnesota landscape reached a temperature of 100 degrees F or greater that day.


Over July 5-6, 1978 slow moving thunderstorms brought 3 to 7 inches of rainfall across portions of southeastern Minnesota. The city of Rochester was especially hard hit with the Zumbro River leaving its banks and flooding many parts of downtown. This flash flood was followed by another the next month in August which also devastated Rochester. As a result, the channel of the Zumbro River through Rochester was re-designed to protect the city from flooding.

July 6, 1997 brought frost to many parts of northern St Louis County, including Tower and Embarrass. Both of these locations in Minnesota have a probability of frost for any day of the year.

Outlook:

Very nice weekend, starting out with sunny skies and cooler than normal temperatures. Warmer on Sunday, with increasing cloudiness and a chance for showers and thunderstorms Sunday night into Monday. Then near normal temperatures. Increasing temperatures by Wednesday and Thursday with a chance for showers returning.