Luck of the Irish Today/New Flood Outlook

Happy St. Patrick’s Day! What an amazing day it is with temperatures in the 60s thanks to strong southwest winds. This makes three years in a row with great weather on St. Pat’s day. I hope everyone was able to enjoy it. Can’t rule out a sprinkle this evening, but should not be too big of a deal.

The new spring flood outlook came out today. Not good news for the upper midwest. Take a look at the forecast.

Note that all of Wisconsin has an above average chance of flooding. This should not come as a surprise with the snowpack that much of the state had. The western part of the state has the best chance of flooding, especially along the Mississippi River.

Here is what the National Weather Service says about our area:

Above Average and High Flood Risk Areas

North Central U.S. and Upper Mississippi River

Heavy late summer and autumn precipitation (twice the normal amount since October in parts of North Dakota and Minnesota) had left soils saturated and streams running high before the winter freeze-up.  NWS models show this year’s snowpack contains a water content ranked among the highest of the last 60 years.  The combination put a large portion of the North Central United States at risk of moderate to major flooding this spring, extending from northeastern Montana through western Wisconsin and along the Mississippi River south to St. Louis.

Information provided by NOAA on March 3, 2011 indicated Fargo, N.D. has a near 95 percent chance of exceeding major flood stage of 30 feet. At a stage of 30 feet, portions of downtown Fargo begin flooding and temporary dike construction is necessary. Approximately a 35 percent chance exists of reaching or exceeding the 40.8 foot record set in 2009. Grand Forks, N.D. has about a 95 percent chance of exceeding major flood stage of 46 feet. A series of storm systems are forecast to move across the region during the next two weeks, which could bring additional snow or rain on top of the remaining snowpack. These systems may cause substantial runoff and the beginning of minor flooding in the southern headwater portion of the Red River of the North, eventually leading to major flooding sometime from the last week of March through early April.

There is approximately a 25 percent chance of Devils Lake, ND exceeding 1,455 feet, which could partially inundate portions of the town of Minnewauken, including critical infrastructure and roads across the lake, emergency service routes and possibly a small section of the Amtrak train line.

There is potential for moderate to major flooding on the Milk River and its tributaries in northeastern Montana.  The Milk River at Tampico (near Glasgow Montana) has about a 95 percent chance of exceeding the major flood stage of 27 feet.  Some minor ice jam flooding is already occurring in Montana; additional major flooding resulting is expected this spring. 

The James River at Huron, SD has about a 95 percent chance of exceeding major flood stage of 15 feet and a 25 percent chance of exceeding the record 21.2 foot level set in 1997. The Big Sioux River at Brookings, S.D., has a greater than 95 percent chance of exceeding major flood stage of 12 feet and about a 50 percent chance of exceeding the 14.77-foot record set in 1969. Warm temperatures in the forecast this week could cause much of the snowpack to melt across South Dakota, setting off moderate to major flooding in eastern South Dakota next week.

The Mississippi River is likely to see major flooding beginning in late March from its headwaters near St. Paul, Minnesota, downstream to St. Louis. St. Paul, MN has about a 95 percent chance of exceeding major flood stage of 17 feet, where secondary flood walls are deployed to protect the St. Paul Airport. Further downstream, there is a 75% chance (3 out of 4 chance) for major flooding on the Upper Mississippi River from Winona, MN, to Keokuk, IA.   Most points from south of  Keokuk to Winfield, MO (about 60 river miles upstream of St. Louis) have greater than a 50% chance of major flooding.  Warm temperatures in the forecast this week could cause much of the snowpack to melt across southern Minnesota. Minor flooding could begin this week on the Mississippi River and its tributaries over southeastern Minnesota and southwestern Wisconsin, leading to moderate to major flooding by early April.

The Mississippi River has a 95% chance of exceeding major flood stage. Rivers are already above flood stage and will get worse as the spring rains arrive.

Now, on to our forecast for next week. We have been talking about the return of the “signature storm” for quite some time. After looking at the models again today, I don’t think they have a firm grip at what is likely to happen in the middle of next week. The GFS and European model have a weaker storm hitting us Tuesday and Wednesday, but this seems way too washed out.

I am not putting too much credence into the models yet. What I find interesting is that the GFS had a much stronger low forecast a few days ago. I still believe we will have a strong storm in the middle of the week. It will likely start as rain, but don’t be surprised by rain changing to snow on Wednesday.

Have a safe St. Patrick’s Day! It is always a day I look forward to because I started at Channel 12 14 years ago today. Slainte.

Mark