Update on river flood warnings; temps ramping up this week

Our high temperatures will be ramping up this week due to a warmer weather pattern, plus shrinking snow cover. At least our overnight lows will be dropping below freezing for several hours each night, which taps the brakes on the snowmelt a bit.

There isn’t any big rain or snow in our forecast this week.

Temperature trends

Tuesday highs are expected to reach the lower 40s in much of eastern Minnesota and western Wisconsin:

Temperatures in the 40s will be widespread on Wednesday:

Highs in the Twin Cities metro area could hit the 50-degree mark on Thursday, followed by the mid-50s on Friday.

By the weekend, most of the metro area snow cover is expected to be melted, and we could reach the upper 50s. On Sunday, there could be more clouds and a few scattered showers, but we’ll still top out in the 50s.

Rain and snow

Areas of fog are possible overnight Monday night and early Tuesday in Minnesota and western Wisconsin. North-central and northeastern Minnesota could see a few flurries overnight Monday night into early Tuesday.

Southwestern Minnesota could see some scattered showers on Tuesday, and the northeast will have a chance of light snow showers Tuesday evening.

The National Oceanic and Atmospheric Administration’s North American Mesoscale forecast model shows the potential precipitation pattern Tuesday:

NOAA NAM simulated radar from Tuesday and Tuesday evening, via tropicaltidbits

As always, updated weather information can be heard on the Minnesota Public Radio Network, and you’ll also see updated weather info on the MPR News live weather blog.

Flooding update

Some new flood warnings, with various start times, were issued by the National Weather Service on Monday.

A flood warning starts late Monday night for the Minnesota River at Henderson, Minn. A flood warning starts late Tuesday night for the Minnesota River in Jordan, Minn., and a flood warning starts Thursday evening for the Minnesota River at Savage, Minn.

You can get flood warning updates by clicking on any location on the NWS Twin Cities website. Areas with flood warnings are shaded green on their main page, and here’s how the map looked late Monday afternoon:

NWS Twin Cities

The very light green area that includes Fergus Falls, Minn., in the upper left of the map, isn’t a warning. It’s just an update on snowmelt:

Hydrologic Outlook
National Weather Service Grand Forks ND
114 PM CDT Mon Mar 18 2019

…FAVORABLE MELT CONDITIONS TO CONTINUE FOR THE CURRENT WEEK…

Generally favorable melt conditions are expected to persist through
the week. Temperatures will top out in the mid to upper 30s at the
beginning of the work week but will gradually warm into the 40s by
the weekend. Weekend temperatures could potentially reach into the
lower 50s across the far southern Red River Valley and the upland
valley fringes. These temperatures will aid in ripening the snowpack
across the region but with low temperatures dipping back well below
the freezing mark, water is not yet expected to begin making its way
into the river system.

No major weather systems are expected to impact the region through
the end of the work week.

A switch to a more active weather pattern is possible heading into
the last week of March. Trends are being monitored for a weather
system to potentially impact the region late in the weekend/early
next week. This system could bring snow, rain, or a mix of
precipitation types to somewhere across the Northern Plains but it
is far too soon to pinpoint any specifics at this time.

An updated thaw progress statement will be issued on Thursday, March
21st regarding the status of the spring snowmelt and future flood
potential.

You can also click on any location on the NWS Advanced Hydrologic Prediction Service  (AHPS) site to get hydrographs of recent and forecast river levels. Some locations list levels in feet above sea level, others list levels in feet above a local reference point.

As of Monday evening, this was the hydrograph for the Mississippi River at St. Paul, which is expected to rise more than 7 feet by late Sunday:

NOAA/NWS/USGS

The Mississippi River will continue to rise at St Paul and at several other locations, as we go through next week. Based on probabilities issued by the NWS earlier this month, there is a 95% chance that the Mississippi River will reach the 17.5 foot level at the St. Paul gauge this spring, and there’s about a 58% chance of reaching 22.5 feet:

NOAA/NWS

What do these river levels mean? Near the bottom of each AHPS page it gives a summary of several river crest impacts for each site. Here are the listings for St. Paul:

NOAA/NWS/USGS

Major flood levels likely in Fargo in April

The Grand Forks, N.D., office of the National Weather Service is showing a greater-than-90-percent chance of the Red River exceeding major flood stage (30 feet) at Fargo this spring:

NWS Grand Forks

The NWS North Central River Forecast Center, headquartered in Chanhassen, shows a 50 to 75 percent chance of reaching major flood stage at Fargo, N.D. during the first week of April, and a greater-than-90-percent chance during the second week of April:

NWS North Central River Forecast Center

Temperature and precipitation patterns will lead to river level forecast updates over the next few weeks.