Thursday, August 11, 2016

August 11, 2016: Recap of Wednesday's heavy rain/flood event that hit parts of Minnesota; Areas of fog tonight; Risk for scattered showers/isolated t-storms through Friday

/Issued 5:37 PM CDT, Thursday, August 11, 2016/

Source, Midwest Regional Climate Center

Heads up if you have travel plans to far southeast Minnesota or far southwest Wisconsin -- The image below is a short term graphical nowcast issued by the La Crosse, Wisconsin National Weather Service ( 1 PM today)

Heavy rain has led to difficult to possibly dangerous travel across Wabasha, Buffalo, and Trempealeau. Law enforcement reports secondary roads are washed out in many areas, and water continues to rise across roads as the rivers swell. Avoid this area if possible.

Forecast for Duluth and Superior

Normal temperatures for Friday

High:  75
Low:   55

Sunrise Friday:  6:03 AM CDT
Sunset Friday:   8:23 PM CDT

Rainfall reports for August 10-11, 2016
Source:  National Weather Service Duluth, Minnesota

Aitkin County

1 S of Hill City, MN:  1.16"
1 NNE of Palisade, MN:  0.77"
Aitkin, MN:  0.44"
Libby, MN:  0.22"

Carlton County

1 SSW of Pleasant Valley, MN:  1.44"
3 WNW of Mahtowa, MN:  1.14"
Wrenshall, MN:  0.89"
2 SW of Moose Lake, MN:  0.87"
1 ESE of Esko, MN:  0.39"
1 NE of Cloquet, MN:  0.28"

Cass County

2 ENE of Sylvan, MN:  1.60"
Cass Lake, MN:  0.35"
Walker, MN:  0.28"

Cook County

4 NE of Grand Portage, MN:  0.52"
Hovland, MN:  0.33"
4 W of Grand Marais, MN:  0.12"

Crow Wing County

Brainerd, MN:  2.09"
7 NW of Brainerd, MN:  1.29"
2 ENE of Gull Lake, MN:  1.22"
1 SW of Breezy Point, MN:  0.87"
1 N of Baxter, MN:  0.75"

Itasca County

12 N of Grand Rapids, MN:  0.40"

Koochiching County

Grand Falls, MN:  0.11"
Northome, MN:  0.08"

Lake County

1 S of Silver Bay, MN:  6.58"
Silver Bay, MN:  4.18"
1 W of Silver Bay, MN:  4.16"
1 NW of Beaver Bay, MN:  4.11"
Wolf Ridge, MN:  0.91"
Two Harbors, MN:  0.35"
25 E of Ely, MN:  0.13"

Pine County

2 N of Greely, MN:  2.38"
6 ESE of Cloverdale, MN:  1.69"
1 WSW of Willow River, MN:  1.20"

St. Louis County

3 SSE of Little Swan, MN:  1.70"
1 SE of Brimson, MN:  1.44"
Embarrass, MN:  0.80"
Skibo, MN:  0.66"
Taft, MN:  0.47"
Makinen, MN:  0.46"
Chisholm-Hibbing, MN (Airport)  0.38"
Floodwood, MN:  0.33"
Cook, MN:  0.31"
2 N of Lester Park, MN:  0.29"
1 WSW of Lester Park, MN:  0.28"
Duluth, MN (NWS)  0.27"
Duluth, MN (Airport)  0.26"

Ashland County

3 N of Butternut, WI:  1.34"
2 SE of Bayfield, WI:  0.80"
Glidden, WI:  0.79"
Ashland, WI (Airport)  0.36"

Bayfield County

5 NW of Sand Bay, WI:  1.61"
9 N of Bayfield, WI:  1.41"
11 W of Drummond, WI:  1.15"
11 SSE of Brule, WI:  1.11"
Bayfield, WI:  0.77"
4 W of Clam Lake, WI:  0.70"
Washburn, WI:  0.30"

Burnett County

3 NE of Randall, WI:  1.75"
Danbury, WI:  1.49"
6 ENE of Hertel, WI:  0.64"

Douglas County

1 S of Hawthorne, WI:  1.27"
Gordon, WI:  1.20"
3 ENE of South Range, WI:  0.61"
South of Superior, WI:  0.61"
1 NNW of Superior, WI:  0.46"
2 ENE of Oliver, WI:  0.44"
Superior, WI (Airport)  0.42"

Iron County

1 WSW of Saxon, WI:  1.34"

Price County

4 SE of Phillips, WI:  1.20"
Park Falls, WI:  0.78"
Phillips, WI:  0.40"

Other rainfall reports

Hayward, WI:  0.61"
Bruno, MN:  1.14"
Gordon, WI:  1.20"

Rainfall totals from outside the Northland for August 10-11, 2016
Source:  NWS Chanhassen, MN

5 N of Willmar, MN:  8.09"
Willmar, MN:  7.90"
3 N of Willmar, MN:  7.87"
6 WSW of New London, MN:  3.09"

2 N of Olivia, MN:  8.78"
5 SE of Lake Lillian, MN:  7.12"
Olivia, MN:  6.54"
Redwood Falls, MN:  4.95"
Owatonna, MN:  4.38"
Montevideo, MN:  4.29"
3 W of Bay City, MN:  4.15"

Recap of last night's event:

Most of the Northland missed out on the excessive rain totals with one small exception to this, that being along the North Shore of Lake Superior, generally centered on the Silver Bay area where flash flooding developed Wednesday evening due to a quick 3-6" of rain.

I think the main reason why the heavier rains missed most of the Northland was the fact that the warm front was farther south than what was expected earlier in the day.  The warm front never really made it much farther north than the Twin Cities -- Thunderstorms developing along and slightly north of that boundary likely kept this front from being able to lift any farther north during the night.

The one thing I find interesting about last night was the small scale flood event that did develop over and near the city of Silver Bay along the North Shore of Lake Superior -- I'm thinking there may have been another boundary up in that area, perhaps an 850mb front which helped to focus a west-east band of thunderstorms producing torrential rainfall for a few hours Wednesday evening.  Lake Superior didn't block those storms from hitting the North Shore, and weather conditions were similar up the shore as they were in the Twin Ports, actually temperatures were slightly warmer in Duluth than they were up in Silver Bay last evening...Both locations had a gusty NE wind coming right off the lake.  But one area was hit hard (Silver Bay) and the other location only picked up around a quarter to half inch of rain (Duluth) Very interesting!

In closing - I don't think Lake Superior played a part on why the Twin Ports missed out on the heavy rain last night.  I think it came down more to where the actual boundaries were located as to what areas saw heavy rain and flooding Wednesday night.

Weather Summary for NE Minnesota and NW Wisconsin
Date:  August 11, 2016

A humid day but temperatures weren't too warm thanks to the abundant cloud cover across the Northland, however, there has been some clearing at times especially over northern/western portions of the area.  Highs today were in the 70s to around 80 degrees with 60s near Lake Superior.  Dew points were mostly in the 60s today and winds were variable in direction at around 10 mph.  The surface map late this afternoon was a mess and featured low pressure of 1010mb over southeast Manitoba Province; low pressure of 1008mb over western Upper Michigan and also over eastern Nebraska.  There's a stationary front stretching from far southern Minnesota to central Wisconsin to central Upper Michigan.  A cold front was over the eastern Dakotas and there was a trough extending from southern Manitoba Province to northeast Minnesota to northern Wisconsin.

Forecast Discussion for NE Minnesota and NW Wisconsin

Tonight (August 11)

Areas of fog otherwise generally mostly cloudy skies although some clearing could occur from time to time.  A chance for showers or thunderstorms mainly over western portions of the Northland.  Low pressure will remain over Manitoba Province tonight while another low moves into Iowa.  Low temperatures will be in the 50s and 60s with south or east winds at 5 to 15 mph.

Friday (August 12)

Areas of fog possible mainly during the morning otherwise mostly cloudy to partly cloudy with a chance for scattered showers or thunderstorms.  Low pressure centers will remain to our northwest and south on Friday while a surface and upper level trough heads into the Upper Midwest.  Highs on Friday will be in the 70s to lower 80s with 60s near Lake Superior.  Lows Friday night will be in the 50s and 60s.  Variable to east wind at 5 to 15 mph.

Note:  Thunderstorms that do develop into Friday could produce heavy downpours and some lightning but severe weather is not expected.

Extended Forecast

Saturday and Sunday (August 13-14)

Can't rule out a few spotty showers on Saturday as cold air aloft and a mid/upper level trough remain over the area, most of us should remain dry though.  Highs on Saturday and Sunday are expected to be in the 70s, possibly near 80 degrees in a few locations.  Lows Saturday night and Sunday night should be in the 50s and 60s.