Friday, June 17, 2016

June 17, 2016: Humid with a chance of showers and thunderstorms this weekend some of which could be strong to severe

/Issued 4:29 PM CDT, Friday, June 17, 2016/

Saturday's severe weather outlook.  Source, WSI; Storm Prediction Center.

Sunday's severe weather outlook.  Source, Storm Prediction Center.

Low temperature forecast for tonight.  Source, National Weather Service Duluth, Minnesota.

High temperature forecast for Saturday.  Source, National Weather Service Duluth, Minnesota.

Slight risk 5-10% chance for rainfall to exceed flash flood guidance on Saturday in northern Minnesota and far northwest Wisconsin (Green outlined area on map)  Source, Weather Prediction Center.

Preliminary rainfall reports for June 17, 2016

International Falls, MN:  0.28"
Littlefork, MN:  0.29"
Effie, MN:  0.24"
Cass Lake, MN:  0.22"
Walker, MN:  0.27"
Longville, MN:  0.13"
Brainerd, MN:  0.32"
Grand Rapids, MN:  0.13"
Orr, MN:  0.23"
Cook, MN:  0.04"

Weather Summary for NE Minnesota and NW Wisconsin
Date:  June 17, 2016

Showers and thunderstorms have moved farther east into the Northland this afternoon than what was forecast 24 hours ago.  This activity has been occurring to the north of an area of extreme instability analyzed over southwest Minnesota, eastern South Dakota and eastern Nebraska where late afternoon surface-based CAPE ranged from 3000-7000 j/kg; This along with a warm and moist advection pattern has led to an area of rain and thunderstorms today over north central Minnesota, the majority of the storms have been under severe criteria in our area today but heavy rainfall and lightning have been common.  Severe thunderstorms with wind damage and hail have been occurring this afternoon across portions of west central and southwest Minnesota with a lot more instability for the storms to work with in that part of the state compared to areas farther north.  Highs today in areas that had rain were generally in the 60s while 70s and lower 80s were common in locations that have not had rain today.  Dew points late this afternoon were in the 55-65 degree range so it has turned a little more humid than Thursday.  Winds were generally variable in direction at 5 to 15 mph.

Forecast Discussion for NE Minnesota and NW Wisconsin

Confidence:  Low to Medium.

Tonight:  Scattered showers and thunderstorms could develop at times as a cold front moves southeast into northeast and central Minnesota.  Otherwise expect mostly cloudy to partly cloudy skies with lows in the 50s and 60s.  Winds light and variable at around 10 mph.

Saturday:  Cold front which moves into central and northeast Minnesota tonight stalls out and turns into a warm front -- This boundary will lift slowly north and is forecast to reach the Ontario-Minnesota border by daybreak on Sunday.  A warm, moist and unstable airmass will be found over the Northland tomorrow and with a front over us the potential exists for a few rounds of showers and thunderstorms.  A few of the storms could become strong to severe with a threat of hail and gusty winds.  Highs are forecast to be in the 70s and 80s, cooler along the North Shore of Lake Superior.  Lows will be in the 60s to lower 70s.  South or east winds are expected at 10 to 15 mph.

Note:  Thunderstorms that develop through Saturday night will be capable of producing locally heavy rainfall as dew points will be in the 60s to around 70 degrees with PWATS of 1.20-1.80".

...Extended Forecast...

Very warm and muggy on Sunday with highs in the 80s to lower 90s.  Dew points will range from 65 to around 75 degrees.  A cold front approaching from the west-northwest could help to generate a few strong to severe thunderstorms especially late Sunday afternoon or Sunday evening.  A morning round of thunderstorms is also possible mainly targeting northern Minnesota the way it looks now.

Cooler and less humid on Monday with highs in the 70s.

Forecast for Duluth and Superior

Tonight - Mostly cloudy.  A few showers possible.  Low 58 to 63, a little cooler closer to Lake Superior.  Wind variable around 10 mph.

Saturday - Humid.  Scattered showers and thunderstorms possible.  Considerable cloudiness although some peeks of sun is possible.  High 72 to 77 but cooler near Lake Superior.  Wind southeast at 10 to 15 mph.

Normal temperatures for Saturday

High:  72
Low:   50

Sunrise Saturday:  5:14 AM CDT
Sunset Saturday:   9:06 PM CDT