/Issued 4:22 PM CDT, Monday, July 2, 2018/
Source: http://www.wpc.ncep.noaa.gov
Greatest chance for a few severe thunderstorms tonight is over the Brainerd Lakes area with isolated strong to severe thunderstorms possible in the marginal risk area.
Isolated strong to severe thunderstorms are possible Tuesday mainly north of a line from Brainerd to Duluth to Two Harbors.
Source: http://www.pivotalweather.com
Note: Here are two mesoscale/convection allowing models showing how things could evolve tonight into Tuesday morning.
12z HRW WRF-NSSL model (7.2.2018)
Simulated Radar Forecast from 7 PM this evening to 1 PM Tuesday.
Source: http://www.pivotalweather.com
18z 3km-NAM (7.2.2018)
Simulated Radar Forecast from 7 PM this evening to 1 PM Tuesday.
•Flash Flood Watch in effect from 8 PM this evening through Tuesday morning for parts of the Northland (Green area on map)
•Significant rainfall has fallen over parts of the Northland over the past 24 to 36 hours leading to moist soils.
•Thunderstorms are expected to develop and become more numerous tonight, and storms could track over the same areas leading to heavy rainfall.
•Rainfall potential of 2 to 4 inches with localized higher amounts possible.
Weather Synopsis
We started the day with a lot of sunshine but changes are happening quickly this afternoon as moisture and instability begin to build north, and one sign of that occurring is the mid level cloud deck which has been moving E/NE into the Northland this afternoon. There have been some echoes showing up on radar imagery as well this afternoon but most of this is just virga or rain that isn’t reaching the ground. It was a mild early July day with highs today in the upper 70s to lower 80s.
Tonight and Tuesday:
A warm front will lift north out of south central Minnesota tonight, this front is expected to lift into northern Minnesota on Tuesday. Moisture will continue to increase tonight thanks to a southwesterly low level jet of around 30 to 40 knots. Instability will also increase with elevated CAPE of 500 to around 1500 j/kg. Showers and thunderstorms should become more widespread in portions of Northland this evening or during the overnight hours, and this activity could continue through Tuesday morning — Thunderstorms could track over the same areas which will increase the risk of heavy rainfall and flash flooding late tonight into Tuesday morning. It does appear that the greatest potential for heavy rain and flooding for tonight and Tuesday will be over parts of north central and east central Minnesota into northeast Minnesota with a lesser risk across northwest Wisconsin. It’s uncertain exactly where storms will setup tonight into Tuesday morning with conflicting model data this afternoon, some models show things a little farther south impacting the Duluth area, while others have it staying mainly west/north of Duluth.
Lows tonight will be in the upper 50s to upper 60s with highs Tuesday in the 70s and 80s but it will be cooler at times near Lake Superior.
Independence Day:
Low pressure deepens over central Manitoba Province with a cold front extending south of that low into western Minnesota. Potentially very moist and unstable airmass near and east of this cold front on Wednesday with one or more rounds of showers and thunderstorms with a threat for strong to severe thunderstorms and heavy rainfall. Highs on the 4th of July are forecast to be in the 70s and 80s with some locations in northwest Wisconsin possibly getting into the lower 90s, cooler temps expected near Lake Superior.
Note: It will be turning muggier over the next few days with dew points in the mid 60s to mid 70s Tuesday and Wednesday in northeast Minnesota and northwest Wisconsin.
Normal Temperatures for Tuesday at Duluth, Minnesota
High: 75
Low: 54
Sunrise Tuesday: 5:20 AM CDT
Sunset Tuesday: 9:06 PM CDT
Tim