/Issued 7:22 AM CDT, Friday, August 31, 2018/
…Flash Flood Watch in effect for parts of northeast Minnesota and northwest Wisconsin from this evening into Saturday morning, this flash flood watch does include the cities of Duluth and Superior.
Note: A flash flood watch means that flash flooding is possible in or close to the watch area.
09z RAP model
12z HRRR model
Radar forecast valid from 1 PM today to 4 AM Saturday.
This model shows scattered thunderstorms developing by mid or late afternoon over north central/western areas of Minnesota, storms would then move generally toward the east this evening.
Scattered showers and thunderstorms have been occurring early this morning mainly in northwest Wisconsin into far eastern Minnesota, heavy downpours and some lightning have been the main threats from these storms. A warm advection pattern has been the main driving force behind this early morning convection.
We’re looking at a muggy final day of August across the Northland with dew points today in the 60s, possibly up around 70 degrees this afternoon in southern portions of the area.
Surface map at 8 AM had a cold front draped from far northwest Minnesota to central South Dakota with a SW mid/upper level flow covering the northern Plains and upper Midwest as energy digs E/SE out of the northern Rockies.
An area of higher instability is already in place across the upper Midwest this morning, and this area of instability will remain over the area through this evening with CAPE from 1000 to around 3000 J/kg along with very steep mid level lapse rates from 7.0 to around 8.5 c/km. Mid and upper level winds and the amount of wind shear combined with the strong instability and the approach of a cold front and any possible disturbance moving into our area will provide the necessary lift for thunderstorm development with a few strong to severe thunderstorms possible from mid or late afternoon and through the evening hours.
Damaging winds and large hail will be the main threats if severe storms develop later today.
Heavy rain is also possible with PWATS in the 1.50 to 1.90 inch range late this afternoon/evening. If storms start to move over the same location for a few hours, that would increase the potential for flash flooding.
Otherwise for today we can expect mostly cloudy skies, although some breaks in the clouds are certainly possible at times, highs will range from the upper 60s to upper 70s.
Note: Saturday is looking like a nicer day around here with some sun especially by the afternoon, highs are forecast to be in the 70s, not bad at all for the first day of September!