Wet and stormy: multi-inch storm waves this week

Minnesota has a way of skipping seasons. One week it's snowing. The next we're under siege with multiple waves of showers and thunderstorms.

Our overnight light and thunder show was mostly sub-severe for the Twin Cities. Some borderline severe 1-inch diameter hail fell across the northern Twin Cities.

• 2 NNE Blaine [Anoka Co, MN] PUBLIC reports HAIL of quarter size (M1.00 INCH) at 5:55 AM CDT

Stronger storms rumbled  south of the metro overnight. Hail greater than 1 inch in diameter pelted Owatonna, Minn., overnight. The quarter in the photo below is about 1 inch in diameter.

Multiple low-pressure waves

A series of low-pressure waves triggers multiple rounds of thunderstorms this week. Storm coverage will be spotty today, then more numerous storms and downpours fire again overnight and into Wednesday.

The National Oceanic and Atmospheric Administration's High-Resolution Rapid Refresh future radar model seems to have a good handle on the overall storm picture through tonight. A few scattered, quick hitting thundershowers fire today. More organized storm waves rumble into southern Minnesota tonight.

Slight severe risk

NOAA's Storm Prediction Center paints a slight risk for s few severe storms across Minnesota today. The best chance for widespread severe weather is south of Minnesota.

Steamy air mass today

Southern Minnesota busts out into a warm and steamy air mass this afternoon.

Dew points in the 60s make it feel humid out there today. We may bust into sunshine this afternoon. That should be enough to send temps into the 80s across southern Minnesota. Temps will push 90 degrees along the Iowa border today. Welcome to July.

Heavy rainers

Local downpours will occur during the storm waves this week. Many towns will pick up 2 to 4 inches of rainfall by Wednesday night. Flash flooding is a distinct possibility.

Flash flood potential

NOAA issues flash flood guidance based on factors like current soil moisture and topography. Rainfall rates of one to two inches of rain in an hour will be enough to trigger flash flooding in many Minnesota counties this week.

Flash Flood Guidance products are issued on a twice-daily basis at about 11 a.m. and 9 p.m. Central Time. National Weather Service Weather Forecast Offices (WFOs) use this guidance when issuing flash flood watches and warnings to the public. It should be noted that these values are meant to be used only as guidance. Topography and/or urbanization in some areas are also contributing factors to flash flooding.

Flash Flood Guidance is used to predict the occurrence of flash flooding in a specific area based on specified rainfall amounts within a given duration of time. The River Forecast Center (NCRFC) calculates and issues products with guidance values for 1, 3 and 6-hour rainfall totals for all counties within the NCRFC region.

The heaviest rainfall should arrive with Wednesday's low pressure wave. We come up for air Thursday, before the next wave arrives Friday and Saturday.

Cooler days ahead

Enjoy the summery warmth today. Temps crash later this week.