Spotty T-showers overnight into Thursday

Deep Blue

Talk about a deep blue Minnesota summer sky.

6 21 blue sky
Blue summer sky in the southwest metro. Paul Huttner/MPR News

Our first full day of astronomical summer gives way to nagging T-Storm chances overnight and Thursday.

Severe thunderstorm watch west

Create a More Connected Minnesota

MPR News is your trusted resource for the news you need. With your support, MPR News brings accessible, courageous journalism and authentic conversation to everyone - free of paywalls and barriers. Your gift makes a difference.

A severe T-Storm watch is in effect until 10 pm for the Red River Valley and much of western Minnesota.

6 21 watch
NOAA

URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 361

NWS Storm Prediction Center Norman OK

505 PM CDT Wed Jun 21 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of

Western Minnesota

Eastern North Dakota

Northeast South Dakota

* Effective this Wednesday afternoon and evening from 505 PM

until 1000 PM CDT.

* Primary threats include...

Scattered large hail and isolated very large hail events to 2

inches in diameter possible

Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms will intensify over eastern ND/SD and track

eastward across the watch this afternoon and evening. Locally

damaging winds and hail will be possible in the stronger cells.

Thunder threat

Synoptic meteorology in summer often means more subtle weather features. Weaker fronts and subtle differences in air masses can make it harder to forecast precise T-storm locations. That's a welcome challenge for us as meteorologists. But still a challenge.

A weak low pressure trof crosses Minnesota overnight. A broken line of storms may accompany that low pressure wave overnight. New storms may fire along a developing warm front south of the Twin Cities. The two features may bump into one another close to the Twin Cities around midnight. Keep an eye out for lightning after dark, and an ear out for thunder in the hours surrounding midnight.

NOAA's NAM 3 km model shows scattered coverage on storms tonight. But if one develops overhead, expect a light show, thunder, downpours, and possible hail.

6 21 nammy
NOAA via tropical tidbits.

Slight severe risk

I agree with NOAA's discussion that there are limiting factors for severe weather tonight. Still, a slight risk for a big chunk of Minnesota.

6 21 risky
NOAA

Farther north into southeast South Dakota/southwest

Minnesota/northwest Iowa area, there is increased uncertainty about

storm development during the late afternoon/evening over this area,

as some model guidance maintain a cap during peak heating in the

wake of morning convection. However, convergence associated with a

surface low and an associated warm front and an approaching cold

front/trough line suggest some potential for storm development.

Given large CAPE values over this region and sufficient deep layer

shear for organized storms, a conditional severe risk will be

maintained over this region.

Guidance is more supportive of storms developing along a cold front

moving into northwest Minnesota and northeast South Dakota and

spreading eastward during the evening hours. Strong vertical shear

will support a few severe storms. This activity is expected to

spread eastward and develop southeastward as a strengthening warm

advection pattern develops from Minnesota into Wisconsin during the

overnight hours.

6 21 lily
Weather Lab lily. Paul Huttner/MPR News.

Another cool front

We managed 80 degrees in the twin Cities Wednesday. Another cool front means we enjoy another few days with highs in the 70s. Temps struggle to climb to the 70 degree mark this weekend.

6 21 wxx
NOAA via Weather Bell.

Cool start to July?

I'm still searching for the usually inevitable July heat wave. Not finding it yet. Upper air trends continue to suggest a potentially cool pattern for the Upper Midwest through late June into early July.

6 21 814temp.new (1)
NOAA

NOAA's GFS 16-day temperature output continues to advertise cooler than average weather into the 4th of July.

6 21 16
NOAA via IPS Meteostar

Stay tuned.