Here Comes Summer
This is the week most Minnesotans have been waiting for. Summer weather finally takes hold.
A change in our upper airflow has the jet stream lifting northward this week. That means more sun...and warmer temps in the 80s for Minnesota.
Combine the extra sunshine with the brightest days of the year ahead as we approach the summer solstice and we may see an outbreak of a "light-shock" this week...Minnesotans searching for long lost sunglasses and wandering around in a summer induced stupor.
Let's track the warm up as we head through this week.
9:00 pm Sunset time at MSP Airport starting Wednesday
July 9th 9:00 pm or later sunsets in the metro for the next 28 days
A welcome change in the jet stream:
It's been a bonus spring for your ferns and hostas which are attacking your sidewalk.
For the past 4 months, the jet stream has snaked relentlessly overhead, bringing a consistent series of storms to Minnesota. The result? A busted drought, soggy fields. rising lake and river levels.
Now it's time for the sun loving flowers.
You can think a change in the jet stream for our sunnier, warmer turn this week. This map shows the reason...the jet finally lifting north toward the Canadian border...a more "climatologically favored" location for mid-June.
Bigger Picture: AO shifts "Positive"
The Arcitc Oscilation keeps track of "Rossby Wave" patterns in the northern hemisphere. When the AO is negative, Minnesota usually lies under a trough of low pressure...meaning cold and wet weather.
This week the AO shifts positive...and our weather fortunes will change for the sunnier.
How long will it last? AO shifts tems to hold for a while...which means summer may (finally) be here to stay.
From fog to sun?
Our AM fog should gradually burn off today, and the sun should return this afternoon.
Here's the European Model "meteogram" with the hour by hour breakdown.
(Temps are in Celsius; 25C = 77F)
A light west wind flow is easing in some slightly drier air from the Dakotas today.
Warmer week ahead:
Here's the Euro model for this week. Notice more sun symbols this week...and temps in at least the upper 70s to near 80.
NOAA's GFS model is more optimistic about temps in the low 80s for the metro and southern Minnesota.
Tuesday night thunder?
The week's best thunder threat works in late Tuesday night/Wednesday AM. Here's the NAM model animation which blows up rain over southern MN early Wednesday AM.
SPC keeps the severe risk south of the metro...over I-90 and northern Iowa.
Western Heat Wave Builds:
Summer is going strong out west...and some of that warmth will spill into Minnesota in the next 2 weeks. Check out the triple digit highs baking the west.
Highs in the 90s to near 100 are as close as Denver, where high fire danger is back...and may make national news this week.
Heat in our future?
Nobody can credibly tell you what the upcoming summer will bring...there are few strong links to summer climate patterns in Minnesota. But this year is starting to remind me of the spring/summer of 1983. That year started with a cool spring...it seemed like we would never see the sun. Then in late June a light switch flipped...and we ended up racking up 26 days at or above 90F that year. We sweated through 12 days in July above 90F...and 11 in August in the "Summer of '83."
I can't say for sure we'll see prolonged heat waves this summer...but it won't surprise me to see our weather pattern do a 180-degree turn...and bring some significant 90 degree heat by July & August this year.
Time will tell.
Bottom Line: Chances are excellent for a major warm up this week...and we may have left the cool rainy days in the 60s behind for a long time.
Weather fingers and toes crossed on that one.