Posted at 8:45 AM on July 12, 2011
by Paul Huttner
Filed under: Heat
Enjoy the quiet!
You won't hear the hum from buzzing air conditioners through Thursday. But get ready to see a jump in your A/C bill later this month.
Free A/C for now & showery morning south:
An east-west band of showers is sliding through southern Minnesota Tuesday morning. The area should skirt mainly south of the metro, with rain showers from Mankato to Rochester. The upper air disturbance triggering the showers will slide east of Minnesota late today, and sunshine will increase in the metro and southern Minnesota this afternoon.
Prolonged heat wave builds this weekend!
After our reluctant spring, it's starting to look like the summer of 2011 will be remembered as hot & steamy. Some numbers so far.
8 days at or above 90 degrees so far
13 days of 90 degree weather is average for MSP
20+ days at or above 90 by the end of July?
Call it "crazy hot." This is going to be a hot one folks.
A massive ridge of high pressure will expand in the upper atmosphere this weekend. The pattern will pump road buckling heat into Minnesota starting on Friday and Saturday, peaking by Sunday and Monday.
Temperatures may approach 100 in the metro and southern Minnesota by Sunday, with heat index values (the "feels like" temperature) over 110 degrees.
The GFS model is hinting that the 90+ degree heat wave could last at least 2 weeks, basically for the rest of July. The prolonged heat wave could push the number of 90 degree days in the metro and much of Minnesota from the current total of 8, to over 20 by month's end.
The North Shore and cool breezes off Lake Superior will be looking awfully tempting by next week!
Heat helps crops, so far:
The recent heat is helping crops in Minnesota. July is running about 7 degrees above average so far. According to the latest crop report, the average height of corn in Minnesota increased from 25 inches to 39 inches last week. That's 14 inches in 7 days...or about 2" per day! No wonder they say you can "hear the corn grow."
The intense and prolonged heat wave to the south may begin to affect corn crops in Iowa and other Midwest states. It will be interesting to see where we are at in about 2 weeks, and whether markets will respond to a growing heat wave and potentially dry weather scenario in the Midwest through the end of July.
After a nice dry stretch of weather, get ready for the next batch of heavy thunderstorms in southern Minnesota.
Another major storm complex, possibly an MCS, is expected to develop Wednesday night into Thursday morning. This time, locally heavy (and potentially flooding) rainfall could be the primary feature of the storms.
As the hot dome of high pressure nudges back north into Minnesota Thursday, an upper air disturbance will ride along the periphery of the expanding heat dome into southern Minnesota.
The system will likely trigger a developing MCS with torrential rains overnight.
Slow movement may produce multiple inch rainfalls in some areas of central & southern Minnesota by Thursday noon. Some 1" to 3"+ rainfall totals are quite possible with this system.
Depending on which model you look at, the heaviest rainfall may be focused in central Minnesota near St. Cloud & Brainerd, and/or near the Twin Cities.
"Nocturnal" Thunderstorm Season Ahead:
Wednesday night's storms may be the opening salvo in what meteorologists sometimes call the "nocturnal thunderstorm season."
Some info about nocturnal thunderstorms:
-They tend to develop and strengthen at night
-They tend to develop and favor warm fronts at the surface
-They tend to roam around the northern periphery of hot high pressure domes.
-They are climatologically favored in late July & August.
Nocturnal storms can produce copious flash flooding rains. Be alert for possible flash flooding in the wee hours of Thursday morning!