Updraft: August 12, 2009 Archive

Finally, summer

Posted at 8:13 AM on August 12, 2009 by Paul Huttner

They say timing is everything.

If that's true, then our first extended statewide blast of summer is coming at the best time.

The PGA is in town. Summer vacations are peaking. The lakes are warming up for one last swim or canoe trip. The corn and other crops need a shot of heat to finish development. It's all coming together to showcase Minnesota's finest weather just in time for the State Fair.

The overall weather pattern has changed this week over North America. The chilly vortex that has been dealing Minnesota regular cool fronts has retreated into the Arctic. It's cooler in Alaska than in Minnesota, as it should be in summer. All seems well with the weather world as what appears to be a persistent ridge of high pressure builds in over the Upper Midwest. The pattern looks as if it may last for the next few weeks, bringing us a much deserved summery end to our summer season that could last into fall.

Why is the pattern changing? It could be that the El Nino that is taking hold in the Pacific is starting to affect global circulation patterns. It's certainly shut down any Atlantic hurricane development this summer so far. We're well into August and still looking for T.D. Two to become the season's first named storm this week.

All indications are that the current El Nino event could be of moderate or strong magnitude this winter. If that happens the odds are very good for a milder than average winter in the Upper Midwest. Many have enjoyed our cool but pleasant summer so far. I for one would be happy if we closed August on a warm note, and if above average temperatures lingered right into December.

Stay tuned.

PH

Air Quality Advisory issued for Twin Cities

Posted at 4:40 PM on August 12, 2009 by Paul Huttner

Twin Cities Air Quality Index (AQI) is climbing this week.

We've been breathing easy this summer. It may get a little tougher this week.

The Minnesota Pollution Control Agency (MPCA) has issues an air pollution health advisory for the Twin Cities for Thursday. The combination of light winds from the south and stagnant air will cause particulates to rise this week.

There are two main factors that trigger these alerts in the metro.

1) Light southerly flow transports humidity and fine particulates from pollution sources in the Ohio Valley and areas to the south.

2) Upper level high pressure causes air to sink and creates stagnation near the ground level. This traps pollutants that are produced locally and they accumulate in our air. Local sources of pollution include your car, lawn mower and your bonfire.

This would be a good week to skip that backyard bonfire. I've never understood why people want to have a fire on days when it's nearly 90 degrees anyway. (Yes, I'm editorializing here.)

The forecast is for moderate levels of particulates the rest of this week. Take it easy outside of you are affected by respiratory problems.

We're close to 90 today in the metro and it looks like the heat will build through Saturday. We could see some mid to upper 90s this week in western Minnesota. I would not be shocked to see 100 degrees in the Dakotas this week.

Stay cool!

PH