Updraft: December 2, 2009 Archive

Minnesota Lakes: Late freeze up

Posted at 8:14 AM on December 2, 2009 by Paul Huttner

Keep an eye on your favorite lake this week. You may be the first to see a new coating of ice.

Lakes in Minnesota are freezing up at least two weeks later than average this year. Our mild November weather is the reason. You know it's late when you see fishing boats on Lake Minnetonka on November 30th as I observed this year.

Joel Rosen is a weather observer on Park Lake in Carlton County south of Duluth. My colleague Mark Seeley passes along Joel's observation from Monday.

"Park Lake is about 40% frozen over this morning (Dec 1) and some of the ice has apparently frozen and re-frozen a few times....I'd have to do some digging in my narratives, but I think it's pretty rare for this lake to freeze all the way across this late in the year and then open up before re-freezing again. The average date for final freeze-up is approximately Nov 18, and the latest on record is Dec 9, 1998. In that year the lake went through 3 cycles of completely iced over. Overall, it seems that not only is the date for freeze-up getting later, but the frequency of freeze/thaw cycles in November has also increased in the last 10 years. I will send another brief message when Park Lake freezes over for the winter, (likely tomorrow night)."

I will keep an eye on Lake Minnetonka near the weather lab this week to see if the bays begin to freeze up. In the 70's and 80's it was common to see people are skating by Thanksgiving weekend.

Please send along any observations of freeze up this week. The data is hard to come by.

Cold Surge: How long will it last?

It's interesting to watch the GFS model attempt to resolve the duration of this weeks cold snap. Yesterday the GFS was hinting at multiple surges of cold polar air coming south right through mid-month. In the overnight runs, the GFS returns to a zonal (west to east) flow in the northern U.S. in about 10 to 12 days.

Overnight GFS model run hints at much milder air returning to the Midwest by mid month.

This flow brings milder Pacific air into the region. In fact, the GFS is hinting at a return to (possibly much) above average temps before mid-month. It will be interesting to see if the cold can persist, or if milder air gushes back into the Midwest by mid-month.

Stay tuned!

PH

2009 Hurricanes: No U.S. strikes...first time in 3 years

Posted at 4:37 PM on December 2, 2009 by Paul Huttner

2009 tropical cyclone tracks in the Atlantic Basin. The USA got lucky this year.

Insurance company executives are breathing a big sigh of relief this month.

The Atlantic hurricane season officially ended November 30th. For the first time in 3 years, no hurricanes made landfall in the United States. And yes, you can thank El Nino.

According to NOAA, 2009 was least active Atlantic hurricane season in 12 years, since 1997. Just nine named storms, three hurricanes, and two major hurricanes formed this year. An average season has 11 named storms and six hurricanes, including two major hurricanes. Two systems, Claudette and Ida, brought tropical storm force winds to the U.S. mainland.

One interesting way to illustrate the drop in activity from 2008 is by counting the number of flights the hurricane hunters make. NOAA and the U.S. Air Force flew 38 hurricane hunter aircraft reconnaissance missions over the Atlantic Basin this year. They flew 169 in 2008.

Hurricane forecasters scrambled this year to adjust forecasts downward as El Nino rapidly developed in the tropical Pacific. The warmer Pacific Ocean water weakens easterly winds in the tropics that steer storms, and increases westerly wind shear that tears developing storms apart.

It's too early to know if El Nino will have an effect on the 2010 season, according to the NOAA release. ""El Niño is expected to reach peak strength this winter, and will likely continue into the spring. It is far too early to say whether El Niño will be present next summer," said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA's Climate Prediction Center.

NOAA will issue its initial 2010 Atlantic Hurricane Outlook in May, prior to the official start of the season on June 1.

PH