Sunday, October 18, 2009

Fleeting Sunshine

Today: nicest day of the week? Sunshine lingers part of the day, temperatures a few degrees cooler than yesterday's 63 degree F. high.

Significant rain event likely later this week: .50 to 1" amounts possible, maybe 1.5" for parts of central Minnesota.

Temperatures warm enough aloft for mostly rain, although some wet snow may wrap into the storm circulation (northern MN) by late Thursday and Friday.

Next Saturday appears to be the nicer, drier day of the weekend with some sun, temperatures a few degrees cooler than average.

Drought conditions improving statewide thanks to a very wet October.

September: worldwide sea and land temperatures were the second warmest since 1880.

Arctic sea ice retreat: third greatest since measurements were first kept in 1979 (details below).

Hurricane Rick threatens the Cabo San Lucas area of Baja Mexico with hurricane-force winds by Tuesday.


Thanks to Veronika Pinke for this amazing reminder of how spectacular autumn can be....long shadows, low, scrappy clouds, refreshing intervals of refreshing sunshine and cooling winds. Oh, if only we could limit the amount of cooling. For more eye-opening photos from Ms. Pinke click here.

The United (Extreme) States of America. What a crazy week. For evidence please take a look at the map above, courtesy of Ham Weather, a division of WeatherNation. The USA is PLASTERED with icons showing only a week's worth of record lows, highs, snowfall and rainfall. To get the details (on a very cool, interactive map, click here, and put your computer's cursor over each dot to get specific information for each city).

Sunday was a sight for sore, slushy, partially-frostbitten eyes: 63 in the shade, about 5 degrees above average for a change. We hang onto a little warmth today, the weak remains of a cool frontal passage cooling us off a few degrees. But the sun should stream through, the weather a non-factor for any ball games and chores later today. Yes, a retreating ridge of high pressure hangs on long enough for us to salvage a fairly decent Monday. If you need dry weather take full advantage of today and Tuesday, because a fairly significant rain event is shaping up for the latter half of the week. A full-latitude trough of low pressure, a massive wrinkle of chilly air aloft, will advance east from the Rockies, sucking moisture from the Gulf of Mexico and hurling it north. As the air rises and cools water vapor will condense out into visible cloud droplets - a few countless trillion drops will coalesce (combine) to form raindrops, gravity eventually pulling them down the ground by Wednesday and Thursday. The computer models are fairly impressive: over an inch of rain may soak much of Minnesota, the heaviest rains possible from late Wednesday into Thursday. Each successive computer run has been placing the track of the low pressure system farther north, meaning warmer air should be able to penetrate far enough north for mostly rain. We can't rule out a changeover to wet, slushy snow, mainly over far northern and northwestern Minnesota, by Thursday, a sloppy inch or two not out of the question near Bemidji and Grand Rapids. It's WAY to early to even speculate about amounts, but rest assured: the vast majority of this week's upcoming "precipitation" should fall as rain - the way it should this time of year. The good news: rain should wind down by Friday, setting the stage for a pretty nice Saturday, with enough sun for low 50s - cooler than average by a few degrees, but not to hard to take with the sun bobbing in and out of scrappy stratocumulus clouds. More rain may streak in by late Sunday, the timing still very much up in the air. No question we've slid into a wetter weather pattern: good news for Minnesota's ongoing, perpetual drought. We're in much better shape than we were 2-3 weeks ago, no extreme drought anywhere to be found in the state (check out the latest Drought Monitor summary for Minnesota below). In short: October, the way it SHOULD be with glimpses of sun, and a good chance you'll be getting friendly with your favorite umbrella by midweek.



NAM Predicted Rainfall later this week. The heaviest streaks of rain (1 to 1.5") are forecast to set up from near Willmar northeast to St. Cloud and the Hinkley area. As the track of the storm shifts over time the heaviest rains may also shift - stay tuned as we try to fine-tune the timing and the amounts from the upcoming storm. Right now it appears the heaviest rains may fall from late Wednesday into Thursday.

The combined global land and ocean surface temperature was the second warmest September on record, according to NOAA’s National Climatic Data Center in Asheville, N.C. Based on records going back to 1880, the monthly National Climatic Data Center analysis is part of the suite of climate services NOAA provides. NCDC scientists also reported that the average land surface temperature for September was the second warmest on record, behind 2005. Additionally, the global ocean surface temperature was tied for the fifth warmest on record for September. For more details click here to read a full report from NOAA.

On Sept 12, 2009, the extent of sea ice in the Arctic reached the third lowest level ever recorded since satellite records began in 1979. The National Snow and Ice Data Center estimates that the overall extent dropped to 5.1 million square kilometers, well below the average minimum extent of 6.71 million square kilometers (1979-2000). Only 2007 and 2008 have had lower ice extents. The small increase in 2009 was mostly due to ice spreading caused by strong polar winds. Ice concentration and thickness, however, have not increased, making predictions about a rebound in Arctic ice premature at this moment. (source: NOAA. For more details click here - it's worth it just to see the animation of sea ice over time, pretty fascinating - and vaguely alarming - stuff).

Hurricane Rick. For a time on Sunday sustained winds in this category 5 hurricane reached 160-180 mph, making it an extreme hurricane. Thankfully (for residents near Cabo San Lucas, Mexico) the storm is forecast to pass over colder Pacific Ocean water, the hurricane predicted to be a minimal category 1 hurricane by the time it passes near Cabo by midweek). Even so, the storm is capable of torrential rains, 80+ mph winds and a 4-8 foot storm surge by late Tuesday. Even though it's been a relatively quiet year in the Atlantic the Pacific has been a different story, with a number of severe hurricanes and typhoons (same thing as a hurricane, but they're called typhoons in the western Pacific).

Projected Path of Hurricane Rick. This experimental graphic, from Ham Weather, shows all the models taking Rick to the northeast, brushing the southernmost tip of Baja Mexico. Although the CMC model reduces the sustained winds to 60 mph by the time Rick brushes the Cabo San Lucas area, the GFDL model is more ominous, hinting that the hurricane may sustain it's intensity for a few more days. This discrepancy points out the inherent limitations of hurricane prediction: the models do a pretty good job predicting the TRACK of these massive storms, but forecasting INTENSITY is far more problematic.

Paul's Outlook for the Twin Cities

Today: Partly cloudy, breezy, a bit cooler than yesterday. Winds: North 5-15. High: 59

Tonight: A little starshine poking through early, then increasing clouds, chilly. Low: 44

Tuesday: Mostly cloudy, chance of a shower late. High: 54

Wednesday: Rain likely, a cold wind. High: 50

Thursday: Rain, possibly heavy at times, raw. High: 47

Friday: Showers taper, possibly mixing with a little wet snow far north. High: 44

Saturday: Partly sunny, cool breeze (but dry). High: 51

Sunday: Sunny start, clouds increase, chance of showers late. High: 53

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