Wednesday, July 7, 2010

Weekend Weather Blues



Wednesday Almanac. Over half an inch of rain fell in Alexandria, nearly a quarter inch in the Twin Cities (although many suburbs of St. Paul saw between .25 and .50" of rain during the late afternoon and evening hours). St. Cloud picked up only a trace of rain - not a drop at Redwood Falls.

Wednesday Soakers. The western metro saw little or no rain yesterday, while the close-in suburbs got inundated with rain. These are Doppler radar rainfall estimates, the dark-green shaded areas picked up over 1" of rain, those little yellow blotches of color signify at least 1.5" of rain near Fridley, Shoreview and Lino Lakes.

Useless Trivia. Think your swimming pool is big? Check this out, allegedly the world's biggest swimming pool, roughly 1 mile long and nearly 13 meters deep - in Chile, if you're interested. Wow.

Another day, another spirited round of window-rattling downpours and rumbling thunderstorms. Nothing severe, but a reminder that this is peak season for electrostatic bipolar generators (T-storms). Storms mushroomed right over the metro area, the far western suburbs saw very little rain Wednesday, while the inner suburbs, downtowns and suburbs of St. Paul saw the heaviest rain. It's classic summertime weather, morning sun heating up the ground and the air immediately above the ground, rising thermals of warm, sticky air punching through a weak inversion (temperatures rising with altitude), then accelerating skyward, mutating into bloated cumulocongestus and cumulonimbus (thunderheads). Winds aloft were weak yesterday, we didn't have the wind shear necessary to spin up tornadic storms. I'm still trying to get an accurate tornado count for Minnesota: it's at least 31, my hunch is that we've seen more than that since the first twister touched down June 17.

The drought has eased across all of Minnesota, with the exception of the Arrowhead, soil moisture is more than adequate, there's been enough warmth for healthy crop growth - no widespread hailstorms capable of flattening crops, no extensive flooding or standing water in the fields. It's been a (very) good growing season - hopefully these positive trends will continue. So far so good.

Welcome to a beautiful summer day, leave the umbrella at home, I think we'll get a break from the cycle of sun-clouds-thunder that we've been putting up with in recent days. A drying westerly breeze will tug the mercury into the upper 70s and low 80s, plenty of blue sky, a few decorative (popcorn) cumulus clouds drifting overhead. Dew points drop into the 50s, back into the comfortable range. Enjoy the break, because the respite from thunder and lightning may not last for long.

Much of Friday looks sunny (and a few degrees warmer), before a southbound cool front sparks a few late-day and nighttime T-storms, spreading from north to south across the state late tomorrow. You know what's coming next: OF COURSE that front is going to stall...and linger...and foul up part of our weekend. The latest NAM/WRF model prints out nearly 2" of rain Saturday and Saturday night. The timing is very much up in the air, but right now I can't be too optimistic about the state of our weather Saturday or Sunday. At least it will be relatively warm: low to mid 80s southern MN, maybe some 70s up north, enough cloud cover to significantly reduce the risk of a debilitating sunburn. Great news - thanks Paul! I have a few suggestions what you can do with that Doppler of yours!

Soggy Saturday Blues. The latest NAM/WRF model suggests a weak frontal boundary setting up over central or southern Minnesota, capable of acting like a shower/thunder magnet, as much as 4-8 hours of rain may fall Saturday and Saturday night, models printing out nearly 2" of rain between breakfast Saturday and early Sunday. Something to look forward to.

A difference of 50-75 miles in where that front ultimately stalls will make the difference between torrential showers/storms and partly sunny skies - far northern MN may salvage some sun both days, Saturday and Sunday. Too early to say with any level of confidence. Just pack for (some) rain, and be pleasantly surprised if the sky draped over your head actually cooperates with your outdoor plans.

Sunday Shocker. Hard to imagine, but more showers and storms are likely Sunday as a front meanders nearby. It's still too early to nail down which parts of the state will see the heaviest/steadiest rain - if the wettest weather sets up over southern MN, then far northern counties may see sunshine much of the day - it probably won't rain STATEWIDE the entire day - the odds of a daylong rain event are slim. Stay tuned as we try to pinpoint the best times of the weekend to try to sneak outside.

If it's any consolation I see little or no chance of any sizzling heatwaves engulfing Minnesota anytime soon - the GFS model is hinting at low 90s the weekend of July 17-18, but no extended spells of nasty heat & humidity. Some good news there. Residents living out east, where the mercury has soared above 100 for the past few days, would LOVE to have a little rain - I guess 80s would feel like a cool front in Baltimore, where the mercury soared to 105 on Tuesday. We have that going for us...

Here in the Land of Low Weather Expectations we're always delighted with the weather turns out better than predicted. That's my hope for this upcoming weekend.

Inside a Tornado. I've seen a lot of (amazing) tornado chasing videos, but NEVER one like this. The twister passes right over this (heavily reinforced) armor-plated vehicle, called the "Dominator" - as it encounters a tornado near Goshen, Wyoming. Please don't try this at home.

Rotation! If you witness the cloud base of a thunderstorm lowering and rotating, be on the lookout for tornado formation. Professional storm chasers Andy Gabrielson and Kory Hartman from Severe Studios intercepted this "supercell" thunderstorm near Platte, South Dakota, which did go on to spawn a tornado. Amazing video.

Another Fluke? Global temperatures (land and ocean) were the warmest ever recorded from January through May, 2010, averaging about 1 degree F warmer than the long-term averages, the warmest in 131 years of record-keeping. More details from those radicals at NASA here.

What Happened to Normal? Nationwide, June brought 5 TIMES as many record highs as record lows. Although no one heatwave proves anything, the trends continue to alarm professional climatologists. The story in Climate Progress is here.

Jeff Masters, in his excellent "Wunderblog" post, wrote:

Kuwait, Saudi Arabia, Iraq, Chad, Niger, Pakistan, and Myanmar have all set new records for their hottest temperatures of all time over the past six weeks. The remarkable heat continued over Africa and Asia late this week. The Asian portion of Russia recorded its highest temperate in history yesterday, when the mercury hit 42.3°C (108.1°F) at Belogorsk, near the Amur River border with China. The previous record was 41.7°C (107.1°F) at nearby Aksha on July 21, 2004. (The record for European Russia is 43.8°C–110.8°F–set on August 6, 1940, at Alexandrov Gaj near the border with Kazakhstan.) Also, on Thursday, Sudan recorded its hottest temperature in its history when the mercury rose to 49.6°C (121.3°F) at Dongola. The previous record was 49.5°C (121.1°F) set in July 1987 in Aba Hamed.We’ve now had eight countries in Asia and Africa, plus the Asian portion of Russia, that have beaten their all-time hottest temperature record during the past two months. This includes Asia’s hottest temperature of all-time, the astonishing 53.5°C (128.3°F) mark set on May 26 in Pakistan.
Troubling Trends. If climate change really was a hoax, if there were no discernible trends in the data, you would expect to see roughly as many record lows as record highs in any given year (or decade). And yet the national data sets continue to show consistently more record highs than lows around the USA. There were more record lows than highs in the 60s and 70s, but since the 80s the trends have reversed. Since 2000 (nationwide) there have been twice as many record highs as lows. Go figure.

* New Temperature Record at BWI (Baltimore): Atmospheric or Asphaltic? Anthony Watts (who I respect) has a thought-provoking story about how hot air over airport runways may be biasing the temperature records. He may have a point, there may be a (warm) bias at some of the regular reporting stations, most of which are located at airports. But over 100 climate stations around the USA are positioned well away from warm urban areas (and hot runways). These rural reporting stations show the same warming trend in recent decades. The story is here.

* A Connection Between Global Warming and Extreme Weather. I'm all for coincidence and serendipity, but it sure seems like we've been experiencing an unusual number of record events in recent months, a rash of 1-in-500 and 1-in-1,000 year events, historic floods in Arkansas, Nashville and Oklahoma City. The U.K.'s Met Office has released more data on a possible link between the 4% increase in water vapor worldwide and what appears to be a spike in these extreme weather events - click here to read their explanation.


Paul's Star Tribune Outlook for St. Cloud and all of central Minnesota

Today: Nicest day in sight, plenty of sun, a comfortable breeze, slight drop in humidity. Winds: W 10-15. High: near 80

Thursday night: Mostly clear and comfortable. Low: 61

Friday: Sun much of the day - thunderstorms possible late Friday and Friday night. High: 82

Saturday: Sticky and unsettled, showers and T-storms likely, locally heavy rain possible. Winds: S 10-20. High: 83

Sunday: Still muggy and mostly cloudy with more showers and storms. Winds: SW 10-15. High: 81

Monday: Showers linger (especially southern MN). Some clearing central and north. High: near 78

Tuesday: Partly sunny, drying out statewide. High: 81

Wednesday: Sunny and warmer. High: 85

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