Tuesday, April 13, 2010
Tracking a few blobs on Doppler?
Weather Headlines
* Excessive rainfall amounts south/west metro from Monday night's slow-moving thunderstorms that flared up along a warm front, some 3-6" rainfall estimates near Willmar & Hutchinson. .90" fell at St. Cloud.
* Slight risk of strong/severe thunderstorms Wednesday afternoon as a cooler front approaches, latest NAM model prints out .28" Wednesday PM hours. Best chance of a shower, T-shower? From 3 pm to 8 pm Wednesday.
* Another phenomenal weekend is shaping up, bright sun, low 60s, still 5-10 degrees warmer than average statewide.
* After Wednesday showers/storms next chance of rain won't come until Wednesday of next week.
* Rainfall since mid March running 10-25% of normal cross much of central and east central Minnesota.
* March recap for the USA: significantly warmer than average, probably a lingering symptom of El Nino.
* NOAA issues a "Red Tide Warning." What the heck is a red tide warning, and why Minnesotans won't have to worry about it.
* First images from the latest weather satellite, GOES 15.
* Two fewer glaciers at Glacier National Park in Montana.
"Train Echo Effect." Much like the cars of train pass over the same section of track, Monday night's thunderstorms kept redeveloping over the same counties just south/west of the Twin Cities. This kind of scenario often results in flash flooding, especially when the ground is saturated/waterlogged.
Gulley-Gushing Rains. Doppler radar estimates show some 3-5"+ rainfall amounts from Delano westward to Willmar and Hutchinson. .73" of rain fell at MSP International in Richfield, .90" at St. Cloud, .58" at Alexandria, but a meager .03" fell at Duluth, barely enough to settle the dust.
Am I the only one who enjoys falling asleep with lightning zigging and zagging overhead, serenaded by a distant rumble of thunder? Oh. I'm even more dysfunctional than I suspected. Maybe it was the sound of a long, lost friend, rain slapping up against the window, the faint, drumming sound of a heavy shower hitting the rooftop. It was nice hearing, seeing, SMELLING rain again, after a long absence of anything even approaching a real "storm." Rainfall amounts from Monday night's warm frontal passage were extremely fickle and variable, the heaviest amounts south/west of the Twin Cities, where a few towns picked up 1-2 MONTH'S worth of rain in a few hours. Check out the Doppler radar estimates below, some crazy extremes close to home.
Tuesday Numbers. 69 in the Twin Cities, 65 at St. Cloud, 71 at Rochester and a balmy 78 reported at Redwood Falls. Contrast that with a brisk 54 at Duluth, a jacket-worthy 47 up at Grand Marais, a little free air conditioning blowing off Lake Superior.
Midday Puddles? The latest NAM model brings the cool front through during the midday or early afternoon hours. Moisture, wind shear and instability aloft will be marginal for anything severe (we are not in a slight risk of severe storms from SPC) but I could still see a few heavy/strong storms as cooler air advances from the Dakotas. The odds of a widespread, statewide severe storm outbreak? Small.
A Growing Rainfall Deficit. Since mid March much of the area has picked up only 10-25% of the rain that should have fallen. Far southeastern MN has been wetter, closer to the storm track.
Skies clear Thursday, winds gradually swinging around to the west, then the northwest by Friday, pumping cooler, drier air of Canadian ancestry into Minnesota. A big bubble of high pressure arrives over the weekend, a bright, sun-scrubbed sky Saturday (with less wind). I could envision a touch of frost north of St. Cloud Saturday, again Sunday morning with dry air overhead, light winds enabling the mercury to sink to frosty levels. Sunshine should be the rule from Thursday through Tuesday of next week, a gradual warming trend returns next week, the next chance of rain not coming until Wednesday of next week. I'm still a bit worried about a statewide lack of (soaking) rain in recent weeks, the fire danger is still very high over western and northern Minnesota. These fickle showers just aren't getting the job done, not sure we'll see enough rain from today's random showers/storms to make much of a difference. Call me crazy but I think we're going to be wrestling with drought conditions over much of Minnesota this summer. I hope I'm wrong with that (reckless) prediction, but I'm seeing how the pattern is setting up for spring, how the biggest, wettest storms continue to detour south of Minnesota. Hope I'm wrong on that score, for the sake of farmers, gardeners, anyone with a lawn. Time will tell...
Whispers of El Nino. The Minnesota Arrowhead experienced a record-warm March, compared to long-term averages since 1895. Much of Minnesota trended well above average in the temperature department, probably a symptom of El Nino, which sparked a cool, wet stormy spell of weather across much of the deep south. All the details from NOAA are here.
Climbing Out of a Rainfall Rut. March precipitation trended well below average, especially over eastern Minnesota - even drier conditions just east over Wisconsin. Rainfall amounts since March 1 are running 1-3" below average over much of the state.
"Supercell" Notice how the hail core in this North Dakota storm leaned over to one side with altitude, evidence of strong wind shear, changing wind direction/speed as you rise up through the atmosphere. In this kind of a highly-sheared environment warm, moist updrafts can be "protected" for long periods of time, not choked off (automatically) by rain and hail-cooled air. This can prolong the spin, the rotation, leading to tornadogenesis....preceded by a lowering cloud base (wall cloud) and tornado formation, however rare. Fewer than 1 in 100 thunderstorms will ever go on to spin up a tornado. The bottom line: a tornado is a process, not an object, the visible manifestation of an especially violent thunderstorm updraft.
Forecast Calls for Blowing Dust. This was the scene in western Kansas, where sustained winds of 30-40 mph. whipped up dust, dropping visibilities to near zero at times, strong enough to ruin paint finishes on cars, strong enough to rattle 18-wheel rigs on the interstates. Much of the Plains is too try...
GOES-15. The latest and last in the series of GOES satellites, GOES-15 launched from Cape Canaveral on March 4. After 5 more months of testing the satellite (in geosynchronous orbit, 22, 300 miles above the equator) will be handed over to NOAA for operations. It's a back-up, in case any of the existing GOES satellites experience technical malfunctions. Read more about GOES-15 here.
Two Fewer Glaciers at Glacier National Park. Pictures don't lie, although I'm sure the conspiracy theorists and professional deniers will find another excuse. "No Paul, the glacier isn't melting, the mountain is getting BIGGER!" O.K. In 1850 there were reportedly 150 glaciers at Glacier National Park. With two fewer glaciers the number is now down to 25. Better load the kids up into the SUV and get out to Montana fast. For more on what's happening at the park, click here for an article from RockyMountainClimate.org.
Paul's SC Times Outlook for St. Cloud and all of central Minnesota
Today: Fading sun, windy and warm. A few strong T-storms possible by afternoon and evening. Winds: SE 15-30. High: 73
Tonight: A few lingering showers, possibly a heavy T-storm. Low: 58
Thursday: Partly sunny, breezy and cooler (less humid). High: 66
Friday: Plenty of sun, a fresh breeze. High: 61
Saturday: Bright sun, less wind (N at 5-15). High: 63
Sunday: Frosty start over parts of central, northern MN. Blue sky, still phenomenal. High: 62
Monday: Still sunny, still dry. High: 63
Tuesday: Sun gives way to increasing clouds. High: 65
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