Saturday, August 8, 2009

Heat Advisory, Tornado Watch West 'til 7 pm

Saturday Update

* Tornado Watch for central and southwestern MN until 7 pm this evening - this watch area does include the immediate St. Cloud area.

* Lot's of weather: 3-5" of rain since Thursday night for much of the St. Cloud area, some flooding reports, downed trees, powerlines, lightning strikes, 1-2" hail reports.

* Isolated severe storms may flare up AGAIN later today - slight risk.

* Heat Advisory southern MN: could feel like 100 over far southern/southeastern MN later today.

* Sun returns for a time this afternoon, but the atmosphere remains ripe for rough storms.

* Behind cool front: Sunday should be sunnier, drier, less humid - a few degrees cooler, but probably a better outdoor day across most of Minnesota.

Storm Rainfall estimated by Doppler Radar. The "key" is on the extreme left of the graphic. Everything within the yellow-shaded area picked up 1.5"+ rain, within the light red area: over 3". The dark red regions signify 5" or more of rain in the last 24 hours. As you can see many communities soaked up over 3-4" of rain overnight, over a MONTH'S WORTH of rain in 24 hours, give or take. This was on top of the .50 to 1.5" that fell Friday morning, by the way. So the bottom line: anywhere from 2-6" of rain has drenched central Minnesota, including the Twin Cities metro area. Not enough to break the drought altogether, but certainly put a big (runny) dent in the middle of it!

Predicted Temperature at 7 pm this evening. 90 is still a pretty good bet from the Twin Cities south to the Iowa border. Highs reach the 80s over central Minnesota, but check out the readings near Bemidji and Grand Rapids: holding in the 60s? That's right, a 30-40 degree temperature spread is possible later today from north to south, especially when you consider that dew points in the 70s will make it FEEL like 100 degrees over far southern Minnesota.

Dew Point Temperatures predicted for 7 pm this evening. Mid 70s? Yikes! We are talking breath-TAKING humidity levels later today. When there's this much water in the air your body can't cool itself naturally by evaporating sweat. The evaporation process results in cooling (that's why you feel chilled when you step out of the shower). But when the air is thick with water vapor the evaporation process breaks down and you can overheat much faster.

SPC Outlook for later today - 30% risk of severe weather within 25 miles of any point within the red/hashmark region - including the St. Cloud area. More watches/warnings are possible later on, especially south/east of us. I expect a lower risk of severe weather (and less heat/humidity) for St. Cloud and the Brainerd Lakes area today, where the cool front will come through earlier in the day, lowering the overall risk. That said, it'll be a close call: stay alert for possible watches and warnings out there later today.


Heat Advisories are posted across southern Minnesota later today - take the heat seriously.

Near 90 later today with hazy sunshine on the increase.

Another .25-50" of rain possible by late afternoon/evening as a cool frontal passage sparks more storms.

Slight risk of isolated severe storms later today, can't rule out an isolated tornado.

Sunnier, drier, a couple degrees cooler Sunday - overall a BETTER DAY for the lake or pool.

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