Wednesday, August 25, 2010

8/25/10: Wednesday's Weather Report

Issued at 3:19 PM CDT, Wednesday, August 25th, 2010

Updated information about the tornado outbreak that hit Minnesota on June 17th, 2010. Source: National Weather Service Chanhassen, Minnesota.

*Number of confirmed tornadoes from 6/17/10: 27, but the final count will likely top 40. As it stands now, June 17th, 2010 will go down as the biggest tornado outbreak to ever hit Minnesota. The previous record of 27 tornadoes occurred on June 16th, 1992.

*Three EF-4 tornadoes occurred in Minnesota on June 17th, 2010. This was the first EF-4 tornado across the state since the Granite Falls EF-4 back on July 25th, 2000.

*June 17th, 2010 had the greatest number of tornadoes (EF4 or greater) in one day in Minnesota since the Black Sunday outbreak on April 30th, 1967.

*Four EF-4 tornadoes across the Upper Midwest on June 17th, 2010 (3 in Minnesota) (1 in North Dakota) makes it the most of any outbreak in the U.S. since the "Super Tuesday Outbreak" which occurred on February 5th-6th, 2008.

*Number of tornado fatalities from June 17th, 2010 was 4, making it the highest in Minnesota since July 5th, 1978.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

High pressure averaging 1025 mb was centered over the Eastern Dakotas-Western Minnesota This Afternoon. Cool temperatures with partly cloudy-mostly sunny skies covered our local area Today with highs in the middle 60s to lower 70s. Dewpoints Today were generally in the 40s with PWS of just one half inch! Winds Today were out of the northwest around 20 mph or less.

Today's Upper Level Analysis:

Vigorous 500 mb trough (5640 meters) was starting to exit off to the east of the Upper Midwest late Today per water vapor satellite imagery with a northwest flow aloft covering our area. An upper level ridge of high pressure (5940 meters) covered much of the Central-Southern Rockies Today per RUC model analysis.

Tonight through Thursday Night:

Dry high pressure will be right over the Upper Midwest Tonight before it begins to push off to our southeast Tomorrow and Tomorrow Night. Mostly clear skies with lows in the 40 and lower 50s will occur Tonight with some 30s possible in the typical cold spots. Highs Tomorrow will be mainly in the 70s with lows Tomorrow Night in the 40s and 50s. Northwest winds Tonight will decrease to under 15 mph. Winds will become south/southwest Tomorrow and Tomorrow Night under 20 mph.

Extended Forecast:

Southerly winds will increase across our area from Friday through next Monday as a frontal boundary stalls out to our west-north with an upper level trough covering the Western U.S. and an upper level ridge off to our southeast. Above normal temperatures with highs in the 70s and 80s with lows in the 50s to lower 60s are expected in Northern Minnesota and Northwest Wisconsin for Friday and Saturday. It appears that dewpoints will remain fairly low into Saturday with mainly 50s and perhaps a few lower 60s around our area, a muggier airmass is then forecast to move north into the Upper Midwest toward Sunday and early next week when a cold front begins to settle slowly southeast out of the Northern Plains. This boundary combined with the increasing amounts of moisture and some instability should give way to some showers/thunderstorms around the area, perhaps as early as Sunday in Northern Minnesota, but more likely for early next week throughout Northern Minnesota-Northwest Wisconsin.

5 Day Forecast for Duluth/Superior

.Tonight... Mostly clear. Low 45 to 50. Wind northwest at 5 to 15 mph.

.Thursday... Mostly sunny. High 70 to 75. Wind west at 5 to 15 mph.

.Thursday Night... Mostly clear. Low 50 to 55. Wind south to southwest at 5 to 15 mph.

.Friday... Mostly sunny. High 75 to 80.

.Friday Night... Mostly clear. Low 55 to 60.

.Saturday... Mostly sunny. High 80 to 85.

.Saturday Night... Mostly clear. Low 58 to 63.

.Sunday... Partly cloudy. High 80 to 85.

Normal High Temperature Today 72 degrees

Normal Low Temperature Today 52 degrees

Tim