Thursday, August 26, 2010

8/26/10: Thursday's Weather Report

Issued at 4:39 PM CDT, Thursday, August 26th, 2010

A hint of Autumn in the air earlier Today in parts of Northern Minnesota and Northwest Wisconsin. Here are some low temperatures from Today. Source: NWS Duluth, Minnesota.

Hibbing MN: 39 degrees

International Falls MN: 40 degrees

Silver Bay MN: 37 degrees

Grand Marais MN: 36 degrees

Cook MN: 39 degrees

Hayward WI: 40 degrees

2 miles South of Tower MN: 38 degrees

Embarrass MN: 36 degrees

3 miles East of Orr MN: 39 degrees

Weather Headlines:

*Tranquil weather to hold through the weekend

*Changes ahead for next week

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A great late Summer day (very typical for late August) across our area with plenty of sunshine, comfortable humidity with Afternoon dewpoints generally in the 50s along with southerly winds around 20 mph or less, although a light east wind has developed This Afternoon at the Duluth Harbor. Highs Today were generally in the 70s, except upper 60s at the Duluth Harbor.

Today's Upper Level Analysis:

Northwest 500 mb flow continued across the Upper Midwest per RUC model analysis and water vapor satellite imagery. An upper level ridge (5940 meters) covered the Southwest half of the U.S. with lots of very warm temperatures with 90s and even some low 100s Today from Montana through parts of the Dakotas, down through the Western High Plains and Rockies while 850 mb temperatures ranged from +20/+32 degrees C across those areas. The Northern Rockies will see a huge drop in temperatures by this weekend as a baroclinic zone starts to tighthen up (a sure sign of fall).

Tonight through Friday Night:

An area of high pressure will remain centered to our southeast during this period while a weak warm front lifts N-NE through Minnesota into Friday, then a frontal boundary will stall out well to our west-north by Tomorrow Night. Mostly clear skies are forecast from Tonight through Friday Night with lows in the 40s and 50s Tonight and the 50s to near 60 degrees Friday Night. Highs Tomorrow will be in the 70s and 80s. Patchy fog could develop late Tonight and early Tomorrow Morning, mainly in low lying areas and near rivers. Humidity levels will remain comfortable through Tomorrow Night with dewpoints generally in the 50s across our area. Winds will be out of the south at 5-15 mph Tonight, increasing to 10-20 mph Tomorrow and Tomorrow Night with gusts to 30 mph during the day Friday thanks to a southwest low level jet which will increase to between 30-55 knots Tomorrow and Tomorrow Night per latest model guidance.

Note: Winds Tomorrow may have an easterly component to them around the head of Lake Superior, if this happens then high temps would likely hold in the 60s in Superior and Downtown Duluth.

Extended Forecast:

An upper level trough currently over British Columbia and the Northeast Pacific will move into the Western U.S. through the weekend before heading into the Northern Plains and Upper Midwest late this weekend and early next week. A tight temperature gradient will develop from Saturday through Monday with some places in Montana holding in the 40s with even some possible snow at times in the Mountains while widespread 80+ degree high temperatures occur in the warm sector across the Upper Midwest and Central Plains. A stationary front representing this temperature contrast will remain to our west-north through Sunday before it shifts south/east during the early to middle portion of next week the way it looks now.

Strong southerly winds will continue across the Upper Midwest this weekend with a gradual increase in moisture with 60+ degree dewpoints expected by Sunday and early next week. Instability will also begin to come up by early next week, and this combined with the approaching front should result in scattered showers/thunderstorms around our area from Monday into Tuesday, but far Northern-Northwest parts of our area could see some activity as soon as Sunday or Sunday Night.

High temperatures in Northern Minnesota and Northwest Wisconsin will be in the 70s and 80s Saturday and Sunday with lows in the 50s and 60s both nights.

By the middle of next week the forecast models are at odds as to whether or not an upper level low/trough develops around the Upper Midwest and tracks toward the Great Lakes with a threat of rain/possible thunder, or if dry weather will occur for next Wednesday/Thursday. The models should start to converge on a solution in coming days.

5 Day Forecast for Duluth/Superior

.Tonight... Mostly clear. Patchy fog possible late. Low 50 to 55. Wind south to southeast at 5 to 15 mph.

.Friday... Patchy fog possible early. Mostly sunny. High 75 to 80 but cooler closer to Lake Superior. Wind south to southeast at 10 to 20 mph.

.Friday Night... Mostly clear. Low 55 to 60. Wind south at 10 to 20 mph.

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

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

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

.Sunday Night... Partly cloudy. Low 60 to 65.

.Monday... Showers or thunderstorms possible. Partly sunny. High 80 to 85. Chance of rain 20%.

Normal High Temperature Today 72 degrees

Normal Low Temperature Today 52 degrees

Tim