Tuesday, August 31, 2010

8/31/10: Tuesday's Weather Report

Issued at 4:15 PM CDT, Tuesday, August 31st, 2010

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A cold front which brought the showers and embedded thunderstorms to the area last night and early Today was now centered over Eastern Minnesota as of 3 PM. A muggy and warm airmass continued along and ahead of this boundary Today with drier and cooler conditions behind this front. High temperatures were in the 70s to lower 80s Today with dewpoints ranging from the 50s in Western-Northwest areas (behind the cold front) to the 60s/70s elsewhere. Winds Today were out of the south or west at 10-20 mph with a few higher gusts.

Today's Upper Level Analysis:

Broad upper level trough continued to cover the Western U.S. Today with an 80 knot mid level jet streak and a 110 knot upper level jet streak in place over parts of the Northern Plains/Upper Midwest Today out ahead of this 500 mb trough.

Tonight:

Look for the cold front to pass through Eastern Minnesota-Northwest Wisconsin This Evening. There is still a risk for some showers or thunderstorms before Midnight, mainly along and south-east of a line from Shell Lake to Ashland Wisconsin. CAPES will generally be less than 1000 j/kg This Evening ahead of the cold front with Lifted Indices around -3 degrees C. The better shear is found along and west of the cold front, so the prospects for severe weather are relatively low across Northwest Wisconsin early Tonight. Heavy downpours, wind gusts up to 40 mph and occasional lightning strikes will be the main risks if any thunderstorms do develop. Otherwise look for partly-mostly cloudy skies across our area Tonight with lowering humidity and cooler temperatures compared to the past few nights. Lows Tonight will be in the 40s and 50s with westerly winds at 10-20 mph ushering in 40-50 degree dewpoints along with cold advection with 850 mb temps falling from +12/+16 degrees C to around +7/+10 degrees C during the night.

Wednesday and Wednesday Night:

High pressure will move across the Upper Midwest on Wednesday with partly cloudy-mostly sunny skies. High temps will mainly be in the 70s with dewpoints in the 40s and 50s, winds will be out of the west, north or east under 20 mph. By Wednesday Night, high pressure moves off to our east while a new area of low pressure takes aim at the Upper Midwest. Tonight's cold front will stall out and turn into a warm front by Wednesday Night, but this boundary will remain well to our south. Look for some rain and isolated thunderstorms to spread north/east into our local area by Wednesday Night along with mostly cloudy skies. Lows Tomorrow Night will be in the 50s with south or east winds under 20 mph.

Extended Forecast:

Low pressure will deepen as it lifts N/NE into Lake Superior from Thursday into Friday while an upper level trough digs south/east into the Upper Midwest. Much cooler temperatures with highs in the 60s to around 70 degrees are forecast on Thursday with 50s and 60s expected on Friday. Low temps will be in the 40s and 50s both nights, but some 30s can't be ruled out in the typical cold spots for Friday Night. Areas of rain will likely occur around Northern Minnesota and Northwest Wisconsin from Thursday into Friday with the possibility for a few thunderstorms on Thursday.

5 Day Forecast for Duluth/Superior

.Tonight... Turning cooler and less humid. Partly cloudy. Low 50 to 55. Wind west to southwest at 10 to 20 mph.

.Wednesday... Less humid. Partly cloudy. High 73 to 78. Wind west at 10 to 15 mph becoming southeast late.

.Wednesday Night... Mostly cloudy. Showers developing. Low 53 to 58. Wind southeast at 10 to 15 mph. Chance of rain 50%.

.Thursday... Mostly cloudy. Occasional showers. High 60 to 65. Chance of rain 60%.

.Thursday Night... Mostly cloudy. Showers possible. Low 47 to 52. Chance of rain 40%.

.Friday... Mostly cloudy. Showers possible. High 58 to 63. Chance of rain 20%.

.Friday Night... Becoming partly cloudy. Low 45 to 50.

.Saturday... Mostly sunny. High 65 to 70.

Normal High Temperature Today 70 degrees

Normal Low Temperature Today 50 degrees

Tim