Friday, August 20, 2010

8/20/10: Friday's Weather Report

Issued at 3:50 PM CDT, Friday, August 20th, 2010

Note: Heavy rainfall and isolated severe weather affected portions of Northern Minnesota and Northwest Wisconsin late last night/This Morning as a bow echo and large complex of rain/thunderstorms moved quickly toward the northeast.

Local Storm Report from Friday, August 20th, 2010. Source: NWS Duluth, MN.

*2:56 AM CDT 8/20/10: Thunderstorm Wind Damage. McGrath MN (Aitkin County) Some trees down.

*7:24 AM CDT 8/20/10: 1.25" diameter hail. Kennan WI (Price County)

*8:00 AM CDT 8/20/10: Heavy rain, 2.26". Cass Lake MN (Cass County)

*8:00 AM CDT 8/20/10: Heavy rain, 1.65". Floodwood MN (St. Louis County)

*9:30 AM CDT 8/20/10: Heavy rain, 2.29". Phillips WI (Price County)

*10:00 AM CDT 8/20/10: 0.88" diameter hail. Mercer WI (Iron County)

*10:05 AM CDT 8/20/10: 1.00" diameter hail. Mercer WI (Iron County) Trees down and power outages as well.

*11:00 AM CDT 8/20/10: Heavy rain, 0.92". Duluth MN-National Weather Service (St. Louis County)

*11:00 AM CDT 8/20/10: Heavy rain, 1.90". Two Harbors MN (Lake County)

Rainfall report from Northeast Minnesota and Northwest Wisconsin. Date: Thursday/Friday, August 19th and 20th, 2010. Note: Rainfall totals through around 7 AM CDT This Morning.

Duluth MN: 0.52"

Brainerd MN: 0.64"

Grand Marais MN: 0.34"

Hibbing MN: 0.81"

Ashland WI: 0.33"

Hayward WI: 0.51"

Cook MN: 0.35"

Northome MN: 0.32"

8 miles South of Bigfork MN: 0.63"

2 miles South of Tower MN: 0.56"

4 miles East of Island Lake MN: 1.02"

Silver Bay MN: 0.66"

Bruno MN: 0.67"

12 miles North of Isle MN: 1.44"

9 miles North of Bayfield WI: 0.42"

Solon Springs WI: 0.60"

Winter WI: 0.97"

Webster WI: 0.74"

Upson WI: 0.35"

Sarona WI: 0.98"

30 Day Outlook for September 2010. Issued by the Climate Prediction Center on Thursday, August 19th, 2010.

For Duluth:

Equal Chances for Above Normal, Normal or Below Normal Temperatures.
Equal Chances for Above Normal, Normal or Below Normal Precipitation.

90 Day Outlook for September through November 2010. Issued by the Climate Prediction Center on Thursday, August 19th, 2010.

For Duluth:

40% Chance for Above Normal Temperatures.
Equal Chances for Above Normal, Normal or Below Normal Precipitation.

Weather History:

On this date in 2004... A record low temperature of 36 degrees occurred at Duluth, MN.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A warm front as of 3 PM was centered along a line from near Brainerd Minnesota to Wausau Wisconsin with a cold front across Western Minnesota and an area of low pressure averaging 1002 mb in Western Minnesota. A wide variety of weather was occurring Today depending on what side of the warm front you were on. Temperatures This Afternoon have warmed into the 80s from Pine River to Hinckley Minnesota and points southwest from there with dewpoints in the 65-75 degree range! Widespread 70s to lower 80s with dewpoints in the 60s and 70s were found across Northwest Wisconsin. North of the warm front, temperatures were stuck in the 60s and lower 70s Today with even cooler temperatures in the 50s at the head of Lake Superior. Some sunshine has broken out at times Today, especially in Western-Southwest parts of our area, elsewhere skies were mostly cloudy Today. Areas of fog were common near Lake Superior due to the east wind and high amounts of moisture in place. The complex of rain/thunderstorms which moved across our area early Today moved out This Morning leaving behind mainly dry conditions by This Afternoon. Winds Today were out of the south or east around 15 mph or less.

Today's Upper Level Analysis:

Westerly flow aloft was in place over the Upper Midwest Today per RUC model analysis. A rather potent shortwave trough was moving across the region Today per water vapor satellite imagery.


An area of low pressure which was over Western Minnesota This Afternoon will move east This Evening while the warm front which was lined up from Central Minnesota to Central Wisconsin sinks south during the night in response to the surface low heading east through the Upper Midwest. Latest meso-analysis shows quite a bit of instability has built up late This Afternoon over all but Northeast areas of Minnesota. CAPES ranged from 1000-2500 j/kg with Lifted Indices anywhere from -3/-8 degrees C with Lapse Rates around 6.5 c/km. There is also some fairly decent convergence and moisture convergence near this system from Central Minnesota east through Northwestern Wisconsin, but thus far all the action has been from Southern through Northeastern Wisconsin This Afternoon. There is still a possibility that we could see a few showers or thunderstorms develop before Midnight Tonight mainly in Northwest Wisconsin into Eastcentral Minnesota. If thunderstorms can develop, they could turn severe thanks to enough shear in place (Around 30 knots) The winds in the mid/upper levels of the atmosphere have decreased significantly Today, and this would result in a fairly slow movement of any storm which increases the threat for locally heavy rainfall thanks to the high amounts of moisture in the atmosphere, dewpoints in the 60s and 70s, PWS around 1.50" with 850 mb td's >12 degrees C. The greatest potential for some additional rain This Evening would be along and south of a line from Leader to Duluth Minnesota, including all of Northwest Wisconsin. The threat for showers/thunderstorms will end by Midnight with partly-mostly cloudy skies through the night along with areas of fog which could become dense, especially around Lake Superior. Lows Tonight will be in the 50s to lower 60s with winds becoming north or east under 15 mph.

Saturday and Saturday Night:

High pressure will build into our area from the northwest during this period, areas of fog should burn off before 9 AM Tomorrow, otherwise look for partly-mostly sunny skies on Saturday with highs in the 70s and 80s. Clear-partly cloudy skies with lows in the 50s to lower 60s can be expected Saturday Night. Winds during this period will be out of the north, northeast or northwest under 20 mph.

Extended Forecast:

An upper level ridge of high pressure will be in control of our weather for Sunday and Sunday Night with high temperatures in the 70s and 80s with lows in the 50s and 60s. A cold front is set to move across our area from west to east by Monday Night/Tuesday Morning, enough moisture and instability should be in place near this front to cause some showers or thunderstorms from Monday Evening through early Tuesday. Highs on Monday will be in the 70s and 80s with lows Monday Night in the 50s and 60s.

5 Day Forecast for Duluth/Superior

.Tonight... Areas of fog which could be dense at times. Mostly cloudy. Showers or thunderstorms possible before 10 PM. Low 53 to 58. Wind east at 5 to 15 mph. Chance of rain 20%.

.Saturday... Areas of fog early, otherwise partly to mostly sunny. High 75 to 80 but cooler near Lake Superior. Wind north to northeast at 10 to 15 mph.

.Saturday Night... Mostly clear. Low 55 to 60. Wind east at 5 to 15 mph.

.Sunday... Partly cloudy. High 77 to 82 but cooler near Lake Superior.

.Sunday Night... Partly cloudy. Low 58 to 63.

.Monday... Partly cloudy. High 78 to 83.

.Monday Night... Showers or thunderstorms possible. Mostly cloudy. Low 60 to 65. Chance of rain 40%.

.Tuesday... Partly sunny. High 70 to 75.

Normal High Temperature Today 73 degrees

Normal Low Temperature Today 53 degrees