Saturday, September 4, 2010

9/4/10: Saturday's Weather Report

Issued at 4:02 PM CDT, Saturday, September 4th, 2010

...All headlines issued by the National Weather Service Duluth, Minnesota...

*FROST ADVISORY*

Timing:

Midnight CDT Tonight until 8 AM CDT Sunday.

Counties included in the advisory:

Koochiching MN...Itasca MN...Central and Northern St. Louis MN...Lake MN...and Cook MN...

Some cities included in the advisory:

International Falls MN...Littlefork MN...Bigfork MN...Grand Rapids MN...Hibbing MN...Ely MN...Cotton MN...Orr MN...Two Harbors MN...Silver Bay MN...Isabella MN...Grand Marais MN...Hovland MN...and Grand Portage MN...

Discussion:

High pressure with mainly clear skies and diminishing winds will cause low temperatures to drop into the lower to middle 30s in the advisory area which will cause areas of frost Overnight into early Sunday Morning north of the Twin Ports.

A frost advisory means that frost is possible. Sensitive outdoor plants and or crops may be killed if left uncovered. More cold-hardy plants are not apt to be harmed by frost.

Damaging winds (tropical storm force) developed over parts of Lake Superior and Upper Michigan on Friday, September 3rd, 2010 as a powerful Autumn type low pressure system moved across Lake Superior. Here are some peak wind gusts that occurred on Friday. Source: NWS Marquette, Michigan.

Houghton County Airport MI: 52 mph

Copper Harbor MI: 53 mph

Ojibway Isle Royale: 66 mph

Grand Marais: 64 mph

Munising MI: 52 mph

Stannard Rock Lake Superior: 72 mph

Caribou Island: 54 mph

Point Iroquois/Whitefish Bay Lake Superior: 55 mph

Low temperature report from earlier Today, Saturday, September 4th, 2010. Source: NWS Duluth, MN.

Duluth MN: 42 degrees

International Falls MN: 38 degrees

Two Harbors MN: 39 degrees

Ely MN: 39 degrees

Littlefork MN: 39 degrees

Embarrass MN: 35 degrees

3 miles East of Orr MN: 38 degrees

Rainfall report from Friday, September 3rd, 2010. Source: NWS Duluth, MN.

Duluth MN: 0.14"

Ashland WI: 0.24"

Hayward WI: 0.38"

Embarrass MN: 0.23"

Butternut WI: 0.27"

Gurney WI: 0.48"

Upson WI: 0.83"

Madeline Island: 0.29"

4 miles West of Clam Lake WI: 0.33"

Washburn WI: 0.56"

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Deep low pressure (990 mb) was centered over Northern Quebec Province Canada late Today with high pressure (1018 mb) centered in Northwestern Missouri. Mostly sunny skies covered our area Today with high temperatures in the middle 50s to middle 60s with dewpoints down into the 35-45 degree range with PWS of just around 1/2"! Winds Today were out of the west or northwest at 10-25 mph.

Today's Upper Level Analysis:

Northwest flow aloft covered the Upper Midwest Today per water vapor satellite imagery with a strong upper level trough in place over the Upper Midwest/Great Lakes/Central-Eastern Canada. A strong baroclinic zone existed Today with +20/+32 degree C 850 mb temperatures covering the Western High Plains and Rockies with zero/+4 degree C 850 mb temperatures from Central Canada through the Upper Midwest per RUC model analysis.

Tonight:

High pressure will be centered to our south/southeast Tonight. Look for mostly clear skies with winds out of the north or west under 15 mph. Low temps Tonight will be in the 30s and 40s, but a few of the typical cold spots could slip into the upper 20s by dawn. Patchy frost is expected late Tonight, especially along and north of Highway 2 in Minnesota and inland from the North Shore of Lake Superior.

Sunday and Sunday Night:

High pressure will push off to our south/east during this period while low pressure moves into the Western High Plains. Partly cloudy-mostly sunny skies are on tap for Sunday with highs mainly in the 60s to lower 70s. Partly-mostly cloudy skies are forecast Sunday Night with lows in the 40s, but some 30s are possible in the Arrowhead. Winds will become south/east during this period at 10-20 mph.

Extended Forecast:

A rather strong area of low pressure at the surface and aloft will head northeast out of the Western High Plains/Northern Plains and will pass through the Upper Midwest from Monday Afternoon into Tuesday Morning. This system will not have much moisture to work with as dewpoints are expected to remain in the 50s in our area with PWS generally ranging from 1.00-1.25", this system will be very dynamic though thanks in part to a strong mid/upper level jet of 70-100 knots. Areas of rain will develop and spread northeast across Northern Minnesota and Northwest Wisconsin from Monday into Monday Night with rain coming to an end on Tuesday. At this time it appears that the heaviest band of rain will occur west-northwest of our local area, but this will depend on the final track the low pressure system takes. A few thunderstorms can't be ruled out either, especially Monday Evening-Overnight, but severe weather is not expected in our area. High temperatures on Monday will be in the 50s and 60s with lows Monday Night in the 40s and 50s. Highs on Tuesday will only be in the 50s with some Northern areas possibly holding in the 40s most of the day. Lows Tuesday Night will be in the 30s and 40s.

A larger upper level trough is still expected to take shape across the Western U.S. from mid to late week with a southwest flow aloft developing over the Upper Midwest later in the week. Chances for showers/thunderstorms will occur sometime between Thursday-Saturday of next week as the upper trough and area of low pressure, warm front and cold front pass through the Upper Midwest.

5 Day Forecast for Duluth/Superior

.Tonight... Clear. Low 37 to 42, a little milder in Downtown Duluth. Wind northwest at 5 to 15 mph.

.Sunday... Mostly sunny. High 65 to 70. Wind west at 5 to 15 mph.

.Sunday Night... Partly cloudy. Low 45 to 50. Wind becoming east at 10 to 15 mph.

.Labor Day... Mostly cloudy. Showers developing. High 60 to 65 but cooler near Lake Superior. Chance of rain 30%.

.Monday Night... Occasional showers. Mostly cloudy. Low 48 to 53. Chance of rain 60%.

.Tuesday... Showers possible, especially early. Mostly cloudy. High 55 to 60. Chance of rain 40%.

.Tuesday Night... Partly cloudy. Low 40 to 45.

.Wednesday... Mostly sunny. High 60 to 65.

Normal High Temperature Today 68 degrees

Normal Low Temperature Today 49 degrees

Tim