Wednesday, August 18, 2010

8/18/10: Wednesday's Weather Report

Issued at 4:16 PM CDT, Wednesday, August 18th, 2010

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

Note: A *FLASH FLOOD WARNING* remains in effect until 6:15 PM CDT This Evening for Douglas County in Northwest Wisconsin. Some cities included in the warning are...Chaffey WI...South Range WI...Wentworth WI...Poplar WI...Patzau WI...Maple WI...Lake Nebagamon WI...Hawthorne WI...Blueberry WI...And Bennett WI... Thunderstorms earlier Today has resulted in heavy rainfall and flash flooding in the warned area. Local Law Enforcement reported a number of county roads washed out from thunderstorms Today. County roads reported washed out so far include...Highway V, South of Mc Kinley...Highway W...And standing water on a number of other county roads.

Quite a difference in weather was found across Northern Minnesota and Northwest Wisconsin last night and Today. Very cool low temperatures occurred in far Northern Minnesota last night while heavy rainfall and thunderstorms affected areas farther south. Note: Thunderstorms began in the Twin Ports around 4 AM CDT This Morning and continued off an on until 1 PM CDT This Afternoon!

Rainfall totals from Tuesday Night, August 17th, 2010 ending around 7 AM CDT This Morning, Wednesday, August 18th, 2010. Source: NWS Duluth, Minnesota.

Duluth MN: 0.15"

International Falls MN: 0.85"

Hibbing MN: 0.18"

Cass Lake MN: 0.67"

Kabetogama MN: 0.44"

Northome MN: 0.24"

4 miles East of Island Lake MN: 0.42"

Silver Bay MN: 0.27"

Floodwood MN: 0.34"

4 miles South of Bruno MN: 0.42"

3 miles South of Ashland WI: 0.32"

9 miles North of Bayfield WI: 0.25"

Solon Springs WI: 0.35"

Cloquet MN: 2.10"

10 miles South of Superior WI (Pattison Park Ranger Station) 1.98"

Local Storm Report from Today, Wednesday, August 18th, 2010. Source: NWS Duluth, MN.

*2:00 PM CDT 8/18/10: 0.75" diameter hail. 14 miles East of Hayward WI (Sawyer County)

*Douglas County Roads were flooded from Today's thunderstorms.

*Lake Superior Zoo (Duluth, Minnesota) was also flooded by Today's storms.

Low temperature report from This Morning. Source: NWS Duluth MN.

International Falls MN: 43 degrees

Cook MN: 42 degrees

Kabetogama MN: 42 degrees

Northome MN: 43 degrees

Embarrass MN: 41 degrees

3 miles East of Orr MN: 41 degrees

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A cold front has been sagging slowly toward the south since last night and as of late Afternoon this boundary extended from Southcentral Upper Michigan through Northcentral Wisconsin back through Central Minnesota. Scattered showers and thunderstorms occurred near that boundary last night and This Morning generally for areas along and south of Highway 2 in Minnesota, some of those storms produced dangerous lightning strikes along with heavy downpours. Duluth Doppler Radar rainfall estimates indicate that anywhere from 1.50-3.00" of rain may have fallen along and south of a line from Boy River to Hill City to Gowan Minnesota through Poplar and Marengo in Northwest Wisconsin...And along and north of a line from Pine River to Aitkin to Sandstone Minnesota to Hayward Wisconsin.

The widespread cloudiness in Southern parts of our area has limited the amount of warmth and instability This Afternoon which is keeping CAPE values down to generally the 500-1000 j/kg range late Today with Lifted Indices of zero/-2 degrees C. A few showers have been falling at times This Afternoon near the cold front in Southern portions of our area, otherwise it was dry for the rest of us.

High temperatures Today were in the 60s to around 70 degrees Today, but it was cooler at the head of Lake Superior (50s) A rather tight moisture gradient covered our area Today with dewpoints ranging from the 40s in Northern Minnesota with 55-64 degree dewpoints in Northwest Wisconsin back through Eastcentral Minnesota. PWS late Today ranged from 0.70-0.90" along and north of Minnesota's Iron Range to between 1.00-1.40" in Northwest Wisconsin back through the Twin Ports, Brainerd, Hinckley and Pine City. Winds Today were south-southwest or north/east in direction around 20 mph or less.

Today's Upper Level Analysis:

RUC model analysis and water vapor satellite imagery show that a northwest flow aloft covered the Upper Midwest Today with strong winds aloft >60 knots at mid levels and 100 knots at upper levels in place across Central Canada Today. A large upper level low was spinning around over Central-Northern Canada/Hudson Bay Today while upper level ridging was in place over the Southwest U.S. A strong temperature gradient continued Today with 50s/60s across most of Central Canada and Northern Minnesota with temps of 85-100 degrees from the Northern Plains back through the Western High Plains/Rockies/and Southern U.S. The overall 500 mb pattern has a definate Autumn look to it with the strong jet stream and impressive temperature contrasts.


The cold front in Central Minnesota late This Afternoon will drop into Southern Minnesota by dawn. Scattered showers or thunderstorms remain a possibility through around 1 AM Tonight, generally along and south of a line from Brainerd Minnesota to Park Falls Wisconsin, limited instability should keep any thunderstorm from becoming too intense, but there is certainly enough support in the shear department and with the stronger mid/upper level winds to cause more robust convection, but the lack of warm air and instability should be the deciding factor in keeping any thunderstorms from turning severe through the Evening hours. Locally heavy rainfall and dangerous lightning strikes will be the main threat from any thunderstorm This Evening.

An area of high pressure sitting to our northwest This Afternoon will slide to a position north/northwest of our local area by late Tonight. Skies will be partly-mostly cloudy around our area Tonight with perhaps some areas of fog with low temperatures in the 40s and 50s. Winds will be out of the north or east under 15 mph.

Thursday and Thursday Night:

High pressure will be in control of our weather Tomorrow resulting in partly cloudy-mostly sunny skies, low humidity and high temperatures generally in the 70s. By Thursday Night, expect Today's cold front to have stalled out in Southern Minnesota Tomorrow before it starts to retreat toward the N/NE Tomorrow Night. A surge of elevated instability with CAPES from 500-1000 j/kg are forecast to advect north into Central-Eastern Minnesota and Northwest Wisconsin Thursday Night with Lifted Indices of zero/-2 degrees C. Scattered showers or thunderstorms could develop Tomorrow Night especially southwest-south of a line from Cass Lake Minnesota to Hayward Wisconsin. Although widespread severe weather is not expected Thursday Night, an isolated risk for severe thunderstorms does exist with a potential of large hail and or damaging winds...This would include the Counties of Cass, Crow Wing, Southern Aitkin and Pine in Minnesota and Burnett, Washburn and Sawyer in Wisconsin.

Partly-mostly cloudy skies are forecast across our area Tomorrow Night with lows in the 50s to lower 60s. Winds will be out of the southeast or east around 20 mph or less during this period.

Extended Forecast:

A rather vigorous upper level disturbance will be pushing north/east through the Upper Midwest on Friday. Dewpoints climbing into the 60s with PWS of 1.00-1.50" will be in place across our local area out ahead of that disturbance on Friday. Scattered showers or thunderstorms are possible across Northern Minnesota and Northwest Wisconsin from Friday into Friday Evening. Isolated severe thunderstorms could develop on Friday as CAPES climb to around 1000 j/kg with Lifted Indicies of zero/-3 degrees C. Highs on Friday will be in the 60s and 70s with lows Friday Night in the 50s to around 60 degrees.

An upper level ridge will build into our area this weekend which will result in mainly dry conditions with moderating temperatures. Highs on Saturday will be in the 70s and 80s with lows Saturday Night in the 50s and 60s, similar temperatures can be expected for Sunday.

5 Day Forecast for Duluth/Superior

.Tonight... Mostly cloudy with some clearing later in the night. Patchy fog. Low 47 to 52. Wind variable around 12 mph.

.Thursday... Partly cloudy. High 70 to 75. Wind east to southeast at 10 to 15 mph.

.Thursday Night... Mostly cloudy. Showers or thunderstorms possible late. Low 53 to 58. Wind east to southeast at 10 to 15 mph. Chance of rain 40%.

.Friday... Mostly cloudy. Showers or thunderstorms possible. High 65 to 70. Chance of rain 50%.

.Friday Night... Mostly cloudy. Showers or thunderstorms possible early. Low 53 to 58. Chance of rain 30%.

.Saturday... Partly cloudy. High 78 to 83.

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

.Sunday... Partly cloudy. High 78 to 83.

Normal High Temperature Today 74 degrees

Normal Low Temperature Today 54 degrees