Thursday, August 19, 2010

8/19/10: Thursday's Weather Report

Issued at 3:37 PM CDT, Thursday, August 19th, 2010

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


A Flood Watch has been issued for portions of Northeast and Eastcentral Minnesota and Northwest Wisconsin.

Timing: Midnight CDT Tonight through Friday Evening.

Counties affected:

Cook MN...Lake MN...Central and Southern St. Louis MN...Aitkin MN...Carlton MN...Pine MN...Douglas WI...Bayfield WI...Burnett WI...Washburn WI...and Sawyer WI...

Some cities included in the watch:

Grand Marais MN...Silver Bay MN...Isabella MN...Two Harbors MN...Hibbing MN...Cotton MN...Duluth MN...Floodwood MN...Hill City MN...Aitkin MN...McGregor MN...Cloquet MN...Moose Lake MN...Hinckley MN...Pine City MN...Superior WI...Solon Springs WI...Port Wing WI...Bayfield WI...Cable WI...Danbury WI...Siren WI...Minong WI...Spooner WI...Hayward WI...Loretta WI...and Exeland WI...

Recent heavy rainfall combined with additional chances for locally heavy rain beginning late Tonight and lasting into Friday Evening could cause flooding of small rivers...creeks and streams and area roads.

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

*8/18/10: Flash Flood. South Range WI (Douglas County) Douglas County Highway Patrol reports many county roads either washed out or with standing water on them.

*8/18/10: Heavy Rain. South Range WI (Douglas County) 3.75" rainfall total.

*8/18/10: Heavy Rain. 1 mile Southeast of Wentworth WI (Douglas County) 4.25" rainfall total.

Rainfall report from Northeast Minnesota and Northwest Wisconsin. Date: Wednesday, August 18th, 2010. Source: NWS Duluth, MN.

Duluth MN: 0.54"

Ashland WI: 0.80"

Hayward WI: 1.21"

Floodwood MN: 0.65"

4 miles South of Bruno MN: 0.50"

9 miles North of Bayfield WI: 0.42"

Gordon WI: 1.65"

Butternut WI: 0.95"

Upson WI: 0.68"

Gurney WI: 0.63"

Low temperature report from This Morning, Thursday, August 19th, 2010. Source: NWS Duluth, MN.

International Falls MN: 38 degrees

Grand Marais MN: 39 degrees

Ely MN: 39 degrees

Orr MN: 39 degrees

Weather Tidbits:

*Monthly rainfall total at Duluth, Minnesota thru August 18th, 2010: 5.23"
Normal thru the 18th: 2.38"
Departure from normal: +2.85"

*Rainfall total since June 1st, 2010: 13.43"
Normal: 10.83"
Departure from normal: +2.60"

*Precipitation total since January 1st, 2010: 22.58"
Normal: 19.51"
Departure from normal: +3.07"

Weather History:

On this date in 2004... A record low temperature of 37 degrees occurred at Duluth, Minnesota.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A stationary front was draped across Southern Minnesota Today with high pressure of 1016 mb centered over Northwestern Lake Superior. A wide range in temperatures/dewpoints were found on either side of this front Today. Our local area was on the cool side of this boundary Today with mostly sunny skies, dewpoints in the 40s and 50s with highs in the mid 60s to low 70s with 50s around the head of Lake Superior. Highs in the 80s were found across parts of Westcentral-Southern Minnesota Today with dewpoints up into the 60s and even some 70s! Winds across our area were out of the east Today at 10-20 mph.

Today's Upper Level Analysis:

A vigorous short wave trough was progressing east through the Northern-Central Rockies and into the Northern Plains This Afternoon per water vapor satellite imagery. Northwest flow aloft was beginning to ease a bit late Today over the Upper Midwest as Wednesday's system deepens as it moves into Eastern Canada while the flow aloft turns more W/SW over our area in response to the approaching system from the Rockies.


A stationary front over Southern Minnesota This Afternoon will turn into a warm front as it lifts slowly toward the N/NE during the night. A southerly low level jet nearing 25-35 knots combined with forcing near that warm frontal boundary and out ahead of the approaching disturbance from the W/SW will result in the blossoming of scattered showers and thunderstorms across our local area. Precipitation will begin by mid or late Evening in western-southern areas, reaching the Twin Ports between 12-2 AM, then continue to spread farther north to the Arrowhead and Iron Range communities after 3 AM. Deep tropical moisture will spread south to north into our area during the night as dewpoints climb into the 60s in Southern areas while PWS increase to between 1.00-1.75" Tonight. Locally heavy rainfall will be possible especially by late Tonight with areas of flooding possible Overnight. A few of the thunderstorms could also become severe later Tonight as elevated CAPES climb to between 500-1500 j/kg along and south of Highway 2 in Minnesota and generally west of Highway 53 in Northwest Wisconsin. Large hail and damaging wind would be the main threats if severe weather does develop later in the night. Cass, Crow Wing, Aitkin, Pine, Carlton, Southern St. Louis, Douglas, Burnett and Washburn Counties would be most susceptible to getting a few severe thunderstorms late Tonight.

Partly-mostly cloudy skies will cover our area with lows in the 50s and 60s Tonight along with east or southeast winds from 10-20 mph.

Friday and Friday Night:

A rather potent disturbance will pass E/NE through the Upper Midwest on Friday before exiting the region by Friday Night. A warm front will lift N/NE toward Eastcentral Minnesota and Northern Wisconsin on Friday before it pushes toward the south again by Friday Evening. Showers or thunderstorms are expected in Northern Minnesota and Northwest Wisconsin on Friday with precipitation ending from west to east by Friday Evening. Abundant moisture in place...Dewpoints in the 60s with PWS around 1.50-2.00" will result in a potential for heavy rainfall and possible flooding on Friday. There is also a risk for a few severe thunderstorms for Friday, mainly over Northwest Wisconsin and Eastern Minnesota...Or along and south-east of a line from Hinckley Minnesota to Upson Wisconsin. Large hail and damaging wind would be the main threats if severe weather does develop Tomorrow.

Mostly cloudy skies with highs in the 60s and 70s can be expected Tomorrow with partly-mostly cloudy skies with lows in the 50s to around 60 degrees Tomorrow Night. Winds will be out of the south, east or west Tomorrow at 10-20 mph with north or west winds under 15 mph Tomorrow Night.

Extended Forecast:

An upper level ridge of high pressure is forecast to build into the Upper Midwest this weekend which will result in a few days of dry weather along with moderating temperatures, although an east wind could keep it somewhat cooler near Lake Superior especially by Sunday. High temperatures will be in the 70s and 80s for Saturday and Sunday with lows both nights in the 50s and 60s.

The next threat for showers/thunderstorms will come sometime next Monday or early Tuesday as a cold front passes east through the Upper Midwest.

5 Day Forecast for Duluth/Superior

*FLOOD WATCH* valid from Midnight CDT Tonight through Friday Evening...

.Tonight... Becoming mostly cloudy. Occasional showers or thunderstorms developing after Midnight. Locally heavy rainfall possible. Low 53 to 58. Wind east to southeast at 10 to 20 mph. Chance of rain increasing to 70 percent late.

.Friday... Occasional showers or thunderstorms. Locally heavy rainfall possible. Mostly cloudy with areas of fog. High 63 to 68. Wind east at 10 to 15 mph. Chance of rain 80%.

.Friday Night... Mostly cloudy. Showers possible early. Areas of fog. Low 53 to 58. Wind becoming north at 5 to 15 mph. 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.

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

.Monday... Partly sunny. Late day showers or thunderstorms possible. High 77 to 82. Chance of rain 20%.

Normal High Temperature Today 74 degrees

Normal Low Temperature Today 53 degrees