Wednesday, September 22, 2010

9/22/10: Wednesday's Weather Report

Issued at 3:33 PM CDT, Wednesday, September 22nd, 2010

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



1 AM CDT Tonight through late Thursday Night

Counties included in the watch:

Cass MN...Crow Wing MN...Aitkin MN...Southern St. Louis MN...Carlton MN...Pine MN...Douglas WI...Bayfield WI...Ashland WI...Iron WI...Burnett WI...Washburn WI...Sawyer WI...and Price WI...

Some cities included in the watch:

Cass Lake MN...Walker MN...Pillager MN...Fifty Lakes MN...Brainerd MN...Pine Center MN...Hill City MN...Aitkin MN...McGrath MN...Floodwood MN...Duluth MN...Cromwell MN...Moose Lake MN...Hinckley MN...Pine City MN...Superior WI...Solon Springs WI...Port Wing WI...Bayfield WI...Cable WI...Ashland WI...Butternut WI...Hurley WI...Mercer WI...Danbury WI...Grantsburg WI...Minong WI...Shell Lake WI...Hayward WI...Exeland WI...Park Falls WI...Phillips WI...and Ogema WI...


Rainfall totals of 1-4" are possible in the watch area from Tonight through late Thursday Night. Prolonged heavy rain and thunderstorms may result in street flooding and blocked culverts from run-off and debris. Flood prone areas will likely experience the greatest impact from the heavy rain.

A flood watch means there is a potential for flooding based on current forecasts. Monitor later forecasts and be alert for possible flood warnings. Those living in areas prone to flooding should be prepared to take action should flooding develop.

Weather Tidbits:

*Average monthly temperature at Duluth, Minnesota through September 21st.
52.6 degrees/3.6 degrees below average.

*Rainfall total at Duluth Minnesota, through 9/21: 2.12" which is 0.92" below average.

*New summertime record for nighttime lows in the Twin Cities. June through August low temperatures were nearly 5.0 degrees warmer than average. The average low temperature from June through August is 60.5 degrees...This year saw an average nighttime low of 65.4 degrees! The previous record was 65.1 degrees set in 1939. Source: Pete Boulay. Minnesota State Climate Office/Paul Douglas, St. Cloud Times.

*Temperature at the Minneapolis-St. Paul International Airport climbed from the middle to upper 50s at mid-Afternoon Monday (9/20/10) to 80 degrees just before Midnight Monday Night as a powerful warm front lifted north out of southern Minnesota on Monday.

September 2010 at Duluth, Minnesota has seen the fewest 70 and 80 degree days dating back to 2005...

September 2005: 11 days>70 degrees and 5 days>80 degrees.
September 2006: 7 days>70 degrees and 2 days>80 degrees.
September 2007: 5 days>70 degrees and 5 days>80 degrees.
September 2008: 6 days>70 degrees and 1 day>80 degrees.
September 2009: 18 days>70 degrees and 2 days>80 degrees.
September 2010: 1 day>70 degrees...Ending on September 22nd.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Low pressure of 1010 mb was centered in southwest North Dakota with another 1010 mb low extending from southern to northeast Colorado. A warm front as of 3 PM extended from central Nebraska to central Iowa with numerous showers and thunderstorms developing north of this boundary Today across southeast South Dakota, southern Minnesota and portions of northwest Iowa and northeast Nebraska. These storms Today have been prolific hail producers with over 30 reports of large hail (1.00 to as big as 4.25" in diameter) being reported so far Today per Storm Prediction Center with the axis of the hail confined to southeast South Dakota and northeast Nebraska thus far. Well north of the warm front across our local area, skies were starting to cloud up from southwest to northeast with high temperatures Today in the 50s, except for lower to middle 60s from Brainerd to Pine City, east through Siren, Hayward and Phillips. Winds Today were out of the east generally under 20 mph.

Today's Upper Level Analysis:

RUC model analysis and water vapor satellite imagery show a southwest flow aloft developing once again across the Upper Midwest This Afternoon as a potent upper level trough heads east out of the Pacific Northwest with another piece of energy ejecting northeast out of the Southwest U.S. A few disturbances running out ahead of the main system over the Western U.S. has resulted in the showers and thunderstorms Today across portions of the Upper Midwest/Northern Plains.


Low pressure will deepen to around 1003 mb Tonight as it heads northeast into central Nebraska with a warm front inching north toward the Minnesota-Iowa border during the night. A disturbance moving E-NE out of the Northern Plains combined with a 30-45 knot southerly low level jet, and lift occurring along and north of the warm front will combine forces with continued warm air advection and deep moisture transport...Note: PWS This Afternoon of 0.60-0.80" will climb to 1.00-1.75" Overnight... All these factors mentioned above will cause areas of rain and isolated thunderstorms in northern Minnesota and northwest Wisconsin Tonight. At this time it appears that the heaviest rainfall for Tonight (1.00" or greater amounts) will setup south of our local area, but rain totals nearing an inch are possible Tonight in southern areas, or along and south/southeast of a line from Pine City Minnesota to Hurley Wisconsin. Mostly cloudy skies with lows in the 40s and 50s can be expected Tonight with easterly winds at 5-15 mph with gusts up to 25 mph, especially near Lake Superior.

Thursday and Thursday Night:

Low pressure will deepen to around 995 mb during this period as it lifts northeast into southern or central Minnesota by late Thursday Afternoon, this low will then move into northcentral Wisconsin Thursday Night. Strong forcing/lift associated with this low and north of a warm front which will remain south of our local area will result in widespread rainfall across northern Minnesota and northwest Wisconsin from Thursday into Thursday Evening. With PWS of 1.00-1.75" and 850 mb td's of +8/+12 degrees C in place, the threat for very heavy rainfall does exist especially from eastcentral Minnesota through all of northern Wisconsin through Thursday Evening. By Thursday Night, a dry slot lifting northeast may cause the rain to end in portions of northwest Wisconsin, possibly even in eastern Minnesota while northern Minnesota continues to see some rain most of the night. Instability looks limited for Tomorrow, but isolated thunderstorms could develop through Tomorrow Evening across northwest Wisconsin and eastern Minnesota. High temperatures Tomorrow will be in the 40s and 50s, but a few 60s could sneak north into the Hayward, Park Falls and Phillip areas in northwest Wisconsin. Lows Tomorrow Night will be in the 40s and 50s.

Winds Tomorrow and Tomorrow Night will be out of the east or northeast at 10-25 mph with gusts of 30-40 mph especially near Lake Superior.

*Gale Watch* continues for Western and Central Lake Superior, including the Twin Ports Harbor for Thursday Afternoon and Thursday Evening. Northeasterly gales up to 45 knots with peak wave heights of 11 feet are expected during this event.

Rainfall totals between Tonight and Friday should range from 0.50-1.50" across our area, but there will be areas that receive higher amounts of 2-4"...Right now this area looks to be in Northwest Wisconsin and Eastcentral Minnesota.

Extended Forecast:

Deep low pressure (992-995 mb) will reach Upper Michigan and Eastern Lake Superior on Friday...Lingering areas of rain are expected through Friday Morning across our area, then we should see drier conditions Friday Afternoon into Friday Night. A new area of low pressure will then drop south/southeast out of the Northern Plains on Saturday, this disturbance combined with an area of cold temperatures aloft (near -20 degrees C at 500 mb) could promote the development of a few showers on Saturday across our area. Highs will be mainly in the 50s both Friday and Saturday with lows in the 30s and 40s both nights in Northern Minnesota and Northwest Wisconsin.

5 Day Forecast for Duluth/Superior

*FLOOD WATCH* in effect from 1 AM CDT Tonight through late Thursday Night...

*GALE WATCH* in effect for the Duluth/Superior Harbor for Thursday Afternoon and Thursday Evening...

.Tonight... Breezy. Mostly cloudy with occasional showers developing after 7 PM. Low 45 to 48. Wind east at 10 to 20 mph with gusts to 30 mph.

.Thursday... Windy. Scattered showers possible during the Morning becoming a steadier rain during the Afternoon. High 48 to 53. Wind east at 15 to 30 mph with gusts to 40 mph.

.Thursday Night... Windy with occasional rain. Low 40 to 45. Wind east to northeast at 15 to 30 mph with gusts to 40 mph. Wind becoming north at 10 to 20 mph late.

.Friday... Breezy. Mostly cloudy with occasional rain. High 50 to 55. North wind could occasionally gust to 25 mph.

.Friday Night... Partly to mostly cloudy. Low 40 to 45.

.Saturday... Mostly cloudy. Showers possible. High 50 to 55. Chance of rain 20%.

.Saturday Night... Partly to mostly cloudy. Low 38 to 43.

.Sunday... Partly cloudy. High 57 to 62.

Normal High Temperature Today 62 degrees

Normal Low Temperature Today 43 degrees