Saturday, June 5, 2010

6/5/10: Saturday's Weather Report

Issued at 3:52 PM CDT, Saturday, June 5th, 2010

Weather History:

On this date in 2000... A record low temperature of 32 degrees occurred at Duluth, MN.

On this date in 1988 and previous years... A record high temperature of 88 degrees occurred at Duluth, MN.

Here are some rainfall totals across Northern Minnesota and Northwest Wisconsin from 7 AM CDT Friday ending at 7 AM CDT Saturday. Source: NWS Duluth, MN.

Duluth MN (St. Louis County) 0.10"

International Falls MN (Koochiching County) 0.34"

Grand Marais MN (Cook County) 0.62"

Ashland WI (Ashland County) 0.63"

Hayward WI (Sawyer County) 0.40"

Cook MN (St. Louis County) 0.23"

Kabetogama MN (St. Louis County) 0.81"

2 miles South of Tower MN (St. Louis County) 0.30"

Silver Bay MN (Lake County) 0.46"

5 miles Northwest of Washburn WI (Bayfield County) 0.47"

Madeline Island WI: 0.64"

Butternut WI (Ashland County) 0.60"

Upson WI (Iron County) 0.40"

Here are some two day rainfall totals that have occurred between Thursday Night and early Saturday. Source: NWS Duluth, MN.

Duluth MN: 0.27"

International Falls MN: 0.56"

Ashland WI: 0.86"

Hayward WI: 1.19"

Silver Bay MN: 0.62"

5 miles Northwest of Washburn WI: 0.78"

Upson WI: 0.62"

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A large area of light to moderate rain has been pushing east through Southern portions of our area Today. The bulk of this rain occurred along and south of a line from Sandstone MN to Hayward WI east toward the Park Falls and Mercer areas in Northwestern Wisconsin. The rest of our area saw scattered showers Today with a few isolated thunderstorms as well in parts of Northern Minnesota This Afternoon. Partly sunny-mostly cloudy skies were found over our area Today with high temperatures mainly in the 60s to around 70 degrees with cooler 50s near Lake Superior. 850 mb temperatures as of 3 PM ranged from +7/+11 degrees C from northeast to southwest across our area. Winds Today were out of the west or east under 20 mph. Surface map This Afternoon featured low pressure of 1006 mb centered in far Northern Minnesota with a trough (Friday's occluded front) extending in a northwest-southeast fashion from Southern Manitoba Province through Northern Minnesota to Western Lake Superior to Central Upper Michigan. Low pressure of 1004 mb was centered in Northern Iowa with a warm front attached to this low extending from Northcentral parts of Iowa to the Wisconsin-Illinois state line.

Today's 500 mb analysis:

Upper level lows covered Hudson Bay Canada with another one in Southern Manitoba Province. Fast Pacific flow (nearly west-east) continued Today across the Northern half of the U.S. with unusually strong jet stream winds 110-130 knots covering portions of the Northwest U.S./Northern Rockies/Northern Plains Today per RUC model analysis. An upper level ridge (594 meters) covered most of the Southwest U.S. and portions of the Southern Plains Today.


A surface trough in Northern Minnesota This Afternoon will sink slowly south/west during the night. The large area of light-moderate rain in Northwest Wisconsin late Today will exit off to the east between 6 PM-8 PM This Evening, most locations can expect a quarter to possibly half inch of rain in Northwest Wisconsin This Evening. Scattered showers and isolated thunderstorms will continue to develop in Northcentral-Northeast Minnesota through the Evening hours thanks to the trough up north and an area of cold air aloft (H5 temperatures around -15 degrees C) CAPES of 100-500 j/kg combined with Lapse Rates around 7.0 c/km and Lifted Indices of zero/-3 degrees C will also be in place across sections of Northcentral Minnesota This Evening. Severe weather is not expected Tonight, but a limited risk for small hail and wind gusts to 35 mph could occur in the strongest storms. Locally heavy downpours and occasional lightning strikes will also be a threat.

The potential for thunderstorms is expected to end by late Evening, but a few showers could linger through the Overnight hours across Northern Minnesota and Northwest Wisconsin. Partly-mostly cloudy skies are forecast Tonight with areas of fog, which could become dense once again especially near Lake Superior. Lows will be in the 40s to around 50 degrees. Winds will be out of the west, north, or east under 20 mph.

Sunday and Sunday Night:

A surface trough will set-up in Western-Southern parts of our local area on Sunday while an area of cool air associated with 850 mb temperatures of +4/+6 degrees C north of Lake Superior advects south/west into areas near Lake Superior. Note: This airmass will be cold enough Tonight to cause widespread frost north of Lake Superior. The main axis of scattered showers and possibly a thunderstorm or two for Sunday and Sunday Evening is expected to set-up in Western-Southern portions of our local area the way it looks now with smaller chances of showers in Northeast Minnesota and far Northwest Wisconsin. There are differences with the forecast models Today on where the main corridor of showers will occur, the GFS is farther west-south while the NAM-WRF has a more northern solution. Partly sunny-mostly cloudy skies are expected on Sunday with highs in the 50s and 60s, but some locales closer to Lake Superior could have a tough time getting out of the 40s where areas of fog may persist at times on Sunday. Lows Sunday Night under partly-mostly cloudy skies will be in the 30s and 40s. Winds will be out of the west, north, or east at 10-20 mph on Sunday with east or west winds under 15 mph for Sunday Night.

No severe weather is forecast on Sunday due to only marginal amounts of instability. CAPES generally around 150 j/kg with Lifted Indices around zero degrees C, but with cold 500 mb temperatures overhead (around -16 degrees C) small hail cannot be totally ruled out if any stronger storm pops up Tomorrow Afternoon.

Extended Forecast:

Monday looks like it will be dry before another round of rain/showers moves across Northern Minnesota and Northwest Wisconsin during the Monday Night-Tuesday time period. The main warm frontal boundary looks to remain well to our south early next week and this is where the severe weather chances will be located. We could see an isolated thunderstorm Monday Night or Tuesday in our local area as an area of low pressure and occluded front pass through, but moisture and instability look limited this far north for a bigger thunderstorm risk. High temperatures on Monday will be in the 60s and 70s with lows Monday Night in the 40s and 50s. Highs on Tuesday will be in the 50s and 60s, maybe a few 70s depending on the timing of this next system. Lows Tuesday Night will be in the 40s and 50s, the threat for showers should be ending by Tuesday Night the way it looks now as low pressure and it's occluded front exit to our north/east.

The longer range forecast models continue to show a pattern shift taking place for late next week and next weekend with a building upper level ridge of high pressure from the Plains through the Southern/Southeast U.S. while an upper level trough sets-up to our west. A southwest flow aloft will develop across the Upper Midwest by late next week. The models are not in agreement, however, on the timing of the warm front, and where/when the boundary will stall out. The trend with the GFS is for a more progressive system, shoving the warm front north into Minnesota by late next week, while the last run per EUROPEAN model has a much slower outcome with the warm front/stationary front not reaching the Upper Midwest until next weekend. The GFS model over the past few days has been showing abundant low level moisture and quite a bit of instability advecting north into the Upper Midwest late next week/next weekend which could set the stage for occasional thunderstorm/severe thunderstorm complexes, but whether or not these affect our local area or not depends on where the boundary sets-up, also of note is the very strong cap that the GFS has been showing recently for late next week/next weekend for the Upper Midwest with 700 mb temperatures warming to +12/+14 degrees C! That is one strong cap should it develop, and if it does it may keep surface based thunderstorms from developing, but elevated convection could still occur.

5 Day Forecast for Duluth/Superior

.Tonight... Considerable cloudiness, areas of fog which could become dense at times. Showers at times, especially before Midnight. A rumble of thunder also possible. Low 42 to 47. Wind east at 5 to 15 mph. Chance of rain 40%.

.Sunday... Considerable cloudiness, areas of fog which could be dense at times especially early. Showers possible. High 60 to 65 but cooler near Lake Superior. Wind east at 10 to 20 mph. Chance of rain 30%.

.Sunday Night... Partly to mostly cloudy. Showers possible early. Low 40 to 45. Wind east at 5 to 15 mph. Chance of rain 20%.

.Monday... Partly sunny. High 65 to 70.

.Monday Night... Mostly cloudy. Showers possible. Low 48 to 53. Chance of rain 40%.

.Tuesday... Mostly cloudy. Showers possible. High 60 to 65. Chance of rain 40%.

.Tuesday Night... Partly to mostly cloudy. Showers possible early. Low 43 to 48. Chance of rain 20%.

.Wednesday... Partly sunny. High 65 to 70.

Normal High Temperature Today 69 degrees

Normal Low Temperature Today 46 degrees