Monday, May 31, 2010

5/31/10: Monday's Weather Report

Issued at 1:33 PM CDT, Monday, May 31st, 2010

Note: A cold front pushed east across Northern Minnesota and Northwest Wisconsin on Sunday 5/30/10. This boundary did produce some showers and thunderstorms across our area, but as is often the case during the warm season, the precipitation that developed was on the scattered side. Here are some rain totals that occurred on Sunday. Source: NWS Duluth, MN.

International Falls MN (Koochiching County) 0.05"

Grand Marais MN (Cook County) 0.09"

Hayward WI (Sawyer County) 0.12"

Ashland WI (Ashland County) 0.08"

Cook MN (St. Louis County) 0.16"

Kabetogama MN (St. Louis County) 0.43"

3 miles East of Orr MN (St. Louis County) 0.32"

Upson WI (Iron County) 0.20"

Saron WI (Washburn County) 0.31"

Webster WI (Burnett County) 0.13"

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

May end's on a mild note across our local area with high temperatures generally in the 70s with 850 mb temperatures as of 2 PM between +10/+11 degrees C in Northern Minnesota and Northwest Wisconsin. Dewpoints were on the low side Today with generally 40s to around 50 degrees across our area with PWS ranging from .50"-.70". Surface map This Afternoon featured high pressure of 1016 mb centered in Eastcentral Minnesota. A warm front stretched from Southeast Manitoba Province to Northwest Minnesota with a cold front across the Central Dakotas. The atmosphere was destabilizing across parts of Northern Minnesota This Afternoon with latest meso-analysis showing CAPES up to 500 j/kg with Lifted Indices falling to around zero degrees C with low level lapse rates of 7.5-9.0 c/km. Isolated showers have developed within the past hour in portions of Koochiching, Itasca, and Northern Cass Counties in Northern Minnesota with movement toward the east-northeast.

Today's 500 mb analysis:

West-southwest flow aloft covered the Upper Midwest Today with several upper level disturbances tracking generally in a west-east fashion through the Western U.S./Northern Plains/and Upper Midwest.

Tonight:

A cold front which was over the Central Dakotas This Afternoon will track east, reaching Northcentral Minnesota by dawn. The presence of a southwest low level jet 20-35 knots out ahead of this boundary combined with some instability (CAPES <500 j/kg, Lifted Indices around zero degrees C) will help to trigger a few showers or thunderstorms through the night, primarily in Northern Minnesota. A seperate area of spotty showers or thunderstorms could get going later in the night in parts of Eastcentral Minnesota and Northwest Wisconsin, but chances of this occurring are relatively low. The severe weather threat Tonight is minimal in Northern Minnesota due to the low amounts of moisture and instability in place, but there is some shear along with stronger winds aloft in this area, so some gusty winds and or small hail along with occasional lightning strikes and brief heavy downpours are possible in the strongest activity Tonight. Partly-mostly cloudy skies will be found across our area Tonight with lows mainly in the 50s. Winds will be out of the south, southwest, or north under 20 mph.

Tuesday and Tuesday Night:

A cold front is expected to be over Northcentral Minnesota Tuesday Morning, this boundary is then forecast to sink south-southeast through Eastcentral Minnesota and Northwest Wisconsin from Tuesday Afternoon into early Tuesday Evening.

...SEVERE THREAT...

The atmosphere along and ahead of this front will consist of CAPES from 500-1500 j/kg, Lifted Indices of zero/-5 degrees C...Highest values in both departments in Northwest Wisconsin and Eastcentral Minnesota. Winds aloft will also be rather strong with W-SW H5 winds up to 45 knots while an upper level jet of around 90 knots sets-up near or over Northern Minnesota on Tuesday. 0-6 KM Bulk Shear and Effective Bulk Shear will increase to 30-45 knots on Tuesday in Eastern Minnesota/Northwest Wisconsin with 0-3 KM Helicities maxing out at around 200 m2/s2 per 09z SREF model.

The potential does exist for a complex of severe thunderstorms capable of producing damaging winds and large hail to spread E/SE through Southern parts of our local area on Tuesday. The models differ with the exact placement of this feature, the 12z NAM is farther north, while the 12z GFS has a farther south solution. At this time, it appears that areas south of a line from Hinckley Minnesota to Park Falls Wisconsin would be at greatest risk for seeing possible severe weather Tuesday Afternoon...This would include the Counties of Pine MN...Burnett WI...Washburn WI...Sawyer WI...and Price WI...

A few showers or thunderstorms could also occur over the rest of our area on Tuesday before things dry out Tuesday Night as the main boundary exits to our south while high pressure begins to head east out of the Northern Rockies.

Partly-mostly cloudy skies are expected Tomorrow and Tomorrow Night across our area with high temperatures on Tuesday in the 60s and 70s, but a few locales in Northwest Wisconsin could reach the 80s! Lows Tuesday Night will be in the 40s and 50s. Winds will be out of the south, southwest, or north on Tuesday at 10-20 mph with north or west winds Tuesday Night under 20 mph.

Extended Forecast:

The upper level pattern will consist of a nearly zonal west-east flow from Thursday through the weekend. Several upper level disturbances will continue to work east through the Upper Midwest but with such a fast flow aloft, the models are having a difficult time from one run to the next in regards to the timing of such features.

Right now it looks like Thursday and Thursday Night will be dry across Northern Minnesota and Northwest Wisconsin, then from Friday through the weekend we could see some spells of showers or thunderstorms. Severe weather chances look low at this time, but this may change in coming days.

High temperatures for Thursday and Friday will be in the 60s and 70s with lows Thursday Night and Friday Night in the 40s and 50s.

5 Day Forecast for Duluth/Superior

.Tonight... Partly to mostly cloudy. A shower or thunderstorm possible Overnight. Low 50 to 55. Wind southwest at 10 to 15 mph. Chance of rain 20%.

.Tuesday... Considerable cloudiness. Showers or thunderstorms possible. High 73 to 78. Wind southwest at 10 to 20 mph becoming north during the Afternoon. Chance of rain 30%.

.Tuesday Night... Partly to mostly cloudy. Showers possible early. Low 45 to 50. Wind north at 5 to 15 mph. Chance of rain 30%.

.Wednesday... Partly cloudy. High 67 to 72.

.Wednesday Night... Partly cloudy. Low 45 to 50.

.Thursday... Partly sunny. High 68 to 73.

.Thursday Night... Partly to mostly cloudy. Low 48 to 53.

.Friday... Mostly cloudy. Showers or thunderstorms possible. High 65 to 70. Chahnce of rain 20%.

Normal High Temperature Today 68 degrees

Normal Low Temperature Today 45 degrees

Tim