Issued at 5:00 PM CDT, Sunday, May 31st, 2009
Forecast Discussion for Northeast Minnesota and Northwest Wisconsin
Low pressure of 1002 mb was moving east-southeast out of Southeast North Dakota This Afternoon while a warm front which was attached to this low lifts north-east toward Central Minnesota while a cold front moves southeast out of Western Minnesota. Strong warm air advection was occurring Today out ahead of this low and north-east of the warm front and this has helped in producing areas of showers and scattered thunderstorms Today over Northern Minnesota and Northwest Wisconsin. A strong southwesterly low level jet of 30-45 knots was found across our area Today ahead of this weather system which is helping to bring strong warming into our area Today. Dangerous lightning strikes and brief heavy downpours have occurred over parts of the area Today in the stronger storms. A wide range in high temperatures were observed across our area Today with temperatures ranging from the 30s and 40s near Lake Superior to the 60s and 70s from Northwest Wisconsin into Northcentral Minnesota. 850 mb temperatures as of 4 PM CDT ranged from +2 degrees C in extreme Northeast Minnesota to around +15 degrees down around the Walker/Brainerd areas. Winds across the area were out of the south or east Today at 10-20 mph with some higher gusts.
The heaviest rainfall so far Today according to doppler radar rainfall estimates have been across Northern-Northeast Minnesota…Generally across Itasca…Central-Southern St. Louis…into Southern Lake County where rainfall totals of one half inch to 1.50″ fell Today…Some of these totals are probably a bit overdone due to some radar contamination, but there likely was some heavier pockets of rain that fell across parts of the area Today. Another axis of higher QPF was noted over Northeast Douglas…Northern Bayfield…Northern Ashland…and Northern Iron Counties in Northwest Wisconsin with rain totals per doppler radar rainfall estimates ranging from one half inch to around 1.25″.
Note: There were some reports of mixed precipitation across Northeast Minnesota at times Today per hourly surface observation reports…
(Today’s Upper Level Analysis)
Northwest H5 flow continued across the Upper Midwest Today with a strong upper level low centered over Central Quebec while a new disturbance spreads south-east out of Western Ontario-Southern Manitoba. An area of 60-90 meter 12 hour H5 height falls were noted This Afternoon per RUC model analysis near the disturbance over Manitoba.
The low analyzed around the Fargo-Moorhead area This Afternoon will continue to move east-southeast This Evening and will exit to our area to the south-east later Tonight. A cold front attached to this low will swing southeast through Eastcentral Minnesota and Northwest Wisconsin This Evening. A brief rise in instability and moisture will move into Cass/Crow Wing and Aitkin Counties in Minnesota before 9 PM Tonight with CAPES rising to around 500 j/kg with LI’S around zero to -2 degrees C along with Lapse Rates around 7.0 c/km… 0-6 KM Bulk Shear of 50-60 knots with H85 winds from the SW at 30-40 knots combined with H5 winds from the NW around 40-50 knots will be found across those areas I mentioned above through mid-Evening. Dewpoints will climb into the 40s to low 50s through mid-Evening while PWS increase to 1.00″-1.20″… An area of severe thunderstorms did erupt around 4 PM Today across Crow Wing County in Eastcentral Minnesota on the nose of the higher instability currently in Westcentral Minnesota. These storms were moving across Aitkin County as of 515 PM CDT but were decreasing rather quickly as they had farther south-east. A couple more thunderstorms which could be strong to possibly severe may develop through 9 PM CDT Tonight across Crow Wing/Southern Cass/and Aitkin Counties in Northcentral-Eastcentral Minnesota with hail and high winds being the primary hazards. The rest of the area could see scattered showers and isolated thunderstorms This Evening. By later Tonight any lingering shower risk should be confined to Northwestern Wisconsin. Look for partly-mostly cloudy skies Tonight with lows in the 30s and 40s. Winds will be out of the south, east, or north-northwest at 10-20 mph.
(Monday and Monday Night)
A northwest flow aloft will continue across our area during this period with one system exiting to our south-east while a new disturbance takes shape to our northwest. Look for partly-mostly cloudy skies Tomorrow and Tomorrow Night with a few showers possible at times mainly across Northern Minnesota. Highs on Monday will be in the 50s and 60s with lows Monday Night mainly in the 40s. Winds will be out of the north, northeast, or northwest at 10-20 mph.
Monday’s disturbance will continue to track across our area on Tuesday with a possibility for a couple of showers…Then a rather strong area of high pressure will build into the Upper Midwest as this disturbance departs by Tuesday Night and Wednesday. This high will then settle east making way for another cold frontal passage which looks to occur sometime between Thursday or Friday. A few showers or thunderstorms may develop along and ahead of this front later this week depending on the quality of moisture and instability. High temperatures Tuesday and Wednesday will be in the 50s and 60s with lows Tuesday Night in the 30s and 40s with some 20s possible in Northeast Minnesota. Lows Wednesday Night will be in the 30s and 40s. A significant push of cool air may then push into the Upper Midwest toward Friday or next weekend…But the forecast models Today are not in the best agreement as we approach later this week and next weekend.
5 Day Forecast for Duluth/Superior
.Tonight… Scattered showers and possibly a thunderstorm ending before 10 PM…Mostly cloudy skies. Low 35 to 40. Wind east to southeast at 10 to 20 mph…Becoming northeast.
.Monday… Partly to mostly cloudy. High 60 to 65 but cooler near Lake Superior. Wind northeast at 10 to 20 mph.
.Monday Night… Partly to mostly cloudy. Low 40 to 45. Wind north to northwest at 5 to 15 mph.
.Tuesday… Variable cloudiness. High 60 to 65.
.Tuesday Night… Partly cloudy. Low 35 to 40.
.Wednesday… Partly cloudy. High 65 to 70.
.Wednesday Night… Partly cloudy. Low 45 to 50.
.Thursday… Partly cloudy. Showers or thunderstorms possible. High 70 to 75. Chance of rain 20%.
Normal High Temperature Tomorrow 68 degrees
Normal Low Temperature Tomorrow 45 degrees