Sunday, June 20, 2010

6/20/10: Sunday's Weather Report

Issued at 8:43 PM CDT, Sunday, June 20th, 2010

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Partly-mostly sunny skies prevailed Today across our area with some spotty showers affecting portions of Northcentral Minnesota. Highs Today were in the 70s to lower 80s with 850 mb temperatures as of 7 PM ranging from +14/+15 degrees C. Winds Today were variable or calm. Surface map early This Evening featured high pressure of 1020 mb centered over Central Lake Michigan. A stationary front extended from Central Wyoming to Northern Kansas.

This Evening's 500 mb analysis:

Upper level low (570 meters) covered the Pacific Northwest per RUC model analysis. A westerly flow aloft covered the Upper Midwest Today out ahead of this upper low. Scattered strong to severe thunderstorms have been erupting Today in a very unstable environment which extended from the Northern Rockies and Western High Plains down through portions of the Central Plains.

Tonight:

Partly-mostly cloudy skies will prevail across Northern Minnesota and Northwest Wisconsin Tonight as high pressure remains to our southeast while a stationary front continues to sit well to our west and south. Scattered strong to severe thunderstorms will continue to develop through the night from the Dakotas and Nebraska with movement toward the E/SE. The majority of this activity is expected to stay southwest/south of our area Tonight, but a few showers and possibly a thunderstorm could develop at times mainly in Western-Northern areas. Lows Tonight will be mainly in the 50s to around 60 degrees, but a few 40s are possible in the Arrowhead of Minnesota. Winds Tonight will be variable or south/east in direction under 15 mph.

Monday and Monday Night:

Partly-mostly cloudy skies will be found across our area during this period with scattered showers or thunderstorms possible as a somewhat more unstable and moist airmass spreads north into our area. Dewpoints are expected to reach the upper 50s-mid 60s by Monday Afternoon with 850 mb td's of +8/+12 degrees C while PWS increase to between 1.00"-1.25". The latest set of forecast models indicate that CAPES by Monday Afternoon will range from 1000-to around 1500 j/kg while Lifted Indices fall to between -1/-4 degrees C. 0-6 KM BULK SHEAR and EFFECTIVE BULK SHEAR values are forecast to be around 30-35 knots per 15z SREF model. An isolated risk for severe thunderstorms will exist Monday Afternoon/Monday Evening over portions of Northcentral-Eastcentral Minnesota and far Northwest Wisconsin if the instability does develop...Areas that would be affected would generally be along and south of Highway 2 in Minnesota, including the Interstate 35 corridor, and west of Highway 53 in Northwestern Wisconsin. Large hail and damaging winds will be the main threats if any storm does turn severe. Locally heavy rainfall and dangerous lightning strikes will also occur in any thunderstorm. Highs Tomorrow will be in the 70s to lower 80s with cooler temperatures near Lake Superior. Lows Tomorrow Night will be in the 50s to around 60 degrees. Winds during this period will be out of the south, east, or west at 10-20 mph.

Extended Forecast:

An upper level trough and cold front are expected to advance south/east out of the Northern Plains and through the Upper Midwest from late Tuesday into Wednesday. This system could bring some more showers or thunderstorms to our area sometime Tuesday or Wednesday...The forecast models Today are in disagreement on the timing of this system, so things may change as to what day will hold the greater risk for rain. High temperatures for Tuesday and Wednesday will be in the 70s to lower 80s across Northern Minnesota and Northwest Wisconsin with lows Tuesday Night and Wednesday Night in the 50s to around 60 degrees.

5 Day Forecast for Duluth/Superior

.Tonight... Partly cloudy. Low 53 to 58. Wind east to southeast at 5 to 15 mph.

.Monday... More humid. Variable cloudiness. Showers or thunderstorms possible. High 71 to 76 but cooler near Lake Superior. Wind southeast at 10 to 15 mph. Chance of rain 40%.

.Monday Night... Showers or thunderstorms possible, mainly during the Evening. Variable cloudiness. Low 55 to 60. Wind variable at 5 to 15 mph. Chance of rain 40%.

.Tuesday... Partly sunny. Showers or thunderstorms possible. High 73 to 78. Chance of rain 20%.

.Tuesday Night... Showers or thunderstorms possible. Mostly cloudy. Low 55 to 60. Chance of rain 30%.

.Wednesday... Showers or thunderstorms possible. Partly sunny. High 73 to 78. Chance of rain 20%.

.Wednesday Night... Partly cloudy. Low 52 to 57.

.Thursday... Partly cloudy. High 72 to 77.

Normal High Temperature Tomorrow 72 degrees

Normal Low Temperature Tomorrow 50 degrees

Tim