Saturday, May 28, 2011

5/28/11: Saturday's Weather Report

Issued at 5:05 PM CDT, Saturday, May 28th, 2011

Local storm reports from Saturday Afternoon, May 28th, 2011.  Source:  NWS Duluth, MN.

*2:40 PM CDT:  THUNDERSTORM WIND DAMAGE.  6 miles south of Tower, MN (St. Louis county)  Tree blown down blocking Highway 135 near Highway 26.

*3:35 PM CDT:  THUNDERSTORM WIND DAMAGE.  Gilbert, MN (St. Louis county)  Tree down in Gilbert.

*3:50 PM CDT:  THUNDERSTORM WIND DAMAGE.  2 miles north of Side Lake, MN (St. Louis county)  3 trees down blocking Highway 5 and Perch Lake Road.

*3:11 PM CDT:  THUNDERSTORM WIND GUST.  47 mph at Hibbing, MN (St. Louis county)

*3:35 PM CDT:  FUNNEL CLOUD.  3 miles north of Silver Bay, MN (Lake county)

*3:25 PM CDT:  FUNNEL CLOUD.  5 miles west of Silver Bay, MN (Lake county)  Rotating wall cloud with brief funnels or vorticies dipping out of the base of the cloud, no contact with the ground.

Rainfall report for Friday through around 7 AM CDT Saturday, May 27th-28th, 2011.  Source:  NWS Duluth, MN.

Duluth, MN:  0.19"
International Falls, MN:  0.39"
Brainerd, MN:  0.54"
Hibbing, MN:  0.40"
Hayward, WI:  0.25"
4 miles south of Bruno, MN:  0.47"
12 miles north of Isle, MN:  0.54"
Dixon Lake, MN:  0.42"
Cook, MN:  0.25"
Kabetogama, MN:  0.32"
2 miles south of Tower, MN:  0.21"
Upson, WI:  0.40"
Webster, WI:  0.37"
4 miles west of Clam Lake, WI:  0.37"

WEATHER HEADLINES:

-Scattered showers/thunderstorms This Evening
-A few severe thunderstorms through mid-Evening
-Mainly dry for Sunday
-Showers/thunderstorms return Sunday Night thru early Tuesday
-Severe thunderstorms possible Monday-Monday Night

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Low pressure of 998mb was centered in Southern Manitoba Province late This Afternoon.  Scattered showers and thunderstorms did develop during the Afternoon mainly in Northern and Northeast Minnesota as a couple of disturbances rotated around that low.  Moisture was on the low side Today with dewpoints mainly in the 40s, but winds aloft were very strong with a 110+ knot upper level jet in Southern Minnesota while mid level winds of 40-50 knots were found in our area, this combined with ample amounts of shear resulted in a few severe thunderstorms during the Afternoon hours.  The area southwest of International Falls, and also near Silver Bay and west of Silver Bay have seen the bulk of the more intense storms so far Today with even some reports of funnel clouds and wall clouds near Silver Bay, Minnesota around 3 PM Today.  High temperatures under partly to mostly cloudy skies were in the 50s and 60s but some spots in Northwest Wisconsin and Eastcentral Minnesota made it into the 70s.  Winds Today were out of the south, southeast, or southwest at 5-15 mph with stronger gusts.

Today's Upper Level Analysis:

500mb trough covered portions of the Northern Plains and Upper Midwest with -20 to -25 degree C H5 temperatures in these areas.  A belt of strong winds aloft >120 knots extends from Northcentral California to
Eastern Upper Michigan per RUC model analysis.

Tonight:

Low pressure will remain to our northwest.  Scattered showers and thunderstorms will continue through Midnight with dry conditions expected Overnight.  A few severe thunderstorms remain a possibility through 9-10 PM This Evening, mainly in Northeast-Eastern Minnesota into Northwestern Wisconsin.  Hail to 1" in diameter and wind gusts around 60 mph are the main hazards, along with dangerous lightning strikes and heavy downpours.  Latest meso-analysis as of 5 PM CDT showed CAPES of around 500 j/kg with Lifted Indicies of zero to -2 degrees C.  Lapse Rates were in the 6.5-8.5 c/km range.  Around 40 knots of shear was in place with up to 25 knots of 1km shear.  Any storm that can organize enough may pose an isolated tornado risk thru 7 PM This Evening due to the favorable shear and helicity.  Partly-mostly cloudy skies are forecast Tonight with lows mainly in the 40s.  Winds will be out of the south or west at 5-15 mph with some higher gusts.

Sunday:

Partly to mostly sunny skies can be expected as low pressure passes north of the area.  Highs will be in the 60s and 70s with west winds under 20 mph.

Sunday Night:

Strong low pressure of around 995mb will move into Colorado with a warm front attached to that low pushing north into Southern Minnesota.  Low level moisture and elevated instability will start to increase Tomorrow Night as a southerly low level jet develops out ahead of this system.  Scattered showers or thunderstorms should begin to impact Southern portions of our area by Sunday Night.  Mostly cloudy skies with lows in the 40s to around 50 degrees can be expected with winds becoming east or southeast at 5-15 mph.

Extended Forecast:

Powerful area of low pressure of 990-995mb will lift north out of the Western High Plains and will reach the Northern Plains by Monday Night.  A warm front attached to this low will lift north out of Southern Minnesota while a strong cold front surges E-NE out of the Dakotas, passing through our local area late Monday Night/Tuesday Morning.

Dewpoints by Monday Afternoon away from Lake Superior will climb into the 50s and 60s with PWS of 1.25-1.50" and 850mb td's of +10 to +16 degrees C.

Upper level winds will be very strong on Monday with a 110+ knot jet coming out of the Western High Plains while mid level winds of 60-80 knots overspread the Upper Midwest.  The low level jet will also be on the increase from Monday into Monday Night with speeds of 40-55 knots.

A round of showers and thunderstorms will probably occur Monday Morning into midday Monday as instability increases from south to north.  There might be a severe weather risk during that time with hail being the main hazard.

By Monday Afternoon/Evening, CAPES are forecast to climb to 1000-2500 j/kg with Lifted Indicies from -2 to -7 degrees C.  Shear of 40-50 knots will be in place with 1km helicity values of 150 m2/s2 to 300 m2/s2.

It's uncertain whether or not additional showers and thunderstorms will develop Monday Afternoon and Monday Evening due to a rather stout cap that is forecast to spread into the area with 700mb temperatures approaching +12 degrees C!

If thunderstorms can redevelop late Monday Afternoon/Evening, then a severe weather threat would occur with hail, high winds, and a few tornadoes certainly possible.  The tornado risk would be greatest near the warm front which by late Monday Afternoon should be centered somewhere in Central Minnesota, possibly even Northcentral Minnesota.

A risk for showers or thunderstorms should continue late Monday Night into Tuesday Morning as the cold front passes through the area.

High temperatures on Monday will be in the 40s near Lake Superior with 70s and even a few 80s possible in Southern areas with 50s in Northern Minnesota.  Lows Monday night will be in the 40s and 50s with a few 60s in Southern areas.  Highs for Tuesday will be in the 60s and 70s with lows Tuesday Night in the 40s to lower 50s.

5 DAY FORECAST FOR DULUTH/SUPERIOR

"SEVERE THUNDERSTORM WATCH"
Timing:  Until 10 PM CDT Tonight.

.Tonight...  A few showers and thunderstorms ending before Midnight.  Variable cloudiness.  Low 43 to 48.  Wind variable, becoming west to southwest at 10 to 20 mph.

.Sunday...  Partly sunny.  High 65 to 70.  Wind west at 10 to 20 mph.

.Sunday Night...  Mostly cloudy.  Occasional showers possible.  Low 40 to 45.  Wind east at 10 to 20 mph.

.Memorial Day...  Breezy with occasional showers and thunderstorms.  Mostly cloudy.  High 50 to 55 but cooler near Lake Superior.  East winds could occasionally gust to 25 mph.

.Monday Night...  Mostly cloudy.  Showers or thunderstorms possible.  Low 45 to 50.

.Tuesday...  Breezy.  Partly to mostly sunny.  High 70 to 75.  Wind becoming west to southwest with gusts to 30 mph.

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

.Wednesday...  Partly cloudy.  High 65 to 70.

Normal temperatures for Tomorrow

High:  68
Low:  44

Sunday's Pollen Forecast:

Tree:    Moderate
Grass:  None
Weed:  None

Sunrise Tomorrow:  5:20 AM CDT
Sunset Tomorrow:   8:52 PM CDT

Tim