Friday, July 8, 2011

7/8/11: Friday's Weather Report

Issued at 2:40 PM CDT, Friday, July 8th, 2011

Local Storm Report
Source:  NWS Duluth, MN.

*5:53 PM CDT 7/7/11:  THUNDERSTORM WIND DAMAGE.  6 miles west of Ray, Minnesota (Koochiching County)  Some branches and tree limbs blown down.  1 tree blown over on part of Highway 217.

*9:30 PM CDT 7/4/11:  THUNDERSTORM WIND DAMAGE.  Gheen, Minnesota (St. Louis County)  Several trees across Jansen Road, just north of Gheen.  Power was out for 12 hours.  *Delayed report*

Rainfall report for Thursday, July 7th, 2011
Source:  NWS Duluth, MN.

Littlefork, MN:  0.41"
Cook, MN:  0.20"
Gunflint Trail Lake, MN:  0.60"
3 miles east of Orr, MN:  0.23"
Finland, MN:  0.19"
2 miles south of Tower, MN:  0.14"
Ashland, WI:  0.18"
Gurney, WI:  0.17"

WEATHER HEADLINES:

-Dry weather thru the Evening
-Risk for showers and thunderstorms starting late Tonight, lasting thru Sunday Night
-Small chance for severe weather thru the weekend
-Near to above average temperatures thru next Monday

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

High pressure was centered to our north/east while low pressure was centered in Western South Dakota and Central Alberta Province.  A warm front extended from Northcentral South Dakota to Southern Minnesota as of mid-Afternoon.  A cumulus field has developed This Afternoon near the lake breeze boundary in Northeast Minnesota and Northwest Wisconsin while some high level clouds streak E-SE across Northern Minnesota, otherwise skies were mostly sunny Today with highs in the 70s and 80s.  As previously stated, the lake breeze has returned Today after about a 6 day abscence, but so far it hasn't been too extreme as Afternoon temperatures were still in the low to mid 70s along the North and South Shore of Lake Superior.  Dewpoints Today were holding in the comfortable 50s to lower 60s with PWS of 0.60-0.90".  Winds Today were out of the southwest or east at 5-15 mph with a few higher gusts.

Today's Upper Level Analysis:

500mb trough was moving east across the Pacific Northwest into the Northern Rockies while a nearly stationary upper level low churns over Alberta Province.  Strong 12 hour 500mb height falls of 60-120 meters was occurring Today near this system across the Northern Rockies and Westcentral Canada per RUC model analysis.  Westerly H5 flow was occurring east of this system across the Upper Midwest Today while a deep upper level trough remained in place over Eastern Canada per water vapor satellite imagery.

Tonight:

High pressure to our east and low pressure to our west will result in a southerly flow across our area.  A warm front will approach Central Minnesota Overnight while a disturbance tracks east across the Northern Plains.  Showers and thunderstorms will occur in North Dakota and Western Minnesota Tonight where some severe weather is possible with favorable instability, moisture and shear in place.  A low level jet increasing to 30-50 knots should maintain some sort of convective complex which should ride along and north of the warm frontal boundary Overnight.  At this time, it appears that the Northern-Western portions of our area would be most at risk for getting some showers and thunderstorms especially after Midnight.  The severe threat should diminish by the time the storms get into our area with less instability and moisture, but locally heavy rainfall and dangerous lightning will be a threat...The majority of the storms for late Tonight should affect Koochiching, Itasca, Cass, Crow Wing and Aitkin Counties in Minnesota.  Northwest Wisconsin, Northeast and Eastern Minnesota should be mainly dry through the night.  Low temperatures Tonight under partly to mostly cloudy skies will be in the 50s and 60s, but a few 40s are possible in the Arrowhead.  Winds Tonight will be out of the south or east under 20 mph.

Saturday and Saturday Night:

Low pressure will be centered well to our northwest during this period while a cold front moves slowly east-southeast into Northern and Central Minnesota by Saturday Night.  A weakening low level jet Tomorrow Morning may keep a cluster of showers and embedded thunderstorms going in Northcentral-Eastern Minnesota and possibly into Northwest Wisconsin, this activity if it does occur should weaken by the Afternoon and this should allow for some clearing.  As long as the clearing takes place we will see the atmosphere become unstable with CAPE of 1000-2500 j/kg with Lifted Indices of -2 to -5 degrees C for Saturday Afternoon-Evening.  There should be just enough lift near the surface boundary to get some showers and thunderstorms to develop by mid or late Afternoon which will then spill over into Saturday Evening.  Isolated severe thunderstorms could develop during that time period with 0-6 KM and Effective Bulk Shear of around 30-40 knots while 500mb wind speeds max out around 30 knots while a 60-75 knot upper level jet will be situated to our west-northwest.  Large hail and damaging winds would be the main threats if severe weather develops.  Heavy rainfall is also possible with PWS of 1.00-1.50" and dewpoints in the 60s to around 70 degrees.  Lightning will also be a threat from any thunderstorm.  Highs on Saturday will be in the 70s and 80s with lows Saturday Night generally in the 60s.  Winds will be out of the south, east or west under 20 mph during this period.

Extended Forecast:

Low pressure will be tracking through Western-Northern Ontario Province from Sunday into Monday.  A cold front attached to this low will sweep southeast and through Northern Minnesota and Northwest Wisconsin from Sunday into early Monday.  The airmass along and ahead of this boundary will become quite unstable Sunday Afternoon-Evening with CAPE forecasted to range from 1500-3000 j/kg with Lifted Indices of -3 to -7 degrees C.  Dewpoints in the 60s to lower 70s and PWS around 1.25" can also be expected.  Scattered showers and thunderstorms are possible across our area from Sunday into early Monday.  Isolated severe thunderstorms could develop Sunday Afternoon and or Evening, primarily in Northwestern Wisconsin and Eastcentral Minnesota.  Large hail and damaging wind would be the main threats once again along with locally heavy rainfall and dangerous lightning.  High temperatures for Sunday will be in the 80s and 90s with lows Sunday Night in the 50s and 60s.  Less humid conditions return for the early to mid part of next week as high pressure builds into the Upper Midwest.  High temperatures on Monday will be in the 70s and 80s with lows Monday Night mainly in the 50s.

5 DAY FORECAST FOR DULUTH/SUPERIOR

.Tonight...  Clear to partly cloudy.  Low 51 to 56.  Wind east to southeast at 10 to 20 mph.

.Saturday...  More humid.  Showers or thunderstorms possible.  Variable cloudiness.  High 77 to 82.  Wind south at 10 to 20 mph.  Chance of rain 40%.

.Saturday Night...  Humid.  Scattered showers or thunderstorms, mainly during the Evening.  Variable cloudiness.  Low 60 to 65.  Wind southwest at 10 to 15 mph.  Chance of rain 40%.

.Sunday...  Humid.  Showers or thunderstorms possible, mainly during the Afternoon.  Partly sunny.  High 82 to 87.  Chance of rain 20%.

.Sunday Night...  Showers or thunderstorms possible.  Partly to mostly cloudy.  Low 55 to 60.  Chance of rain 20%.

.Monday...  Mostly sunny.  Less humid.  High 75 to 80.

.Monday Night...  Fair.  Low 51 to 56.

.Tuesday...  Fair.  High 70 to 75.

Normal temperatures for Today

High:  76 degrees
Low:  54 degrees

Saturday's Pollen Forecast:

Grass:  High
Tree:    None
Weed:  None

Sunrise Tomorrow:  5:24 AM CDT
Sunset Tomorrow:   9:04 PM CDT

Tim