Monday, August 29, 2016

A nice stretch of weather ahead, mild temps during the day, cool at night; Warmth, humidity and rain chances return Labor Day weekend

/Issued 5:10 PM CDT, August 29, 2016/

Looks like any shower/t-storm activity is going to remain south of Duluth and Superior this evening but with the cold front still to our west as of 5 PM an isolated storm could still develop.











Tonight's low temperature forecast.



















Tuesday's high temperature forecast.



















Weather Summary for northeast Minnesota and northwest Wisconsin
Date:  August 29, 2016

A mostly cloudy start to the day gave way to partly to mostly sunny skies across most of the area this afternoon.  Once the sun came out, temperatures climbed quickly with highs in the mid 70s to low 80s with mid 80s in the Aitkin and Hinckley areas late this afternoon.  It was also on the muggy side today with late afternoon dew points in the 60s to around 70 degrees.  Winds today were out of the south, west or northwest at 5 to 15 mph.

Forecast Discussion for northeast Minnesota and northwest Wisconsin

...Short Term Forecast...

This evening

A cold front analyzed from northern Minnesota to northeast South Dakota at 4 PM will move toward the east and should clear the area by late tonight.  The atmosphere has recovered nicely after the storms and lingering clouds earlier today.  Mesoanalysis shows CAPE of 1500-3000 j/kg across the Northland with steep mid level lapse rates around 7.0 c/km.  Lifted indices ranged from -4 to -9 C from north to south across the area.  The limiting factors for widespread thunderstorms and severe weather this evening is the lack of wind shear as well as the weak winds aloft.  Also, the convergence along and ahead of this cold front is quite weak -- Scattered showers and thunderstorms are still expected to develop despite the negatives that are in place, most of this convection would occur thanks to the moist and unstable airmass that is already in place.  There is still a chance that a few storms could pulse up to near severe criteria this evening mainly over eastern Minnesota and northwest Wisconsin.  Gusty winds and hail would be the primary hazards if a stronger thunderstorm does develop.  Heavy downpours and lightning will also occur in any thunderstorm this evening as PWATS increase to around 1.40-1.70".

Late tonight

Turning cooler and less humid under partly cloudy skies.  Areas of fog could develop.  Lows will be in the 50s and 60s with winds turning to the north or northwest at 10 to 15 mph.

Tuesday (August 30)

A pleasant day with much lower humidity.  Highs will be in the 70s with lows in the 40s and 50s.  Winds will be out of the northwest at 10 to 20 mph.  Sky conditions are expected to vary between clear or partly cloudy.

...Extended Forecast...

Wednesday and Thursday (August 31-September 1)

Nice weather continues on Wednesday and Thursday with dry conditions.  Highs both days should mainly be in the 70s with lows Wednesday night in the 40s and 50s.  Note:  An east wind looks like it will develop on Thursday which may keep temperatures in the 60s near the immediate Lake Superior shoreline.

Forecast for Duluth and Superior

.Tonight...  Partly to mostly cloudy.  Isolated showers and thunderstorms possible this evening.  Turning less humid late.  Low 56 to 61.  Wind west to southwest at 5 to 15 mph becoming northwest.

.Tuesday...  Less humid.  Partly cloudy.  High 72 to 77.  Wind northwest at 10 to 20 mph.  Dew point in the 50s.

Normal temperatures for Tuesday

High:  71
Low:   52

Sunrise Tuesday:  6:26 AM CDT
Sunset Tuesday:   7:51 PM CDT

Tim

1-2"+ rain totals in much of northern Minnesota from last night's storms; Humid with additional t-storms possible late this afternoon/evening

/Issued 12:57 PM CDT, Monday, August 29, 2016/

Early afternoon visible satellite imagery and surface analysis - See map below.  Source, http://weather.cod.edu/satrad/

The main feature to watch today is the cold front which was over northwest Minnesota early this afternoon -- This front will move east and is forecast to move into northeast Minnesota by late this afternoon and into northwest Wisconsin this evening.  Debris clouds in the wake of the early morning storms were beginning to shrink/erode in northeast Minnesota and skies should become partly to mostly sunny by 2 PM where it's still overcast at Noon today.

Temperatures will warm into the 70s and perhaps the 80s depending on how soon and for how long skies will remain partly cloudy.  Dew points will hold in the 60s while the instability increases as skies clear this afternoon.  By late afternoon, CAPE of 1500-3000 j/kg is forecast to be in place across parts of the Northland.

Scattered showers and thunderstorms should develop between 4-6 PM today and linger through the evening hours.  At the moment, it looks like the better chances for additional storms later this afternoon will be along and south of Highway 2 in northeast Minnesota and will include all of northwest Wisconsin.

Wind shear is on the marginal side today, and winds aloft are also on the weak side.  The low level jet is forecast to be in the 25-30 knot range which is also marginal.  So although scattered thunderstorm development is possible later today, the overall severe weather potential is relatively low, but pulse type storms containing hail and gusty winds can't be ruled out.  Heavy downpours will probably be one of the bigger hazards due to the abundant moisture in place.  Lightning will also be a hazard from any thunderstorm.
















Severe weather outlook through this evening.  Source, Storm Prediction Center.
























12-hour enhanced satellite loop starting at 11:30 PM last night (Aug 28) ending at 11:30 AM today (Aug 29)  Source, unisys.com

Colder cloud tops show up in darker blue and green colors - Temperatures as low as 60 below to around 70 below zero Celsius last night associated with the large thunderstorm complex that affected much of the Northland.

















Thunderstorm cloud tops were so tall prior to sunset last evening that it was casting shadows downstream of where the thunderstorms were located.  Check out these visible satellite images from 7:15 PM and from 7:45 PM CDT Sunday evening, August 28, 2016. Source, http://weather.cod.edu/forecast/

By the way cloud tops with the massive supercell/tornadic thunderstorm just northeast of Ada, Minnesota last evening ranged from 60,000-69,000 feet -- Incredible!
































Rainfall reports for August 28-29, 2016
Source; CoCoRaHs; MesoWest; National Weather Service Duluth, MN

Crane Lake, MN 3 W:  2.98"
Lake Winnibigoshish, MN:  2.88"
Orr, MN 3 E:  2.43"
Kabetogama, MN:  2.41"

Bigfork, MN 8 S:  2.23"
Hibbing, MN:  2.17"
Littlefork, MN:  2.03"
Cook, MN:  1.98"

Iron Junction, MN 3.4 WNW:  1.85"
Embarrass, MN:  1.85"
Grand Falls, MN:  1.81"
Keewatin, MN 0.2 SSE:  1.71"

Littlefork, MN 1 NNE:  1.71"
Grand Rapids, MN 12 N:  1.40"
Chisholm, MN 0.4 WSW:  1.28"
Island Lake, MN 4 E:  1.27"

Togo, MN:  1.19"
Deer River, MN 3.7 W:  1.09"
Cook, MN 14.8 WSW:  1.08"
Duluth, MN (NWS total)  1.04"

Winton, MN 0.1 WSW:  1.01"
Duluth, MN (Airport)  0.99"
Pillager, MN 5.1 N:  0.97"
Duluth, MN 17.6 NNW:  0.94"

Hermantown, MN 9.3 NNE:  0.93"
Cloquet, MN 3.1 ENE:  0.85"
Pine River, MN 2.7 NE:  0.84"
Kabetogama, MN 1.5 NW:  0.80"

Longville, MN 6.2 SW:  0.78"
Duluth, MN 4.2 NNE:  0.74"
Emily, MN 1 SSE:  0.74"
Barnes, WI 2.2 S:  0.69"

Two Harbors, MN 3.6 WNW:  0.67"
Two Harbors, MN:  0.67"
Carlton, MN 5.6 NE:  0.64"
Duluth, MN 7.9 SW:  0.59"

Superior, WI (Airport)  0.59"
Duluth, MN 1.9 NNE:  0.58"
Brainerd, MN 6.9 NW:  0.55"
International Falls, MN:  0.55"

McGregor, MN 7.3 N:  0.53"
Brainerd, MN:  0.49"
Silver Bay, MN:  0.49"
Two Harbors, MN 9.7 NNE:  0.48"

Askov, MN 0.8 S:  0.47"
Isabella, MN:  0.46"
Mahtowa, MN 3.2 NW:  0.43"
Poplar, WI 7.8 SSW:  0.39"

Moose Lake, MN:  0.31"
Grand Marais, MN 4.4 W:  0.28"
Minong, WI:  0.25"
Tofte, MN 4.9 NE:  0.23"

Mellen, WI 18.6 SW:  0.21"
Hinckley, MN:  0.21"
Ashland, WI 0.5 WNW:  0.20"
Odanah, WI 1.6 E:  0.19"

Tim



Sunday, August 28, 2016

Warm and muggy on Monday with dew points approaching 70 degrees, highs around 80; Risk for strong to severe thunderstorms in parts of the Northland through Monday evening

/Issued 4:57 PM CDT, Sunday, August 28, 2016/

Visible satellite image from 4:30 PM today.  Source, http://weather.cod.edu/satrad/

Warm front extends from northern and eastern North Dakota southeast toward the Twin Cities late afternoon, this front will lift north/northeast through the night.  Scattered thunderstorms should erupt near and north of this boundary tonight, some of these storms could become strong to severe.
















Tonight's severe weather outlook.  Source, Storm Prediction Center.














Severe thunderstorm outlook for Monday, August 29, 2016.  Source, Storm Prediction Center.














Tonight's low temperature forecast.




















Monday's high temperature forecast.




















Last week's temperature departure map.  The greatest departures from normal last week were once again found closer to Lake Superior where above average temperatures occurred.  Southern portions of northwest Wisconsin had below average temperatures last week while most of northern Minnesota had near to slightly below normal temperatures for the week of August 21st.
















Below average precipitation in most of the Northland for the week of August 21st.  The only exception to this was far eastern portions of northwest Wisconsin from Ashland and Hurley south to Park Falls -- Those areas had near normal precipitation totals last week.
















Temperature and precipitation report for Duluth, Minnesota - Airport location.

August 21-27, 2016

High temperatures:

8/21:  70 F/-4 degrees below normal
8/22:  81 F/+8 degrees above normal
8/23:  85 F/+12 degrees above normal
8/24:  82 F/+9 degrees above normal
8/25:  72 F/-1 degree below normal
8/26:  73 F/Normal
8/27:  64 F/-8 degrees below normal

Low temperatures:

8/21:  50 F/-4 degrees below normal
8/22:  55 F/+1 degree above normal
8/23:  66 F/+12 degrees above normal
8/24:  57 F/+4 degrees above normal
8/25:  55 F/+2 degrees above normal
8/26:  53 F/Normal
8/27:  57 F/+4 degrees above normal

Total precipitation:  0.33"
Normal:  0.86"
Departure:  -0.53" below normal

Note:  Only a few more days left of August and for Meteorological summer 2016

Stats for Duluth, Minnesota

Total precipitation for August (thru the 27th)  3.24"
Departure:  +0.04" above normal

Precipitation total since June 1st:  12.09"
Departure:  +0.81" above normal

Average temperature for August (thru the 27th)  67.6 degrees
Departure:  +2.9 degrees above normal

24 days so far this month with a high temperature of at least 70 F (Average is 23 days)
11 days so far this month with a high temperature of at least 80 F (Average is 7 days)

72 days so far this summer with a high temperature of at least 70 F (Average is 65 days)

28 days so far this summer with a high temperature of at least 80 F (Average is 23 days)

Note:  The average temperature so far for the summer of 2016 (thru Aug 27) 65.4 degrees which is +2.0 degrees warmer than normal.

Weather Summary for northeast Minnesota and northwest Wisconsin
Date:  August 28, 2016

Widespread low clouds and some fog this morning gave way to increasing amounts of sunshine during the afternoon hours.  High temperatures were generally in the 70s with late afternoon dew points in the 50s in far northeast Minnesota and in the 60s over the rest of the area.  Winds today were out of the south or east at 5 to 15 mph.

Forecast Discussion for northeast Minnesota and northwest Wisconsin

...Short Term Forecast...

Tonight (August 28)

Showers and thunderstorms should increase in coverage in western-northern areas this evening...Storms should then move toward the east or east-southeast reaching eastern Minnesota and far northwest Wisconsin well after midnight.

Some of the storms could be strong to severe tonight especially across north central Minnesota but there is at least a marginal risk for storms to be strong to severe as far east as far northwest Wisconsin overnight.

The setup in place tonight will feature a warm front lifting slowly N/NE into the Northland.  CAPE has increased to 1000-2000 j/kg late this afternoon over most of the Northland with Lifted Indices of about -2 to -6 degrees Celsius.  An area of higher CAPE 3000-5000 j/kg covered the eastern Dakotas and western Minnesota late this afternoon and storms should develop on the nose of this higher instability gradient this evening.

Large hail and strong winds will be the main threats from storms that become severe tonight in parts of the Northland.

There is a chance for a few tornadoes mainly before Midnight generally along and near a Grand Forks to Fargo line east toward Moorhead, Crookston, Detroit Lakes and Park Rapids -- Storm relative helicity values have increased to around 300 m2/s2 late this afternoon per mesoanalysis in that area...If storms can develop this evening they will have a chance to produce a tornado.

Low temperatures tonight will be in the 60s with 50s along the North Shore of Lake Superior.  Winds will be out of the south or east at 5 to 15 mph.

Monday (August 29)

Warm front is forecast to lift north into Ontario Province but a cold front will move through the Northland during the afternoon/evening hours.  If the atmosphere can recover after tonight's storms, then a chance for more strong to severe thunderstorms exists in northeast Minnesota and northwest Wisconsin during the afternoon and evening.

The amount of instability over our area could be higher tomorrow with CAPE possibly in the 3000-4000 j/kg range with Lifted Indices of -4 to -9 degrees Celsius along with mid level lapse rates around 7.0 c/km.

Low level jet although not as strong as tonight (30-40 knots) should still be in the 25-35 knot range on Monday with mid level winds around 30 knots.  Deep layer wind shear is forecast to be at around 30 knots or so.  Note:  The winds aloft and amount of deep layer wind shear that is forecast tomorrow isn't the best but should still be enough to get the job done assuming there is enough clearing before late Monday afternoon.

High temperatures on Monday will be in the 70s and 80s with dew points in the 60s to lower 70s.  Lows Monday night will be in the 50s and 60s.  South or southwest winds tomorrow at 10 to 20 mph will become west or northwest tomorrow night.

...Extended Forecast...

Tuesday and Wednesday (August 30-31)

High pressure builds into the Upper Midwest resulting in dry weather with cooler temperatures and much less humid conditions.  Highs Tuesday and Wednesday are forecast to be in the 70s with lows Tuesday night in the 40s and 50s.

Forecast for Duluth and Superior

.Tonight...  Partly to mostly cloudy.  Showers and thunderstorms possible mainly after Midnight.  Low 62 to 66.  Wind southeast at 5 to 15 mph.

.Monday...  Muggy.  Partly to mostly cloudy.  Showers and thunderstorms possible early and again by late afternoon.  High 79 to 84.  Wind south at 10 to 20 mph.  Dew point around 70 degrees.

Normal temperatures for Monday

High:  72
Low:   52

Sunrise Monday:  6:25 AM CDT
Sunset Monday:   7:53 PM CDT

Tim


August 28, 2016: Occasional strong to severe thunderstorms possible in parts of the Northland tonight through Monday evening

/Issued 10:50 AM CDT Sunday, August 28, 2016/

Heads up for tonight - Could turn a little stormy at times as a warm front lifts north out of southern Minnesota.

Here's the severe thunderstorm outlook for tonight from the Storm Prediction Center (8 AM update)












Excessive rainfall outlook from the Weather Prediction Center.  This is valid through 7 AM CDT Monday.
















This was the setup for Saturday, August 27, 2016.  Cold temperatures aloft with just enough warming near the surface making the atmosphere unstable, this combined with a strong upper level low pressure system helped to produce scattered severe thunderstorms Saturday afternoon in far eastern North Dakota and far western Minnesota.  Source, http://weather.cod.edu/forecast/
















Filtered storm reports map for August 27th, 2016.  Source, Storm Prediction Center.

Several reports of large hail and a couple reports of tornadoes on Saturday in extreme eastern North Dakota and far western Minnesota.  Biggest hail size was 2.00 inches in diameter (Larger than golf balls)















Rainfall reports for August 27, 2016
Source:  National Weather Service Duluth, Minnesota; CoCoRaHs; MesoWest

Kabetogama, MN 1.5 NW:  0.85"
Kabetogama, MN:  0.72"
International Falls, MN:  0.59"
Littlefork, MN:  0.57"

Iron Junction, MN 3.4 NNW:  0.49"
Bigfork, MN:  0.43"
Duluth, MN 4.2 NNE:  0.40"
Spooner, WI 10.6 WNW:  0.39"

Duluth, MN 3.0 NE:  0.37"
Hibbing, MN:  0.34"
Winton, MN 0.1 WSW:  0.34"
3 E of Orr, MN:  0.33"

Duluth, MN (Airport)  0.32"
Cook, MN:  0.32"
Siren, WI:  0.29"
Hayward, WI:  0.27"
Barnes, WI 2.2 S:  0.26"

Cloquet, MN 3.1 ENE:  0.25"
Hayward, WI:  0.27"
Embarrass, MN:  0.24"
4 W of Clam Lake, MN:  0.22"

Mellen, WI 18.6 SW:  0.22"
Hovland, MN 0.1 NE:  0.21"
Iron River, WI 7.2 SE:  0.17"
Hayward, WI 9.2 NNE:  0.16"

Stone Lake, WI 2.0 NW:  0.15"
Grand Rapids, MN:  0.13"
Park Falls, WI 1.3 N:  0.12"
Ashland, WI 0.5 WNW:  0.12"

Two Harbors, MN:  0.11"
Superior, WI (Airport)  0.07"

Mostly cloudy skies continue over most of the Northland late this morning but I do think will see these clouds slowly erode this afternoon which should lead to at least partially sunny skies in most of the area during the afternoon hours.  Highs today will warm into the 70s with a few locations possibly nearing 80 degrees if skies clear soon enough.

-Focus for tonight and also on Monday will be the potential for a couple rounds of strong to severe thunderstorms which could affect parts of the Northland.

-A warm front approaching from the southwest along with a reservoir of unstable air with CAPE >2000 j/kg will be found over western and central Minnesota with steep mid level lapse rates also in place.  We should see thunderstorms develop this evening or overnight tonight across western, central and northern Minnesota with a threat for large hail and damaging winds...Heavy rain is also possible which could lead to flash flooding.

-Monday could also turn stormy at times as a cold front approaches the Northland from the northwest during the afternoon/evening hours.  If the atmosphere can recover after tonight's round of storms, then there could be another round of strong to severe thunderstorms in portions of the Northland especially from late Monday afternoon through Monday evening.  Hail and gusty winds appear to be the main threats from this activity later Monday.

Tim



Friday, August 26, 2016

August 26, 2016: Not a total washout this weekend but scattered showers, few t-storms possible both Saturday and Sunday; Turning muggier by Sunday and Monday

/Issued 4:33 PM CDT, Friday, August 26, 2016/

Source, 18z HopWRF-ARW model run.
















Tonight's low temperature forecast.




















Saturday's high temperature forecast.




















Low temperature reports for August 26, 2016
Source:  National Weather Service Duluth, Minnesota

International Falls, MN:  39 F
1 E Birchdale, MN:  40 F
5 NW Ash Lake, MN:  41 F
Crane Lake, MN:  41 F
Embarrass, MN:  42 F
Bigfork, MN:  43 F
Cass Lake, MN (DNR)  44 F
1 S Hill City, MN:  44 F
Bruno, MN:  45 F
Chisholm-Hibbing, MN (Airport)  45 F

Weather Summary for NE Minnesota and NW Wisconsin
Date:  August 26, 2016

Lots of sunshine this morning gave way to partly to mostly cloudy skies this afternoon.  High temperatures were generally in the 70-75 degree range with a few locations mainly in far northeast Minnesota holding in the upper 60s late this afternoon.  Winds today were mostly out of the south or southwest at around 10 mph so much less wind today compared to previous days.

Forecast Discussion for NE Minnesota and NW Wisconsin

...Short Term Forecast...

Tonight (August 26)

Partly to mostly cloudy skies tonight with lows in the 50s to around 60 degrees with winds out of the south or east at 5 to 15 mph.  High pressure over the Upper Midwest and Great Lakes will move slowly toward the east tonight while a disturbance approaches from the west and also from the southwest.

Saturday (August 27)

Occasional showers are possible tomorrow but I don't think this will be an all day rain event, in fact some parts of the Northland could remain dry through most of the day.

It's a somewhat complicated setup Saturday as a disturbance lifts northeast out of the central Plains while another one moves east out of the northern Plains -- There will be a warm front associated with the disturbance to our southwest but this boundary will stay well to the south of the Northland.

Showers could develop at times as low level moisture increases through the day.  Dew points are expected to rise into the mid 50s to low 60s with PWATS of around 1.00-1.25".

Colder temperatures moving in aloft (H5 temps nearing -15 degrees Celsius) will help make the atmosphere a little unstable Saturday afternoon-evening with CAPE possibly approaching 1000 j/kg in western portions of the Northland -- This will probably lead to a couple of thunderstorms with a potential for some hail and or gusty winds.

Highs on Saturday are forecast to be in the 60s and 70s with lows in the 50s to lower 60s.  Winds will be out of the south or southeast at 10 to 15 mph.

...Extended Forecast...

Sunday and Monday (August 28-29)

Mild temperatures and more humid conditions on the way for Sunday and Monday as a weak boundary (More or less a warm front) sets-up over the Upper Midwest while a cold front moves southeast across the Northland during Monday afternoon and Monday night.

High temperatures on Sunday and Monday are forecast to be in the 70s and 80s with dew points climbing into the 60s, possibly up around 70 degrees.

Looks like there will be quite a bit of instability over the Northland Sunday and Monday per model projections but the winds aloft look fairly weak especially on Sunday but even on Monday the mid-upper level winds don't look very strong.  The low level jet is forecast to be in the 15-25 knot range on Sunday and a little stronger Monday 25-35 knots.

With the boundary near the area coupled with the moist and unstable airmass there certainly could be some showers and thunderstorms that bubble up Sunday and Monday but the overall severe weather threat is relatively low, but isolated stronger thunderstorms are possible.

Forecast for Duluth and Superior

.Tonight...  Partly to mostly cloudy.  Low 55 to 60.  Wind south to southeast around 10 mph.

.Saturday...  Mostly cloudy but can't rule out some partial sunshine.  Scattered showers possible especially by late morning into the afternoon.  High 67 to 72.  Wind southeast at 10 to 15 mph.

Normal temperatures for Saturday

High:  72
Low:  53

Sunrise Saturday:  6:22 AM CDT
Sunset Saturday:   7:56 PM CDT

Tim