Sunday, July 10, 2016

July 10, 2016: Showers/t-storms possible at times through Monday night; Gusty southwest wind, dry and in the 80s Tuesday. Rainfall and wind reports from this morning in this post

/Issued 5:41 PM CDT, Sunday, July 10, 2016/

The strength of the upper trough and surface low over the northwest U.S. and western High Plains is impressive for early July.  This system moves into the Upper Midwest tonight and Monday.  Source,

Severe weather outlook for tonight.  Source, WSI; Storm Prediction Center.

Note:  Remember the 5 point scale with 1 being the lowest risk for severe thunderstorms and 5 being the highest risk.

Severe weather outlook for Monday, July 11.  Source, WSI; Storm Prediction Center.

Still under a slight risk for rainfall to exceed flash flood guidance through Monday night.  Tonight's threat area is mostly in central Minnesota and far western Wisconsin.  Source, Weather Prediction Center.

Monday's threat area for rainfall to exceed flash flood guidance covers all of northeast Minnesota and northwest Wisconsin.  Source, Weather Prediction Center.

Last week's temperature departure map.  Above to near average temperatures in most of the Northland except in far northern Minnesota where below to near average temperatures occurred last week.

Most of the Northland had below to near average precipitation last week.

The map below shows the difference in the number of 90 degree days for the period 1981-2010 vs. 1951-1980.  Pretty interesting map here with fewer 90 degree days in southwest Minnesota and in much of the central Plains (Blue areas) while northern Minnesota and northern Wisconsin have seen more 90 degree days 1981-2010 compared to 1951-1980 (Pine/red areas)  Source, IEM; Paul Douglas St. Cloud Times)

How many 90 degree days so far in 2016?
Source:  Paul Douglas St. Cloud Times

Twin Cities:  6
Average:  10
Warmest so far:  96 degrees on June 25
2015 total:  4 days

St. Cloud:  2
Average:  8
Warmest so far:  93 degrees on June 25
2015 total:  2

Duluth:  1
Average:  1
Warmest so far:  92 degrees on May 6
2015 total:  3

Rainfall report for July 10, 2016

Totals listed below are from the storms earlier Sunday morning.

Aitkin, MN:  1.58"
Brainerd, MN:  1.38"
McGregor, MN:  0.93"
Hinckley, MN:  0.36"
Siren, WI:  0.33"

Pine River, MN:  0.20"
Phillips, WI:  0.14"
Walker, MN:  0.14"
Cloquet, MN:  0.13"
Duluth, MN:  0.02"
Superior, WI:  0.01"

Temperature and precipitation report for Duluth, Minnesota - Airport location

July 3-9, 2016

High temperatures:

7/3:  78 F/+3 degrees above normal
7/4:  76 F/+1 degree above normal
7/5:  85 F/+9 degrees above normal
7/6:  82 F/+6 degrees above normal
7/7:  72 F/-4 degrees below normal
7/8:  71 F/-5 degrees below normal
7/9:  74 F/-2 degrees below normal

Low temperatures:

7/3:  52 F/-2 degrees below normal
7/4:  56 F/+2 degrees above normal
7/5:  63 F/+9 degrees above normal
7/6:  60 F/+5 degrees above normal
7/7:  59 F/+4 degrees above normal
7/8:  54 F/-1 degree below normal
7/9:  51 F/-4 degrees below normal

Total precipitation:  0.84"
Normal:  0.99"
Departure:  -0.15" below normal

Peak wind gusts from Sunday morning, July 10, 2016
Source:  National Weather Service Duluth, Minnesota

12:20 AM:  3 W of Schley, MN (Cass County)  36 mph

12:55 AM:  6 NNW of Walker, MN (Cass County)  39 mph

2:44 AM:  1 ENE of Longville, MN (Cass County)  51 mph

2:55 AM:  Hill City, MN (Aitkin County)  54 mph

3:07 AM:  2 S of Hill City, MN (Aitkin County)  51 mph

3:38 AM:  7 WSW of Pine River, MN (Cass County)  50 mph -- Wind broke screen door on house.

4:13 AM:  1 ENE of Pine River, MN (Cass County)  43 mph

4:30 AM:  5 S of Emily, MN (Crow Wing County)  34 mph

4:53 AM:  3 NE of Jenkins, MN (Crow Wing County)  34 mph

Weather Summary for NE Minnesota and NW Wisconsin
Date:  July 10, 2016

Things are playing out a little differently than expected but hey that's weather for ya! A large thunderstorm complex (MCS -- Mesoscale Convective System) dropped south/southeast out of the Dakotas into western, central and southern Minnesota this morning; this blob of storms has delayed the northward advancement of a warm front which as of 4 PM today was still south of Minnesota.  The airmass remains stable north of that boundary across the Northland today with much more unstable air confined to the Dakotas and far western portions of Minnesota this afternoon.  Mostly cloudy skies covered most of the area today although there has been some clearing that is pushing toward the north/east this afternoon.  Highs today were in the 60s and 70s with near 80 degree temperatures in extreme northern Minnesota where sunshine has been more abundant today.  Winds on this Sunday have been out of the east or southeast at 10 to 20 mph.

Forecast Discussion for NE Minnesota and NW Wisconsin

Confidence:  Medium.

Tonight (July 10)

Low pressure over western South Dakota late this afternoon will lift slowly north during the night.  A warm front will eventually shift north into western-southern Minnesota.  Low level jet is forecast to increase to 35-40+ knots over Minnesota tonight with continued warm and moist air advecting into the Northland along with a gradual increase in elevated instability as CAPE builds to over 1000 j/kg from SW-NE during the night.

Showers and thunderstorms should develop across parts of the Northland tonight with western-southern areas having the greatest chance at getting this convection.  Heavy rain and lightning will be the main threats along with possible flooding if storms begin to move over the same location for a few hours.  A risk of a few strong to severe thunderstorms as well late tonight with hail and gusty winds.

Low temperatures will be in the 50s and 60s with south or east winds at 10 to 20 mph.

Monday (July 11)

Lower confidence on how things will play out Monday.

On the big picture will have an unusually strong surface and upper level area of low pressure lifting slowly north through North Dakota while a warm front shifts slowly north/east into the Northland followed by a cold front Monday night.

This system combined with favorable jet dynamics will promote good forcing over our area tomorrow which could lead to showers and thunderstorms tracking across parts of the area during a good portion of the day -- Should this scenario play out then we would have less heating and instability available for severe weather, although a few severe storms could still develop with hail and strong wind being the main threats as storms remain slightly elevated.

The other scenario would be for morning-early afternoon storms moving away allowing for some afternoon clearing; followed by scattered strong to severe thunderstorms during the late afternoon/evening hours...All modes of severe weather would be possible as the atmosphere would have much more instability available for a storm to tap into, and temperatures would also be a lot warmer if skies clear a bit tomorrow afternoon.

As for the 'potential' parameters that may be in place Monday

CAPE of 1000-2000 j/kg, possibly as high as 3000-4500 j/kg depending on if clouds decrease

Lifted indices ranging from -4 to around -10 degrees Celsius

Mid level lapse rates of 6.0-8.0 c/km

Dew points in the 60s to lower 70s with PWATS of 1.50-2.20"

Low level jet out of the south at 30-40 knots, possibly as high as 50 knots

1km shear increasing to 25-35 knots with 0-1 km helicity values around 100-200 m2/s2

Those are the pros, now to the cons

Strongest mid level winds might stay west of the greatest instability axis which could cut down on the overall coverage/duration of severe weather

0-6 KM Shear and Effective Bulk Shear generally around 30 knots or less

*The potential for a higher end severe weather day certainly does exist across the Northland for Monday but a few things will have to occur for that to happen and I'm not sure everything will come together just right for this to occur* Stay tuned!

As for temperatures on Monday -- Highs are expected to be in the 70s and 80s but near 90 degree temperatures are possible in far southern areas.  Lows Monday night will be in the 60s to lower 70s.  Winds will be out of the south or east at 10 to 20 mph.

Forecast for Duluth and Superior

Tonight - Mostly cloudy.  Showers and thunderstorms possible after midnight.  Low 58 to 63.  Wind east to southeast at 10 to 20 mph.

Monday - Showers and thunderstorms possible otherwise mostly cloudy skies with some sunny breaks possible.  High 75 to 80, cooler near Lake Superior.  Wind southeast at 10 to 20 mph.

Tuesday - Breezy but dry.  Highs in the 80s.  Southwest wind gusting to 25 mph.

Normal temperatures for Monday

High:  76
Low:   55

Sunrise Monday:  5:26 AM CDT
Sunset Monday:   9:01 PM CDT