Sunday, July 9, 2017

Risk of strong-severe thunderstorms this evening south of the Twin Ports. Dry with seasonable temps Monday followed by much cooler temperatures for midweek

/Issued 4:32 PM CDT, Sunday, July 9, 2017/


18z NAM NEST model valid for 7 PM this evening


Primary threats through this evening in central/southern Minnesota:  Isolated tornadoes, large hail quarter size to golf ball size and damaging wind gusts 60 mph or greater.


19z RTMA model -- Average temperature in South Dakota at 2 PM today 97.3 degrees -- In Minnesota the average temperature was 77.5 degrees.

NW flow keeping the core of the heat west/southwest of the Northland, this will continue most of this week as the hottest temperatures remain to our west/southwest.


Note:  Well it has been a wet summer here in the Northland it's been a different story to our west where persistent heat and dry weather has led to a growing area of severe and extreme drought across the Dakotas/western High Plains region.

You can certainly tell by looking at the map below where it rained today -- A pocket of rain cooled air over the Twin Ports and surrounding areas of northwest Wisconsin and east central Minnesota with warmer temperatures north and south where there has been little or no rain today (thru 3 PM)

Note:  This temperature image was from 1 PM today, July 9, 2017.


Temperature departure map for the week of July 2, 2017


Precipitation departure map for the week of July 2, 2017

Temperature and precipitation report for Duluth, Minnesota (Airport location)

July 2-8, 2017

High temperatures

7/2:  75 F/Normal
7/3:  73 F/-2 degrees below normal
7/4:  78 F/+3 degrees above normal
7/5:  86 F/+10 degrees above normal
7/6:  85 F/+9 degrees above normal
7/7:  70 F/-6 degrees below normal
7/8:  79 F/+3 degrees above normal

Low temperatures

7/2:  51 F/-3 degrees below normal
7/3:  49 F/-5 degrees below normal
7/4:  52 F/-2 degrees below normal
7/5:  59 F/+5 degrees above normal
7/6:  64 F/+9 degrees above normal
7/7:  54 F/-1 degree below normal
7/8:  52 F/-3 degrees below normal

Total precipitation:  1.88"
Normal:  1.01"
Departure:  +0.87" above normal

Rainfall totals for July 9, 2017 (thru 3 PM)

Hayward, WI:  0.30 in
Hill City, MN:  0.24 in
Phillips, WI:  0.23 in
Saginaw, MN:  0.22 in
Barnes, WI:  0.21 in
Minong, WI:  0.21 in
Moose Lake, MN:  0.19 in
Ashland, WI:  0.18 in
Duluth, MN (Airport)  0.11 in
Grand Rapids, MN:  0.08 in
Two Harbors, MN:  0.01 in

Weather Synopsis

Skies have been mostly sunny this afternoon over northern Minnesota while farther south skies have been partly sunny to mostly cloudy.  The area of rain which affected parts of the Northland this morning into the early afternoon hours has shrunk a bit and has shifted slightly farther south as of 3 PM with most of the scattered showers affecting east central Minnesota and portions of northwest Wisconsin.  Highs today were mainly in the 70s with 60s for those areas that had rain -- Temperatures in far northern Minnesota were approaching 80 degrees this afternoon.

A well defined frontal boundary was over central Minnesota this afternoon with temperatures in the 80s to lower 90s just south of this front with cooler air north of it.  Instability has been increasing in central Minnesota this afternoon with CAPE of 1000-2500 j/kg while mid level lapse rates of 7.0-8.0 c/km continue to advect E/NE out of the northern Plains -- Mid level winds from the NW at 40-50 knots while southwest winds at 850mb have increased to ~30 knots per meso-analysis from 3 PM today.  Scattered thunderstorms should erupt late this afternoon and continue this evening across west central, central and southern portions of Minnesota as well as in parts of west central Wisconsin.  The turning of wind direction with height will cause rotating thunderstorms to develop enhancing the potential for large hail bigger than quarter size.  In addition, 1 km shear to 25 knots and Storm Relative Helicity of 200-300 m2/s2 supports a risk of a tornado or two through early this evening in central or southern Minnesota.

The Northland should escape most of the rough weather this evening although a few stronger storms could develop while affecting primarily western-southern sections of the area through the evening hours with a low risk of hail and strong winds but heavy downpours and lightning could be a bigger threat out of this activity this evening in southern sections of the Northland.

Partly to mostly cloudy skies are expected tonight with lows in the 50s to lower 60s with 40s possible in the typical cold spots.

Monday looks dry with highs in the 70s to lower 80s -- Could be some fog or low clouds that form late tonight, lingering into Monday morning but this should burn off before Noon.  Low pressure and cold front which was over central Minnesota this afternoon will push farther south/east Monday as high pressure moves over the upper Midwest.

Our next opportunity for showers and thunderstorms will occur Tuesday into Wednesday as low pressure, warm front and cold front move across the upper Midwest.  Still too early to tell where the greatest severe threat/heavy rain potential will be with this next system, although early signs point to the west half and south half of Minnesota having the greatest potential for some severe weather and heavy rain Tuesday afternoon through Tuesday night.

Highs Tuesday are expected to be in the 70s and 80s with cooler temperatures near Lake Superior as a lake wind intensifies during the day.  Much cooler for Wednesday with highs only in the 50s near Lake Superior with 60s over the rest of the Nortlhland.

Forecast for Duluth and Superior

.Tonight...  Partly to mostly cloudy.  Isolated showers mainly before midnight.  Low 52 to 57.  Wind variable around 10 mph.

.Monday...  Partly to mostly cloudy.  High 73 to 78 but cooler near Lake Superior.  Wind variable around 12 mph.

Normal temperatures for Monday

High:  76
Low:   55

Sunrise Monday:  5:25 AM CDT
Sunset Monday:   9:03 PM CDT