Thursday, July 13, 2017

Second coldest high temp on record today, July 13 at Duluth, Minnesota. Chilly tonight; Back to normal Friday (70s) Little muggier Saturday with highs ~80; Lake breeze (Cooler Sunday) Forest Lake, MN tornado info in this post

/Issued 5:53 PM CDT, Thursday, July 13, 2017/


RAP 18z model valid for 5 AM Friday.

High pressure settling into the Northland tonight lead to light winds and some clearing during the night which will set the stage for very cool temperatures for areas away from Lake Superior in northeast Minnesota and northwest Wisconsin.  Widespread 40s are expected with 30s likely in the traditional cold spots.  It will be a bit warmer, however, near Lake Superior.



One tornado in Minnesota early Wednesday morning with 5 tornado reports in eastern North Dakota Tuesday evening.  Note:  More info on the Minnesota tornado down below.

Tornado Number one track map.  Source:

Tornado Number 1 - Columbus/Forest Lake, Minnesota
Counties:  Anoka, Washington


Date:  July 12, 2017
Time:  2:28 AM - 2:37 AM CDT
EF Rating:  EF-1
Estimated Peak Winds:  90 mph
Path Length:  8.8 miles
Max Width:  300 yards
Injuries/Deaths:  None

Summary:  This tornado started 6 miles west-southwest of Forest Lake and tracked 4 miles northeast of Hugo.

Radar loop from the Forest Lake tornado early Wednesday morning.  Source:

Radar loop from 4-10 PM Tuesday, July 11, 2017.  Source:

Watch the rapid development of supercell thunderstorms over eastern North Dakota ~5PM Tuesday.

7:30 PM radar image from July 11, 2017 -- Amazing looking hook between Hillsboro and Buxton in eastern North Dakota -- This was a long track tornado.  Source:

Velocity image from 7:30 PM, July 11, 2017 -- Wow!  Source:

Weather Synopsis

Very cool temperatures remained over the Northland today under mostly cloudy skies with lingering drizzle and fog near Lake Superior.  Skies in far northern Minnesota have been clearing this afternoon, mostly up near the Ontario border.  Highs today were in the mid 50s to low 60s with mid 60s and low 70s in far northern Minnesota.

NW flow aloft covered the upper Midwest today with an upper level low pressure system centered just west of northwest Lake Superior late this afternoon -- This upper low will continue to move slowly toward the east/southeast through Friday while high pressure builds over Minnesota before it moves to the south/east by Friday night.

For tonight partly to mostly cloudy skies.  Lingering drizzle early with areas of fog through the night.  Lows in the 40s with 30s over interior sections of northeast Minnesota and northwest Wisconsin, away from Lake Superior.

Friday looks like a nice summer day with low dew points while high temperatures get back to where they should be in mid July (70s)  Areas of fog burning off before 10 AM otherwise mostly sunny to partly cloudy skies for Friday.

Warm and moist advection pattern spreads into the area from the W-NW Friday night/Saturday morning as a cold front approaches from the NW.  Elevated instability will be on the increase Friday night with CAPE of 500-1500 j/kg over our area while steep mid level lapse rates of 7.0-8.0 c/km move into the area. Winds aloft look strong with mid level northwesterlies of 30-45 knots with deep layer wind shear forecast to be in the 30-40 knot range -- A few strong thunderstorms are possible in parts of the Northland late Friday night or Saturday morning as that aforementioned cold front moves through.  Hail and gusty winds will be the main threats if stronger storms do develop.

Saturday afternoon looks dry as the cold front exits the Northland to the south/east.  Highs Saturday will be in the 70s and 80s.  It will also become more humid Saturday especially in east central Minnesota and northwest Wisconsin where dew points are forecast to range from 65 to around 70 degrees.  Not as muggy in northern Minnesota due to an earlier cold frontal passage.

The entire Northland will be dry and less humid Sunday as high pressure passes through the upper Midwest.  Lake wind develops keeping temperatures in the 60s near Lake Superior while farther inland away from Lake Superior highs will be in the 70s.

Weather Tidbits:

*High temperature so far today, July 13, 2017 -- 57 degrees.  Second coldest high temperature on record for July 13 dating back to 1870.  The coldest high temperature on record for July 13 is 53 degrees set in 1883.  Note:  See top 5 list below.

1:  53 F in 1883
2:  57 F in 2017
3:  58 F in 1920
4:  59 F in 1993
5:  60 F in 1895

Forecast for Duluth and Superior

.Tonight...  Areas of fog and drizzle.  Mostly cloudy.  Low 46 to 51.  Wind northeast around 10 mph becoming light and variable.

.Friday...  Milder! Patchy low clouds or fog early otherwise mostly sunny.  High 74 to 77.  Wind variable around 12 mph.

.Saturday...  Humid.  Isolated showers or thunderstorms possible during the morning.  Some sun.  High 80 to 85.  Dew point 63 to 68.

Normal temperatures for Friday

High:  77
Low:   56

Sunrise Friday:  5:29 AM CDT
Sunset Friday:   9:00 PM CDT