Tuesday, July 19, 2016

July 19, 2016: Excessive Heat Watch remains in effect Wednesday and Thursday; Amazon jungle humidity levels with 70+ degree dew points. Risk for showers/t-storms through Thursday (some strong to severe)

/Issued 5:43 PM CDT, Tuesday, July 19, 2016/

Amazon jungle type humidity levels will move into the Northland Wednesday as dew points climb to around 70 degrees, possibly as high as 73 to 77 degrees in parts of the area.  Here's the dew point forecast valid for Wednesday afternoon per 18z NAM.  Source, http://weather.cod.edu/

Similar conditions expected for Thursday with more steamy dew points expected.  Thursday afternoon dew point forecast per 18z NAM.  Source, http://weather.cod.edu/

Excessive heat watch continues for the counties shaded in dark red on the map below.  More information at the link below.  Source, National Weather Service Duluth, Minnesota.


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

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

Tonight's low temperature forecast.  Source, National Weather Service Duluth, Minnesota.

Wednesday's high temperature forecast.  Source, National Weather Service Duluth, Minnesota.

Weather Summary for NE Minnesota and NW Wisconsin
Date:  July 19, 2016

A nice day under mostly sunny to partly sunny skies.  Highs were in the 80s with 60s and 70s around Lake Superior.  Dew points have come up a bit this afternoon and ranged from the mid 50s to mid 60s with 70 degree dew points up into western, central and southern Minnesota.  Winds today were out of the south or east at 10 to around 20 mph.

Forecast Discussion for NE Minnesota and NW Wisconsin

Confidence:  Medium.

Tonight through Thursday (July 19-21)

Tropical level humidity and very warm temperatures will be the big story through Thursday.  A large ridge of high pressure with 500mb heights of 594 meters will cover the Plains while low pressure along with a warm front and cold front move slowly east/northeast into the Northland.

Dew points should climb into the 60s and 70s in our area Wednesday and in the 70s to around 80 degrees Thursday.

High temperatures are forecast to be in the 80s and 90s Wednesday and Thursday with heat index values (Feels like temperature) of 95 to around 105 degrees Wednesday afternoon and again Thursday afternoon.

Note:  Will likely see the excessive heat watch change to an excessive heat warning or heat advisory by late tonight or early Wednesday morning.

Low temperatures tonight will be in the 60s to lower 70s with lows Wednesday night mainly in the 70s.

Note:  Expect cooler temperatures around Lake Superior -- Especially along the North Shore.  60s at night and 70s to lower 80s during the day, it will be humid though, so even along the North Shore of Lake Superior it will feel somewhat uncomfortable although not as oppressive as it will be in other parts of Minnesota.

For the Twin Ports:  A stronger lake breeze did develop today but this probably won't be the case Wednesday or Thursday as winds turn more out of the south or possibly southwest.  If an offshore wind does develop, then very warm to hot temperatures possibly close to 90 degrees will occur even below the hill in Duluth, but if a lake breeze develops or carries over from tonight..then high temperatures would be fairly similar to today (Tuesday) with temperatures in the 70s.

Thunderstorm chances:  Isolated to scattered coverage of showers and thunderstorms from late tonight through Thursday across the Northland but warmer temperatures moving in aloft (CAP) may prevent storms from forming.  H7 temperatures are expected to range from around +12 to +14 degrees Celsius Wednesday and Thursday which is a fairly strong cap.  However, should this cap be weaker or if something can break it, then scattered convection would develop.  Given the expected amount of instability, moisture, wind shear and stronger mid/upper level winds near our area the potential does exist for strong to severe thunderstorms with damaging winds and large hail.  Torrential rainfall will also occur should storms develop as PWATS average around 1.50" through Thursday.  Also expected frequent cloud to ground lightning near any thunderstorm.

Forecast for Duluth and Superior

Event:  *Excessive Heat Watch for Duluth*
Timing:  Wednesday afternoon through Thursday evening

Event:  *Excessive Heat Watch for Superior*
Timing:  Thursday morning through Thursday evening

Tonight - Partly to mostly cloudy.  Showers or thunderstorms possible after midnight.  Low 60 to 65.  Wind east to southeast at 10 to 15 mph.

Wednesday - Muggy.  Showers or thunderstorms possible mainly in the morning.  Partly to mostly cloudy.  High 82 to 87.  Dew points around 70.  Afternoon heat index temperature of 90 to 95 degrees.  Wind south at 10 to 20 mph.

Normal temperatures for Wednesday

High:  77
Low:  56

Sunrise Wednesday:  5:35 AM CDT
Sunset Wednesday:   8:54 PM CDT