/Issued 4:17 PM CDT, Wednesday, April 29, 2015/
Weather map for Sunday, May 2, 2015. A cold front (Blue line on the map) moving southeast out of North Dakota and Northwest Minnesota could bring some showers or thunderstorms to Northeast Minnesota and Northwest Wisconsin on Sunday. The computer models are beginning to increase the amount of instability and moisture with this system which may lead to a greater risk for convection in our area, things could change though so stay tuned. Source, Weather Prediction Center.
Not a lot of rain with Friday’s cold front with amounts probably around a tenth of an inch or less in most spots. Source, NAM – 12km model (18z run) TropicalTidbits.com
An upper level low/trough is centered to our east today, this system is dropping due south and won’t affect the Northland. Source, 4:30 PM CDT water vapor satellite image; College of Dupage website.
7 day rainfall forecast valid through Wednesday, May 6, 2015. Source, Weather Prediction Center. A quarter to half inch of rain is possible by the middle of next week in Northeast Minnesota and Northwest Wisconsin — This would come in a few waves; One on Friday, another either Saturday Night or Sunday, and a third wave starting around the middle of next week.
Note: We’ve already had a few bouts of thunderstorms here in the Northland this spring. The chances for stronger thunderstorms increases here during the next few months so I figured now would be a good time to refresh your memory on the difference between a watch and warning, what exactly defines a severe thunderstorm, and the different types of thunderstorms. Source, Weather Spotter’s Field Guide handbook
Watch: Conditions are favorable in a region for severe thunderstorms or tornadoes to develop or to move into your area. Watches are generally issued for a 4-8 hour period. Be ready for storms in the near future. Take action to protect property before the storms arrive in your area.
Warning: There is either imminent threat or an actual occurrence of large hail, damaging winds or a tornado. When a warning is issued, respond immediately to protect life and property. Warnings are generally issued for 30-60 minutes.
*A severe thunderstorms has at least one of the following:
*Hail that is 1 inch or larger: The size of a quarter.
*Wind gusts of at least 58 mph or higher. 50 knots.
There are 5 types of thunderstorms:
-Ordinary or Single Cell Storm: Single cell storms are short lived, and usually not severe.
-Pulse Storm: A pulse storm is a single-cell thunderstorm that is usually not strong; when it is of substantial intensity, it produces severe weather for short periods of time. Such a storm weakens and then generates another short burst or pulse.
-Mutlicellular Cluster: This type is the most common storm, consisting of a group of ordinary cells and various stages of the thunderstorm life cycle.
-Multicellular Line: This category is a long line of storms with a continuous, well developed gust front along the leading edge.
-Supercell: A supercell is a highly organized thunderstorm with an extremely strong updraft. They exhibit persistent storm-scale rotation of the updraft-downdraft couplet or mesocyclone.
Typically we get roughly 30-40 thunderstorm days a year in both Minnesota and Wisconsin.
Weather Summary for April 29, 2015
Location: Northeast Minnesota and Northwest Wisconsin
High pressure is in control of our weather for the most part Today although there is an upper level trough dropping almost due south through the Central/Eastern Great Lakes region Today, were also seeing a disturbance move S/SE out of Southeast Manitoba Today which led to a bit more cloudcover than originally forecast in parts of the Northland — The sunniest spots were over the Arrowhead and also in Eastern portions of Northwest Wisconsin Today. Temperatures remained mild Today with highs in the upper 50s to middle 60s but it was cooler close to Lake Superior. Winds were generally out of the north or northeast at 5 to 15 mph.
Forecast Discussion for Northeast Minnesota and Northwest Wisconsin
Short Term Forecast – Confidence: High.
Tonight (April 29)
An area of high pressure will move off to our north/east during the night. Partly to mostly cloudy skies will cover the area with lows in the 30s and 40s. Winds will turn to the east at 5 to 15 mph.
Thursday and Thursday Night (April 30)
Dry Tomorrow with highs in the 50s and 60s but it will be cooler near Lake Superior as we see a more pronounced lake breeze form. Sunny to partly cloudy skies are expected with winds out of the south or east at 5 to 15 mph.
Partly to mostly cloudy skies for Thursday Night. A cold front moves into Western Minnesota by daybreak with a chance for showers moving into North Central Minnesota after Midnight Tomorrow Night. Lows Thursday Night will be in the 30s and 40s with south or east winds at 10 to 15 mph.
Extended Forecast – Confidence: High.
Friday through Sunday (May 1-3)
A weakening cold front will pass through the Upper Midwest on Friday. Some showers are possible in parts of the Northland mainly before mid Afternoon Friday…The computer models are starting to show some instability building up during the Afternoon-Evening hours near this weak boundary, so we could see a few pop-up showers or thunderstorms redevelop late Friday Afternoon mainly over Eastern Minnesota and Northwest Wisconsin. High temperatures on Friday are forecast to be in the 50s and 60s with 70s possible west of a International Falls to Aitkin line. Lows Friday Night will be in the 40s and 50s.
High temperatures on Saturday should climb into the 70s across the Northland, a few spots might even make a run at 80 degrees! Winds will be out of the south or southwest so the warm temperatures should even make it into Superior and Downtown Duluth, but it will be cooler along the North Shore of Lake Superior or northeast of the Twin Ports.
Looks mainly dry although a few showers can’t be ruled out in far Northern Minnesota Saturday Afternoon with another chance for a few showers or thunderstorms Saturday Night in Western-Northern portions of Minnesota. Lows Saturday Night will be in the 40s and 50s.
A cold front will move through the area on Sunday. One difference I have seen in the model guidance Today for Sunday is a lot more instability than what the models were showing 24 hours ago. The EURO is quite bullish painting a 1000+ j/kg of CAPE across much of Central and Eastern Minnesota Sunday Afternoon, this would be enough to fuel stronger thunderstorms especially if we have enough moisture in place, along with stronger winds aloft and favorable amounts of wind shear. The NAM also has a nice surge of elevated CAPE moving NE into the area late Saturday Night (The end of their run) There is a chance for some showers or thunderstorms in the Northland on Sunday so keep that in mind if you have outdoor plans. High temperatures on Sunday are forecast to be in the 60s and 70s.
Long Range Forecast – Confidence: Medium to High.
Monday and Tuesday (4th-5th) look mainly dry at this time. Rain is possible at times from the 6th-9th as low pressure approaches from the west and south, also appears will have an area of high pressure sitting to our north, so a stronger lake wind and cool temperatures will likely setup near Lake Superior during the middle to end of next week.
Temperatures from the 4th-9th are forecast to be near to above average.
5 DAY FORECAST FOR DULUTH AND SUPERIOR
.Tonight… Some clouds. Low 30 to 35. Wind east to northeast at 10 to 15 mph.
.Thursday… Cooler. Mostly sunny. High 51 to 56 but cooler near Lake Superior. Wind east at 10 to 20 mph.
.Thursday Night… Partly to mostly cloudy. Low 35 to 40. Wind east at 10 to 15 mph.
.Friday… Considerable cloudiness. Showers possible mainly before Noon. High 57 to 62.
.Friday Night… Partly cloudy. Low 42 to 47.
.Saturday… Partly cloudy. High 72 to 77.
.Saturday Night… Partly cloudy. Low 50 to 55.
.Sunday… Partly to mostly cloudy. A few showers or thunderstorms possible. High 68 to 73 but it may be cooler near Lake Superior.
Normal temperatures for Wednesday
Sunrise Thursday: 5:56 AM CDT
Sunset Thursday: 8:17 PM CDT