Wednesday, May 25, 2016

May 25, 2016: Fog and drizzle lingers into Thursday morning; 70s to around 80 degrees on Thursday (Much cooler near Lake Superior) Storm reports included in this post. Frost potential June 3rd-5th

/Issued 6:45 PM CDT, Wednesday, May 25, 2016/

Upper Midwest radar loop ending at 6:30 PM CDT May 25, 2016.  Source, WSI.

Note:  Rain is coming to an end a few hours earlier than expected in Duluth and Superior, still a chance for a few scattered showers for the rest of tonight in the Twin Ports but fog and drizzle will likely be the main weather hazards tonight.

Thursday's severe weather outlook.  Source, WSI; Storm Prediction Center.

Enhanced risk for severe thunderstorms (Orange shaded area on map)
Slight risk for severe thunderstorms (Yellow shaded area on map)
Marginal risk for severe thunderstorms (Light green shaded area on map)
Dark green=Risk for non-severe thunderstorms

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

Long range trends continue to support a cooler weather pattern for the first weekend of June with a possible frost threat sometime between June 3rd-5th in northeast Minnesota and northwest Wisconsin.

 Image below is from today's 12z EUROPEAN model valid for next Friday, June 3, 2016 -- 850mb temperature anomaly forecast.  Blue and purple colors represent below to well below average temperatures.

Low temperature forecast for tonight.  Source, National Weather Service Duluth, Minnesota.

High temperature forecast for Thursday.  Source, National Weather Service Duluth, Minnesota.

Filtered storm reports map for May 24, 2016.  Source, Storm Prediction Center.

Red dots=Tornado reports
Blue dots=Damaging wind reports (58 mph or stronger)
Green dots=Large hail reports (1.00" or greater in diameter)

Note:  106 warnings were issued in parts of 12 states on Tuesday.  73 severe thunderstorm warnings and 33 tornado warnings.

Montana, Colorado, Texas, Oklahoma, Arkansas, Missouri, Kansas, Nebraska, South Dakota, Minnesota, Wisconsin and Upper Michigan.

*Local Storm Reports*
Source:  National Weather Service Duluth, Minnesota

*4:44 PM CDT 5/24/16:  THUNDERSTORM WIND DAMAGE.  6 NW of Mercer, WI (Iron County)  Trees down at Highway 51 and Moose Lake Road.

*7:41 PM CDT 5/24/16:  HAIL.  0.25".  Pine River, MN (Cass County)  Lots of pea sized hail.

*7:59 PM CDT 5/24/16:  HAIL.  0.25".  2 SW of Rossburg, MN (Aitkin County)  Peas to 0.5 inch hail.

*8:33 PM CDT 5/24/16:  HAIL.  0.88".  3 NE of Pontoria, MN (Cass County)

*3:20 PM CDT 5/25/16:  HAIL.  1.50".  1 N of Minong, WI (Washburn County)

Weather Summary for NE Minnesota and NW Wisconsin
Date:  May 25, 2016

A foggy, windy and chilly day near Lake Superior with east winds in the 15 to 30 mph range with temperatures holding in the 40s to low/mid 50s.  The remainder of the Northland had milder temperatures with highs in the 60s and 70s today.

Low pressure has moved into eastern North Dakota late this afternoon with a warm front extending southeast through south central Minnesota.  An area of rain with embedded thunderstorms has been tracking north/northeast across most of the Northland this afternoon with heavier downpours occurring at times.  A few strong to severe thunderstorms have also occurred this afternoon in parts of northwest Wisconsin with enough instability in place to produce these stronger storms -- Afternoon mesoanalysis showed around 500 j/kg of elevated CAPE in place in northwest Wisconsin.

Forecast Discussion for NE Minnesota and NW Wisconsin

Confidence:  Medium to High.

Tonight:  A warm front will lift slowly north/northeast out of southern Minnesota while a cold front heads northeast into the Upper Midwest, low pressure will remain over the northern Plains.  Scattered showers and a few thunderstorms will persist over the Northland tonight.  Note:  The greatest instability should remain over western/southern portions of the area with CAPE up around 500 j/kg with Lifted Indices of 0 to -2C.  Around 30 knots of deep layer shear is in place along with favorable effective storm relative helicity values of 100-200 m2/s2 near the warm front which will lift into central Minnesota tonight...An isolated risk for strong to severe thunderstorms will be found near this warm front tonight with hail and gusty winds being the main threats.  Low temperatures will be in the 50s with 40s near Lake Superior.  Winds will be out of the east or southeast at 5 to 15 mph with higher gusts near Lake Superior.

Thursday:  An area of low pressure will move into southern Ontario Province while a warm front and cold front continue to track through the Northland.  The chance for showers and thunderstorms isn't as high tomorrow as it was for today but with lingering moisture, instability and a few boundaries nearby, a few showers and thunderstorms could develop.  If thunderstorms do form they will have favorable convective parameters in place for a risk of isolated strong or severe thunderstorms especially over northwest Wisconsin.  Highs on Thursday will be in the 70s to around 80 degrees with much cooler temperatures near Lake Superior.  Lows Thursday night will be in the 50s and 60s with 40s near Lake Superior.  Winds will be out of the south or east at 5 to 15 mph.

...Looking ahead...

Confidence:  Medium.

A risk for showers and thunderstorms continues on Friday and Saturday (27th-28th) We might dry out on Sunday and possibly for most of Memorial Day but confidence on that actually happening is low.

A southwest flow aloft will remain in place through early next week with moist and unstable air pushing north into the Upper Midwest at times -- Low pressure disutrbances will eject out of the Rockies and Plains and those features combined with passing warm fronts and cold fronts will help trigger a couple rounds of showers and thunderstorms over the Northland through the middle of next week.

Looking farther out...A scattered frost potential continues in parts of the Northland during the June 3-5 time frame as much cooler air drops south out of central Canada.

Normal temperatures for May 26th at Duluth, Minnesota

High:  65
Low:   43

Sunrise Thursday:  5:22 AM CDT
Sunset Thursday:   8:50 PM CDT