Monday, May 23, 2016

May 23, 2016: Scattered showers/t'storms tonight; 70s to around 80 degrees on Tuesday (Isolated t'storm risk)

/Issued 5:48 PM CDT, Monday, May 23, 2016/

Upper Midwest radar loop ending at 5:30 PM CDT, May 23, 2016.  Source, WSI.

Scattered showers and thunderstorms affecting northwest Wisconsin and parts of northern and eastern Minnesota late this afternoon.  So far the rain has stayed away from Duluth, will see if that continues this evening.

A wetter weather pattern across the Upper Midwest through the holiday weekend but it likely won't rain every day through Memorial Day, and some locations might actually miss out on a lot of the rain, that's how it works with thunderstorms, some areas get a lot of rain, others not as much.  Source, Weather Prediction Center (7-day rainfall forecast valid through May 30, 2016)

The 2016 U.S. tornado season is running below average through May 22nd.  Source, Storm Prediction Center.

Average:  691 tornadoes through the 22nd of May.
Actual total:  499 tornadoes.

127 tornado reports so far this month in the U.S.  The average for May is 186 tornadoes (1986-2015 average)  Note:  The NCDC 1991-2010 average is 243.  Source, @USTornadoes; Storm Prediction Center.

*February 23rd continues to hold the number one spot for most active tornado day so far this year with a total of 52 tornadoes.

*26 preliminary tornadoes on May 22nd -- 6th most active tornado day so far this year.

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

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

Weather Summary for NE Minnesota and NW Wisconsin
Date:  May 23, 2016

A morning round of showers and thunderstorms affected western portions of the Northland, generally west of a line from International Falls to Brainerd, this activity weakened as it moved east so much of northeast Minnesota remained dry today.

Showers and thunderstorms redeveloped late this afternoon over northwest Wisconsin with most of this activity through 4 PM today along and east of a line from Pine City to Solon Springs to Bayfield.  Moisture and instability has come up today as expected but the amount of instability is fairly low with CAPE values generally around 500 j/kg per mesoanalysis.  Dew points have climbed into the mid 50s to around 60 degrees though and PWATS have increased to over 1.30" this afternoon which is leading to heavy rainfall rates of a half inch to one inch an hour in parts of northwest Wisconsin late this afternoon.

Mostly cloudy skies were common in the Northland today with mild late spring temperatures with highs in the 70s to lower 80s.  Winds were out of the south or southwest at 10 to 20 mph with higher gusts.

Forecast Discussion for NE Minnesota and NW Wisconsin

Confidence:  Medium to Low.

Starting off with tonight -- The best convergence has setup over northwest Wisconsin into extreme eastern Minnesota and this has led to an area of showers and thunderstorms which should continue while moving northeast this evening.  Heavy rainfall and lightning will be the main hazards out of this activity with a slight chance for hail and gusty winds before 10 PM.

A few showers and thunderstorms will also affect extreme northern Minnesota and the Arrowhead this evening.  Elsewhere the trends don't look very promising for rain tonight but with the weak instability and moisture already in place and with a weak boundary to our west, a few showers or thunderstorms could certainly sprout up from time to time through the night.

Could be some patchy fog late tonight but this should burn off Tuesday morning.  Low temperatures tonight will be in the 50s and 60s with southerly winds at 5 to 15 mph.

Next order of business is what happens on Tuesday?  Frontal boundary which is currently sitting to the north/west of the Northland pushes south tomorrow as high pressure builds southeast toward northern Ontario and Hudson Bay -- A few of the computer models want to develop scattered showers and thunderstorms across the Northland on Tuesday with a potentially unstable and moist airmass overhead.

Highs on Tuesday will be in the 70s and 80s but turning cooler near Lake Superior.  Winds will be out of the south or east at 5 to 15 mph.

...Looking ahead...

Confidence:  Low.

From mid to late week will have high pressure near Hudson Bay while low pressure systems eject northeast out of the Rockies and Plains -- Periods of showers and thunderstorms are possible over the Northland on Wednesday, Thursday and Friday.

High temperatures are forecast to be in the 60s to around 70 degrees from Wednesday through Friday but it will be cooler near Lake Superior due to a stronger onshore flow...Fog and drizzle could also develop near Lake Superior from mid to late week.

Normal temperatures at Duluth for May 24th.

High:  65
Low:  43

Sunrise Tuesday:  5:24 AM CDT
Sunset Tuesday:   8:48 PM CDT