Monday, May 15, 2017

Rainfall totals of 1-4 inches today in parts of northwest Wisconsin. Dry this evening; Showers/T-storms return at times Tuesday; More rain expected Wed-Thu AM

/Issued 5:53 PM CDT, Monday, May 15, 2017/



12z NSSL WRF-ARW model


Greatest chance for severe thunderstorms tonight is over southern Minnesota, but non-severe thunderstorms are possible farther north across the Northland.


A marginal risk (Dark green area) of severe thunderstorms includes all of northwest Wisconsin and east central Minnesota and northeast Minnesota Tuesday.


With several rounds of rain the next few days this will increase the threat for river flooding over all of Wisconsin and over all but northern portions of Minnesota.


It was a bright and noisy early morning in parts of the Northland as strong thunderstorms with vivid lightning moved through parts of the area.


Enhanced Infrared Satellite image from 3:30 AM today.

Rainfall reports from around the Northland for May 15, 2017

Note:  Totals listed below are thru 5:30 PM today.

Glidden, WI:  4.66 in
Barnes, WI:  2.12 in
Ashland, WI:  1.97 in
Solon Springs, WI:  1.56 in
Minong, WI:  0.97 in
Washburn, WI:  0.83 in
Clam Lake, WI:  0.37 in
Moose Lake, MN:  0.18 in
Cloquet, MN:  0.11 in
Isabella, MN:  0.10 in
Orr, MN:  0.09 in
Duluth, MN (Airport)  0.08 in
Hill City, MN:  0.07 in
Two Harbors, MN:  0.07 in

Weather Synopsis:

A nice start to the 2017 thunderstorm season as scattered elevated strong thunderstorms developed early this morning while moving off toward the east/southeast -- The bulk of these storms were focused along and south of the Highway 2 corridor in northeast Minnesota, these storms also moved across parts of northwest Wisconsin.  Torrential downpours and frequent lightning occurred with these storms, and hail was also reported in parts of the area.

More rain and scattered thunderstorms occurred today in much of northwest Wisconsin while eastern Minnesota dried out after morning-early afternoon showers and thunderstorms.

Northern Minnesota has stayed dry most of the day, and as a result the warmest temperatures were found in that area with highs today in the 70s while farther south where clouds and rain has occurred, highs were in the 50s and 60s with 40s near Lake Superior.

-Looks like most of tonight will be dry in northeast Minnesota while rain and a few thunderstorms diminish from west to east in northwest Wisconsin this evening.

-The warm front which was farther north at this time yesterday has shifted south as expected due to the thunderstorms north of that front today -- This warm frontal boundary was more or less over northern Iowa late this afternoon, and additional showers and thunderstorms will develop near this boundary across southern Minnesota this evening and through the overnight hours...These storms will lift north/east and are expected to reach southern portions of the Northland after midnight.

-Tuesday will find the warm front lifting north out of southern Minnesota but how far north this boundary gets is uncertain.  Showers and thunderstorms should continue to develop at times along and north of that warm front Tuesday with most of the Northland having the potential for seeing this activity.

As for the threat for severe weather in the Northland:  This threat looks greatest Tuesday afternoon or Tuesday evening but the chance for severe weather is still relatively low.  There is uncertainty on how unstable it will get Tuesday PM with models projecting CAPE anywhere from 500 j/kg to as much as 2500 j/kg.  Shear looks strongest through the early evening hours, generally around 40-50 knots which is favorable for organized storms.  Mid level winds also look favorable, and there should be a rather strong low level jet at around 35-45 knots.  The main unknown is how unstable it will get in our area, and also the location of the warm front later Tuesday afternoon.  If thunderstorms become strong to severe the main hazards will be from hail and possibly strong wind gusts.  A limited risk for a tornado in east central Minnesota or northwest Wisconsin but this chance looks very low at the moment.

Otherwise the potential for heavy downpours and lightning will continue with any thunderstorm that develops through Tuesday night.

-Another round of rain is expected to affect parts of east central Minnesota, northeast Minnesota and northwest Wisconsin Wednesday into early Thursday morning as another area of low pressure lifts northeast out of the central Plains.

Forecast for Duluth and Superior

.Tonight...  Partly to mostly cloudy.  Low 42 to 47.  Wind east at 10 to 20 mph.

.Tuesday...  Occasional showers.  Thunderstorms also possible.  Mostly cloudy.  High 55 to 60 but cooler near Lake Superior.  Wind east at 10 to 20 mph.

Normal temperatures for Tuesday

High:  62
Low:   41

Sunrise Tuesday:  5:32 AM CDT
Sunset Tuesday:   8:38 PM CDT