Sunday, April 30, 2017

Major spring storm on the way with several inches of wet snow and some rain (Duluth, MN May 1st snowfall record of 1.6" will be broken)

/Issued 5:28 PM CDT, Sunday, April 30, 2017/

Note:  Could be some higher snowfall amounts especially in the 4-6" zone.

Latest headlines from the National Weather Service in Duluth, Minnesota.

Pink:  Winter Storm Warning
Purple=Winter Weather Advisory


12z Duluth WRF model -- Monday afternoon temperatures.

Flooding has been a very serious problem the past few days in parts of the Midwest!  Look at these 24 hour rainfall totals from Saturday morning thru Sunday morning.  Source:

Significant river flooding is expected the next few days in parts of Illinois and Missouri.  Source:

Temperature departure map for the week of April 23rd.  Source:

Precipitation departure map for the week of April 23rd.  Source:

Temperature and precipitation report for Duluth, Minnesota (Airport location)

April 23-29, 2017

High temperatures:

*=Record coldest high temperature for the date

4/23:  45 F/-8 degrees below normal
4/24:  41 F/-13 degrees below normal
4/25:  59 F/+5 degrees above normal
4/26:  36 F/-19 degrees below normal
*4/27:  30 F/-25 degrees below normal
4/28:  49 F/-7 degrees below normal
4/29:  48 F/-8 degrees below normal

Low temperatures:

4/23:  31 F/-2 degrees below normal
4/24:  31 F/-3 degrees below normal
4/25:  36 F/+2 degrees above normal
4/26:  25 F/-9 degrees below normal
4/27:  23 F/-12 degrees below normal
4/28:  28 F/-7 degrees below normal
4/29:  25 F/-11 degrees below normal

Total precipitation:  1.00"
Normal:  0.67"
Departure:  +0.33" above normal

Note:  How often does Duluth get a 1 inch or greater snowfall total in May?  Have to go back to May 7th, 2010 when 4.4 inches of snow fell; Before that May 7th, 2002 with a snowfall of 1.5 inches.

*Record snowfall total for May 1st at Duluth, Minnesota is 1.6 inches which was set in 1970.  Should have no problem breaking this record Monday.

*Dating back to 1874 (142 years) Only 2% of May firsts have had a snowfall total of at least 1.0 inch at Duluth, Minnesota.  So to get more than an inch of snow on the 1st of May is quite rare even for a location this far north!

May climate normals for Duluth, Minnesota

Normal high:  51.4 degrees
Precipitation:  3.23"
Snowfall:  0.4"

Warmest May on record:  57.4 degrees in 1977
Coldest May on record:  38.8 degrees in 1907

Wettest May on record:  7.99" in 1899
Driest May on record:  0.15" in 1976

Snowiest May on record:  8.1" in 1954

Normal high on the 1st:  57 degrees
Normal high on the 31st:  67 degrees

Normal low on the 1st:  36 degrees
Normal low on the 31st:  45 degrees

Note:  Duluth averages 8 days in May with a high temperature of at least 70 degrees, and 2 days with a high temperature of at least 80 degrees.  Last May had 10 days with a high temperature of 70 degrees or warmer, and 4 days with a high temperature of 80 degrees or warmer.

Astronomical data for May

Sunrise on the 1st:  5:53 AM CDT
Sunrise on the 31st:  5:18 AM CDT

Sunset on the 1st:  8:19 PM CDT
Sunset on the 31st:  8:54 PM CDT

Weather Synopsis:

There is a major spring storm affecting much of the central U.S.  At 3 PM today there were two surface lows stretching from east central Kansas to eastern Missouri.

To the W/NW of the low in eastern Kansas a significant snowstorm has been occurring with blizzard conditions in parts of north Texas, western Oklahoma, western Kansas, eastern Colorado and southern Nebraska while to the east of the low widespread heavy rain causing significant flooding, and there's also been some severe weather and tornadoes.

The storm to our south will be lifting N/NE through Monday night with the surface low reaching northeast Iowa Monday morning and the Wisconsin-upper Michigan state line Monday evening.

Precipitation will become more widespread from south to north in northeast Minnesota and northwest Wisconsin later tonight with precipitation persisting into Monday night.  Multiple precipitation types can be expected ranging from snow to rain with even some sleet thrown in!

As is often the case with late season snow events, temperatures will be marginal for an all snow event , and when it does snow some of it will probably melt on contact, the exception to this will be if or when heavier snow bands move through parts of the area, this is when our best chance for accumulating snow will be.

Road conditions could be slick and hazardous especially before Noon Monday with some roads likely becoming snow and slush covered and slippery.  By Monday afternoon pavement temperatures with the help of chemicals (Assuming public works will be using them) should lead to mostly wet roadways except possibly for the higher elevated areas away from Lake Superior where some roads could remain snow or slush covered.  Note:  If heavier snowfall persists into Monday afternoon it may help keep the pavement temps cool enough to maintain slushy/slick roads in parts of the area, keep that in mind if you have travel plans beyond Monday morning.

Here are links to Minnesota and Wisconsin road conditions



Storm timeline for the Twin Ports of Duluth and Superior

*Windy this evening with patchy light rain or light sleet possible at times.  East to northeast wind 20 to 30 mph with higher gusts.

*After midnight:  Rain becoming more widespread with rain mixing with and changing to wet snow most likely toward daybreak (After 4-5 AM)

*Monday morning:  Wet snow which could mix with rain/drizzle at times below the hill in Duluth.  Should remain all snow on top of the hill.

*Monday afternoon through Monday evening:  Snow continues with varying intensities.  Closer to Lake Superior expect rain and snow which will switch to snow from time to time.

*Strong northeast winds will continue into late Monday afternoon with wind gusts of 25 to 35 mph, possibly up to 40 mph.

*I'm still thinking the Twin Ports will end up with 2 to 4 inches of snow Monday with the highest totals likely occurring on top of the hill.