Monday, April 25, 2011

4/25/11: Monday's Weather Report

Issued at 4:01 PM CDT, Monday, April 25th, 2011

Weather tidbits for Duluth, Minnesota:

*Back to back days with a high temperature of at least 60 degrees, April 24th-25th, 2011.  Last time this happened was back on October 13th-14th, 2010.
*Monthly precipitation total (thru the 24th):  2.04"/0.40" above average
*Monthly snowfall total (thru the 24th)  9.4"/3.7" above average
*Seasonal snowfall total (thru April 24th, 2011):  92.2"/10.0" above average

Weather History:

On this date in 1990:  A record high temperature of 81 degrees occurred at Duluth, Minnesota.

Weather headlines:

-Big changes underway
-Powerful E-NE winds develop near Lake Superior Tuesday Morning, lingering thru Wednesday Morning
-Strong, slow moving storm lifts north into the area Tuesday-Wednesday
-Rain and snow to accompany this storm, substanial amounts of snow possible for some

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Another gorgeous spring day with high temperatures in the 60s with a 70 degree reading reported at Superior, WI late This Afternoon.  Partly to mostly sunny skies covered the area Today with a couple brief light showers or sprinkles This Afternoon in far Northern Minnesota and also out toward the Cass Lake, Walker, MN areas.  Low level lapse rates >8.0 c/km combined with a cold front nearby and some lingering cold air aloft resulted in some weak instability Today which resulted in these spotty brief showers.  Winds Today were variable under 12 mph.  Surface map as of 3 PM featured a cold front in Northern Minnesota with high pressure of 1020mb near Southern Hudson Bay.  Low pressure of 998mb was centered in Eastcentral Oklahoma.  Note:  A late season brand of arctic air covered portions of Northern-Central Canada Today behind the Northern Minnesota cold front, Afternoon temperatures were only in the 20s and 30s from Central Ontario and points north with 850mb temperatures of -4 to -12 degrees C!

Today's Upper Level Analysis:

A powerhouse jet stream with speeds >130 knots was pushing southeast out of Northern California This Afternoon per RUC model analysis.  This jet stream energy is helping to fuel another big spring storm across the Southern Plains Today.  Another thing which is adding to this storm's intensity is the temperature contrast which ranged from the 90s and low 100s in portions of Texas Today to the 30s just north of Lake Superior.

Tonight:

Partly to mostly cloudy skies will be found in our area Tonight with a cold front in Northern Minnesota becoming stationary or sagging slowly south, there might be a few light showers near this boundary in far Northern Minnesota through mid-Evening, otherwise dry conditions will continue.  Lows Tonight will be in the 30s and lower 40s with winds becoming east at 5-15 mph, but wind gusts over 20 mph will develop near Lake Superior.

Tuesday and Tuesday Night:

Strong low pressure of 998mb located in Eastern Oklahoma This Afternoon will head N-NE into Southern-Central Wisconsin by late Tuesday Night, pressures will drop to between 986-990mb as the low heads into Wisconsin.  High pressure located to our northeast combined with the low to our S-SE will cause the pressure gradient to really tighten up during this period.  Forecast models (06z, 12z, and 18z runs) show 850mb wind speeds increasing to 50-70 knots Tuesday and Tuesday Evening in portions of Northwest Wisconsin, Western Lake Superior, and the Twin Ports vicinity, this could lead to very strong winds near Lake Superior.  Wind speeds of at least 20-40 mph will likely occur, but gusts could exceed 50 mph!  Wind speeds farther inland should be in the 10-25 mph range.

Rain associated with that Southern Plains low will push north into Eastern Minnesota and Northwest Wisconsin on Tuesday with mainly dry conditions for Northern Minnesota.  Highs Tomorrow will be in the 40s and 50s in Northern Minnesota with 30s and 40s for the rest of our area.

Lift and dynamic cooling processes will likely cause the rain to mix with sleet and snow in parts of Northwest Wisconsin and Eastern Minnesota Tuesday Night, and it's possible that the mixed precipitation will transition to all snow during the night.  850mb temperatures are forecast to range from -1 to -4 degrees C Tuesday Night which is sufficently cold enough to support frozen precipitation, however, temperatures near the surface may stay just warm enough to keep most of the precipitation in the form of rain.  Note:  These late season snow events are very tricky, and usually only impact small areas.  There is still a potential for several inches of wet heavy snow Tuesday Evening into Wednesday Morning for parts of Northwest Wisconsin, the Twin Ports, and Eastern Minnesota and winter weather headlines may be needed at some point, if frozen precipitation does develop.

Low temperatures Tuesday Night will be mainly in the 30s.

Extended Forecast:

Low pressure at the surface and aloft will become nearly stationary in the Upper Midwest for Wednesday while a secondary low, which will become the dominant low heads northeast out of the Southern Plains to Lake Huron from Wednesday into Thursday.  Unsettled weather with lingering rain and or snow showers will likely continue Wednesday into early Thursday in Northwest Wisconsin and in Northern-Eastern Minnesota.  High temperatures for Wednesday and Thursday will be in the 30s and 40s with a few 50s possible on Thursday.  Low temperatures Wednesday Night and Thursday Night will be in the 30s.

Friday, April 29th looks dry at this time with milder temperatures as southerly winds develop out ahead of the next low pressure system and cold front which will sweep across the area this weekend.  Looks like will get some additional rain at times between Friday Night and Sunday, and by Sunday the temperatures could become cold enough once again to produce a rain/snow mix in parts of our area.

Note:  Prior runs of the GFS model were showing a rather intense storm for the middle of next week, Tuesday-Thursday, May 3rd-5th time frame, but the most recent run (12z) has backed away from that idea.  EURO model wasn't showing much of a storm until Today's 12z run, and now this run is cranking out a rather potent storm for the Plains and Upper Midwest sometime the middle of next week.

5 Day Forecast for Duluth/Superior

.Tonight...  Partly to mostly cloudy.  Turning breezy.  Low 35 to 40.  Wind east at 5 to 15 mph, increasing to 15 to 25 mph Overnight.

.Tuesday...  Windy.  Mostly cloudy.  Rain developing during the Afternoon.  High 40 to 45.  Wind east at 20 to 35 mph with gusts to 50 mph possible.

.Tuesday Night...  Windy.  Rain, sleet, and snow possibly turning to all snow.  Low 30 to 33.  Wind east to northeast at 20 to 35 mph with gusts to 50 mph possible during the Evening.

.Wednesday...  Breezy.  Rain and snow.  High 35 to 40.  Wind north to northeast at 15 to 25 mph.  Total snowfall accumulations of 1-2" possible.

.Wednesday Night...  Occasional rain or snow showers.  Mostly cloudy.  Low 30 to 35.

.Thursday...   Rain or snow showers possible early.  Partly sunny.  High 45 to 50.

.Thursday Night...  Partly cloudy.  Low 30 to 35.

.Friday...  Partly cloudy.  High 55 to 60.

Normal temperatures for Today

High:  54
Low:  33

Sunrise Tomorrow:  6:02 AM CDT
Sunset Tomorrow:   8:12 PM CDT

Note:  Duluth Harbor water temperature as of April 25th, 2011:  38.5 degrees F

Tim