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Updraft: February 17, 2010 Archive

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Forecast: Warmer pattern ahead?

Posted at 8:30 AM on February 17, 2010 by Paul Huttner

We're due for some warmer weather, and it looks like we may get a break in about 10 days.

Early signs point to a milder, lamb-like start to March this year. It appears our predominantly northwest upper level flow will give way to more southerly winds as we move into March.

If today's medium range forecast maps are correct, temperatures could push 40 degrees in much of southern Minnesota by March 1st. If we can crack 40, it would be the first time in 3 months, since December 1st when the metro basked in 47 degree warmth.

In the short term, our sunny and mild weather will linger this week. Look for highs in the lower 30s today and Thursday in eastern Minnesota with 20s west.

1MaxT1_mpx.png

Temperatures will trend slightly downward this weekend, and next week does look 5 to 10 degrees cooler (highs around 20-25, lows near 10?) before we begin the warm up by the following weekend.

Then get set for what could be a few days with near 40 as we open March. Of course, March is our second snowiest month, so we know even though we melt a lot of snow in March, we'll likely still get plastered with an infamous "state tournament snowstorm" next month.

Higher sun plays a role:

You can feel the warmth of the sun these days in the midday sky. It's undeniable now. At 34 degrees above the noon horizon, the sun is a full 9 degrees higher in the sky that it was in late December. We'll gain another 11 degrees of elevation to 45 degrees by March 20th.

1 sun angles.gif

The higher sun angle and increasing daylight means we're getting more than double the solar energy from the sun compared to late December. The sun is just too high in the sky now for us to stay cold forever. That's one reason we're seeing afternoon temperatures surge into the low 30s these days. It's also why the sun is able to reach into previously shady nooks and crannies to melt snow on roads and sidewalks.

We've also gained about two hours of daylight since late December. We're gaining a full 3 minutes of daylight each day, that's about 21 minutes a week.

Enjoy the brighter days and milder afternoons, and I'll be keeping an eye on the maps to see if our 1st 40 degree reading in 3 months stays on track for around March 1st.

PH

North Shore Chinook: Silver Bay 45 degrees!

Posted at 2:50 PM on February 17, 2010 by Paul Huttner

Some call it the Swedish Riviera. Today the North Shore is living up to that name.

Most of Minnesota was enjoying temperatures in the 20s and lower 30s this afternoon. But in a quirk of Minnesota weather, temperatures surged to 45 degrees this afternoon at Silver Bay. Bank thermometers flashed as warm as 42 degrees on the streets of Grand Marais this afternoon.

WEATHER ROUNDUP FOR MINNESOTA
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
200 PM CST WED FEB 17 2010

Northeast Minnesota

CITY SKY/WX TMP DP RH WIND PRES REMARKS
DULUTH MOSUNNY 36 15 42 N10 30.01F
ELY SUNNY 34 10 37 N8 30.02S WCI 27
HIBBING SUNNY 35 8 32 NW13 30.05F WCI 26
EVELETH SUNNY 37 5 25 N9 30.05S
DULUTH HARBOR SUNNY 36 19 51 W9 30.04S
TWO HARBORS SUNNY 39 16 38 N6 29.99S
SILVER BAY SUNNY 45 10 24 NW8 29.98F
GRAND MARAIS Harbor 41 7 24 N8 30.00S
G MARAIS ARPRT (Top of hill) SUNNY 34 3 27 NW12 29.97S WCI 25

So why is it warmer on the North Shore today than anywhere else in Minnesota?

It's called downslope. And it's the same atmospheric phenomenon that produces the big Chinook Winds on the eastern slopes of the Rockies near Denver and Rapid City.

1 chinook.jpg

Anyone who's driven Highway 61, the Gunflint Trail or skied Lutsen knows that the Sawtooth Mountains abruptly rise over 1,000 feet above Lake Superior in a short distance. As the air rushes down the slopes on a northwest wind, it warms at the rate of about 5 to 10 degrees per thousand feet of descent. We call this the dry adiabatic lapse rate in meteorology.

On days like today when temperatures are in the lower 30s on top of the hill, the air can easily warm 10 degrees as it flows downslope toward Lake Superior. It's one of the "best kept secrets" of North Shore weather. North Shore communities are often warmer on days like this than anywhere in the Upper Midwest. In fact at 2pm CST today, Silver Bay at 45 is warmer than Chicago (32), St. Louis (33) Kansas City (39) and even Atlanta (43)!

Another factor in warming the North Shore is the pine tree effect. The upstream air mass is already warmed on the iron range by the sunlight interaction with the coniferous forests. So temperatures are already in the 30s even before the air begins to descend toward the big lake.

We can truly boast some of the warmest temperatures in the middle part of the nation right here in Minnesota today, thanks to the North Shore Chinook!

PH

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