“Spring” arrives; “Average” winter; Sunday snow stays south?

Astronomical Spring 2013

To astronomers, today is an important day on the calendar.

At precisely 6:02 AM today, the sun crossed directly over the equator on its annual trek northward into the northern hemisphere.

The increasing daylight will eventually lead to warmer days, melting snow, and temps that will finally end this barbaric deep freeze we call March 2013.

Today in Updraft we explore the winter that was, the "spring" such as it is, and look ahead for signs of warmer weather on the horizon.

Is it April yet?

"Make no big decisions in Minnesota in March." - Dave Moore WCCO TV News legend

"Spring" Arrives:

It happened quietly and without fanfare.

When the sun crossed the equator at 6:02 AM CDT this morning, spring began in the northern hemisphere. It's called the Vernal Equinox.

"Equinox" means "Equal Night." There is roughly 12 hours of daylight and darkness everywhere on earth today.

At noon today the sun will be roughly 45-degrees above the southern horizon in the Twin Cities. It climbs higher in the sky each day, until it reaches peak at about 68.5 degrees above the southern horizon at noon on June 21st this year.

The increasing daylight adds up, and we go from 12 hours today...to 15 hours and 36 minutes of daylight by the summer solstice.

The extra daylight and solar energy is important, because eventually it will heat up the northern hemisphere and bring us milder temps. It's just a painfully slow process for many Minnesotans this year.

Hang in there...warmer days and melting snow are truly close at hand.

Last "coldest" day?

Winter overstays her welcome one more day this year.

Today will be the "last coldest" day this season in Minnesota. It truly is all uphill (or downhill?) from here.

I don't think we'll see another day this cold until December of this year.

Tomorrow will feel much better, with little wind and temps in the mid-upper 20s. We crack 30-degrees by Friday and into the weekend.

Baby steps.

Milder days ahead?

The overall pattern looks gradually warmer in the next week.

40 degrees should pay us a visit by the middle of next week.

Looking further ahead, the Arctic Oscillation (AO) suggest a shift into the positive phase. That usually brings warmer weather to Minnesota.

After a strongly "negative phave" event of the AO this week, There are signs the AO could go strongly "positive" in early April...and we could see a string of snow melting days in the 40s...and maybe some 50s in the next 2-3 weeks.

We got burned by a "false positive" AO forecast two weeks ago, so I'm keeping my hopes low, but the signs are good.

"Average" Winter:

Yes, this truly is a "real winter" in Minnesota this season.

Still, for all the legitimate complaints about the cold I've heard lately, "meteorological winter" was pretty close to average in Minnesota.

-Temps average +1.0F at MSP. (Dec-Mar)

-Season snowfall so far is almost exactly average...with 49.3" so far at MSP Airport...just +0.2" vs. average.

-An "average" winter brings 54.4" of snowfall to the Twin Cities.

-Last winter we eked out just 23.3"

It's March that has been unusually cruel with temps -5.0F so far this month. This winter has been "back loaded" with the bulk of the cold and snow coming since February 1st.

Sunday Snow Chances: Staying south of Minnesota?

The vast majority of the more reliable forecast models steer a winter storm south of Minnesota Sunday. The Euro & Canadian GEM lead the way.

NOAA's GFS has been tracking the low further north Tuesday...but the overnight GFS runs bumped the storm to the south in line with the other models.

I'm leaning toward the southern solution which looks credible to me given the upper air pattern. The best bet is that the snow will stay south of Minnesota this weekend.

Right now I don't see any significant snow events in the forecast.

Weather fingers and toes crossed.

PH