Daytime temps will start to get warmer

Many folks may be outside celebrating, basking in the warmth that they had expected to feel more than 3 1/2 weeks ago.

Most of the weather talk around the Inland Northwest during the past month has been about the record snows of this winter season. As of Wednesday, Spokane’s winter of 2007-08 had moved up another notch to become the second snowiest on record with 89.5 inches. Coeur d’Alene continued to add to its unprecedented totals, now pushing 170 inches in a season; the average is 67 inches.

Of course, we wouldn’t have so much snow to talk about this late winter and early spring if the temperatures had not been cold enough to support this kind of precipitation. In the last 43 days, 30 days have seen below normal average daily temperatures. Of the remaining 13 days, five came in right at average, leaving eight days of “above normal” temperatures, the bulk of which occurred during early March.

Winter as a whole was unusually cold and snowy for a good portion of the U.S. Thirteen states saw winter season temperatures which were below normal. Surprisingly, temperatures across both Washington and Idaho came in near normal for the winter of 2007-08. In the contiguous United States, this winter was the coldest since 2001, though the average temperature (nationally) did come in just slightly (0.2 degrees F) above the 20th century average.

Now that temperatures have warmed up to where they should be (and then some), you might be wondering if it’s even possible to see any more snow. Just how warm is too warm to get snow? I have often written about the misconception that surface temperatures have to be at or below freezing to get snow. All of our precipitation (including rain, snow, sleet and hail) actually starts out as snow up in the clouds. The type of precipitation we see depends on the temperatures the snowflakes encounter as they fall to the ground.

Of course, if temperatures are at freezing (32 degrees) or below from the cloud all the way to the ground, the snowflake will remain a snowflake, and that is what we will see. But even if temperatures are much warmer than that at the surface, it is still possible to get snow. Though temperatures may be in the upper 30s or lower 40s where we are all walking around, the air usually gets colder with increased elevation.

Theoretically, it is possible to get snow with a surface temperature of 50 degrees. though that is extremely rare. Snow will generally start to mix in with rain once surface temperatures are in the lower 40s. Average daytime highs in Spokane and Coeur d’Alene are in the upper 50s now, with average nighttime lows in the mid 30s.

By the end of April, average afternoon highs will be in the low 60s with average nighttime lows in the upper 30s. Could we still yet get more snow? It is highly unlikely, though Coeur d’Alene’s latest measurable snow occurred on May 6, 1950 with a surprising 2 inches.

A stickler for technicalities

Though the term “hail” has been thrown around a lot lately, most of the precipitation we’ve seen over the past week has been “snow pellets” or “graupel.” If you look closely at what hits the ground, you would see that they are indeed little pellets of snow, like mini-snowballs. True hail is made of layers of ice and comes out of thunderstorms during the warm season.