Lay of the land affects temperature

I was driving around the other evening, and happened to notice several of the temperatures being reported on those billboard sign temperature displays. Readings varied from the upper 20s to the mid 30s. When I got to my house, my weather station was reporting 41 degrees. Official temperatures taken in Coeur d’Alene, the Spokane Valley, and the Spokane Airport had a variation of about 5 degrees.

The topic seems to come up often as to whose temperature is correct for a particular city. Actually, all the temperatures may be accurate for the specific location (though those billboard temps have a track record of being way off base on a warm, sunny and windless afternoon). Across North Idaho there is incredible variation in the lay of the land. Even across a short distance you can come across vast differences in elevation, proximity to water, and surface types (i.e. asphalt to forest).

All of these things will have an impact on the temperature of the air. Even within the city, it is not surprising to have a variation of 5 to 7 degrees from one spot to the next. And between neighbors, the location of a vegetable garden, whether in a low spot in your backyard, or on a slight ridge in your neighbor’s, can mean the difference between a frozen tomato plant and one that may survive another day.

Of course, now that we’re in November and have had a good hard freeze, including a record low in the lower 20s a little over a week ago in Coeur d’Alene, thoughts turn from the harvest to winter weather. The average high on this date is 50 degrees, with an average low of 34. Those warm Indian summer days of October will be a distant memory as we move toward the much colder and wetter pattern of November. Average rainfall jumps an inch from last month’s, with a November normal of 2.97 inches. Strengthening La Niña conditions mean we’ll likely be looking at higher numbers than that. During the La Niña winter of 2000-01, several inches of snow fell on Nov. 8. It was a record 132 days before we saw bare ground again. That was one long winter. Average snowfall for the month is 7.8 inches.

As snow becomes a more frequent possibility, along with other types of hazardous winter weather, the National Weather Service will be issuing various types of winter weather watches and warnings to give you the heads up on what you’ll be up against. It is good to remember the difference between a watch and a warning so you won’t have to unnecessarily panic over the potential of a severe winter storm. A watch is usually issued 1 to 3 days out, when conditions are potentially favorable for certain types of hazardous winter weather. Computer models these days can perform some amazing feats at predicting the location of a stormy low pressure system that is still days away. When it comes to predicting snowfall amounts though, a difference of only 20 or 30 miles in the location of a low, or a temperature forecast off by only a few degrees can mean the difference between a dusting and a dumping of the white stuff. Watches are issued to indicate that the potential for stormy conditions exists, and that meteorologists will carefully monitor the situation. As soon as hazardous weather is deemed imminent, a warning of some sort will be issued, usually 12 to 24 hours out, and viewers can use that information to properly prepare for what’s coming.