Randy Mann: Area likely to remain dry, warm most of September

September is normally the third driest month of the year with an average of 0.67 inches of precipitation at Spokane International Airport. Last year, the airport received a healthy 1.56 inches of moisture and the average temperature was 2.8 degrees above normal.

The strong ridge of high pressure that continues to dominate the western half of the nation should keep things drier and warmer than normal this month. As the ridge hangs on in the West, it continues to look wet and chilly in the central portions of the country. It’s quite possible that an early freeze may damage late-planted crops in the Midwest later this month.

I also believe that we’ve seen the last of the 90-degree temperatures for this season, despite some 80-degree temperatures early in the week. Scattered areas of frost are possible by late September, but mainly in the higher elevations. Hard freezes are expected in October, even in the lower elevations of the Inland Northwest.

Some showers and chilly weather are expected in late September around the new moon. October may start out milder and drier than normal, but moisture should start increasing later in the month as the high pressure ridge starts to break down.

Snow is not very common in October, but elevations above 5,000 feet may see some measurable snowfall. The most snow ever measured in October at Spokane and Coeur d’Alene happened on Oct. 22, 1957. The airport reported 5.9 inches while Coeur d’Alene measured 6.8 inches of snow.

November should see above normal amounts of precipitation across the Inland Northwest. As of early September, we still have a very weak El Nino sea-surface temperature pattern. El Nino is the warming of ocean waters near the equator that often results in less snowfall during the winter in the Inland Northwest. Some computer models are predicting this El Nino to strengthen over the next several months, but it has been weakening over the last few weeks and could continue to dissipate.