Cooler weather ahead but rain, snow no longer likely

Wendilyn Grasseschi
Times Reporter

After some forecasts – and much hope – that rain and possibly even some light snow could arrive this weekend, the latest forecasts are now trending dryer for the weekend and once again, warmer than normal for next week.
This is unwelcome news to Mammoth and all of the Eastern Sierra suffering from the smoke and economic impacts of the huge Creek Fire, which was still growing as of press time and was at about 237,000 acres and only about 50 percent contained.

The fire was not considered to be a threat to Mammoth, however, due to several changes in the fire behavior in the parts of the fire nearest Mammoth.

Mammoth forecaster Howard Sheckter summed up the unfortunate forecast details Wednesday.

“The small weather feature breaking off for the Westerlies today, which is working with the remains of Maria, will split and head down the coast leaving little or no rain for the Creek Fire,” he said. “Even the polar jet will remain mostly to our north with just some cooling and some wind to help disperse some the smoke from Mono County Saturday and Sunday.”

The cool down will not last long, either, he said.

“The long wave trof with the breeze will shift quickly east and high pressure aloft to the west will take over, with yet another week of above normal temps expected for our county,” he said. “(I am) hoping that the East/Northeast winds aloft and at the surface will help keep most of the smoke from the Creek Fire to the west of the Sierra Crest.

“Longer range, I see another strong ridge building over the far Eastern Pacific into California early next week. Although this will bring more fire weather headaches for the firefighters as temperatures soar to the high nineties again in the Central Valley by mid-week, the pattern also suggests a stronger surface high and northeast flow for Mammoth, which means better air quality beginning Sunday night and into next week, because there looks to be several periods of down-sloping winds on the west side of the Sierra... for the Mammoth Area, we should get “good” air quality developing early next week and good to “moderate” air quality more often than not through much of next week.”

His words were echoed by the National Weather Service Reno office on Wednesday.

“Widespread haze with areas of thicker smoke will remain for today as light west-southwest flow continues, “they said. “Southwest winds increase Thursday, which could improve conditions, but smoke from nearby fires may get transported east-northeastward.

There will be a cooling trend Friday into the weekend, they said. “Mild afternoons and crisp mornings with dry conditions will last into Thursday. Temperatures look to drop to 5-10 degrees below normal this weekend as unsettled weather impacts the region.

There could be some rain and/or high elevation snow late Saturday through Sunday, but most of it will likely be north of the Reno and I-80 area and up into Oregon, they said.

“It continues to look drier overall with the potential for precipitation mainly north of I-80 and into the Tahoe Basin,” they said. “Best chances look to be for locations along the Oregon border. It will also be windier this weekend with much cooler temperatures.”

Tahoe area forecaster Bryan Allegretto also noted that any precipitation this weekend will likely stay to the north of Mono County, barely brushing even the Tahoe area.

“Since Friday, the model riding has been a roller coaster with the forecast models going big on some runs with an AR (atmospheric river) of moisture for northern California,” he said. “Even Sunday night the Canadian model was going big along with the other models...The latest trend on the models is for this trough to not dig as far south down the coast, with the northern Sierra on the southern edge of the precipitation as the system pushes through.

“You can see that the heavy rains stay in far northern California and the Pacific Northwest,” he said. “Then the precipitation moves east into the Rockies. That is also the areas that have the best chance to see accumulation snowfall in the upper elevations.”

What will the winter bring? Allegretto said there is still too much uncertainly to go out on a limb.

“There is a lot to look at as winter gets closer, and we will dive into the details more as we get closer to winter and the patterns we could see becoming clearer,” he said.

Then he offered a caveat regarding long-term forecasting, just as Sheckter always does.

“Of course, we always preach about how inaccurate long-range forecasts are historically in the weather world, especially seasonal forecasts,” he said. “It's fun to play around with them, but never buy stock in them.”