US October temperature and precipitation forecast maps offer a glimmer of hope for California and parts of the West. For the first time in months, the California precipitation forecast map has not been colored in dry brown, indicating drier-than-normal conditions.
Likewise, the temperature forecast map is not glowing red, like a stove top stove on high.
On both October maps, released by the National Oceanic and Atmospheric Administration on September 30, California and neighboring states are colored neutral white. This means that experts expect equal chances that temperatures and precipitation will be above average, near average or below average.
Forecast maps from the National Oceanic and Atmospheric Administration do not expect California to be warmer or drier than average in October.
(Paul Duginsky/Los Angeles Times)
If this sounds a bit like cold relief, remember that maps for several months put California and the West in the hotter and drier categories than average. So this is an improvement.
Normal precipitation for October in downtown Los Angeles is 0.58 inches. The NOAA Climate Prediction Center projections mean that the odds of a month that is wetter than average are as good or better than the odds of a month that is drier than average. The maps show the probability, or percentage, based on the climate record from 1991 to 2020.
October is not a rainy month in Los Angeles. The rainiest months in Southern California are December, January, and February.
Climate scientist Bill Patzert said the latest region-wide storms dropped 1.41 inches of rain on downtown Los Angeles in early March. Since March 15, downtown has had about half an inch of intermittent monsoon rain, but Southern California has not had any regional rain for about seven months.
“Any change in the atmospheric pattern that has us trapped in this drought would be welcome,” Patzert said. He said the system expected to arrive on Friday would be the first North Pacific front since March.
Washington, most of Oregon and northern Idaho are depicted in the NOAA forecast map as being wetter than normal. And a portion of this wetter-than-normal green stretches south into drought-stricken northern California.
This map predicts that a wide swath of the center of the country from North Dakota to Wisconsin and south to New Mexico, Texas, and Louisiana will be wetter than average. This month, map brown has appeared in the Northeast and New England, and it is expected to be drier than usual in October.
In the temperature forecast, the eastern United States from the Rocky Mountains will be warmer than usual, while coastal areas of Washington and Oregon are expected to be cooler than usual. During October, California, Nevada, and Arizona are expected to have equal chances of being warmer than average, or cooler than average.
The outlook for October is for drought conditions to improve or end in much of the Pacific Northwest, and continue or worsen in California.
(Paul Duginsky/Los Angeles Times)
If the temperature and precipitation forecast offers some slightly positive news, the drought map is Debbie Downer of Prediction Maps. Much of the West is colored brown, indicating that the drought will continue or worsen. But a closer look shows some signs of hope around the edges. The drought is expected to end or improve in Washington and parts of Oregon and Idaho, as well as in parts of the upper Midwest and the Great Plains.
Dehydrations of this size take a long time to develop, and are unlikely to go away in a month, so this is not particularly surprising.
Central to all of this is the fact that October is the peak month for hurricanes in the western Pacific. Tropical cyclones can move on the far side of the ocean from California to the north or northeast, where they may affect the jet stream.
The jet stream, also called a storm track, is a narrow band of strong winds that rush from west to east in the upper levels of the atmosphere. Strong storms like hurricanes can harden the jet stream patterns of low pressure basins and high pressure ridges, like battle rope waves, and these changes can affect the west coast of North America.
So storms on the other side of the world can add an element of uncertainty to California’s temperature and precipitation forecast, especially in October.
After months of being in a constant cycle of heat, drought and wildfires, Californians can hardly be blamed for finding some slight encouragement in NOAA’s October forecast.