The NOAA just updated its outlook for January 2023. The forecast looks perfect for the Sierra Nevada, with below-average temperatures and above-average precipitation expected.
The full discussion is below:
Early in the month, much of the CONUS is expected to experience above-normal temperatures, while below-normal temperatures are likely from California to the Intermountain West. During week-2, the favoring of above-normal temperatures remains for the Northeast, Great Lakes, and much of the Great Plains, while the signal for below-normal temperatures abates over the West. Combining the outlooks for the first two weeks, with model output for the latter half of the month results in a favoring of above-normal temperatures from the Great Plains to the East Coast, with the highest odds across the Northeast. A small area of below-normal temperatures are favored across portions of California, Nevada, and Oregon, mainly due to signals early in the month. Odds across the Great Plains are lower than many dynamical models, partially due to the lagged impacts from a Phase 7 MJO during DJF and partially due to the possibility of a late month negative NAO, which would both support a colder period across much of the Central and Eastern CONUS. Dynamical models, lagged MJO impacts, and a projected positive PNA for much of the month all support above-normal temperatures for much of Alaska.
The precipitation outlook is less certain for the latter portions of Jan 2023. A wet start to the month from California to the Northern Plains supports above-normal precipitation from South Dakota to Utah, and across the entirety of the West Coast States. Portions of those areas are likely to receive enough precipitation in the first week of Jan 2023 to exceed the threshold for above-normal precipitation. Consistent with the ongoing La Nina, signals for below-normal precipitation persist across the Rio Grande Valley while above-normal precipitation is still slightly favored from the Tennessee Valley to the Great Lakes and portions of the Northeast. Above-normal precipitation is favored across Northern, Western, and Southern Mainland Alaska, while signals over the interior are mixed. A stormy pattern early in the month supports the wet signal along the southern coast of Alaska, while later in the month, the wet signal spreads across more of the state, consistent with the ongoing La Nina. Lagged impacts from a Phase 7 MJO indicate that troughing can help steer storms into Western Alaska for the following 10 days with a shift toward a more split storm track 15-20 days later, so the supports the North-South expanse of the area where above-normal precipitation is favored.