NOAA June 2023 Outlook: Warm Start to June Expected for Northern CONUS

The NOAA recently released its outlook for June 2023. It’s expected to be warmer than normal across the northern CONUS and all Alaska, as well as parts of the southwest. The High Plains, Central Rockies, and Great Basin areas can all expect higher than average precipitation.

Discussion below:

Expect a warm start to June throughout the northern CONUS. This likely warm start supports increased probabilities for above-normal temperatures from the Pacific Northwest east to the Northern Great Plains. This favored area of above-normal temperatures extends southward to the Central Great Plains and Middle Mississippi Valley, where low soil moisture conditions are likely to warm surface temperatures. The week 3-4 GEFS and ECMWF models, C3S model, and recent daily CFSv2 model runs for June support to increased probabilities for above-normal temperatures across parts of the Northeast. Based on the NMME, C3S, and decadal trends, above-normal temperatures are favored for parts of the Southwest, Rio Grande Valley, Gulf Coast, and Florida. Increased probabilities for above-normal temperatures are forecast for nearly all of Alaska, consistent with dynamical and statistical tools. The one exception is the western coast of Alaska due to below-normal SST anomalies across the eastern Bering Sea.

 Elevated probabilities of above-normal precipitation exist across portions of the High Plains, Central Rockies, and Great Basin. This wet signal is also present in the monthly NMME and consistent among daily CFSv2 model runs for June. Therefore, above-normal precipitation is favored for those areas during June. The NMME along with an increased potential for an early season TC to emerge from the western Caribbean Sea favors above-normal precipitation for parts of the Southeast. Based on the NMME and El Niño precipitation composites, elevated probabilities for below-normal precipitation are forecast for southeastern Alaska and parts of the Pacific Northwest. A large area of EC was necessary in the June precipitation outlook due to weak or conflicting signals among the guidance and lower predictability associated with convective rainfall during the late spring and early summer.