Discussion: Currently, soil moisture anomaly analysis reveals very dry conditions in California, Nebraska and Texas (Fig. 1). Most of the U.S. is observing anomalous dry conditions which is typical of lengthy period of La Nina coupled with cool phase of the Pacific decadal oscillation (-PDO). Also typical of a long-term La Nina/-PDO regime is wet soils in the Ohio Valley and vicinity. The U.S. soil moisture rankings indicate the intensity of the dryness in California and the Great Plains plus Montana is historic ranking either in the top 5% or 1% driest on record (Fig. 2).
Fig. 1-2: U.S. soil moisture anomalies and historic ranking.
The soil moisture change analysis for April (so far) indicates drier conditions in the central Great Plains, California and the immediate Gulf of Mexico while parts of the East trend wetter (Fig. 3). The seasonal soil moisture change is much drier across northern California and moderately drier in Nebraska and Texas plus parts of the Southeast U.S. into Florida (Fig. 4). Louisiana and Michigan are much wetter.
Fig. 3-4: U.S. soil moisture change in April and also since Jan. 31.
NCEP CAS soil moisture anomaly forecasts reveal that late spring dry soil regions are most-concentrate on Texas and California (Fig. 5). The model indicates that the character of soil moisture over the summer season is expanding dryness throughout the Great Plains while continuing in California but with some relief due to a wet monsoon pattern in parts of the Southwest U.S. (Fig. 6). Dry soils also expand eastward into the Midwest U.S. while also intensifying in Montana. Other precipitation forecasts are scaringly dry. The NMME global forecast broken down to just the U.S. reveals a very dry summer for the Great Plains into the Northwest U.S. (Fig. 7). The Climate Impact Company constructed analog (CIC-CA) forecast of precipitation anomalies for MAY/JUN/JUL 2022 reveal Great Basin to central Great plains to Texas dryness (Fig. 8) becoming more concentrated on Texas to Iowa for mid-to-late summer (Fig. 9). Note the considerable wet risk centered on the Carolinas in the East. The CIC-CA projection of Palmer Hydrological Drought Index (PHDI) for JUL/AUG/SEP 2022 reveals a West and Central U.S. drought pattern while the Carolinas are soaking wet (Fig. 10).
Fig. 5-6: NCEP CAS soil moisture anomaly forecast for the U.S. in May and August.
Fig. 7: NMME model projection of anomalous precipitation across the U.S. for JUN/JUL/AIG 2022.
Fig. 8-9: Climate Impact Company constructed analog precipitation forecast for MAY/JUN/JUL 2022 and JUN/AUG/SEP 2022.
Fig. 10: Climate Impact Company constructed analog precipitation forecast for Palmer hydrological drought index for JUN/AUG/SEP 2022.