United States: Widespread surplus throughout W, SW States

18 April 2023

THE BIG PICTURE
The 12-month forecast ending in December 2023 indicates extreme to exceptional surpluses throughout many western states, as well as in states outside the continental United States. Some intense deficits are expected in Florida and the Pacific Northwest, as well as areas of Alaska.

Extreme to exceptional surplus is forecast in:

California, throughout the state, with areas near the cities of San Jose and Fresno experiencing the most intense anomalies.
Central to northeastern Nevada, appearing north of the city of Eureka and spreading further east into western Utah.
Southeastern Idaho, near the city of Pocatello.
Southeast Oregon, in areas east of the Malheur National Forest.
Western Colorado, spanning areas north of the city of Grand Junction and spreading further south along the state’s western border.
Western to south-central New Mexico, appearing in the city of Gallup into the Gila National Forest, and into the city of Las Cruces.
Central and northeastern Arizona, appearing in Flagstaff and in the Navajo Nation region.
West-central Montana, near areas of the Helena-Lewis and Clark National Forest.
East-central South Dakota, near the Crow Creek Reservation.
Various regions of Alaska, with the most concentrated anomalies appearing in western coastal regions of the North Slope Borough, as well as northern regions of the Lake and Peninsula Borough.

Extreme to exceptional deficits are expected to appear in:

Florida, widespread throughout the state, with concentrations near the Goethe State Forest, as well as throughout Lake Okeechobee.
Northeast Alaska, near the Arctic National Wildlife Refuge and east of the Chalkyitsik area.
Central Washington, appearing near the village of Leavenworth, spreading further south through the Yakama Indian Reservation and into regions near Bend, Oregon.
Central Idaho, near central areas of the Salmon-Challis National Forest.
Northern Utah, in northern areas of the Ashley National Forest.

Southeastern coastal areas of Louisiana.

The 3-month maps (below) show the evolving conditions in more detail.

FORECAST BREAKDOWN
The forecast through June 2023 indicates that intense surpluses in western states will remain, with extreme to exceptional anomalies persisting in central to southern California, central to northeastern Nevada, central Arizona, northwest Utah, and western Colorado, and southern Idaho. Similarly intense surpluses are expected to persist in pockets throughout the state of New Mexico. Intense deficits, mostly of severe to extreme intensity, are expected throughout the state of Florida, as well as northwestern Montana and central Idaho.

Outside of the Continental U.S., major surpluses are anticipated to persist in northwest and southwest and southeast regions of Alaska, near the Arctic National Wildlife Refuge and east of the Chalkyitsik area. Deficits of moderate to severe intensity are expected to persist in northeastern Alaska.

From July through September 2023, surpluses in central to western California are expected to shift into transitional conditions, while surpluses in Nevada, southern Idaho, western to northern Utah, and Oregon will persist. Similarly, existing pockets of surplus in New Mexico, Arizona, and Colorado will also continue. Deficits in Florida are expected to lessen in intensity, though isolated areas of extreme to exceptional deficits are expected to continue in Washington.

The forecast for the final months – October through December 2023 – surpluses will continue in the western states, with mild to moderate deficits in the southeast transitioning into surpluses of similar intensity.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
Thousands of acres of farmland in California's Central Valley region have been destroyed due to torrential rainfall in the area. “All of the crops are completely flooded and ruined,” local Martina Sealy said. “It takes a lot of jobs for people. That’s a lot of food that we provide for up and down California and all around the nation. It’s pretty scary.” Cotton and alfalfa are among some of the crops that have been destroyed. Sealy went on to add that the situation will worsen once the snowpack from the Sierra Nevada melts. “When the snow melts, there’s nowhere for it to go besides here.” In the summer, flooding is expected to triple in severity, threatening the safety of local communities and billions of dollars in losses.

Ed Clark, director of NOAA’s National Water Center, stated that approximately 44% of the U.S. is at risk for flooding this spring, and that the combination of California’s rainfall and snowpack is expected to worsen conditions for spring floods. As of April 13th, the U.S. Drought Monitor shows large areas of California, Nevada, and Utah have snowpack levels over twice as much as normal. Combined with the area’s elevated soil moisture, the threat of spring flooding has increased significantly, especially at high elevations.

The U.S. Drought Monitor depicts 88 percent of Florida experiencing abnormally dry conditions, with more than half the state experiencing severe drought. According to data, the state is in its worst drought since 2012 after an exceptionally dry winter and beginning of spring. Almost all major cities are reporting water deficits, with Orlando reporting only 1.89 inches of rainfall since the beginning of the year. The city of Naples has reported less than an inch of rainfall. The Florida Forest Service stated that the drought has triggered dozens of wildfires, destroying more than 5,200 acres. One of the larger wildfires in Central Florida has reportedly ruined more than 3,200 acres in Volusia County.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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