Risk of moderate flooding for parts of central and eastern United States
According to NOAA's Spring Outlook released today, rivers in western New York and eastern New England have the greatest risk of spring flooding in part because of heavy snowpack coupled with possible spring rain. Meanwhile, widespread drought conditions are expected to persist in California, Nevada, and Oregon this spring as the dry season begins.
"Periods of record warmth in the West and not enough precipitation during the rainy season cut short drought-relief in California this winter and prospects for above average temperatures this spring may make the situation worse," said Jon Gottschalck, chief, Operational Prediction Branch,NOAA's Climate Prediction Center.
NOAA's Spring Outlook identifies areas at risk of spring flooding and expectations for temperature, precipitation and drought from April through June. The Spring Outlook provides emergency managers, water managers, state and local officials, and the public with valuable information so they will be prepared to take action to protect life and property.
Record snowfall and unusually cold temperatures in February through early March retained a significant snowpack across eastern New England and western New York raising flood concerns. Significant river ice across northern New York and northern New England increase the risk of flooding related to ice jams and ice jam breakups. Rivers in these areas are expected to exceed moderate flood levels this spring if there is quick warm up with heavy rainfall.
There is a 50 percent chance of exceeding moderate flood levels in small streams and rivers in the lower Missouri River basin in Missouri and eastern Kansas which typically experience minor to moderate flooding during the spring. This flood potential will be driven by rain and thunderstorms.
Moderate flooding has occurred in portions of the Ohio River basin, including the Tennessee and Cumberland rivers from melting snow and recent heavy rains. This has primed soils and streams for flooding to persist in Kentucky, southern Illinois, and southwest Indiana with the typical heavy spring rains seen in this area.
Minor river flooding is possible from the Gulf Coast through the Ohio River Valley and into the Southeast from Texas eastward and up the coast to Virginia. The upper Midwest eastward to Michigan has a low risk of flooding thanks to below normal snowfall this winter. Though, heavy rainfall at any time can lead to flooding, even in areas where overall risk is considered low.
El Niño finally arrived in February, but forecasters say it's too weak and too late in the rainy season to provide much relief for California which will soon reach its fourth year in drought.
Drought is expected to persist in California, Nevada, and Oregon through June with the onset of the dry season in April. Drought is also forecast to develop in remaining areas of Oregon and western Washington. Drought is also likely to continue in parts of the southern Plains.
Forecasters say drought improvement or removal is favored for some areas in the Southwest, southern Rockies, southern Plains, and Gulf Coast while drought development is more likely in parts of the northern Plains, upper Mississippi Valley and western Great Lakes where recent dryness and an outlook of favored below average precipitation exist.
Current water supply forecasts and outlooks in the western U.S. range from near normal in the Pacific Northwest, northern Rockies, and Upper Colorado, to, much below normal in California, the southern Rockies, and portions of the Great Basin.
If the drought persists as predicted in the Far West, it will likely result in an active wildfire season, continued stress on crops due to low reservoir levels, and an expansion of water conservation measures. More information about drought can be found at www.drought.gov.
Above-average temperatures are favored this spring across the Far West, northern Rockies, and northern Plains eastward to include parts of the western Great Lakes, and for all of Alaska. Below normal temperatures are most likely this spring for Texas and nearby areas of New Mexico, Colorado, Kansas, and Oklahoma.
For precipitation, odds favor drier than average conditions for parts of the northern Plains, upper Mississippi Valley, western Great Lakes, and Pacific Northwest. Above average precipitation is most likely for parts of the Southwest, southern and central Rockies, Texas, Southeast, and east central Alaska. Hawaii is favored to be warmer than average with eastern areas most likely wetter than average this spring.
Now is the time to become weather-ready during NOAA's Spring Weather Safety Campaign which runs from March to June and offers information on hazardous spring weather—tornadoes, floods, thunderstorm winds, hail, lightning, heat, wildfires, and rip currents—and tips on how to stay safe.
Provided by NOAA Headquarters