Long Range Weather Forecast Discussion May 10-24
James Munley
Long Range Weather Forecast Discussion May 10-24
210 PM EDT Thu. May 7, 2026
May 10-14: An upper-level low over eastern Canada will continue to send multiple shortwaves across the East. This will keep conditions cool and wet. A ridge is forecast in the West with a trough in the East.
An upper-level low over eastern Canada will continue to send multiple shortwaves across the East. This will bring cool, unsettled weather across the central and eastern states. Frontal passages will cause showers and storms across the eastern and central states. Below-normal temperatures will spread into eastern states through Tuesday. A strengthening ridge across the West will cause above-normal temperatures. The warm air will gradually move into the central states by midweek.
May 15-19: Most of the guidance indicates a trough, ridge, and trough pattern from the West Coast to the East. The GFS develops a closed low over the western Atlantic.
A large area of low pressure will cover the eastern states. Return moisture around the eastern ridge will spread into the Southern Plains. A front will push through the southern Plains to the North with some light and storms possible.
Above normal temperatures are forecast from the Mississippi Valley to the Pacific Coast, the Gulf Coast, and the Southeast. Anomalies are expected to be near or greater than 8°F in parts of the Rockies.
Below-normal precipitation is forecast for northern California, the Northwest, the northern and parts of the central Rockies, the Plains, and the Mississippi Valley, parts of the Gulf Coast, and the Midwest. The probability of occurrence is 35 percent. Above-normal precipitation is forecast for parts of the northern Plains to the Northeast. The probability of occurrence is nearly 43 percent.
May 20-24: A ridge, trough, and ridge is forecast across the country. Guidance is well-established for this pattern.
Low pressure develops in the southern Plains on Wednesday and tracks east to the Carolina Coast by Friday. The system will spread rain and possibly thunderstorms in its path. A Pacific system pushes into the Northwest on Friday, bringing rain and mountain snow from the Northwest into parts of the Intermountain West.
Below normal temperatures are forecast for the West Coast states, parts of the Great Basin, parts of the upper Mississippi Valley, most of the Midwest, the Great Lakes region, the northern Mid-Atlantic, and the Northeast. Anomalies are expected to be near 4°F. Above normal temperatures are forecast for the southern and parts of the eastern Plains and most of the Rockies. Anomalies are expected to be 6°F or greater in some locations.
Below normal precipitation is forecast for parts of central and northern California and the Northwest. The probability of occurrence is 35 percent. Above normal precipitation is forecast for the southern Plains, the Mississippi Valley, the Great Lakes region, the Ohio and Tennessee Valleys to the Gulf Coast. The probability of occurrence reached 40 percent across the ArkLaTex region.
Jim Munley
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