Long Range Weather Forecast Discussion April 25-May 9
1608 PM Tue. Apr 22, 2025
Apr. 25-29: A trough is forecast in the West with a zonal flow and above normal heights across the eastern and central states. The trough gradually pushes towards the Plains by the end of the period as a ridge builds into the West Coast.
Low pressure and its associated frontal systems will cause widespread showers and thunderstorms with locally heavy rain, possibly for portions of the central states eastward into the Northeast later this week and into the weekend. An upper trough will move from the eastern Pacific into the West and Bring precipitation to the Northwest. Snow will be likely for the higher elevations across the north-central Rockies. Cyclogenesis will take place with deep moisture ahead of the upper trough and developing storm system causing an increase in the rain and thunderstorm chances across the central states over the weekend and into early next week.
Apr. 30-May 4: A ridge builds into the West pushing the western trough to the East.
TEMPERATURES
<
Yellow-2-4°F Above
Orange-4-6°F Above
Red-6-8°F
or Greater Above
Light Blue 2-4F Below
Medium Blue-4-6F Below
Dark Blue-6-8F or Great Below
Above-normal temperatures are forecast for the country. Anomalies could be 8°F or more.
PRECIPITATION
Yellow 35%Below
Brown-35-45% Below
Dark Brown-45-55% Below
Light Green-30-35% Above
Medium Green-35-45% Above
Dark Green-45-55%Above
Below-normal precipitation is forecast for northern California, a portion of Washington and Oregon, eastern Texas, the Southeast, the Tennessee Valley, the Mid-Atlantic, and the Northeast. The probability of occurrence is 35 percent. Above-normal precipitation is forecast for the upper Mississippi Valley, parts of the eastern Rockies, and most of the Plains. The probability of occurrence is near 35 percent.
May 5-9: Guidance is in fair agreement on the flow for this period. A trough is forecast in the West and the East with a ridge in between. The models show differences in the strengths of the troughs.
TEMPERATURES
Yellow-2-4°F Above
Orange-4-6°F Above
Red-6-8°F
or Greater Above
Light Blue 2-4F Below
Medium Blue-4-6F Below
Dark Blue-6-8F or Great Below
Below-normal temperatures are forecast for northern California and the Northwest. Anomalies are expected to be near 4°F. Above-normal temperatures are forecast for the Rockies to the Atlantic Coast. Anomalies could be 8°F or more.
PRECIPITATION
Yellow 35%Below
Brown-35-45% Below
Dark Brown-45-55% Below
Light Green-30-35% Above
Medium Green-35-45% Above
Dark Green-45-55%Above