Scattered Rain then Dry.

General Overview: AN ACTIVE WEATHER PATTERN WILL UNFOLD ACROSS MUCH OF THE NATION OVER THE NEXT SEVERAL DAYS. THE MOST SIGNIFICANT THREAT WILL BE SEVERE THUNDERSTORMS ACROSS THE SOUTH CENTRAL REGION AND GULF COAST EARLY IN THE PERIOD, WITH THAT ACTIVITY SHIFTING EASTWARD AS THE WEEK PROGRESSES. A POTENT LOW PRESSURE SYSTEM TRACKING ACROSS THE UPPER MIDWEST AND GREAT LAKES WILL BRING HEAVY SNOW TO THE NORTHERN TIER AND RAIN TO A BROAD SWATH OF THE CENTRAL AND EASTERN UNITED STATES. A SECONDARY LOW WILL DEVELOP ALONG THE EASTERN SEABOARD BY MID-WEEK, BRINGING RAIN AND THUNDERSTORMS TO THE NORTHEAST AND MID-ATLANTIC BEFORE PUSHING OFFSHORE. THE WEST WILL REMAIN RELATIVELY UNSETTLED WITH PRECIPITATION ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES, WHILE WELL-ABOVE-NORMAL TEMPERATURES BUILD ACROSS THE INTERIOR WEST AND SOUTHWEST THROUGH THE EXTENDED PERIOD.

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EAST: The eastern United States will experience a dynamic and evolving weather pattern through the forecast period. To start the week, a cold front extending from the Gulf Coast northeastward will be the primary focus for rain and thunderstorm activity across the Southeast and along the Gulf Coast. Showers and thunderstorms will be widespread from the lower Mississippi Valley through the Deep South and into the Florida Peninsula, with rain also spreading northward along the Eastern Seaboard from the Mid-Atlantic into portions of New England. A high pressure system centered over the Great Lakes will keep conditions relatively quiet across the interior Northeast initially, though clouds and rain will encroach from the south and east.

By Tuesday evening, the storm system that has been tracking across the Upper Midwest will push into the Great Lakes region, bringing widespread rain and the potential for thunderstorms across the Ohio Valley and Mid-Atlantic. Snow will continue to fall across the Upper Great Lakes and into portions of the northern tier behind the low. A warm front lifting northeastward will help focus heavy rainfall across the interior East, while a cold front sweeping through the region will bring a line of showers and storms.

The most significant threat for the East arrives Wednesday into Thursday, as a low pressure system develops and intensifies along the Mid-Atlantic and Northeast coastline. This coastal low will bring heavy rain and thunderstorms to the Mid-Atlantic, with rain spreading across much of the Northeast. Snow will be possible across interior New England and elevated terrain as colder air wraps in behind the system. The low will eventually push offshore by Thursday, but not before delivering a prolonged period of rain to the densely populated I-95 corridor. By Thursday evening, the low tracks off the coast with a cold front sweeping through, leaving behind drier and cooler conditions across the region. Lingering rain and snow showers are possible across the Great Lakes and northern New England in the wake of the departing system.

**Temperature Anomalies:**

– Days 1-3: Temperatures will start near to slightly below normal across much of the Northeast and Great Lakes, running 3 to 6 degrees below average in some areas. The Southeast will be near normal. By Day 3, a notable cold anomaly of 6 to more than 12 degrees below normal will settle across the Great Lakes, Ohio Valley, and portions of the Mid-Atlantic and Southeast in the wake of the frontal passage.

– Days 4-6: Below-normal temperatures will persist across the Great Lakes, Ohio Valley, and portions of the Mid-Atlantic and Southeast, with anomalies of 3 to 9 degrees below average. The cold gradually moderates toward the end of this period, though the Appalachians and surrounding areas may remain 3 to 6 degrees below normal through Day 6.

– Days 7-10: A gradual warming trend takes hold across the East, with temperatures trending back toward or slightly above normal. By Days 9 and 10, above-normal readings of 3 to 6 degrees are expected to spread across much of the Northeast, Mid-Atlantic, and Southeast, signaling a return to a more seasonable and eventually warmer pattern.

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CENTRAL: The central United States will be at the heart of the most impactful weather during the early part of the forecast period. A vigorous low pressure system will be positioned near the Nebraska-Iowa border Monday evening, with a cold front extending southwestward and a warm front pushing to the east. This setup will generate a broad area of rain and thunderstorms across the Central Plains, Midwest, and into the South Central region. **Severe thunderstorms will be a significant threat across the South Central states, including portions of the lower Mississippi Valley and Gulf Coast, where conditions will be favorable for damaging winds, large hail, and possibly tornadoes.** This severe weather threat is the most notable hazard of the period for the central United States and should be taken seriously.

As the low deepens and tracks northeast into the Great Lakes by Tuesday, heavy snow will develop across the Upper Midwest and northern portions of the Central Plains. The combination of a strong low and ample moisture will support heavy snowfall accumulations across the Dakotas and Minnesota, with rain and thunderstorms continuing across the central and southern Plains. An occluded front wrapping around the low will help focus precipitation across the Upper Midwest and Great Lakes, where snow will be widespread.

By Wednesday, the low will have shifted well to the northeast, and a broad area of high pressure will build into the Central Plains and Midwest, bringing a return to drier and quieter conditions. Thunderstorm activity will diminish across the South Central region, though isolated showers may linger near the Gulf Coast. A new low pressure system will begin to develop across the Central Plains by Thursday, with precipitation returning to portions of the region by the end of the forecast period. Snow showers will be possible across the northern High Plains and into the Dakotas as this new system organizes.

**Temperature Anomalies:**

– Days 1-3: The North Central region will experience notably below-normal temperatures, running 6 to more than 12 degrees below average across the Dakotas and Minnesota early in the period. The Central Plains and Midwest will be near normal to slightly below normal. By Day 3, the cold anomaly expands southward and eastward as the frontal system pushes through, with readings 3 to 6 degrees below average across a broad area of the Midwest and Central Plains.

– Days 4-6: Temperatures will moderate across the central United States, trending back toward or slightly above normal across much of the Central Plains and Midwest. The warming trend will be most pronounced across the western portions of the region, while near-normal readings persist farther east. By Day 6, above-normal temperatures of 3 to 6 degrees will spread across the Central and Southern Plains.

– Days 7-10: A broad and persistent above-normal temperature regime will take hold across the central United States, with anomalies of 3 to 6 degrees above average covering the Central Plains, Midwest, and South Central regions. The warmth will be most pronounced across the Central Plains and into the South Central states, continuing a trend toward well-above-normal temperatures that will likely persist into the extended period.

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WEST: The western United States will see a mixed bag of weather through the forecast period. A low pressure system over the Desert Southwest early in the week will help generate scattered showers and some thunderstorm activity across portions of the Southwest and into the southern Rockies. Meanwhile, a separate low pressure system will be positioned near the Pacific Northwest coast, bringing rain to the coastal areas of Oregon and Washington and snow to the higher elevations of the Cascades and northern Rockies. Thunderstorm activity will also be noted across portions of the northern Rockies and Intermountain West early in the period.

By Tuesday, the Pacific Northwest low will push inland, spreading precipitation across the northern Rockies and into the northern High Plains. Snow will be likely at higher elevations, with rain at lower elevations. The Southwest will remain unsettled with continued shower and thunderstorm chances, particularly across the higher terrain of the Four Corners region.

As the week progresses into Wednesday and Thursday, a broad area of high pressure will build across the Interior West, bringing drier conditions to much of the region. However, precipitation will continue across the Pacific Northwest and northern Rockies as a new system approaches from the Pacific. Snow will be possible at the higher elevations of the Cascades, northern Rockies, and into the northern Great Basin. The Southwest will trend drier as high pressure dominates, but the Pacific Northwest will remain active with continued rounds of rain and mountain snow through the end of the forecast period.

**Temperature Anomalies:**

– Days 1-3: The West will be dominated by above-normal temperatures, particularly across California, Nevada, Arizona, and the Desert Southwest, where anomalies of 6 to more than 12 degrees above average are expected. The Pacific Northwest will be near normal to slightly above normal. The northern Rockies and Intermountain West will also trend above normal by Day 3, with anomalies of 3 to 9 degrees above average spreading across a large portion of the region.

– Days 4-6: The above-normal temperature signal will intensify and expand across the Interior West. The Desert Southwest, Great Basin, and Rockies will see anomalies of 9 to more than 12 degrees above average, representing a significant and potentially record-challenging warmth event for mid-May. The Pacific Northwest will also trend above normal during this period, with anomalies of 3 to 6 degrees above average.

– Days 7-10: The above-normal temperature pattern will begin to relax somewhat across the West, though readings will remain above average across much of the region. The Interior West and Southwest will still be running 3 to 6 degrees above normal, while the Pacific Northwest trends back toward near-normal values. The overall pattern will remain warmer than average through the end of the 10-day period.

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TROPICAL: The Atlantic and Eastern Pacific basins are both quiet at this time. No tropical cyclone activity is expected in either basin during the next seven days, and no areas of disturbed weather are currently being monitored for development. Conditions remain unfavorable for tropical cyclone formation across both the Atlantic and Eastern Pacific through the near-term forecast period.