Rain Moving Out

**General Overview:**

AN ACTIVE WEATHER PATTERN IS EXPECTED ACROSS MUCH OF THE CONTIGUOUS UNITED STATES OVER THE NEXT SEVERAL DAYS. THE MOST SIGNIFICANT WEATHER CONCERN WILL BE THE THREAT OF HEAVY RAIN AND FLASH FLOODING ACROSS THE GULF COAST AND SOUTH CENTRAL REGIONS, WHERE MULTIPLE ROUNDS OF THUNDERSTORMS ARE ANTICIPATED. A BROAD AREA OF RAIN AND THUNDERSTORMS WILL ALSO AFFECT MUCH OF THE CENTRAL AND EASTERN UNITED STATES AS A SERIES OF FRONTAL BOUNDARIES REMAIN ACTIVE THROUGH THE PERIOD. THE PACIFIC NORTHWEST WILL SEE UNSETTLED CONDITIONS AS A FRONTAL SYSTEM PUSHES ONSHORE, WHILE THE INTERIOR WEST WILL EXPERIENCE A MIX OF PRECIPITATION TYPES WITH SNOW POSSIBLE AT HIGHER ELEVATIONS. TEMPERATURES WILL TREND ABOVE NORMAL ACROSS THE NORTHERN PLAINS AND MUCH OF THE CENTRAL UNITED STATES AS THE PERIOD PROGRESSES, WHILE BELOW-NORMAL TEMPERATURES LINGER ACROSS PARTS OF THE CENTRAL PLAINS EARLY BEFORE MODERATING.

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**EAST:** A complex and active weather pattern will dominate the eastern United States through the period. To start, a low pressure system positioned near the Mid-Atlantic coast is accompanied by a warm front extending offshore and a cold front sweeping southward through the region. This setup is generating widespread rain and thunderstorms from the Southeast through the Mid-Atlantic and into the Northeast. Rain is expected across much of New England and the coastal Mid-Atlantic, while thunderstorm activity dominates from the Carolinas southward through the Deep South and into the Gulf Coast. The Great Lakes region is also seeing precipitation, with rain and some snow possible in the far northern portions near the Canadian border.

By Sunday evening, the cold front pushes well offshore, with a cold front positioned just east of the coastline. Rain lingers across portions of the Northeast and Great Lakes, while thunderstorm activity continues to dominate the Southeast and Gulf Coast. The heavy rain and flash flooding threat remains most acute across the Gulf Coast states, where multiple rounds of convection are expected to produce dangerous rainfall accumulations. This heavy rain and flash flooding threat is a primary concern for the region and should be monitored closely.

As the week progresses into Tuesday and Wednesday, a new low pressure system develops across the northern Rockies and pushes a cold front southward through the interior West, while a separate low pressure system becomes established near the Northeast coast. Rain and thunderstorms continue across the Southeast and Gulf Coast, and rain spreads into the Mid-Atlantic and portions of New England once again as the coastal low organizes. The Great Lakes region will see additional rounds of rain through midweek. By Wednesday, the cold front associated with the coastal low has pushed offshore, leaving rain and some thunderstorm activity lingering across the Southeast and Gulf Coast, while the Northeast transitions to a period of rain.

**Temperature Anomalies:**

– Days 1-3: Temperatures are running near to slightly below normal across much of the Northeast and Mid-Atlantic early in the period, with a modest below-normal signal over portions of the Mid-Atlantic. By Day 3, temperatures trend back toward or slightly above normal across most of the East, with above-normal readings developing across the Great Lakes and Ohio Valley.

– Days 4-6: A warming trend takes hold across the eastern United States, with above-normal temperatures becoming more widespread from the Great Lakes through the Ohio Valley and into the Mid-Atlantic. Anomalies of 6°F or more above normal are possible across portions of the Great Lakes and Midwest by Day 5, with the warmth extending into the Northeast by Day 6.

– Days 7-10: Above-normal temperatures persist across the Great Lakes and upper Midwest into the extended period, though anomalies gradually moderate. Portions of the Northeast see near- to slightly below-normal readings during Days 7-8 before trending back toward normal by Days 9-10.

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**CENTRAL:** The central United States will be dominated by widespread thunderstorm activity and the persistent threat of heavy rain and flash flooding, particularly across the South Central region. A slow-moving frontal boundary and multiple low pressure systems will keep the region unsettled through much of the period. The Gulf Coast states face the highest flash flooding risk, with heavy rainfall expected to be especially dangerous across portions of the central and western Gulf Coast, where training thunderstorms could produce significant rainfall totals. This flash flooding threat is the top weather concern for the region.

Thunderstorm coverage extends northward through the Mississippi and Ohio Valleys on Saturday and Sunday, with rain and thunderstorms affecting areas from the Central Plains eastward through the Midwest. By Monday, the thunderstorm activity begins to shift and consolidate, though the South Central region continues to see active convection. A new area of low pressure developing across the Central and Northern Plains by Tuesday will bring a cold front southward, helping to reorganize the precipitation pattern. Thunderstorms remain widespread across the South Central states and into the lower Mississippi Valley through Wednesday, while the Central Plains see a gradual decrease in precipitation coverage behind the frontal passage.

**Temperature Anomalies:**

– Days 1-3: Temperatures across the Central Plains start the period running notably below normal, with anomalies of 6°F or more below normal across portions of the Central and Northern Plains on Day 1. This cold anomaly diminishes by Day 2 and largely disappears by Day 3, with temperatures trending back toward or above normal across the region. The South Central region remains near normal through this period.

– Days 4-6: A significant warming trend develops across the Central region, with above-normal temperatures spreading from the Northern Plains southward through the Central Plains. Anomalies of 6 to locally 12°F above normal are expected across portions of the Northern Plains and upper Midwest by Days 4-5, with the warmth extending broadly through the Midwest and Great Lakes. The South Central region sees near-normal to slightly below-normal temperatures in areas where persistent cloud cover and rainfall limit daytime heating.

– Days 7-10: Above-normal temperatures persist across the Northern Plains and upper Midwest into the extended period, though the magnitude of the anomalies gradually decreases. The Central Plains trend toward near-normal readings by Days 9-10, while the South Central region remains near to slightly below normal.

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**WEST:** The western United States will see an active weather pattern develop as the period progresses. Early in the period, a low pressure system is positioned over the Great Basin, generating scattered precipitation across portions of the interior West. Snow is possible at higher elevations across the Rockies and Cascades, while lower elevations see rain. The Pacific Northwest will see an approaching frontal system bring rain and an occluded front to the region by Monday, with precipitation spreading inland across the Northwest. Snow is possible in the higher terrain of the Cascades and northern Rockies.

By Tuesday, a more organized low pressure system pushes a cold front southward through the Pacific Northwest and into California, bringing widespread rain to the coast and lower elevations and snow to the mountains. The Pacific Northwest sees the most active conditions during this period, with rain continuing through Wednesday as the frontal boundary lingers. The interior West sees a mix of precipitation types, with rain at lower elevations and snow at higher elevations across the Rockies and Sierra Nevada. By Wednesday, rain and mountain snow continue across the Pacific Northwest and portions of the northern Rockies, while the Southwest remains relatively dry.

**Temperature Anomalies:**

– Days 1-3: Temperatures across the Pacific Coast states start the period running above normal, with anomalies of 6°F or more above normal across portions of California and the Pacific Northwest on Day 1. By Day 2, the above-normal signal shifts northward into the Pacific Northwest and northern Rockies, while California trends back toward near normal. By Day 3, above-normal temperatures are widespread across the northern and central Rockies and Pacific Northwest, with anomalies of 6°F or more above normal in some areas.

– Days 4-6: The above-normal temperature signal continues across much of the West early in this period, particularly across the northern Rockies and portions of the Great Basin. However, as the active frontal pattern brings cooler air into the Pacific Northwest and northern California by Days 5-6, temperatures trend below normal across those areas, with anomalies of 6°F or more below normal developing across the Pacific Northwest and northern Great Basin by Day 6.

– Days 7-10: Below-normal temperatures persist across portions of the Pacific Northwest, northern California, and the Great Basin through the extended period, with anomalies remaining 3 to 6°F below normal in some areas. The Southwest and southern Rockies trend toward near-normal to slightly above-normal readings by Days 9-10.

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**TROPICAL:** The Atlantic and Eastern Pacific basins are currently quiet. No tropical cyclone activity is expected across either basin during the next seven days, and no disturbances are currently being monitored for development potential.