Below Average Temperatures Continue

GENERAL OVERVIEW: A complex multi-low pressure system is driving the most significant weather threats, with heavy rain and flash flooding possible across portions of the northern Rockies and adjacent High Plains, and a severe thunderstorm threat extending across the Central Plains. A broad shield of rain and thunderstorms covers a large portion of the central and eastern United States, while the Pacific Northwest continues to see precipitation associated with onshore flow. As the period progresses into early next week, the primary storm system tracks eastward, spreading precipitation across a wider area while the most intense threats gradually shift. By mid-week, a new frontal boundary pushes southward through the central part of the country, maintaining an active pattern through at least Wednesday. Temperature anomalies through the period are generally modest, with above-normal readings most persistent across the North Central states and portions of the West, while near-normal to slightly below-normal temperatures affect parts of the Northeast and Mid-Atlantic early in the period.

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EAST:

The East begins the forecast period under the influence of a low pressure system tracking across the Northeast, bringing widespread rain to New England, the Mid-Atlantic, and portions of the Southeast. On Saturday, rain is occurring broadly across New England and the Mid-Atlantic, with additional rain and thunderstorm activity noted across the Southeast and along the Gulf Coast. A cold front extending southward from the Northeast low is helping to organize precipitation across the Carolinas and into the Deep South. By Sunday, the precipitation shield remains expansive, with rain and thunderstorms continuing across much of the Southeast, the Ohio Valley, and the Mid-Atlantic. Severe thunderstorms are not explicitly highlighted for the East during this period, but the broad coverage of rain and thunderstorms warrants attention across the Southeast and Gulf Coast states through Sunday.

Into Monday, the precipitation focus shifts somewhat as the Northeast system weakens and pulls away, though rain and thunderstorm coverage persists across the Southeast and along the Gulf Coast. A frontal boundary remains draped across the region, keeping moisture in place. By Tuesday, a new low pressure system is developing off the Mid-Atlantic coast, with an associated cold front and warm front helping to organize rain across the Southeast and coastal areas. Rain coverage remains broad across the Southeast and Mid-Atlantic through Tuesday. By Wednesday, rain and thunderstorm activity continues across the Southeast and Gulf Coast, with a low pressure system positioned off the Mid-Atlantic coast maintaining onshore flow and precipitation chances for coastal areas.

Temperature Anomalies:
-Days 1-3: Temperatures across New England and the Mid-Atlantic are running slightly below normal on Day 1, with anomalies of roughly 3 to 6 degrees below average in portions of the Northeast and Mid-Atlantic coastal areas. The Great Lakes and Ohio Valley are near to slightly above normal. By Day 3, a notable warm-up is underway across the Great Lakes and Ohio Valley, with above-normal anomalies of 3 to 6 degrees developing, while New England transitions toward near-normal readings.

-Days 4-6: Above-normal temperatures become more established across the Great Lakes and Ohio Valley by Days 4 through 6, with anomalies of 3 to 9 degrees above normal across the upper Great Lakes and into portions of New England by Day 5. The Mid-Atlantic and Southeast coastal areas see a brief period of below-normal temperatures around Day 5, with anomalies of 3 to 6 degrees below average, before moderating. By Day 6, above-normal readings spread broadly across the Great Lakes, Ohio Valley, and into New England.

-Days 7-10: The above-normal temperature signal persists and even strengthens across the Great Lakes, Ohio Valley, and Northeast through Days 7 and 8, with anomalies of 3 to 6 degrees above normal across a broad swath from the Great Lakes into New England and the Mid-Atlantic. By Days 9 and 10, the anomaly signal becomes less pronounced, with much of the East trending toward near-normal conditions, though modest above-normal readings linger across the Great Lakes region.

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CENTRAL:

The Central region is home to the most significant weather hazards during the opening days of the forecast period. On Saturday, a heavy rain and flash flooding threat is explicitly highlighted across portions of the northern Rockies, including Montana and adjacent areas, where multiple low pressure centers are in close proximity and moisture is being focused by complex terrain. This is the highest-impact threat in the region and should be monitored closely. Simultaneously, a severe thunderstorm threat is highlighted across a corridor from Nebraska and Kansas southward through Oklahoma and into Arkansas, where a vigorous dryline and frontal interaction are supporting the potential for organized convection. Rain and thunderstorms are widespread across the Central Plains, stretching from the Dakotas southward through the Mississippi Valley.

By Sunday, the severe thunderstorm threat diminishes somewhat, but a broad area of rain and thunderstorms continues from the Central Plains southward through the South Central states. A low pressure system tracking through the Central Plains is maintaining active weather, with precipitation extending from the Dakotas through the Mississippi valley. 

Into Monday, the precipitation shield remains extensive across the Central region, with rain and thunderstorms covering much of the area from the Central Plains eastward through the Mississippi Valley and into the South Central states. A cold front is draped across the Central Plains, and a low pressure system near the Kansas-Oklahoma border is helping to sustain convective activity. By Tuesday, a low pressure system over the Central Plains continues to drive rain and thunderstorms across a broad area from the Northern Plains southward through the South Central states, with the precipitation axis shifting gradually eastward. By Wednesday, a cold front sweeping southward through the Central Plains is the primary focus, with rain and thunderstorms continuing across the South Central states and the lower Mississippi Valley.

Temperature Anomalies:
-Days 1-3: The North Central states, particularly the Dakotas and into Minnesota, are running notably above normal on Day 1, with anomalies reaching 9 to 12 degrees or more above average in the northern tier. Warmer-than-normal conditions extend southward through the Central Plains, with anomalies of 3 to 6 degrees above normal across much of the region. By Day 2, the above-normal signal remains strong across the Northern Plains and extends into the Missouri Valley, while portions of the South Central states also trend above normal. Day 3 continues the above-normal pattern across the Central Plains and into the Missouri Valley, with anomalies of 3 to 6 degrees above normal widespread.

-Days 4-6: Above-normal temperatures persist across the Northern Plains and Central Plains through Days 4 and 5, with anomalies of 3 to 6 degrees above normal. The South Central states see a mix of near-normal to slightly above-normal readings. By Day 6, the above-normal signal in the Central region becomes more confined, with the most notable warmth shifting toward the northern tier, while portions of the South Central states trend toward near-normal or slightly below-normal conditions.

-Days 7-10: The above-normal temperature signal in the Central region becomes more diffuse through Days 7 through 10. The Northern Plains retain modest above-normal anomalies of 3 to 6 degrees through Day 9, while the remainder of the Central region trends toward near-normal conditions. By Day 10, only scattered areas of modest above-normal readings remain across the Northern Plains and Central Plains.

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WEST:

The West is an active zone throughout the forecast period, driven by a series of Pacific systems and associated frontal boundaries. On Saturday, a broad area of rain and thunderstorms covers the Pacific Northwest, with precipitation extending southward along the Pacific Coast and into the northern Rockies. Multiple low pressure centers are present across the region, and heavy rain with flash flooding is explicitly highlighted across portions of the northern Rockies, particularly in Montana and adjacent terrain, where the combination of complex topography and moisture-laden flow is creating a significant rainfall threat. Mixed precipitation is also noted across portions of the higher terrain of Idaho, Wyoming, and Colorado, where snow is possible at elevation.

By Sunday, the precipitation focus in the West shifts somewhat, with rain continuing across the Pacific Northwest and mixed precipitation — including snow at higher elevations — noted across portions of the northern Rockies, including Idaho and Wyoming. A low pressure system over the Pacific Northwest is helping to maintain onshore flow and precipitation across the region. Into Monday, rain continues across the Pacific Northwest and northern Rockies, with mixed precipitation again possible in the higher terrain of the northern Rockies. A low pressure system over the Pacific Northwest and another over the Great Basin are keeping the region unsettled.

By Tuesday, the Pacific Northwest remains active with rain, and a low pressure system over the Great Basin is contributing to precipitation across portions of the Intermountain West. Wednesday brings continued rain across the Pacific Northwest and the northern Rockies, with a low pressure system over the Great Basin maintaining precipitation chances across portions of the Mountain West.

Temperature Anomalies:
-Days 1-3: On Day 1, portions of the Pacific Northwest and northern Rockies are running slightly below normal, with anomalies of 3 to 6 degrees below average in scattered areas. The remainder of the West is largely near normal. By Day 2, below-normal anomalies persist across portions of the northern Rockies and Pacific Northwest, while the Desert Southwest sees isolated areas of slight above-normal readings. Day 3 brings a notable shift, with above-normal temperatures developing broadly across much of the West, including the Pacific Coast states, the Great Basin, and the Desert Southwest, with anomalies of 3 to 6 degrees above normal widespread. The northern Rockies and Pacific Northwest retain a below-normal signal on Day 3.

-Days 4-6: Above-normal temperatures become more widespread and pronounced across the West through Days 4 through 6. The Pacific Coast, Great Basin, and Desert Southwest see anomalies of 3 to 9 degrees above normal, with the warmest departures focused across the Mountain West. The Pacific Northwest sees a brief period of above-normal readings by Day 4 before moderating. By Day 6, above-normal temperatures remain entrenched across much of the Mountain West and Desert Southwest, with anomalies of 3 to 6 degrees above normal.

-Days 7-10: The above-normal temperature signal in the West remains robust through Days 7 and 8, with the Mountain West — particularly the central and southern Rockies — seeing anomalies of 6 to 12 degrees above normal, representing the most pronounced warm anomaly in the country during this period. The Pacific Northwest sees near-normal to slightly below-normal readings by Days 9 and 10, while the Mountain West and Desert Southwest retain above-normal anomalies, though the magnitude diminishes somewhat by Day 10.

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TROPICAL: No tropical cyclone activity is anticipated across the Atlantic basin during the next seven days. In the eastern North Pacific, a disturbance is being monitored well to the southwest of Hawaii, with a greater-than-60-percent chance of development into a named storm over the next seven days. This system poses no threat to the contiguous US.