Rain and High Elevation Snow in the Southwest

General Overview: A SERIES OF LOW-PRESSURES AND FRONTS WILL BRING AN ACTIVE PATTERN WITH RAIN AND THUNDERSTORMS LIKELY ACROSS MUCH OF THE CENTRAL AND EASTERN US THROUGHOUT THE MAJORITY OF THE WEEK. THE WESTERN US WILL SEE AN UPTICK IN PRECIPITATION THROUGH THE WORK WEEK, PARTICULARLY ALONG THE ROCKIES.

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EAST: A well-organized low pressure system will track over Quebec and Ontario early this week, being the predominant driver of weather across the Eastern US. On Monday, a cold front extends from the Great Lakes southwestward, with a warm front pushing northeastward into New England and southeastern Canada. Rain will likely be see across much of the northern half of the region, while thunderstorms are possible along and ahead of the cold front from the mid-South into the Southeast coast. A secondary area of low pressure is noted near the Gulf Coast, adding to the moisture feed into the Southeast.

By Tuesday, a secondary area of low-pressure will push into the Ohio Valley and mid-Atlantic corridor, with precipitation coverage expanding from the Mid Mississippi Valley to the Northeast. Thunderstorms remain possible across portions of the Tennessee Valley and lower Mississippi Valley. 

By Wednesday, the cold front has pushed into the Southeast and Gulf Coast, with thunderstorms erupting from the lower Mississippi Valley through the Carolinas and into the mid-Atlantic. Rain continues across a broad swath of the East from the Ohio Valley into New England. High pressure begins to build in behind the departing system, bringing a gradual end to precipitation from west to east.

By Thursday, a new low pressure system develops off the Northeast coast, bringing a renewed threat of rain to the Great Lakes and Northeast, also extending southward across the eastern coast. A warm front associated with this coastal low pushes northward into New England, creating a complex precipitation pattern with the potential for freezing rain in transitional zones. Thunderstorms continue to affect the Gulf Coast region ahead of a trailing cold front.

Temperature Anomalies:

– Days 1–3: Temperatures will run well below normal across much of the East, with the greatest departures — as much as 6 to 12°F or more below average — focused across the Ohio Valley, mid-Atlantic, and Southeast. The Northeast begins near to slightly below normal before moderating slightly by Day 3 as the pattern evolves.

– Days 4–6: A notable warm-up begins across the Northeast and mid-Atlantic, with temperatures running 6 to locally 12°F above normal in those areas by Days 4–5. Meanwhile, below-normal temperatures persist across the Great Lakes and Ohio Valley, with anomalies of 6°F or more below average. By Day 6, below-normal readings spread more broadly across the East.

– Days 7–10: Below-normal temperatures continue to dominate across the Great Lakes, Ohio Valley, and Southeast, with anomalies of 6 to locally more than 12°F below average in some areas. The pattern gradually moderates across the far Northeast by the end of the period.

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CENTRAL: On Monday, a low pressure system centered over the northern Rockies drives a cold front southeastward, with areas of thunderstorms likely across the Central Plains and Mid Mississippi Valley.

By Tuesday, multiple low pressure centers are evident across the Central US, and precipitation coverage expands considerably. Thunderstorms continue across the South Central region and into the lower Mississippi Valley, while rain extends broadly across the central Plains and Midwest.

By Wednesday, a high pressure system builds into the central Plains, helping to suppress precipitation across much of the region. However, rain and thunderstorms persist across the South Central states and into the lower Mississippi Valley ahead of the advancing cold front.

By Thursday, high pressure dominates across the central Plains and South Central region, bringing a drier pattern to much of the area. Scattered precipitation chances remain across the Northern Plains and Upper Midwest.

Temperature Anomalies:

– Days 1–3: The central United States will see a mixed temperature pattern. The South Central region, including Texas, will run below normal by 3 to 6°F or more early in the period. The northern Plains will trend near to slightly below normal, while portions of the central and southern Rockies see near-normal readings. By Day 3, a warming trend develops across the South Central states, with above-normal anomalies of 6°F or more emerging across the southern Plains.

– Days 4–6: A significant cold outbreak develops across the central United States. The Central Plains, Midwest, and northern Rockies will experience temperatures running 6 to more than 12°F below normal, with the most extreme negative anomalies centered over the central Plains and southern Rockies by Days 4–5. This cold pattern is persistent and will impact a large portion of the central U.S. through the end of this period.

– Days 7–10: Below-normal temperatures gradually moderate across the central United States, though readings remain below average across portions of the central and northern Plains into the Midwest. The southern Plains begin to trend back toward near-normal or slightly above-normal readings by the end of the period.

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WEST: The Western US will see a relatively quiet start to the period, though precipitation chances will increase as the week progresses. On Monday, rain and snow are noted across portions of the Pacific Northwest and the northern Rockies, associated with low pressure along the coast and into the northern intermountain region. Thunderstorms are possible across portions of the Southwest. Snow is noted across higher elevations of the Rockies and Cascades.

By Tuesday, an active pattern develops across the West, with multiple low pressure systems affecting the region. Snow and mixed precipitation — including freezing rain — spread across a broad area of the northern and central Rockies, with the highest elevations seeing the most significant snowfall accumulations. Rain and thunderstorms continue across the Desert Southwest and into the southern Rockies. The Pacific Northwest sees rain along the coast with snow at higher elevations.

By Wednesday, precipitation coverage contracts somewhat across the West, with snow and mixed precipitation lingering across the northern Rockies and portions of the central Rockies. High pressure building into the central Plains begins to influence the western periphery of the region. The Pacific Northwest remains unsettled with rain and mountain snow.

By Thursday, snow and rain continue across portions of the Pacific Northwest and northern Rockies, while the remainder of the West trends drier as high pressure dominates.

Temperature Anomalies:

– Days 1–3: The West will be the warmest region of the country during this period. The Pacific Northwest and northern Rockies will see temperatures running 6 to more than 12°F above normal, with the greatest positive anomalies focused over the Pacific Northwest. The Southwest and California will see near-normal to slightly above-normal readings, with isolated pockets of below-normal temperatures across portions of the Southwest by Day 3.

– Days 4–6: Above-normal temperatures persist across the Pacific Northwest, northern Rockies, and much of the West Coast, with anomalies of 6 to 12°F above average. The interior Southwest and portions of the Great Basin trend toward near-normal readings, with some below-normal pockets developing across the Southwest by Day 6.

– Days 7–10: The above-normal temperature signal expands and strengthens across the West. Much of the West — from the Pacific Coast through the Rockies and into the Desert Southwest — will be running 3 to 6°F or more above normal, with the most significant warmth concentrated across California, Nevada, and the Desert Southwest. This warmth persists through the end of the forecast period.

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TROPICAL: No tropical cyclone activity is expected in either the Atlantic or Pacific Basin over the next seven days.