Near or Just Above Normal

General Overview: AN ACTIVE WEATHER PATTERN IS EXPECTED TO UNFOLD ACROSS MUCH OF THE COUNTRY OVER THE NEXT SEVERAL DAYS. THE MOST SIGNIFICANT HAZARDS WILL BE CONCENTRATED ACROSS THE SOUTH CENTRAL REGION, WHERE HEAVY RAIN, FLASH FLOODING, AND SEVERE THUNDERSTORMS POSE SERIOUS THREATS THROUGH THE EARLY PART OF THE PERIOD. A SECONDARY AREA OF CONCERN INVOLVES MIXED PRECIPITATION, INCLUDING HEAVY SNOW, ACROSS PORTIONS OF THE NORTHERN ROCKIES AND ADJACENT HIGH PLAINS. MEANWHILE, A BROAD AREA OF RAIN AND THUNDERSTORMS WILL AFFECT A LARGE SWATH OF THE CENTRAL AND EASTERN UNITED STATES AS AN ACTIVE FRONTAL PATTERN PERSISTS. TEMPERATURES WILL TREND WELL ABOVE NORMAL ACROSS THE CENTRAL UNITED STATES AND INTO THE GREAT LAKES AND NORTHEAST BY THE LATTER HALF OF THE FORECAST PERIOD, WHILE THE WEST WILL SEE A MIXED TEMPERATURE SIGNAL THAT EVENTUALLY TURNS BELOW NORMAL ACROSS PORTIONS OF THE PACIFIC COAST STATES.

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EAST: A complex frontal pattern is influencing the eastern United States during the early part of the period. A low pressure system tracking along or near the Mid-Atlantic coastline is bringing rain and thunderstorms to portions of the Southeast, Mid-Atlantic, and into southern New England. A cold front extending southward from this system is helping to focus precipitation across the Carolinas and into the Gulf Coast states. Rain and thunderstorm coverage is widespread from the Tennessee Valley northeastward through the Appalachians and into the Mid-Atlantic corridor. Severe thunderstorms are possible across portions of the central Appalachians and adjacent piedmont areas during the first day of the period. By the second day, the frontal system pushes offshore, but lingering rain and thunderstorm activity continues across the Southeast and Gulf Coast, with the overall threat gradually diminishing as high pressure begins to build in from the north. The remainder of the period features a quieter pattern across the East, with mostly dry conditions expected as the ridge strengthens. Temperatures during the early days run near to slightly below normal across the Mid-Atlantic and portions of New England, but a warming trend takes hold by the middle and latter portions of the period, with above-normal readings becoming widespread from the Great Lakes southward through the Ohio Valley and into the Northeast.

Temperature Anomalies:

– Days 1-3: Near to slightly below normal across much of the Northeast and Mid-Atlantic, with modest below-normal anomalies of around 3 to 6°F in the Mid-Atlantic region; near-normal conditions across the Southeast and Gulf Coast.

– Days 4-6: A warming trend takes hold, with temperatures rising to 3 to 6°F above normal across the Ohio Valley, Great Lakes, and portions of the Northeast. The Mid-Atlantic corridor also begins to trend above normal.

– Days 7-10: Above-normal temperatures become well-established and widespread across the Northeast, Great Lakes, and Ohio Valley, with anomalies of 6°F or more above normal in some areas. The warming signal persists through the end of the period, though some moderation is possible by Day 10.

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CENTRAL: The most impactful weather across the central United States during the early portion of the period is focused on the South Central region, where a potent storm system is generating a significant threat for heavy rain and flash flooding. A large area stretching from the central Gulf Coast northward through the lower Mississippi Valley and into the Arkansas and Oklahoma region is under the gun for dangerous rainfall accumulations capable of producing life-threatening flash flooding. This heavy rain and flash flooding threat is the primary hazard of the period and warrants close attention. Concurrent with the flooding threat, severe thunderstorms are possible across portions of the Southern Plains and lower Mississippi Valley during the first day, with the threat shifting northward and eastward by the second day as the system evolves. A broad corridor of rain and thunderstorms extends well northward into the Central Plains and upper Midwest ahead of the advancing frontal boundary.

As the period progresses into the Day 3 timeframe, a new low pressure system organizes across the Central Plains, maintaining a threat for severe thunderstorms across portions of Oklahoma and Kansas. Rain and thunderstorm activity remains widespread across the Midwest and Central Plains through the middle of the period before gradually tapering as the pattern transitions. Temperatures across the central region undergo a dramatic shift, going from well below normal during the early days — particularly across the Central and Northern Plains — to significantly above normal by the latter half of the period as a strong ridge builds.

Temperature Anomalies:

– Days 1-3: Temperatures are running 6 to more than 12°F below normal across the Central and Northern Plains, stretching from the Dakotas southward through Nebraska, Kansas, and into Colorado. Near-normal readings are found across the South Central region.

– Days 4-6: A significant warming trend begins, with temperatures rising to 6 to 12°F above normal across the Northern Plains and into the upper Midwest. The below-normal signal across the Central Plains erodes rapidly. Isolated pockets of below-normal temperatures linger across portions of the Southern Plains and South Central region early in this window.

– Days 7-10: Above-normal temperatures dominate the entire central region, with anomalies of 6 to more than 12°F above normal widespread from the Northern Plains through the Midwest and into the Great Lakes. The warmth is most pronounced across the Dakotas, Nebraska, and the upper Midwest. This above-normal signal persists and remains robust through the end of the period.

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WEST: The western United States is under an active pattern driven by a series of low pressure systems and associated frontal boundaries during the early part of the period. Multiple low pressure centers are positioned across the Pacific Northwest, the Great Basin, and the Desert Southwest, bringing widespread rain and thunderstorm activity to portions of the region. Mixed precipitation, including snow at higher elevations, is occurring across the northern Rockies in association with the active storm track. The Pacific Northwest is seeing periods of rain associated with onshore flow and frontal passages. Across the Desert Southwest and into the southern Rockies, scattered shower and thunderstorm activity is possible as moisture streams northward ahead of frontal boundaries. The overall pattern remains unsettled through the early days of the period before a gradual transition toward a more amplified ridge begins to take shape across the interior West by the middle of the period.

Temperatures across the West are above normal during the early days, particularly across California and the Pacific Northwest, where anomalies of 6 to more than 12°F above normal are observed. However, as the period progresses into the Day 7 through Day 10 timeframe, a significant pattern change brings well-below-normal temperatures to the Pacific Coast states, particularly across Oregon, northern California, and Nevada, with anomalies dropping to 6°F or more below normal. This cooling trend is associated with the arrival of a deeper trough digging into the western states.

Temperature Anomalies:

– Days 1-3: Temperatures are running 6 to more than 12°F above normal across California and the Pacific Northwest. The interior West, including Nevada and portions of the Great Basin, is also above normal. Isolated pockets of below-normal temperatures are found across the southern portions of California and the Desert Southwest.

– Days 4-6: The above-normal signal expands across the Pacific Northwest and into the northern Rockies, with anomalies of 6 to more than 12°F above normal across Oregon, Washington, Idaho, and Montana. The interior West remains above normal. A small area of below-normal temperatures persists across the Desert Southwest.

– Days 7-10: A significant pattern change brings below-normal temperatures to the Pacific Coast states, with anomalies of 6°F or more below normal across Oregon, northern California, and Nevada. The interior Northwest and northern Rockies transition toward near-normal or slightly below-normal readings. The below-normal signal is most pronounced and persistent through the end of the period across the Pacific Coast.

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TROPICAL:  No tropical cyclone activity is expected across either the Atlantic or Eastern Pacific basin during the next seven days.