Staying Cool
Temperatures will remain below normal for most today, with the largest anomalies seen in the Dakotas.
GENERAL OVERVIEW: AN ACTIVE WEATHER PATTERN IS UNDERWAY ACROSS THE CONTIGUOUS UNITED STATES AS A SERIES OF FRONTAL BOUNDARIES AND LOW PRESSURE SYSTEMS DRIVE WIDESPREAD RAIN, THUNDERSTORMS, AND HEAVY RAIN THREATS ACROSS MULTIPLE REGIONS. TROPICAL STORM BERTHA IS CURRENTLY POSITIONED NEAR THE GULF COAST AND IS CONTRIBUTING TO HEAVY RAINFALL AND FLASH FLOODING CONCERNS ACROSS PORTIONS OF THE SOUTHEAST. A COLD FRONT SWEEPING THROUGH THE CENTRAL AND EASTERN PORTIONS OF THE COUNTRY WILL FOCUS ADDITIONAL THUNDERSTORM AND HEAVY RAIN ACTIVITY THROUGH THE WEEKEND. THE WEST WILL SEE SCATTERED THUNDERSTORM ACTIVITY ASSOCIATED WITH MULTIPLE LOW PRESSURE SYSTEMS, WHILE A BROAD WARMING TREND TAKES HOLD ACROSS MUCH OF THE NATION HEADING INTO NEXT WEEK.
EAST:
The forecast period begins with an active weather setup across the East, as Tropical Storm Bertha is currently situated near the central Gulf Coast, bringing heavy rain and flash flooding potential to portions of the Southeast, including areas of Alabama, Georgia, and the Carolinas. Heavy rain and flash flooding are possible across this region through Friday as the storm’s moisture interacts with a frontal boundary draped across the area. Thunderstorms are widespread across the Southeast, and Tennessee Valley during this period. Heavy rain and flash flooding concerns are also highlighted across portions of Kansas and Missouri, extending into the mid-Mississippi Valley region.
By Saturday, the cold front remains offshore along the East Coast, with a low pressure system developing near the Mid-Atlantic coast. The Southeast will see lingering thunderstorm activity as the remnant moisture from Bertha continues to interact with the frontal boundary. Heavy rain and flash flooding remain a concern across portions of the Southeast, including the Carolinas and Georgia.
Into Sunday and Monday, the coastal low continues to influence the Northeast and Mid-Atlantic, with rain and thunderstorms persisting from the Carolinas northward into the Atlantic. The Southeast gradually dries out as the frontal boundary lifts northward, though scattered thunderstorms remain possible across the region. By Monday evening, a broad area of rain and thunderstorms covers much of the eastern seaboard from the Mid-Atlantic through New England, with rain extending into the Ohio Valley and Great Lakes region as another system moves in from the west.
Temperature Anomalies:
-Days 1-3: Temperatures across the Ohio Valley, Great Lakes, and into portions of the Mid-Atlantic and Tennessee Valley will be running below normal by as much as 6 to locally 12 degrees, particularly across the central Great Lakes and Ohio Valley on Day 1. The Northeast sees near-normal to slightly below-normal temperatures. The Southeast is generally near normal.
-Days 4-6: Below-normal temperatures gradually moderate across the East. A brief period of slightly below-normal temperatures is noted across portions of the Mid-Atlantic on Day 4. By Days 5 and 6, much of the East trends toward near-normal to slightly above-normal conditions, with above-normal temperatures becoming more widespread across the Northeast by Day 6.
-Days 7-10: Temperatures across the East trend toward near-normal to slightly above-normal conditions through the end of the forecast period, with most areas showing little departure from climatological averages.
CENTRAL:
The forecast period opens with a low pressure system over the central Plains, with a warm front extending southward into the southern Plains and a cold front sweeping through the central and northern Plains. Rain and thunderstorms are widespread across the central Plains, with heavy rain and flash flooding possible across portions of Kansas and Missouri. Thunderstorms are also noted across portions of the southern Plains and into the lower Mississippi Valley. A high pressure system over the central Rockies provides a brief break in precipitation for portions of the northern and central Plains.
By Saturday, the cold front continues to push eastward, and a new low pressure system develops over the southern Plains. Rain and thunderstorms persist across portions of the central Plains and into the Midwest, with heavy rain and flash flooding remaining a concern across Missouri and surrounding areas. The western Gulf Coast sees thunderstorm activity as moisture continues to stream northward ahead of the frontal boundary.
Into Sunday, multiple low pressure systems are noted across the central region, including one over the central Plains and another over the southern Rockies. Thunderstorms continue across portions of the central Plains and into the Midwest, with scattered activity also noted across the southern Plains. By Monday, thunderstorm activity becomes more widespread across the central Plains, stretching from the Dakotas southward through Kansas and into the southern Plains, with rain and thunderstorms also affecting portions of the Rockies and High Plains.
Temperature Anomalies:
-Days 1-3: Temperatures across the central and northern Plains, as well as the Midwest, will be running below normal by 3 to locally more than 12 degrees, with the most pronounced cold anomalies centered over Kansas and Nebraska on Day 1. By Day 3, the below-normal signal weakens somewhat but still covers portions of the central Plains and Midwest.
-Days 4-6: A significant warming trend develops across the central region. By Days 4 and 5, above-normal temperatures spread across much of the northern and central Plains, the Rockies, and into the Midwest, with anomalies of 3 to 6 degrees above normal becoming widespread. This warming trend continues and expands through Day 6.
-Days 7-10: Above-normal temperatures persist across the central Plains and southern Plains through the end of the forecast period, with anomalies of 3 to 6 degrees above normal noted across portions of Texas, Oklahoma, Arkansas, and surrounding areas. The northern Plains and Midwest trend toward near-normal conditions by Days 9 and 10.
WEST:
The forecast period begins with an active pattern across the West, as multiple low pressure systems are positioned along the Pacific Coast and across the Intermountain West. Thunderstorms are widespread across portions of the Southwest, Great Basin, and into the Rockies, consistent with the summer monsoon pattern. Scattered rain and thunderstorms are also noted across portions of the Pacific Northwest and northern Rockies. A low pressure system near the southern California coast will contribute to scattered thunderstorm activity across the Desert Southwest and into the southern Rockies through the weekend.
By Saturday, thunderstorm activity continues across the Southwest, Great Basin, and into the central Rockies, with scattered rain also noted along the Pacific Coast from California northward through the Pacific Northwest. Into Sunday and Monday, the thunderstorm pattern persists across the Southwest and Rockies, with additional scattered activity noted across portions of the Great Basin and into the central Rockies. A low pressure system near the southern California coast continues to influence the region through the early part of next week.
Temperature Anomalies:
-Days 1-3: The Pacific Northwest, particularly western Washington and Oregon, is experiencing well-above-normal temperatures, with anomalies of 6 to more than 12 degrees above normal on Day 1. This warmth extends into portions of northern Idaho and western Montana. Meanwhile, portions of California, Nevada, Utah, New Mexico, and southern Colorado are running slightly above normal by 3 to 6 degrees. By Day 3, the above-normal signal expands across much of the West, with the Pacific Northwest, northern Rockies, and portions of the Great Basin all trending warmer than normal.
-Days 4-6: Above-normal temperatures become more widespread across the West, with anomalies of 3 to 6 degrees above normal covering much of the Intermountain West, Great Basin, Pacific Northwest, and Southwest. The warming trend is particularly pronounced across the northern Rockies and portions of the Pacific Coast through this period.
-Days 7-10: Above-normal temperatures persist across much of the West through the end of the forecast period, though the anomalies gradually moderate. The Pacific Northwest and northern Rockies continue to see above-normal readings, while portions of the Southwest and southern California also remain warmer than average. Much of the central and southern Rockies trend toward near-normal conditions by Days 9 and 10.
TROPICAL:
Tropical Storm Bertha is currently located near the central Gulf Coast, in the vicinity of the Louisiana and Mississippi coastline. The storm is producing heavy rainfall and flash flooding concerns across portions of the Southeast, including Alabama, Georgia, and the Carolinas, as it interacts with a frontal boundary draped across the region. Bertha’s moisture is expected to continue fueling heavy rain and thunderstorm activity across the Southeast through the near-term forecast period.
In the eastern Pacific, Tropical Storm Fausto is currently positioned in the central eastern Pacific, well south of the Baja California peninsula. Two disturbances are also being monitored in the eastern Pacific — one located far to the west-southwest of Hawaii in the central Pacific, and another situated near the coast of Mexico in the eastern Pacific near the Gulf of Tehuantepec. Both disturbances carry a greater than 60 percent chance of development into a named storm within the next seven days and will need to be watched closely for further organization.