Weather across America

(NATIONAL) Excessive heat to continue across portions of the Central Plains and Middle Mississippi Valley, severe thunderstorms and excessive rainfall possible from Middle Mississippi Valley to the Northeast, and monsoonal moisture to cause daily rounds of excessive rainfall and isolated flash flooding across portions of the Southwest and Southern Rockies. 

Searing heat will continue across the Mid-Atlantic and Northeast Sunday night before the upper trough over Canada dips down into the region to moderate temperatures a bit Monday. Widespread low temperature records are forecast to be broken across the Mid-Atlantic and Northeast Sunday as lows struggle to drop below the upper 70s and low 80s. 

100F+ degree days will continue across parts of eastern Kansas/Oklahoma into southern Missouri and northern Arkansas over the next couple of days, due to a rigid area of high pressure remaining stationed over the region. Area wide heat index values likely to be between 105-111F on Monday. 

Anomalously warm temperatures visit the Pacific Northwest this week as an upper-level ridge amplifies over the region. High temperatures are forecast to steadily rise over the next few days leading to the possibility for records to be broken. Excessive heat watches, warnings and advisories are in effect for all of the aforementioned areas.

Meanwhile, an elongated surface front will continue to be the focus for severe weather and flash flooding risk from the Central Plains/Rockies to the Northeast over the next several days. Rounds of convection will impact portions of the Ohio Valley and Lower Great Lakes Sunday night leading to the potential for localized heavy rainfall and severe thunderstorms. 

An Enhanced Risk of severe thunderstorms is in effect for parts of the Lower Great Lakes/interior Northeast for Sunday night as damaging wind gusts and tornadoes threaten the region. The severe weather threat shifts into the Northeast/Mid-Atlantic coast on Monday while the greatest flash flooding risk settles over the Central Appalachians and Middle Mississippi Valley through midweek due to the surface front stalling out.

Elsewhere, impulses of upper-level energy will shoot up into the Southwest from Mexico allowing for monsoonal moisture to flow into the region. This will lead to heavy rain and flash flooding to take place over large swaths of Arizona, the Four Corners, and Colorado over the next couple of days.

Slight Risks of excessive rainfall leading to flash flooding are in effect. Scattered to isolated thunderstorms will also impact those areas during this period.