Scattered/isolated Showers Western Washington and Northwest Oregon
Scattered/isolated rain showers will be possible across western Washington and far northwest Oregon today and into this evening. Mostly dry conditions are expected elsewhere.
GENERAL OVERVIEW: AN ACTIVE WEATHER PATTERN UNFOLDS ACROSS MUCH OF THE UNITED STATES OVER THE NEXT SEVERAL DAYS. A FRONTAL SYSTEM TRACKING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST WILL BRING THUNDERSTORMS AND RAIN TO PORTIONS OF THE CENTRAL AND EASTERN REGIONS EARLY IN THE PERIOD, WITH HEAVY RAIN AND FLASH FLOODING CONCERNS FOCUSED ON THE UPPER MIDWEST AND PORTIONS OF THE NORTHEAST AND MID-ATLANTIC. SEVERE THUNDERSTORMS WILL ALSO BE POSSIBLE IN THE UPPER MIDWEST ON DAY 2. MEANWHILE, WIDESPREAD THUNDERSTORM ACTIVITY WILL PERSIST ACROSS THE SOUTHEAST AND GULF COAST THROUGH MUCH OF THE PERIOD. CRITICAL FIRE WEATHER CONDITIONS ARE A CONCERN ACROSS PORTIONS OF THE NORTHERN ROCKIES EARLY IN THE FORECAST. THE WEST REMAINS RELATIVELY QUIET WITH RESPECT TO PRECIPITATION, THOUGH ISOLATED SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE ACROSS THE DESERT SOUTHWEST. ABOVE-NORMAL TEMPERATURES ARE EXPECTED ACROSS MUCH OF THE WEST THROUGH THE PERIOD, WHILE A BRIEF PERIOD OF BELOW-NORMAL TEMPERATURES AFFECTS PORTIONS OF THE CENTRAL REGION BEFORE TEMPERATURES MODERATE LATER IN THE FORECAST.
EAST:
To start the period, a broad area of rain and thunderstorms is affecting the Southeast, Gulf Coast, and Mid-Atlantic regions, with activity extending northward along the Eastern Seaboard. A low pressure system near the Northeast coast is helping to focus rain and thunderstorm activity across the Mid-Atlantic, New England, and into the Carolinas. Heavy rain and flash flooding are possible across portions of the Mid-Atlantic and Northeast, particularly from the Delmarva Peninsula northward through New Jersey, New York, and into New England. Thunderstorm activity is widespread from the Gulf Coast states northward through the Tennessee and Ohio valleys and into the Mid-Atlantic.
As the period progresses into Monday evening, a cold front pushes through the region, with rain and thunderstorm activity continuing across the Southeast, Gulf Coast, and portions of the Mid-Atlantic. A high pressure system building into the Northeast will help to gradually push the frontal boundary southward. Rain and thunderstorms will persist across the Southeast and Gulf Coast states through Tuesday and into Wednesday, with the activity becoming more focused along and south of a stalled frontal boundary. By Wednesday evening, a broad swath of rain and thunderstorms extends from the central Gulf Coast northward through the Tennessee and Ohio valleys and into the Great Lakes region. Rain activity also continues across the Northeast and Mid-Atlantic. By Thursday, thunderstorm coverage remains extensive across the Southeast, Gulf Coast, and into the Ohio and Tennessee valleys, with rain continuing across the Northeast and Great Lakes.
Temperature Anomalies:
-Days 1-3: Temperatures will be near to slightly above normal across much of the East. A modest above-normal signal is noted across portions of New England and the Northeast.
-Days 4-6: Temperatures trend above normal across the Northeast and New England, with near-normal readings across the Southeast and Ohio Valley.
-Days 7-10: Above-normal temperatures persist across the Northeast and New England. Much of the remainder of the East is near normal.
CENTRAL:
A complex frontal pattern dominates the Central region to start the forecast period. Multiple low pressure centers are tracking across the northern and central Plains, with an associated cold front extending southward. Rain and thunderstorms are occurring across portions of the central and southern Plains, with additional activity noted across the Dakotas and into the northern Plains. Critical fire weather conditions are possible across portions of northern Idaho and western Montana early in the period, where dry and windy conditions are expected.
By Monday evening, a low pressure system over the central Plains continues to organize, with rain and thunderstorm activity spreading across portions of Kansas, Nebraska, and into the Dakotas. A cold front extending from this system will focus precipitation along its leading edge. On Tuesday, severe thunderstorms will be possible across portions of the upper Midwest, particularly over Minnesota and the eastern Dakotas, where a low pressure system is deepening. Heavy rain and flash flooding will also be a concern in this same area. Rain and thunderstorm activity continues across the central and southern Plains through Tuesday and Wednesday, with a persistent low pressure system over the central Plains helping to maintain moisture and lift. By Wednesday evening, rain and thunderstorm activity extends from the southern Plains northward through the central Plains and into the upper Midwest. A low pressure system over the central Plains continues to drive precipitation across the region. By Thursday, thunderstorm activity remains widespread across the central and southern Plains, with a cold front pushing through the region.
Temperature Anomalies:
-Days 1-3: Below-normal temperatures are expected across portions of the central Plains, including Iowa, Missouri, and Illinois, where readings may run several degrees below average. Near-normal conditions prevail across much of the remainder of the Central region, with some above-normal readings across the northern Plains.
-Days 4-6: A notable cold anomaly develops across the northern and central Plains, including the Dakotas, Nebraska, and into Kansas, with temperatures running several degrees below normal. Above-normal temperatures are noted across portions of southern Texas and New Mexico.
-Days 7-10: Below-normal temperatures gradually moderate across the central Plains. Near-normal to slightly above-normal conditions return to much of the region by the end of the period, with modest above-normal readings across portions of the southern Plains and Oklahoma.
WEST:
The West is relatively quiet with respect to organized precipitation systems through much of the forecast period. A low pressure system over southern California early in the period contributes to isolated shower and thunderstorm activity across portions of the Desert Southwest, including Arizona and New Mexico. This activity is tied to the ongoing monsoon pattern, with rain and thunderstorms continuing across the Southwest through the period. Isolated rain and thunderstorm activity is also noted across portions of the northern Rockies and into the Pacific Northwest early in the forecast, associated with a weak frontal boundary. By Tuesday, a low pressure system over the Desert Southwest continues to support scattered thunderstorm activity across Arizona and New Mexico, with additional isolated activity across the Great Basin. The Pacific Northwest and Pacific Coast remain largely dry through the period.
Temperature Anomalies:
-Days 1-3: Above-normal temperatures are widespread across much of the West, including California, Nevada, Utah, Arizona, Colorado, and Wyoming, with anomalies of 6 degrees or more above normal in some areas. A notable exception is portions of the Pacific Northwest, particularly Oregon and Washington, where temperatures are running slightly below normal. Montana also features some above-normal readings early, transitioning to below-normal by Day 3, with temperatures running well below average across much of the state.
-Days 4-6: Above-normal temperatures persist across California, Nevada, Arizona, and the Desert Southwest. A significant cold anomaly develops across the northern Rockies and northern Plains, with temperatures running well below normal across Montana, Wyoming, and the Dakotas. The Pacific Northwest transitions to above-normal readings.
-Days 7-10: Above-normal temperatures continue to dominate across the Intermountain West, Great Basin, Desert Southwest, and Pacific Coast. The cold anomaly across the northern Rockies gradually moderates. Near-normal to slightly above-normal conditions are expected across the Pacific Northwest.
TROPICAL:
In the Atlantic basin, no tropical cyclone activity is expected during the next seven days, and no disturbances are currently being monitored for development.
In the eastern Pacific, Hurricane Genevieve is currently located well to the west of the Hawaiian Islands, tracking as a Category 3 hurricane. The storm is not expected to pose any direct threat to the continental United States or Hawaii at this time.