An upper level low will meander near the southern California coast over the next few days.
Article continues below
The low will pull away from the coast slightly on Thursday, resulting in lower precipitation chances that day, then push back towards the coast on Friday.
This feature is expected to enhance precipitation chances, and there is a Marginal Risk of Excessive Rainfall (level 1/4) for portions of southern California today and Friday.
Isolated flash flooding will be possible, especially near steep terrain and burn scars.
For the eastern two thirds of the US, the main weather feature through Friday will be a cold front that will gradually push southeast towards the East Coast.
The front is currently draped from the Great Lakes region down towards north Texas with the tail end of the front banked up against the Rocky Mountains.
The front is expected to push off the East Coast by Friday morning.
Precipitation associated with the front will be focused ahead of and along the boundary while cooler, drier air funnels in behind the front.
Heavy precipitation out ahead of the front could lead to isolated to scattered areas of flash flooding through tonight across the Central Gulf coast and the Southeast.
The highest threat area will be focused along the Mississippi/Alabama border where the highest moisture resides.
There is a Slight Risk of Excessive Rainfall (level 2/4) along the Mississippi/Alabama border and a Marginal Risk of Excessive Rainfall (level 1/4) across the rest of the Central Gulf Coast and portions of Georgia and South Carolina.
As the front progresses, the heavy rain and flash flood threat will shift northeast.
Thursday and Friday, scattered flash flooding will be possible for portions of the Northeast, and there is a Slight Risk of Excessive Rainfall (level 2/4) for those areas.
The highest threat area will stretch from Pennsylvania to Maine on Thursday, then the highest threat will be in Maine on Friday.
Flooding will be most likely in urban areas and areas with poor drainage, but drains could be clogged by leaves that have fallen and cause flooding in areas that usually have decent drainage as well.
The cooler air funneling in behind the front will result in several days of below normal temperatures for the Central and Eastern US.
The northern Plains have already begun to cool, and that cooler air will spread southeast Thursday and Friday.
Widespread highs in the 40s and 50s will be possible across the Upper Midwest on Thursday, approximately 10-15 degrees below normal for this time of year.
Cooler, drier air will reach the East Coast by Friday as the front pushes offshore.
While the Central and Eastern U.S. cool down, the Pacific Northwest will experience above average temperatures through the end of the week as high pressure builds across the region.
High temperatures are forecast to be in the 70s and 80s across Washington and Oregon, and it will be possible for isolated locations to set daily max temperature records each day.
As drier air continues to move into the Northern and Central Plains, fire weather conditions will be dangerous.
Low relative humidity (15-20 percent) and strong winds (20-25 gusting to 30-35 mph) in this region have promoted the Storm Prediction Center to highlight an area of Critical Fire Weather conditions from North Dakota to Kansas through Thursday.
Rapid wildfire spread will be possible, and those affected should listen to local officials for fire safety information. ■