US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
443 PM EDT Fri Sep 03 2021
 
Valid Monday September 06 2021 - Friday September 10 2021
 
Hazards:
- Flooding possible across portions of the Northeast.
- Flooding occurring or imminent across portions of the the Lower Mississippi Valley and the 
Mid-Atlantic.
- Flooding likely across portions of the Upper Mississippi Valley.
 
Detailed Summary: 

The medium range forecast period (Monday, Sep 6 to Friday, Sep 10) may feature some instances of 
heavy rain, particularly later in the period as a potential tropical system develops in the Gulf of 
Mexico, but no hazards outlook areas have been introduced at this time. Additionally, while there 
are not included outlook areas for heavy rain, flooding will remain an ongoing threat in the 
northern Mid-Atlantic due to recent heavy rainfall from the remnants of Ida. 

At the beginning of the period, showers and storms are forecast to develop along a cold front 
moving southward through the eastern and central U.S., with the western portion across the Southern 
Plains and Lower Mississippi Valley expected to slow and remain relatively stationary on Monday 
(Sep 6th). Instances of heavy rain may be possible from the Lower Mississippi Valley into the 
Southern Plains. However, there is not enough consistency amongst the model guidance on the 
location of any widespread, hazardous rainfall. 

Further into the period, a deepening upper-level trough will develop over the Midwest and move 
eastward. At the surface, a low pressure system will move from the Great Lakes on Tuesday (Sep 7th) 
east to New England on Wednesday (Sep 8th). Widespread showers and storms will likely develop along 
an associated eastwardly moving cold front, but the generally fast progression of storms suggests 
instances of heavier rainfall totals should remain isolated. 

Finally, showers and storms are likely to increase along the Gulf Coast beginning as early as 
Tuesday. This will be the result of the potential for one or more tropical waves moving through the 
Gulf of Mexico in addition to the cold front from the system over the Northeast pushing southward. 
However, there is a great deal of uncertainty in the evolution of the pattern across the area. One 
wave moving north from the Bay of Campeche may develop into a tropical system, and a secondary 
closed low may also develop to its east. The track of either potential area of low pressure is also 
uncertain. For these reasons, an outlook area for heavy rainfall will not be introduced at this 
time. However, it is likely one or more will be needed once there is more confidence in the track 
and evolution of the waves and potential tropical system, as well as their interaction with the 
cold front to the north. 

In Alaska, the potential for heavy rain and high winds is anticipated as two systems impact the 
state. Showers will increase across the southeastern Panhandle on Tuesday as an occluding low 
pressure system approaches from the Gulf of Alaska. High winds are also possible across the 
Panhandle with this system. On Thursday (Sep 9th), a second occluding system is expected to 
approach the mainland Southwest from the Bering Sea. Potentially heavy rainfall is forecast along 
the southern Alaskan Peninsula, the southern Kenai Peninsula, and Kodiak Island. However, given the 
region is entering the rainy season, opted not to highlight any outlook areas as the impacts from 
both systems are not expected to be particularly hazardous. In addition to the rain threat, high 
winds are also possible across the Aleutians, Bristol Bay, and further north along the coastal 
Southwest to Norton Sound as the Bering Sea system progresses eastward on Thursday and Friday (Sep 
10). However, given uncertainty in the track of the system, have opted not to highlight an area 
here for now either, but this will be reassessed in the coming days. 
 
Putnam