US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
401 PM EDT Mon Sep 07 2020
 
Valid Thursday September 10 2020 - Monday September 14 2020
 
Hazards:
- Heavy rain across portions of the Central Plains, and the Upper/Middle Mississippi Valley, Fri, 
Sep 11.
- Heavy rain across portions of the Mid-Atlantic, the Northeast, and the Great Lakes, Sun, Sep 13.
- Flooding occurring or imminent across portions of the Lower Mississippi Valley.
- Much above normal temperatures across portions of California, the Great Basin, the Pacific 
Northwest, and the Northern Rockies, Thu-Mon, Sep 10-Sep 14.
- Much below normal temperatures across portions of the Plains, the Rockies, the Great Basin, the 
Great Lakes, the Upper/Middle Mississippi Valley, and the Southwest, Thu-Fri, Sep 10-Sep 11.
- Heavy rain across portions of the Alaska Panhandle, mainland Alaska, and the Aleutians, Sun-Mon, 
Sep 13-Sep 14.
- High winds across portions of mainland Alaska and the Aleutians, Sun-Mon, Sep 13-Sep 14.
 
Detailed Summary:

Upper-level ridge just offshore of the West Coast will continue form Thursday into Monday when an 
upper-level low moves close to the Northwest on Monday.  The near by upper-level ridge will allow 
temperatures to become 12 degrees or higher over the Pacific Northwest from Thursday into Monday.  
In Contrast, a deep upper-level low over the Four Corners Region will allow temperatures to become 
12 degrees below normal or greater over most of the Rockies and Plains on Thursday.  On Friday the 
temperatures will begin to moderate leaving the Northern/Central Rockies/Plains below normal.  The 
temperatures will continue to moderate on Saturday through Monday.  

A developing front over the Plains on Friday into Saturday will be the focus for heavy rain to 
develop over Iowa on Friday.  The rain will be one inch or greater which meets the criteria for 
depicting and area of heavy rain over the region on Friday.   As the front moves eastward an area 
of heavy rain will develop over parts of the Northeast and Mid-Atlantic on Sunday.  

For Alaska, deep low pressure over the North Pacific will deep more  as the storm moves over the 
Aleutian Islands and the Alaska Peninsula on Monday.  The deep low will produce an area of high 
wind over parts of the Aleutian Islands and the Alaska Peninsula on Sunday and Monday.  In 
addition, a plume of moisture associated with the storm will move into parts of the the Aleutian 
Island and the Alaska Peninsula on Sunday and into the Gulf of Alaska Coast on Monday.  The system 
will produce an area of heavy rain from parts of the Alaska Peninsula and the Southwestern mainland 
that will expanse into the Gulf of Alaska Coast on Monday.   


Ziegenfelder