US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
452 PM EDT Fri Oct 15 2021
 
Valid Monday October 18 2021 - Friday October 22 2021
 
Hazards:
- Flooding possible across portions of the Southern Plains.
- Flooding occurring or imminent across portions of the Southern Plains.
- Flooding likely across portions of the Southern Plains.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Thu, Oct 
19-Oct 21.
- Heavy precipitation across portions of the Alaska Panhandle, Fri, Oct 22.
- High winds across portions of mainland Alaska, Tue, Oct 19.
- High winds across portions of mainland Alaska and the Aleutians, Wed-Fri, Oct 20-Oct 22.
 
Detailed Summary:

On Monday, a front over the Northern Rockies to the Southwest will advance eastward to the East 
Coast by Friday. Additionally, the system will produce rain over parts of the Pacific 
Northwest/Northern California on Monday, with some light snow at the highest elevations over parts 
of Northern/Central California.  Scattered rain and highest elevation snow develops over parts of 
the Northern Rockies on Tuesday, with the snow at the highest elevations being heavy.  On 
Wednesday, the boundary will intersect moisture flowing northward out of the Western Gulf of 
Mexico, producing scattered showers and thunderstorms over Central/Southern Plains into the Middle 
Mississippi Valley.

Overnight Wednesday, the showers and thunderstorms move into parts of the Ohio Valley/Great Lakes 
while continuing into the Lower Mississippi Valley and Southern Plains.  Overnight Thursday into 
Friday morning, the showers and thunderstorms will taper off near the Appalachians as the front 
moves east.  High moisture over Florida will produce showers and thunderstorms over the southern 
portion of Florida from Wednesday into Friday.  There are no significant hazards forecast over the 
lower 48 states during the forecast period, except for some flooding over the Southern Plains. 
However, WPC will continue to monitor the situation to see if hazards develop. 

Over Alaska, a deep area of low pressure over the Gulf of Alaska moves eastward to near the 
Panhandle by Tuesday and stalling out.  On Monday, a second area of low pressure moving off the 
Asian continent moves across the Bering Sea on Tuesday, impacting parts of the Western Mainland. 
The low merges with the low over the Gulf of Alaska by Wednesday and moves southward over the North 
Pacific.  The lead low will produce heavy precipitation across parts of the Kenai Peninsula to just 
west of Yakutat on Tuesday into Thursday, and then the precipitation will taper off.

Moreover, the heavy precipitation that was forecast to go into the Alaska Peninsula on Monday into 
Wednesday has changed, so the heavy precipitation will not develop over the Peninsula as WPC has 
thought over the last several days.  Currently, the models will develop heavy precipitation over 
parts of the Panhandle to just west of Valdez on Friday. However, on Monday, high wind will develop 
offshore from the Panhandle, but at this time does not look like a hazard. 

The second low moves into parts of the Western Mainland on Tuesday, producing high winds, with the 
wind being higher just offshore over the western part of the Far North.  The second low will also 
interact with an area of high pressure south of the Aleutians over the North Pacific to produce 
high winds over the Aleutians from Wednesday into Friday.

Ziegenfelder