US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
500 PM EDT Tue Oct 06 2020
 
Valid Friday October 09 2020 - Tuesday October 13 2020
 
Hazards:
- Heavy precipitation across portions of the northern Idaho, Sun-Tue, Oct 11-Oct 13.
- Heavy precipitation across portions of northwestern Wyoming, Sun-Mon, Oct 11-Oct 12.
- Heavy rain from portions of northern California into the Pacific Northwest mainly west of the 
Cascades, Fri-Tue, Oct 9-Oct 13.
- Heavy rain from eastern Texas to much of the lower Mississippi Valley and the Tennessee Valley, 
as well as the interior Southeast into the southern Appalachians, Fri-Sat, Oct 9-Oct 10.
- Heavy rain across portions of the central and southern Appalachians into the interior 
Mid-Atlantic and interior Southeast, Sun-Mon, Oct 11-Oct 12.
- Flooding occurring or imminent across portions of northeastern Florida.
- High winds across much of the central Gulf Coast into the lower Mississippi Valley, Fri-Sat, Oct 
9-Oct 10.
- Much above normal temperatures across portions of the Great Plains into the nearby central and 
northern Rockies, as well as the upper Midwest, Fri-Sun, Oct 9-Oct 11.
- High significant wave heights for coastal sections of Louisiana, Fri, Oct 9.
- Heavy precipitation for the eastern portion of Kenai Peninsula in southern Alaska, Fri, Oct 9.
 
Detailed Summary:

Hurricane Delta strengthened very rapidly earlier today into an extremely dangerous category-4 
hurricane over the western Caribbean Sea.  The hurricane is forecast to track across the western 
Gulf of Mexico Wednesday and Thursday before turning north toward the Gulf Coast on Friday.  Global 
models indicate that Delta will likely expand in size as it moves across the western Gulf and 
begins to interact with the westerlies.  This will likely lead to an expanded coverage of high 
winds and significant waves away from where the hurricane makes landfall.  Delta is currently 
forecast to make landfall on the Louisiana coast as a major hurricane later on Friday.  It must be 
noted that global models still indicate a trend of nudging the forecast track of Delta farther 
westward with each new run.  Please consult the most up-to-date advisories from the National 
Hurricane Center for the latest forecast information on Hurricane Delta.  After landfall, the 
expanded circulation of Delta is forecast to spread high winds well inland across the lower 
Mississippi Valley on Saturday.  In addition, torrential rain is expected to spread further inland, 
likely into the Tennessee Valley into the southern Appalachians later on Saturday before gradually 
becoming less intense by the time the rain reaches the central Appalachians and interior 
Mid-Atlantic early next week.  By then, Delta should have become post-tropical well inland while an 
extratropical low pressure system could be developing near the Mid-Atlantic coast.
 
Outside of Hurricane Delta, a major change in the synoptic pattern is in store as a deep upper 
trough is forecast to work its way across the western U.S into the Plains during the medium range 
period.  A large dome of cold air will settle across much of the western U.S. behind a strong cold 
front.  This will likely bring a period of mixed precipitation to the higher elevations of 
northwestern Wyoming and northern Idaho Sunday and Monday before tapering off on Tuesday.  There 
could be some meaningful snowfall accumulations at the coldest locations.

Ahead of the cold front however, much above normal temperatures are forecast for much of the Plains 
into the nearby Rockies late this week and through the weekend.  In fact, record high temperatures 
near 90 degrees are possible in the central Plains on Friday, followed by the upper 90s possible 
over the southern Plains on Saturday.  Meanwhile, an active weather pattern behind the strong cold 
front will bring persistent rain, some of which heavy, across the Pacific Northwest from the 
Cascades westward, and down into northern California through the medium range period.

Finally, the synoptic pattern appears to be settling down somewhat during the medium range period.  
However, some heavy precipitation should linger across the eastern portion of Kenai Peninsula on 
Friday.  The latest ECMWF indicate that the associated occluded cyclone may retrograde toward the 
coast on Saturday.  Therefore, the heavy precipitation over Kenai Peninsula could linger into 
Saturday.

Kebede