US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
322 PM EDT Tue Apr 14 2020
 
Valid Friday April 17 2020 - Tuesday April 21 2020
 
Hazards:
- Heavy rain across portions of the Southeast, the Lower Mississippi Valley, the Southern 
Appalachians, and the Tennessee Valley, Sat-Sun, Apr 18-Apr 19.
- Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Northern 
Plains, the Tennessee Valley, the Middle Mississippi Valley, the Mid-Atlantic, the Southern 
Appalachians, the Upper Mississippi Valley, and the Southeast.
- Much below normal temperatures across portions of the Central Plains, the Central Great Basin, 
the Northern Plains, the Northern Rockies, the Central Rockies, the Middle Mississippi Valley, the 
Northern Great Basin, the Upper Mississippi Valley, the Great Lakes, and the Ohio Valley, Fri-Sat, 
Apr 17-Apr 18.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Fri-Sun, Apr 
17-Apr 19.
- High winds across portions of mainland Alaska and the Aleutians, Fri, Apr 17.
- Much above normal temperatures across portions of mainland Alaska, Fri-Mon, Apr 17-Apr 20.
 
Detailed Summary:

A realtively quiet medium-range period will be highlighted by a large upper level trough over 
eastern Canada and extending south into the northeastern quarter of the CONUS. Meanwhile, a 
positive PNA phase will also take shape and help to dispense cooler temperatures into the Plains 
and Great Lakes. In fact, temperatures are forecast to be much below normal from the northern 
Rockies and Plains to the western Great Lakes both Friday and Saturday. Daily lows will fall below 
freezing with some parts of the Rockies and central High Plains seeing lows in the teens. The 
Northeast can also anticipate a generally cool pattern through this strtch but tremperatures will 
not be as appreciably cool as they will be in the Plains. The cooler temperature regime in the 
Heartland will moderate and by early next week, temperatures may rebound to above normal levels.

To the southwest, a cut-off upper low will track into Southern California on Friday then track into 
the Southern Plains by this weekend. This disturbance will be responsible for generating additional 
showers and thunderstorms across the Southern Plains and Deep South. There remains some uncertainty 
in where the heaviest rainfall is likely to occur, but ensemble guidance continues to focus the 
best forcing aloft from northern Louisiana to southern Georgia. For these reasons, a threat area 
for heavy rain remains in the forecast but could shift around in the coming days if the best 
forcing aloft were to change position.

Over Alaska, above average temperatures are expected to persist through much of the period, 
particularly for minimum temperatures. The highest anomalies are forecast throughout the northern 
half of the state. Southerly winds could be marginally high late this week over portions of the 
Aleutians, Alaska Panhandle, and the far western mainland ahead of a surface low to the west. 
Additionally, the jet stream pattern favors southerly flow with rich Pacific moisture advected over 
head. This will favor periods of coastal and valley rains as well as mountain snow this weekend. 
Totals remain subject to change as guidance is split on which areas of southern Alaska are most 
heavily impacted.

Mullinax