US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
411 PM EDT Thu Apr 16 2020
 
Valid Sunday April 19 2020 - Thursday April 23 2020
 
Hazards:
- Heavy rain across portions of the Central Plains, the Middle Mississippi Valley, the Lower 
Mississippi Valley, and the Southern Plains, Tue-Wed, Apr 21-Apr 22.
- Heavy rain across portions of the Lower Mississippi Valley, the Central Appalachians, the 
Tennessee Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, the Southern Plains, 
and the Ohio Valley, Wed-Thu, Apr 22-Apr 23.
- Heavy rain across portions of the Southeast, the Mid-Atlantic, the Lower Mississippi Valley, the 
Southern Appalachians, and the Tennessee Valley, Sun-Mon, Apr 19-Apr 20.
- Severe weather across portions of the Lower Mississippi Valley, the Tennessee Valley, the 
Mid-Atlantic, the Southern Appalachians, the Southeast, and the Southern Plains, Sun, Apr 19.
- Flooding occurring or imminent across portions of the Middle Mississippi Valley, the Lower 
Mississippi Valley, the Southern Appalachians, the Upper Mississippi Valley, and the Northern 
Plains.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Mon-Wed, Apr 
20-Apr 22.
- Heavy precipitation across portions of mainland Alaska, Sun, Apr 19.
- Much above normal temperatures across portions of mainland Alaska, Sun-Mon, Apr 19-Apr 20.
 
Detailed Summary:

The medium-range period will be highlighted by a split flow pattern featuring an active branch of 
the subtropical jet as well as an upper level ridge anchored over the west coast of Canada and a 
deep upper trough over eastern Canada. This pattern generally favors cooler temperatures in the 
northeastern quarter of the Lower 48 while the West Coast is seasonably mild. Precipitation wise, 
the most active weather looks to be in the South as a pair of southwestern U.S. upper level 
disturbances traverse the southern states. The first cut-off upper low will track into Southern 
California on Friday then into the Southern Plains by Saturday. This disturbance will be 
responsible for generating additional showers and thunderstorms throughout the Southern Plains and 
Deep South this weekend. Guidance is coming into better agreement on the area most at risk for 
heavy rain extends from northern Louisiana on east to the Carolina coast. These areas also have 
overly saturated soil and have recently felt impacts from heavy rainfall and severe storms, leading 
to additional concerns for flooding. Meanwhile, the atmospheric setup is favorable for severe 
weather across the Deep South on Sunday which has led the Storm Prediction Center to issue an 
enhanced risk on Sunday.

To add insult to injury, a second upper-level trough is forecast to move from the Southwest to the 
South Central U.S. in forecast days 6-7. While there is still uncertainty as to where the heaviest 
precipitation occurs, the signal for heavy rainfall Lower Mississippi Valley and Southeast is 
present with upper level troughing in the Southwest and high pressure positioned off the Southeast 
coast. This should lead to yet another chance for flooding and severe weather over portions of the 
Gulf Coast states that have been drenched by storm systems in recent weeks. There is also the 
chance for heavy precipitation to work its way up the East Coast late next week, but confidence in 
totals and timing are low at this time.

Over Alaska, above average temperatures are expected to persist through much of the period, 
particularly observed minimum temperatures. The highest anomalies are forecast throughout the 
north-central section of the state but western and eastern regions can also anticipate abnormally 
warm conditions. Additionally, the jet stream pattern favors southerly flow with rich Pacific 
moisture advection over much of the mainland. The result is the chance for heavy precipitation, 
lower elevation rain and mountain snow, in the west-central portions of the state this weekend. As 
this round of precipitation exits, an upper trough swinging south of the Aleutians next week will 
send high contents of atmospheric moisture into the Panhandle. Latest model guidance is trending 
slower with the upper trough, however, which could allow more ridging to transpire over the 
Panhandle and help to reduce precipitation totals. This makes the heavy precipitation area in 
southeast Alaska and the Panhandle tricky. Th threat area will remain in place for now but will be 
re-evaluated tomorrow should it need to be dropped from the forecast. 

Mullinax