US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
334 PM EDT Thu Apr 04 2019
 
Valid Sunday April 07 2019 - Thursday April 11 2019
 
Hazards:
- Heavy precipitation across the higher terrain of California, Oregon, and Washington, Sun-Mon, Apr 
7-Apr 8.
- Heavy precipitation across portions of the Northern Rockies and the Northern Great Basin, 
Sun-Tue, Apr 7-Apr 9.
- Heavy precipitation from portions of the Central Rockies to the Upper Midwest, Tue-Thu, Apr 9-Apr 
11.
- Heavy rain across portions of California and the Pacific Northwest, Sun-Mon, Apr 7-Apr 8.
- Heavy rain across portions of the Lower to Middle Mississippi Valley, Sun, Apr 7.
- Heavy rain across portions of the Southern Appalachians, Mon, Apr 8.
- Flooding possible across portions of the Northern Plains and the Northern Great Basin.
- Flooding occurring or imminent across portions of the Mississippi and Missouri River Basins.
- Flooding likely across portions of the Upper Mississippi Valley and the Northern Plains.
- High winds across portions of the Southwest and the Central and Southern High Plains, Tue-Thu, 
Apr 9-Apr 11.
- High significant wave heights for coastal portions of the Pacific Northwest, Sun, Apr 7.
- Heavy precipitation across portions of mainland Alaska and the Aleutians, Wed-Thu, Apr 10-Apr 11.
- High winds across portions of mainland Alaska and the Aleutians, Wed-Thu, Apr 10-Apr 11.
 
Detailed Summary:

Gulf of Mexico moisture streaming northward ahead of a cold frontal boundary moving across the 
Plains and Mississippi Valley will bring the threat for widespread moderate to heavy rainfall at 
the beginning of the medium range period. The heaviest amounts and most likely area for significant 
rainfall should focus from eastern Texas to the lower and parts of the middle Mississippi Valley on 
Sunday, and the Southern Appalachians on Monday. The front will continue its steady progression 
into the eastern U.S. early next week, and the guidance indicates the potential for heavy rainfall 
extending into parts of the Ohio Valley and the northern Mid-Atlantic states, but given uncertainty 
in both amounts and the frontal progression speed, a heavy rainfall area was not included on todays 
hazards chart. There is also likely to be accumulating snowfall across parts of interior New 
England associated with this system, but does not look significant enough to warrant a heavy snow 
area.

An upper level low entering the Pacific Northwest by the end of this weekend will bring another 
round of heavy rain and higher elevation snows to parts of the Pacific Northwest and Northern 
California Sunday into Monday with a chance for significant waves along the coast as well. Heavy 
precipitation (terrain-enhanced rain and mountain snows) pushes eastward Monday-Tuesday into the 
northern Great Basin and parts of the northern/central Rockies. Models have come into better 
agreement with the development of a potentially deep surface low across the Central Plains by next 
Wednesday which will also enhance precipitation north of the low across the north-central Plains 
and into the Upper Midwest Wednesday and Thursday. There is likely to be a region of heavy snowfall 
across the northern edge of the precipitation shield, but enough uncertainty exists to warrant just 
a broad general heavy precipitation area at this time without delineating between the heavy rain or 
heavy snow areas. It is likely there will be a changeover from snow to rain or vice versa as well 
for some locationshpc.fore. Any rainfall though across this area may exacerbate ongoing flooding 
concerns and should be monitored closely. In addition to precipitation threats, models show better 
agreement on a region of high winds associated with this system from the Four Corners region to the 
central and southern High Plains next Tuesday to Thursday.

In the Southwest, an upper ridge will build early next week, potentially bringing the first 100 
degree temperatures of the season to the Desert Southwest. While this may be 10-15 degrees above 
normal, it does not represent a significant hazard as the air mass is very dry and the warm 
temperatures will be short-lived, lasting just Monday and Tuesday before temperatures cool closer 
to normal on Wednesday.

The majority of Alaska will again remain fairly quiet during the medium range period. The exception 
will be the during the April 10-11 period over the Aleutians northward into St. Lawrence Island, 
the Alaska Peninsula, and sections of the southwest mainland. Here, a strong low pressure system 
developing over the northern Pacific will track into the Bering Sea by the middle of next week, 
bringing the potential for high winds and heavy precipitation.

Santorelli