US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
304 PM EDT Thu Sep 19 2019
 
Valid Sunday September 22 2019 - Thursday September 26 2019
 
Hazards:
- Heavy rain from portions of the Central Plains to the Midwest, Sun, Sep 22.
- Heavy rain across portions of the Southwest, Mon-Tue, Sep 23-Sep 24.
- Flooding possible across portions of the Southern Plains, the Upper Mississippi Valley, and the 
Northern Plains.
- Flooding occurring or imminent across portions of the Northern Plains and the Upper Mississippi 
Valley.
- Flooding likely across portions of the Central Plains, the Middle Mississippi Valley, and the 
Southern Plains.
- Heavy rain across portions of the Alaska Panhandle, Mon-Tue, Sep 23-Sep 24.
 
Detailed Summary:

The medium range period (Sunday to Thursday) features two main heavy rainfall threats in the CONUS. 
The first, associated with lingering moisture from what is currently tropical depression Imelda in 
Southeast Texas will likely interact with a frontal boundary as it drops into the Midwest this 
weekend. Though this event will begin at the end of the short range period (Saturday), heavy to 
locally excessive rainfall should continue into Sunday from eastern Kansas to Indiana/southern 
Michigan. Early next week, the boundary may briefly become stationary across parts of the Central 
Plains while a deep upper level low lingers over the Southwest. At this point, models have trended 
toward keeping the upper low across the Southwest by day 7 (Thursday) which should limit any 
potential heavy rainfall across the Central Plains mid to late next week. This prompted the removal 
of a heavy rainfall area from yesterday's chart across eastern Kansas/Oklahoma/western Missouri but 
this will need to continue to be monitored.

The second threat across the Southwest, there are some indications that moisture from Tropical 
Storm Lorena may reach portions of the area and interact with a closed upper level low across 
southern California early next week. There continues to be enough agreement in the guidance to 
warrant a heavy rainfall area today across portions of Arizona. Some uncertainty remains with exact 
rainfall totals and the extent of the heavy rain area, but heavy rainfall at least appears to be a 
threat given the synoptic setup.

An active pattern is expected in Alaska as well during the medium range period as a deep surface 
low moves over/just south of the Aleutians and into the Gulf by Monday. This will likely bring a 
round of potentially heavy rainfall to much of the Alaskan Panhandle Monday-Tuesday, Sep 23 and 24. 
This low may also bring a round of enhanced precipitation to parts of the eastern Aleutians on 
Sunday, though amounts appear to be marginal for a heavy rain area on the hazards chart.

Santorelli