US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
245 PM EDT Wed Sep 18 2019
 
Valid Saturday September 21 2019 - Wednesday September 25 2019
 
Hazards:
- Heavy rain from portions of the Central Plains to the Midwest, Sat-Sun, Sep 21-Sep 22.
- Heavy rain across portions of the Central Plains and the Middle Mississippi Valley, Mon-Tue, Sep 
23-Sep 24.
- Heavy rain across portions of the Southwest, Sun-Tue, Sep 22-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 Great Lakes.
- Flooding likely across portions of the Central Plains and the Middle Mississippi Valley.
- Heavy rain across portions of the Alaska Panhandle, Sat, Sep 21 and Mon-Tue, Sep 23-Sep 24.
- High winds across portions of southern Alaska, Sat, Sep 21.
 
Detailed Summary:

The medium range period (Saturday to Wednesday) remains fairly active in terms of hazardous weather 
threats. Lingering moisture from what is currently tropical depression Imelda will likely interact 
with a frontal boundary as it drops into the Midwest this weekend with heavy to locally excessive 
rainfall likely from eastern Kansas to Indiana where models continue to indicate the potential for 
48-hour rainfall totals of 2-4+ inches. Early next week, the boundary may briefly stall or try to 
lift northward as a warm front across parts of the Central Plains which could lead to a secondary 
area of heavy rainfall across parts of northeast Oklahoma/eastern Kansas into western Missouri. A 
heavy rainfall area was added to today's hazards chart spanning Monday and Tuesday of next week. 

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 this 
weekend into early next week. There is enough agreement in the guidance to warrant a heavy rainfall 
area today across much of southern Arizona. Some uncertainty remains with exact rainfall totals and 
the extent of the heavy rain area, so modifications to this area may be needed in future updates.

Upper level ridging sliding across the Northeast will bring much above normal temperatures (with 
anomalies 10 to 15 degrees above normal) this weekend, but daily max temps are only forecast to be 
in the low to mid 80s which is likely not necessarily hazardous for this time of the year, so opted 
to leave out a hazard area for today.

An active pattern is expected in Alaska as well during the medium range period as a pair of deep 
surface lows drifts from the Aleutians into the Gulf. This will likely bring a couple of rounds of 
potentially heavy rainfall to much of the Alaskan Panhandle on Saturday, and again Monday-Tuesday. 
There is model signal for 5-day rainfall totals (so a combination of the two events) in excess of 
3-4 inches. The first low in the Gulf of Alaska on Saturday could trigger a period of high winds on 
the backside of the system across the Kodiak Island/Cook Inlet area, and through the higher terrain 
of the northern Aleutian range and southwestern Alaskan range. The second low early next week may 
also bring a round of enhanced precipitation to parts of the eastern Aleutians, though amounts 
appear to be marginal at best and doesn't warrant a heavy rain area at this time for the Aleutians.

Santorelli