US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
413 PM EDT Thu Sep 12 2019
 
Valid Sunday September 15 2019 - Thursday September 19 2019
 
Hazards:
- Heavy rain across portions of the Southeast, as well as portions of western Oregon into northern 
California, Sun-Mon, Sep 15-Sep 16.
- Heavy rain across portions of the Carolinas, Tue-Thu, Sep 17-Sep 19.
- Flooding possible across portions of the central Plains, the Great Lakes, the upper Mississippi 
Valley, and the northern Plains.
- Flooding occurring or imminent across portions of the northern Plains.
- Flooding likely across portions of the central Plains, the upper Mississippi Valley, and the 
northern Plains.
- Much above normal temperatures across portions of the central Plains, the Great Lakes, the Upper 
Mississippi Valley, and the northern Plains, Mon-Wed, Sep 16-Sep 18.
- Much below normal temperatures across portions of northern California, the central Great Basin, 
the Pacific Northwest, and the northern Great Basin, Mon-Tue, Sep 16-Sep 17.
- Enhanced wildfire risk across portions of the the central Great Basin, the northern Great Basin, 
and the Southwest, Sun, Sep 15.
- Heavy rain across portions of the southwestern Alaska, Sun-Mon, Sep 15-Sep 16.
- Heavy rain across portions of the Alaska Panhandle and southern Alaska, Thu, Sep 19.
 
Detailed Summary:

Plenty of uncertainty is indicated during the medium range period (Sunday-Thursday) across the 
southeastern U.S. as some of the global models (i.e. ECMWF and UKMET) are now forecasting the 
possibility of a significant tropical cyclone in the vicinity.  This is a major departure from 
earlier forecasts for a weaker tropical system to track across Florida and into the eastern Gulf of 
Mexico before making landfall along the central to eastern Gulf coast.  A wide variety of scenarios 
are depicted amongst the global models.  The GFS continues to keep the earlier scenario of tracking 
a weaker system toward the central Gulf coast.  Meanwhile, the UKMET shows the eastern-most 
solution with the tropical cyclone veering off to the east of North Carolina.  On the other hand, 
the ECMWF tracks the storm dangerously close to the East Coast while the Canadian model stalls the 
storm near the Carolina coasts and gradually transforms it into an extratropical cyclone.  Needless 
to say, the situation is far from certain.  Our coordinated positions of the cyclone with the 
National Hurricane Center basically show the storm stalling near the South Carolina coast by Day 7 
(Thursday).  Therefore, a couple of heavy rain areas are shown for portions of the southeastern 
U.S.  Since the forecast track calls for a slow down of the forward motion of the storm, the 
indicated heavy rain area remains mostly south of Virginia through Day 7 at this point.  

Elsewhere in the U.S., anomalous upper-level ridging is forecast to build across the Great Lakes 
early next week where maximum temperatures anomalies are expected to reach 10 to 20 degrees above 
normal from the central Plains to the Upper Great Lakes from Monday to Wednesday. Minimum 
temperatures could be as much as 25 degrees above normal Tuesday morning, prompting the much above 
normal temperatures area on the hazards map. Actual high temperatures are forecast to range from 
the upper 80s across the central Plains to low 80s across the Upper Great Lakes, with low 
temperatures ranging from the low 60s to low 70s. Meanwhile, a cold front is forecast to cross the 
Great Basin on Monday and will be responsible for an increase in winds and wildfire risk ahead of 
the front on Sunday. Temperatures will drop drastically behind the front and could result in 
scattered frost/freeze for portions of Oregon, Nevada and northern California, where an area of 
much below average temperatures is indicated on the hazards map.  In addition, heavy rain is 
possible in parts of western Oregon and northern California Sunday night into early Monday as the 
associated upper-level trough deepens.

In Alaska, an active and wet pattern is expected during the forecast period. A modest low pressure 
system is forecast to impact the western mainland on Sunday and Monday. Rainfall amounts greater 
than 1 inch will be possible, hence the heavy rain area on the hazards map.  Toward the end of the 
medium-range period, heavy rain is forecast for southern to southeastern Alaska as a moisture-laden 
frontal system pushes onshore.

Kong