US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
450 PM EDT Mon Jun 14 2021
 
Valid Thursday June 17 2021 - Monday June 21 2021
 
Hazards:
- Heavy rain across portions of the Southeast, the Southern Appalachians, the Lower Mississippi 
Valley, the Southern Plains, and the Tennessee Valley, Fri-Mon, Jun 18-Jun 21.
- Heavy rain across portions of the Middle Mississippi Valley, the Great Lakes, and the Upper 
Mississippi Valley, Sun, Jun 20.
- Flooding possible across portions of the Southeast and the Tennessee Valley.
- Flooding occurring or imminent across portions of the Southeast, the Lower Mississippi Valley, 
the Southern Plains, and the Tennessee Valley.
- Excessive heat across portions of the Northern/Central Plains, the Great Basin, the 
Northern/Central Rockies, California, the Pacific Northwest, and the Southwest, Thu-Sat, Jun 17-Jun 
19.
- Excessive heat across portions of the Plains, the Central/Southern Rockies, the Central Great 
Basin, the Great Lakes, the Upper/Middle Mississippi Valley, and the Southwest, Thu, Jun 17.
 
Detailed Summary:

A strong upper-level high over the four-corner region and associated upper-level ridging will aid 
in producing much above normal temperatures across a good portion of the western two-thirds of the 
Lower Forty â€Eight States through Saturday. The Hazards Chart has Excessive Heat depicted over 
the same area as the much above normal temperatures to keep consistent with the chart from Friday 
11 June 2021. The area from parts of the Great Lakes westward to the Central Rockies is depicted as 
an area of Excessive Heat on Thursday. However, the heat index is not high enough for the Excessive 
Heat. The temperature will be from the low 100s to the low to mid-90s on Thursday. The low 
temperatures will be in the low 70s to upper 60s.  

There is another area of Excessive Heat from California to the Northern Intermountain Region to the 
Northern Rockies to the Southwest. The heat index will be very high over the Sacramento Valley and 
the San Joaquin Valley through Saturday, with Saturdayâ€s highest values. On Saturday, the 
temperatures in the valley will range from the upper 90s to the middle 100s. The low temperatures 
on Saturday will be in the 70s and 60s. The rest of the area will have much above normal 
temperatures, with high temperatures in the middle and upper 90s. The ongoing drought has 
contributed to the high temperatures with low moisture in the soil.   

On Sunday, a front returning northward as a warm front will help spawn showers and thunderstorms 
over parts of the Middle Mississippi Valley. The Hazards Chart has an area of heavy rain over the 
region on Sunday. 

Meanwhile, tropical development is possible over the Gulf of Mexico, posing a risk of heavy rain 
along the Western and Central Gulf Coast States starting on Friday and creeping farther north every 
day. The largest areal coverage will be on Sunday and Monday, providing the forecast storm follows 
the current track set by the National Hurricane Center. The area of Heavy Rain on the Hazards Chart 
will be adjusted for the future track of the developing tropical cyclone.  With the uncertainty 
with the development of the storm, it will be important to check the latest medium-range forecasts 
when available and the National Hurricane Center.  

No widespread hazardous weather is expected for Alaska during this time frame.

Ziegenfelder