US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
451 PM EDT Thu Jun 25 2020
 
Valid Sunday June 28 2020 - Thursday July 02 2020
 
Hazards:
- Heavy rain across portions of the Northern Plains and the Northern Rockies, Sun-Mon, Jun 28-Jun 
29.
- Heavy rain across portions of the Upper Mississippi Valley and the Northern Plains, Tue, Jun 30.
- Flooding possible across portions of the Upper/Middle Mississippi Valley, and the Great Lakes.
- Flooding occurring or imminent across portions of the Upper/Middle Mississippi Valley, the 
Mid-Atlantic, and the Northern Plains.
- Flooding likely across portions of the Upper/Middle Mississippi Valley.
- High winds across portions of the Central Rockies, the Central Great Basin, California, the 
Northern Great Basin, and the Southwest, Sun, Jun 28.
- Much above normal temperatures across portions of the Northern/Central Plains, and the Upper 
Mississippi Valley, Sun-Mon, Jun 28-Jun 29.
- Much above normal temperatures across portions of the Great Lakes, the Upper Mississippi Valley, 
and the Northern Plains, Tue-Thu, Jun 30-Jul 2.
- Enhanced wildfire risk across portions of the Central Great Basin and the Southwest, Sun, Jun 28.
- Enhanced wildfire risk across portions of the Southern Rockies, the Central Rockies, the Central 
Great Basin, and the Southwest, Mon, Jun 29.
 
Detailed Summary:

A tight pressure gradient between low pressure over the Great Basin and high pressure over the 
Eastern Pacific will aid in producing high wind over parts of the Great Basin on Sunday.  Over the 
Great Basin into the Southwest fire weather conditions are expected to meet the criteria for 
enhanced wildfire risk on Sunday into Monday.  Upper-level wind over the area will increase on 
Sunday and Monday which will result in surface winds of 30-40 mph with stronger gusts. A very dry 
airmass, and fuels will likely support widespread critical fire weather conditions for on Sunday 
into Monday.

In addition, a developing upper-level low will develop over the Pacific Northwest and will move 
inland to the Northern Rockies and slowly lift northward into Western Canada by Tuesday.  The 
upper-level low will draw moisture over the Northern Rockies/Northern High Plains that will produce 
rain with embedded thunderstorms over the region that will meet the criteria for heavy rain on 
Sunday into Monday.  Downstream from the upper-level low upper-level riding will develop over the 
Upper Midwest which will allow temperatures to become 12 degrees above normal over the area that 
meets the criteria for much above normal temperatures also on Sunday into Monday.  On Tuesday, 
another area of showers and thunderstorms will develop over the Northern Plains.  The rain will be 
heavy enough to meet the criteria for heavy rain over the region.  An upper-level high will develop 
over Southern Canada just north of Lake Superior on Tuesday into Thursday.  The upper-level high 
will allow temperatures to become 12 degrees above normal over parts of the Upper Mississippi 
Valley into the Upper Great Lakes on Tuesday into Thursday which will meet the criteria for much 
above normal temperatures over the area.  

Over Alaska, a robust upper-level trough moving eastward from the East Siberian Sea to the 
northwest mainland coast on Sunday.  The system will produce rain over the Baird mountains and the 
southern hills of the Seward Peninsula but the rain will not be heavy enough to meat the criteria 
for heavy rain over the area.  There will be more chances for copious amounts of showers across 
much of the mainland as the upper trough tracks over the state, while simultaneously ushering in a 
fairly chilly air-mass for late June and early July.

Ziegenfelder