US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
314 PM EST Tue Mar 03 2020
 
Valid Friday March 06 2020 - Tuesday March 10 2020
 
Hazards:
- Heavy precipitation across the upper Great Lakes and upper Michigan, Mon, Mar 9.
- Heavy rain across portions of the lower Mississippi Valley, Sun-Mon, Mar 8-Mar 9.
- Heavy rain across portions of the lower Mississippi Valley into the Tennessee Valley, Tue, Mar 10.
- Heavy snow across portions of the northern Rockies near the Canadian border, Sat, Mar 7.
- Heavy snow in the vicinity of Yellowstone National Park, Sun, Mar 8.
- Flooding possible across the eastern portions of the lower Mississippi Valley, the northern 
Plains, the Tennessee Valley, the Southern Appalachians, and much of the Southeast.
- Flooding occurring or imminent across portions of the Southeast as well as the lower to middle 
Mississippi Valley.
- Flooding likely across portions of the northern Plains.
- High winds across southeastern Massachusetts, Fri-Sat, Mar 6-Mar 7.
- Heavy precipitation across portions of the Alaska Panhandle to the coast sections of southern 
Alaska, Sun-Tue, Mar 8-Mar 10.
- Heavy snow across portions of southern Alaska, Sun-Mon, Mar 8-Mar 9.
- Much below normal temperatures across portions of eastern mainland Alaska, Fri-Sat, Mar 6-Mar 7.
- Much below normal temperatures across portions of western mainland Alaska, Mon-Tue, Mar 9-Mar 10.
 
Detailed Summary:

The prevailing synoptic split flow pattern across the U.S. is forecast to persist through the 
medium range period.  Beginning on Friday, an upper-level trough from the northern stream is 
expected to dip slightly toward and interact with a southern stream trough to result in rapid 
cyclogenesis just off the East Coast.  Models have shown a gradual westward trend on the placement 
of low pressure center for the past few days, allowing an increasing chance of wintry precipitation 
to affect the Northeast Friday night into early Saturday.  However, the latest model outputs 
indicate a slightly more offshore storm track.  As uncertainty remains high with the storm track, 
no areas of heavy wintry precipitation are indicated on the WPC Hazards chart for New England.  
Regardless, the pressure gradient with this low should be strong enough to cause the potential for 
high winds to affect southeastern Massachusetts Friday night into early Saturday.

Behind the departing storm, a cold high pressure system will bring below normal temperatures across 
the eastern U.S. and down into the Deep South through much of the weekend.  However, the persistent 
split flow pattern will appear to re-establish itself as the center of the high pressure system 
reaches the East Coast on Sunday.  Much warmer than normal temperatures are expected to overspread 
the northern Plains during the weekend ahead of a cold front.  Temperatures as much as 30 degrees 
above average will lead to snow melt to commence across the northern Plains into the upper Midwest. 
 In addition, the warmth will accompany with dryness.  This will exacerbate the lack of 
precipitation situation over parts of the northern Plains.

Behind the high pressure system, the split flow pattern will once again lead to moisture from the 
northern and southern stream to merge over the southern to central Plains.  The best chance for 
heavy rain appears to be over the lower Mississippi Valley from Sunday to Monday, shifting a bit 
more to the northeast by Tuesday.  Farther north, a low pressure system should be tracking eastward 
across the lower Great Lakes.  It appears that wintry precipitation is likely across the upper 
Midwest into the upper Great Lakes next Monday into Tuesday.  The precipitation could be heavy in 
these areas depending on the strength of the low.  Farther upstream, the persistent west-northwest 
upper flow arriving from the Pacific Northwest will bring a chance of heavy snow into the northern 
Rockies near the Canadian border on Saturday, moving into the vicinity of Yellowstone National Park 
on Sunday.

Over Alaska, below normal temperatures should moderate from west to east through the end of the 
week as troughing relaxes.  However, another cold upper trough will appear to bring the next 
episode of well-below normal temperatures into the western part of the state for early next week.  
Near the coast, frequent arrival of occluded cyclones will keep a good chance of heavy rain/snow 
along the southern coast of Alaska into the Alaska Panhandle from Sunday onward into early next 
week.  Meanwhile, snow is expected to be heavy along the mountainous terrain of southern Alaska 
during the period.

Kong