…Atmospheric river to produce heavy rain/snow across much of the
Northwest…
…Severe Thunderstorm outbreak and Excessive Rainfall potential from the
South to the Northeast…
… Heavy Mountain West Snow Possible …
…Above average temperatures across the South and East…
The wet Pacific Northwest will continue this weekend as another low
pressure system moves through the region. Some heavier rainfall is likely
overnight and into Sunday day with this surge in moisture across northern
California and southern Oregon. A Slight Risk for Excessive Rainfall is in
effect for Saturday and Sunday to account for the possibility of flooding.
In addition to the flooding threat, there are surf hazards, wind hazards
(power outages are possible with gusts near 60 mph), and there is a river
flooding threat beyond this weekend as some rivers crest pass its
capacity. However, there is hope on the way; a cold front is expected to
clear the area. High temperatures will drop behind the front into the 40s
and most of the heavy rainfall potential should subside, but a few
lingering showers remain possible with moisture still streaming in from
the Pacific.
A major severe weather event is unfolding across the South this afternoon.
A line of thunderstorms is moving across the region with strong gusty
winds and large hail. Additionally, discrete supercells are forming ahead
of the main convective line with possible tornadoes. The conditions are
highly favorable for severe weather and the Storm Prediction Center has
issued a Moderate Risk (level 4/5). The severe weather threat should
continue across the Southeast on Sunday in the form of a combination of
discrete supercells and a linear line of storms called a QLCS
(Quasi-Linear Convective System). Damaging wind gusts, large hail, and
tornadoes will be most likely from north Florida to the Carolinas. The
Ohio Valley may also see strong wind gusts in thunderstorms that develop
as a surface low deepens and moves over the region. A flooding threat will
also ensue with the severe weather threat in the South and Ohio Valley.
For the remainder of today, a Slight Risk for Excessive Rainfall is active
across much of the South. Training thunderstorms may dump 3-6 inches in
the heaviest spots. On Sunday, there is a Marginal Risk for Excessive
Rainfall for the Appalachains as a shield of rain moves northward with the
low pressure and gets enhanced lift with upslope flow along the terrain.
The last big weather story will be the heavy snow in the Mountain West. In
the next 3 days, the northern Rockies and the Cascades may see 1-2 feet of
snow accumulations as moisture from the Pacific continues to funnel into
the region. The snowfall will be enhanced by a stationary boundary draped
across the area and followed by a cold front passage on Sunday. Blowing
and drifting snow may be possible as winds near 40 mph and a few Winter
Storm Warnings are active.
Elsewhere across the rest of the country, the Southwest, South-Central,
and East Coast will be more than seasonably warm as all these regions may
see temperatures more than 20 degrees above average. The desert Southwest
will see highs in the middle 70s, central Texas may approach 90 and
threaten record daily highs, and the east sees highs in the 60s and 70s.
Wilder
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php