…Heavy rain and severe weather chances will spread from the Plains to
East Coast to start the holiday weekend…
…Multiple days of heavy rain may cause flash flooding for portions of
the Louisiana and Texas Gulf Coasts…
…Well above normal temperatures forecast in the northwestern U.S. this
weekend…
Two frontal systems are forecast to move south across the central and
eastern U.S. over the holiday weekend, bringing widespread showers and
thunderstorms from the central and southern Plains through the Mississippi
Valley to the East Coast. Severe thunderstorms will be possible in the
warm sector ahead of the leading cold front where there will be ample
moisture and instability. The Storm Prediction Center has issued a Slight
Risk of severe thunderstorms (level 2/5) for eastern Michigan today and
for portions of the Northeast, Mid-Atlantic, and central Appalachians
Saturday. Damaging wind gusts will be the main severe thunderstorm threat.
Additionally, showers and storms will be capable of producing locally
heavy rainfall that could lead to isolated instances of flash flooding
from the southern Plains to the Northeast. The leading front is forecast
to stall across the South and Southeast later this weekend, producing
widespread showers and storms through Labor Day. The second cold frontal
passage will be mostly dry with the exception of some light showers near
the Great Lakes and Northeast Saturday and Sunday, respectively. The
second front is forecast to slow down as it approaches the stalled front
across the southern tier.
Along the Gulf Coast, an area of low pressure will linger just offshore of
Texas and Louisiana. This system will continue to bring a concentrated
area of heavy rain and thunderstorms to portions of the Louisiana and
upper Texas Gulf Coasts through the weekend. High rain rates and repeating
rounds of storms may lead to scattered instances of flash flooding,
especially in urban and flood prone areas. This area has been highlighted
with a Slight Risk of Excessive Rainfall (level 2/4) for today and
Saturday. Daily thunderstorm chances will also exist over portions of the
Florida Peninsula.
Temperatures across much of the East will generally be cooling down as
precipitation chances increase ahead of the approaching frontal systems,
which will bring an end to the period of record setting heat that impacted
the region this week. The central U.S. will see temperatures fall below
normal this weekend in the wake of the cold fronts. Highs in the southern
Plains will stay in the 80s and lower 90s. Highs in the northern/central
Plains will drop from the 80s to near 90 degrees on Saturday to the 70s on
Sunday. In the West, temperatures will be heating up in the Northwest as
an upper level ridge builds overhead. High temperatures are forecast to be
10-20 degrees above normal, reaching the mid-to-upper 90s to near 100
degrees in some areas. Heat Advisories have been issued for much of
eastern Washington and Oregon and northern Idaho. Those with outdoor plans
for Labor Day weekend should be sure to take frequent breaks from the heat
in the shade and stay hydrated. Elsewhere in the West, temperatures will
generally be near or just above average.
Dolan
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
