…A heat wave to continue across large sections of the West and portions
of southern Florida…
…Record highs likely to continue over the Pacific Northwest and Northern
Great Basin and develop over portions of southern California…
…Heavy rains and potential flooding along the central Gulf coast into
the Southeast…
..A cool and dry airmass to spread east from the Plains into the East over
the next few days..
A large mid to upper level high centered over the Great Basin and
Southwest will continue to drive a heat wave affecting large portions of
the western U.S. late this week into this weekend. Much above average
temperatures likely from the West coast, east across the Great Basin,
Southwest, Rockies and into the Northern High Plains, with high
temperatures expected to be 10 to 20 degrees above average. This will
support the potential for continued record high temperatures Friday and
Saturday over portions of the Pacific Northwest into the Northern Great
Basin and for record highs to develop over portions of southern California
on Saturday. Excessive heat warning and heat advisories are in effect
much of Washington State, Oregon, California, far southern Nevada and into
southwest Arizona. Heat will also persist over the next few days across
South and Southwest Florida where heat advisories are also in effect.
While high temperatures across South and Southwest Florida are not
expected to be as anomalous as across large portions of the West, the
higher humidity (dew points) will produce dangerous heat indices up to 112
degrees. There are approximately 66 million people under a heat warning
and advisories across the West and South and Southwest Florida. In
addition to the heat impacts across the West, the dry conditions, low
relative humidities will also support fire weather conditions from the
Pacific Northwest into California.
Wet weather will persist over the next several days in the vicinity of a
stationary frontal boundary that is expected to remain in place just to
the south of the Gulf Coast and across North Florida. Moisture values are
expected to remain anomalously high along the Gulf coast into portions of
the Southeast and Florida. Waves of heavy rain are likely in this
anomalous moisture axis along and near the stationary frontal boundary
from late this week, through this weekend and into next week. The
potential for several rounds of heavy rains affecting the same general
regions will increase the risk of flash and river flooding. Currently
flood watches are in effect across the Upper Texas coast, eastward across
southern Louisiana and into far southern Mississippi where rainfall totals
of 5 to 10 inches are possible over the next few days.
The only other area of rainfall potential over the next few days across
the Lower 48 will be associated with a quick moving cold front that will
push eastward tonight from the Great Lakes, into the Ohio Valley Friday
and across the Northeast/New England Saturday and Sunday. Showers and
thunderstorms are possible along and ahead of this front, but the fast
movement of the front should keep precip totals from being very heavy.
This front will also be spreading southward tonight from the Mid
Mississippi Valley into the Central to Southern Plains and into the Lower
Mississippi Valley and Tennessee Valley on Saturday. Less favorable
conditions for rainfall expected along these portions of the front
compared to areas of the Northeast and New England, with only light precip
values expected. In the wake of this cold front, below average
temperatures and dry conditions likely from the Plains eastward into the
East, producing early fall like conditions across these areas.
Oravec
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
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