…A Slight Risk of excessive rainfall tonight over the southern
Appalachians and interior Southeast through tonight, shifting into the
northern Mid-Atlantic on Sunday…
…A Slight Risk of severe thunderstorms over parts of the
Central/Southern Plains tonight, over the interior Pacific Northwest and
upper Ohio Valley on Saturday, and across the Southeast and Carolinas on
Sunday…
…Excessive Heat Warnings and Heat Advisories are in effect across the
central/southern Plains into the lower Mississippi/Tennessee Valleys…
The prevailing weather pattern across mainland U.S. will continue to favor
precipitation and cooler than normal temperatures across the northeastern
quadrant of the country while heat will continue in portions of the
interior western U.S. and especially over the southern Plains. A low
pressure system currently centered over the upper Midwest is forecast to
progress slowly but steadily through the Great Lakes for the next couple
of days. This system will be responsible for bringing considerable clouds
along with widespread modest rainfall with embedded thunderstorms across
the Great Lakes reaching into New England by Sunday. The chance of heavy
rainfall will be greater farther to the south in the warm sector across
the southern Appalachians into the interior Southeast through tonight as
clusters of thunderstorms develop ahead of the trailing cold front. Some
of these thunderstorms could become severe across the upper Ohio Valley on
Saturday. By Sunday, the front will progress into the East Coast states
with heavy rain possible over the northern Mid-Atlantic where a low
pressure wave is forecast to form. Farther south ahead of the cold front,
thunderstorms could become severe across the Southeast and into the
Carolinas on Sunday.
Over the western U.S., monsoonal moisture combining with daytime heating
will trigger showers and thunderstorms over parts of the Southwest,
eastern Great Basin, and into the southern Rockies from late afternoon
into late evening during the weekend. An upper-level trough moving
onshore over the Pacific Northwest is forecast to trigger thunderstorms
which could turn severe over the interior sections on Saturday.
Meanwhile, upper-level ridging over parts of the southern Plains and lower
Mississippi Valley will support high temperatures in the upper-90s to
low-100s with dew points in the low to mid-70s across the region. This
level of heat and humidity has prompted Excessive Heat Warnings and Heat
Advisories over parts of the central/southern Plains and across the lower
Mississippi into the Tennessee Valleys. This prolonged stretch of high
temperatures in the upper 90s and triple digits will persist through the
weekend. Low temperatures around 80 degrees are also forecast along the
Gulf Coast with daily maximum heat indices nearing 110F farther inland up
the lower Mississippi Valley. Please practice heat safety if you need to
spend time outdoors or in a building without air conditioning.
Kong/Ziegenfelder
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
