…There is a High Risk of excessive rainfall over parts of the
Middle/Lower Mississippi Valley and the Ohio/Tennessee Valleys on
Saturday; there is a Slight Risk of excessive rainfall over parts of the
Ohio/Tennessee Valleys, Southern Appalachians, and the Southeast on
Sunday…
…There is a Moderate Risk of severe thunderstorms over parts of the
Lower Mississippi Valley and Tennessee Valley on Saturday; there is a
Slight Risk of severe thunderstorms over parts of the Southern
Appalachians and Central Gulf Coast/Southeast on Sunday…
…Light snow over parts of the Northeast on Saturday; Freezing rain over
parts of Northern New England on Saturday; light to moderate snow over the
Upper Great Lakes and light snow over the Northeast on Sunday…
On Saturday, a front extending from the Lower Great Lakes to the lower
Mississippi Valley/Western Gulf Coast will move eastward, with the
northern portion of the front moving off the Northeast/ northern
Mid-Atlantic Coast by Monday evening while the southern half lingers over
the southern Mid-Atlantic/Southeast. Moisture flowing northward out of the
Gulf of America will intersect the boundary, producing life-threatening
rain over parts of the Middle/Lower Mississippi Valley and the
Ohio/Tennessee Valleys. Therefore, the WPC has issued a High Risk (level
4/4) of excessive rainfall over parts of the Middle/Lower Mississippi
Valley and the Ohio/Tennessee Valleys through Sunday morning. Severe,
widespread flash flooding is expected. In addition, areas that normally do
not experience flash flooding will flood. Furthermore, lives and property
are in great danger.
Moreover, showers and severe thunderstorms will develop along and ahead of
the front from parts of the Ohio Valley to the Lower Mississippi
Valley/Western Gulf Coast. Therefore, the SPC has issued a Moderate Risk
(level 4/5) of severe thunderstorms over parts of Lower Mississippi Valley
and Tennessee Valley through Sunday morning. The hazards associated with
these thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a few tornadoes. Additionally, there is an added threat
of EF2 to EF5 tornadoes and hail two inches or greater over parts of the
Tennessee Valley and Lower Mississippi Valley, and severe thunderstorm
wind gusts of 65 knots or greater over parts of the region.
On Sunday, as the front moves eastward, the area of heavy rain moves
eastward to the Ohio/Tennessee Valleys, Southern Appalachians, and the
Southeast. Therefore, the WPC has issued a Slight Risk (level 2/4) over
parts of the Ohio/Tennessee Valleys, Southern Appalachians, and the
Southeast from Sunday into Monday morning. The associated heavy rain will
create mainly localized areas of flash flooding, with urban areas, roads,
small streams, and low-lying areas the most vulnerable.
Likewise, the threat of severe thunderstorms moves eastward and reduces
slightly over parts of the Southern Appalachians and Central Gulf
Coast/Southeast on Sunday. Therefore, the SPC has issued a Slight Risk
(level 2/5) of severe thunderstorms over the Northern/Central Plains and
the Upper/Middle Mississippi Valley from Sunday through Monday morning.
The hazards associated with these thunderstorms are frequent lightning,
severe thunderstorm wind gusts, a few tornadoes, and a minimal threat of
hail.
On Monday, the threat of severe thunderstorms and excessive rainfall will
be a minimal risk over parts of the southern Mid-Atlantic and Southeast.
Moreover, showers and thunderstorms will develop over parts of the
northern Mid-Atlantic to Southern New England on Saturday, with rain over
parts of the Northeast. Snow will develop over parts of Northern New
England. Along the rain-snow line, rain/freezing rain areas will develop,
producing ice accumulation of up to 0.10 inches from late Saturday
afternoon into Sunday morning. Further, light rain and snow will develop
over parts of the Southern Plains on Saturday.
Meanwhile, on Saturday, another developing front over Central Canada will
move southeastward to the Lower Great Lakes, the Lower Mississippi
Valley/Southern Plans, and then northwestward to the Northern Rockies by
Monday evening. The system will produce light to moderate snow over the
Upper Great Lakes and, to a lesser extent, the Upper Mississippi Valley
starting early Sunday morning through Monday evening. Light snow will also
develop over parts of the Lower Great Lakes/Northeast, starting overnight
on Sundays and going into Monday evenings.
Furthermore, a third front will move onshore over the Pacific Northwest on
Sunday, advancing inland to the Northern Intermountain Region and then
dissipating by Monday. However, a fourth front will move onshore over the
Pacific Northwest on Monday into Monday afternoon. The systems will
produce light rain over the Northwest Coast early Sunday morning into
Sunday afternoon. As the front moves inland, the rain will move farther
inland into the Northwest and start over Northern California by late
Sunday afternoon. As the boundary moves farther inland, the rain moves
into the Northern Intermountain Region, and light snow will develop at the
highest elevations of the Cascades.
Ziegenfelder
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
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