…Widespread showers and storms will bring the threat of severe weather
and flash flooding from the Southern Plains eastward through the Middle
Mississippi/Ohio Valleys Monday…
…Another Critical Risk of Fire Weather for the Southern High Plains
Monday…
…Advancing storm system will bring increasing showers and storm chances
to much of the eastern U.S. Tuesday, with another risk of severe weather
in the Ohio/Tennessee Valleys and Mid-Atlantic…
…Unsettled weather in the West, with lower elevation rain and higher
elevation snow, continues Sunday night but will taper off through the day
Monday…
A storm system passing through the central and eastern U.S. will bring the
threat of severe weather and flash flooding as well a risk of fire weather
over the next couple of days. A deep, energetic upper-level trough over
the West will begin to shift eastward over the Plains Sunday night into
Monday. Increased height falls will help to deepen/organize an area of low
pressure in the lee of the Rockies over the Central Plains, with increased
flow helping to reinforce a quasi-stationary frontal boundary extending
eastward through the Middle Mississippi/Ohio Valleys and a dryline
extending southward through the Southern Plains, with a cold front
approaching from the west through the Southern Rockies/High Plains.
Showers and storms will first expand in coverage Sunday night along the
quasi-stationary boundary through the Middle Mississippi Valley eastward
into the Ohio Valley and Mid-Atlantic as moisture advecting northward from
the gulf continues to pool along the boundary. Enough shear will be
present that a few storms may produce some large hail from northern
Missouri eastward through central Illinois/Indiana through Sunday evening,
with a Slight Risk of Severe Weather (level 2/5) in place from the Storm
Prediction Center. An isolated threat for flash flooding will exist here
as well, extending eastward into the Upper Ohio Valley, as heavy rain may
have the tendency to repeat over areas as storms run parallel to the
boundary.
Another day of return flow from the Gulf as well as the arrival of the
upper-level trough from the west on Monday will bring a much broader area
of showers and thunderstorms along the east-west boundary as well as
southward along the dryline through the Central/Southern Plains. Some
supercells are expected to develop along the boundary from southern
Missouri west through southeastern Kansas and southward along the dryline
into central Oklahoma by late afternoon/early evening in the presence of
increasing buoyancy and upper-level shear. The Storm Prediction Center has
issued an Enhanced Risk (level 3/5) of severe weather for the chance of
very large hail as well as damaging winds and a few tornadoes. Some more
isolated storms will be possible further south into northern Texas, with a
Slight Risk in place. A Slight Risk also extends eastward through the Ohio
Valley where some isolated daytime storms and the arrival of storms
growing upscale upstream over the Middle Mississippi Valley/Plains will
bring the threat of damaging winds, as well as large hail and a few
tornadoes. By evening, increasing storm coverage and the potential for
upscale growth into an organized complex of storms, as well as the
tendency for storms to move parallel to the frontal boundary, will lead to
a higher chance of locally heavy rainfall totals and some scattered flash
flooding, with a Slight Risk of Excessive Rainfall (level 2/4) in place.
In addition to the threat of severe weather and flash flooding, very
strong winds upwards of 40 to 50 mph, with gusts as high as 75 mph,
combined with very dry conditions behind the dryline over portions of the
Southern High Plains have prompted another Critical Risk of Fire Weather
(level 2/3) from the Storm Prediction Center Monday.
The system will continue eastward Tuesday, with widespread showers and
thunderstorms expected to redevelop along the quasi-stationary boundary
and ahead of the eastward moving cold front over the Upper Ohio Valley.
The Storm Prediction Center has included another Enhanced Risk of Severe
Weather for the potential of some large hail, damaging winds, and
tornadoes. A more isolated threat extends southwestward ahead of the cold
front into the Tennessee Valley, as well as eastward along the boundary
into the Mid-Atlantic, with Slight Risks in place. An isolated threat for
some flash flooding will exist Tuesday afternoon and evening from the
Ohio/Tennessee Valleys eastward into the Appalachians and Mid-Atlantic,
though the increasing storm speed as the cold front sweeps eastward should
keep rainfall totals lower than on Monday. Light to moderate showers will
expand further northward into the Great Lakes and Interior Northeast
throughout the day Tuesday as well.
Elsewhere, a wintry mix will continue with precipitation over the colder
air north of the boundary into the Northern Plains Sunday night through
Monday morning, with some light additional accumulations possible over
portions of northern Nebraska and southern South Dakota. Widespread lower
elevation coastal/valley rain showers and thunderstorms as well as higher
elevation mountain snow will also continue through Sunday night from
Southern California eastward into the Desert Southwest/Four Corners region
and central/southern Rockies as the deep upper-level trough remains
overhead. Some moderate to locally heavy rainfall totals will be possible
for southern Arizona, and some additional moderate to locally heavy
snowfall accumulations are forecast over the ranges of the central Rockies
into early Monday. Precipitation chances will taper off from west to east
through the day Monday as the trough moves eastward over the Plains.
Temperature-wise, warm, much above average temperatures are most likely
for eastern/southern portions of the country ahead of the approaching
storm system. The cold front will usher in much cooler, below average
temperatures to the Middle Mississippi Valley and Central/Southern Plains
Tuesday. Conditions will initially remain much below average Monday over
portions of the Northern Plains into the West under the upper-level
trough. However, as the trough departs to the east, much warmer
temperatures will begin to expand from the West Coast eastward into
portions the Interior West and the Northern Plains by Tuesday.
Putnam
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php