…Flash flooding and severe weather threat continues over the Midwest the
next couple of days…
…Potentially dangerous heat anticipated across the southern Plains,
lower Mississippi Valley, and Gulf Coast…
A low pressure/frontal system traversing the center of the country
continues to help trigger rounds of showers and thunderstorms leading to
the threat of some flash flooding and severe weather. The system is
forecast to lift northeastward through the Middle Missouri Valley this
(Wednesday) evening. Increasing upper-level support with a strengthening
wave as well as plentiful moisture should lead to some intense, heavy
rain-producing thunderstorms, with a Slight Risk of Excessive Rainfall
(level 2/4) for some scattered instances of flash flooding. In addition,
the Storm Prediction Center has included a Slight Risk of severe weather
(level 2/5) for the risk of some very large hail, damaging winds, and a
few tornadoes with these storms. A similar scenario will play out on
Thursday as the system moves eastward into the Middle Mississippi/Lower
Ohio Valley and Great Lakes region with a broad warm sector supported by
plentiful moisture, instability, and deep-layer shear. Storms should
redevelop during the afternoon, increasing in coverage into the evening,
with another Slight Risk of Excessive Rainfall given the threat for some
heavy downpours and potential training convection leading to some flash
flooding. A Slight Risk of severe weather similarly covers the chance for
some instances of large hail and damaging winds. The system will push into
the Lower Great Lakes and Upper Ohio/Tennessee Valleys by Friday, with
storms likely and some chance of isolated flash flooding and severe
weather.
Heat will remain the major weather story throughout much of the
south-central U.S. through the end of this week and likely beyond.
Widespread highs into the upper 90s and triple digits are forecast to span
from the Southwest to the central Gulf Coast. Elevated humidity levels
will soar heat indices up to around 110 degrees in the southern Plains,
lower Mississippi Valley, and central Gulf Coast. Low temperatures are
anticipated to only drop into the upper 70s and 80s for many locations,
which could break several daily records. This level of heat can affect
anyone without effective cooling and/or adequate hydration. Therefore, it
is imperative to follow proper heat safety and check on vulnerable
individuals.
Elsewhere, some showers and storms will continue over New England as a
frontal boundary lingers in the region. This boundary is expected to
weaken through the day Thursday, with storm chances subsequently tapering
off. To the south, portions of central/south Florida will also see
scattered storm chances the next couple of days as a cold front slowly
pushes through. Some thunderstorms will be possible with a shortwave
passing over portions of the northern Great Basin Thursday and into the
northern Rockies by Thursday evening. Forecast high temperatures are
expected to generally be around average along the East Coast with mid- to
upper 80s expected. Areas of the Great Lakes/Upper Midwest behind the
passing storm system will be cooler with highs in the 70s. More
temperatures near or above average are expected over the northern/central
Plains with highs in the 80s and 90s. Highs across the northern tier of
the West will remain below average, with 70s for the Pacific Northwest and
low 80s into the northern Great Basin, warming closer to average into the
central Great Basin with mid-80s to low 90s.
Putnam/Snell
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
