…Heavy rain and flash flooding threat forecast to stretch from the
central Plains to the Midwest over the next few days…
…Potentially dangerous heat anticipated across the southern Plains,
lower Mississippi Valley, and Gulf Coast…
…Fire weather concerns and poor air quality continues for portions of
the Pacific Northwest, Northern Rockies, and Great Basin…
A mid-August weather pattern continues to take shape this week with
numerous areas of scattered thunderstorms impacting the Nation. A
stationary front currently stretching from the Southeast to the central
High Plains will be the focus for much of this activity, with the boundary
eventually forecast to lift north into the Midwest by Wednesday night due
to a deepening low pressure system in the central Plains. The most likely
weather hazard over the next few days with developing thunderstorms is
expected to be associated with heavy rainfall creating instances of flash
flooding, as well as the potential for isolated areas of damaging wind
gusts. Specifically, three separate areas along the front stand out today
as having the greatest chances for scattered flash floods. Parts of South
Carolina remain sensitive to locally heavy rain as the area continues to
contain saturated ground conditions, leading to a continued threat for
flash flooding as long as the atmosphere supports slow-moving
thunderstorms. For much of eastern Kansas and Missouri, an initial complex
of thunderstorms is forecast to move through the region this morning
containing locally heavy rainfall, while a reforming area of convection
overnight into Wednesday could create additional flooding concerns. This
second round of heavy rain has the potential to produce a narrow corridor
of impressive rainfall totals within a few hours near south-central
Missouri. Additionally, northeast Colorado can expect another round of
storms containing intense rainfall rates this evening as activity forms
along the leeward side of the Rockies and pushes eastward. Residents and
visitors are advised to have multiple ways of receiving warnings, have a
plan should flash flooding occur, and never drive through flooded
roadways. By midweek much of the heavy rain and thunderstorm activity is
anticipated to gradually shift eastward to the Midwest and lower Ohio
Valley, along with the strengthening low pressure system and lifting warm
front. Once again heavy rain will be a concern as ample atmospheric
moisture content creates ripe conditions for scattered vigorous downpours.
Dangerous summer heat will be confined to the southern U.S. this week as
highs into the upper 90s and triple digits span from the Southwest to the
Gulf Coast. The most anomalous and potentially dangerous heat is forecast
across the southern Plains and Gulf Coast States through the end of the
week as highs reach up to 10 degrees above the climatological average for
mid-August. Elevated humidity levels will lead to maximum heat indices up
to 110 degrees during the day and low temperatures only dipping into the
upper 70s and low 80s at night. People spending greater time or effort
outdoors, or in a building without effective cooling, are at an increased
risk of heat-related illnesses.
A persistent pattern supporting fire weather concerns across much of the
central and northern Great Basin is forecast to continue today with dry
terrain and periods of gusty winds. Red Flag Warnings remain in place from
eastern Oregon to Idaho. Ongoing wildfires also continue to spread smoke
into the atmosphere, leading to poor air quality.
Snell
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php