…Increasing severe weather and excessive rainfall threats over the
Central U.S. into mid-week…
…Sweltering heat continues across South Florida and southern Texas while
expanding into the southern High Plains…
An energetic upper-level pattern will bring a couple rounds of storms to
the central U.S. over the next few days. Tonight, moist return flow
following a warm front moving northward through the Plains and ahead of a
dryline over the High Plains will provide more than enough instability to
trigger robust thunderstorm development over the Central Plains.
Increasing upper-level winds will promote supercells with the threat of
large hail and a few tornadoes. Storms are also expected to grow upscale
into one or more organized convective systems, bringing a heightened
threat for potentially widespread, significant damaging winds later this
evening. As such, the Storm Prediction Center has issued a Moderate Risk
of severe weather (level 4/5). Storm chances will shift northeastward into
the Upper Midwest tonight and into the Great Lakes by Monday following an
initial upper-wave/accompanying surface frontal system. An amplifying
long-wave trough over the West will help to enhance lee cyclogenesis over
the High Plains bringing another chance of storms to the Central
Plains/Missouri Valley by Monday evening. The Storm Prediction Center has
included a Slight Risk (level 2/5) for the threat of some more damaging
winds and large hail, and possibly a tornado. Some locally heavy downpours
will also be possible, particularly from the Central Plains into the Upper
Mississippi Valley tonight and the Central Plains once again Monday, with
an isolated chance of flash flooding.
There will be a renewed threat for heavy rainfall and thunderstorms over
the Northern/Central Plains and Upper/Middle Mississippi Valley on Tuesday
as a deepening low pressure system tracks across the region. The Storm
Prediction Center issued an Enhanced Risk (level 3/5) of Severe
Thunderstorms from eastern Kansas to Southwest Wisconsin. There’s also a
Slight Risk (at least 15%) of Excessive Rainfall for parts of southern and
eastern Minnesota, much of Wisconsin and northern Illinois. There are also
some isolated chances for severe weather and excessive rainfall into
northern Texas and eastern Oklahoma.
The active upper-level pattern will also bring some precipitation chances
to the Northern/Central Rockies and eastern Great Basin over the next
couple of days. Rainfall should generally remain light to moderate, though
some locally heavier storms will be possible especially over Wyoming on
Monday. Some heavy snow is expected for much of the Absaroka and Bighorn
mountains, where between 6-12 inches, with isolated higher amounts, of
snow could fall on Tuesday. To the east, an area of low pressure lingering
just off the Atlantic coast of the Southeast with a trailing frontal
boundary moving through Florida will keep temperatures below average on
Monday. Storm chances will decrease tonight and into the day Monday from
north to south as the front pushes southward, expected to clear the coast
by Tuesday morning.
Intense Summer-like heat will continue over portions of South Florida and
from southern Texas into the southern High Plains the next couple of days.
Highs in the 90s with high humidity values for areas closer to the coast
will bring heat indices into the 105-110 degree range. While not as humid,
temperatures will soar into the 100s farther inland into west Texas/the
southern High Plains. Some record-tying/breaking temperatures are
possible. While not as hot, conditions will still be well above average
more broadly across the central/eastern U.S. Highs in 80s will be common,
even into more northerly locations like the Great Lakes and the interior
Northeast. One exception will be where onshore flow keeps things a bit
cooler along the East Coast, with highs in the 60s and 70s expected from
coastal New England south into the Mid-Atlantic and coastal Carolinas.
Highs over the Pacific Northwest/northern Rockies will remain cool tonight
behind a cold front, with highs in the 50s and 60s. These cooler
temperatures will spread southward into the Great Basin Monday. Highs in
the 80s and 90s are forecast south of the front over the Southwest.
Kebede/Putnam
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
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