…Hurricane-force winds and life-threatening storm surge imminent along
the Louisiana coast as Francine makes landfall…
…Torrential rainfall from Francine will spread up the Mississippi Valley
while severe weather threat shifts east into the Florida Panhandle…
…A round of moderate to heavy rain with high-elevation snow will move
across the northern Rockies…
…Elevated to critical fire weather concerns across much of the Great
Basin and portions of the High Plains…
As a large area of high pressure continues to provide fine weather from
the Plains to the East Coast, Hurricane Francine in the Gulf of Mexico is
poised to make landfall on the Louisiana coast late this afternoon.
Spiral rainbands associated with the core of Francine has already
overspread the eastern half of Louisiana with winds continue to
strengthen. Hurricane conditions can be expected to impact the coastal
sections as the eyewall of Francine arrives with life-threatening storm
surge. Farther east into southern Mississippi/Alabama into the western
Florida Panhandle, a threat of severe thunderstorms with embedded
tornadoes is anticipated ahead of a coastal front lifting northward from
the Gulf of Mexico. As Francine makes landfall and heads farther inland,
the tropical cyclone will interact with the cooler and drier air mass that
has been feeding southward from the large high pressure system to the
north. Francine’s interaction with the cool air mass and an associated
upper-level jet stream will result in its gradual lost of tropical
characteristic as it moves farther inland. The heavy rainfall associated
with Francine will then shift farther away from Francine’s center, with
the threat of flash flooding focusing farther north up the Mid-Mississippi
and Tennessee Valleys on Thursday. By Friday, Francine is expected to
transform into a post-tropical cyclone as it begins to stall near/over the
Ozarks and gradually dissipates. The focus will shift farther east from
the Deep South into the Southeast and down toward the Florida Panhandle
for possible severe thunderstorms ahead of a lifting warm front. In
total, Francine is expected to produce rainfall amounts of 4 to 8 inches,
with local amounts to 12 inches for the central/eastern Gulf Coast through
Thursday night. This rainfall could lead to considerable flash and urban
flooding. As Francine pushes northward into the Mid-South and weakens by
the end of the week, additional heavy rain is possible and could lead to
scattered instances of flash flooding. Additionally, a lingering frontal
boundary draped across the Florida Peninsula could lead to localized flash
flooding concerns over the next few days. Residents under
hurricane-related warnings should follow advice of local officials,
including evacuation orders, and never drive across flooded roadways.
Meanwhile, an upper-level trough currently moving onshore into the Pacific
Northwest will bring a round of moderate to heavy rain with high-elevation
snow for the northern Rockies through Thursday night as the deepening
upper-level trough brings a surge of colder air across the region. Most
of the impactful precipitation will be confined to the northern Rockies
and the High Plains of Montana. A few inches of rainfall could produce
flooding concerns throughout northwest Montana, prompting a Slight Risk
(level 2/4) of Excessive Rainfall both through Thursday. Snow levels
dropping to around 7,000-8000 feet may also create hazardous winter-like
conditions for the highest elevations of Idaho and northwest Wyoming. The
other aspect of this system will be associated with gusty winds and
increased fire weather concerns throughout the Great Basin and High
Plains. Strong winds combined with dry vegetation and low relative
humidity are forecast to be more pronounced over the Great Basin today and
increase the chances for erratic fire behavior. Additionally, elevated to
critical fire weather also exists across the High Plains and is most
apparent on Thursday as southerly winds increase in speed. Red Flag
Warnings and Fire Weather Watches have been issued throughout 10 states
between California and Nebraska. Outdoor burning is not recommended
throughout these regions and residents are reminded to not go near any
wildfires as they can spread quickly. The gusty winds and fire weather
danger will shift into the northern and central High Plains on Thursday
and into Friday as a sharp front passes through and a couple of low
pressure system develop.
Otherwise, tranquil weather will prevail from the Great Lakes to much of
the East under the large high pressure system. Well above average
temperatures are expected to overspread the north-central U.S. before a
warming trend is also noticeable across the southern Plains by Friday.
Highs across the northern Plains, Upper Midwest, and Great Lakes are
forecast to reach into the upper 80s and low 90s, while upper 90s
eventually return to the western half of Texas and eastern New Mexico.
Kong/Snell
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
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