…Powerful Pacific storm to bring much colder temperatures and widespread
mountain snow throughout the Intermountain West and Rockies over the next
few days…
…Heavy rain and scattered flash flooding possible across the southern
High Plains on Saturday…
…Above normal temperatures and gusty winds forecast across the central
and northern Plains today, resulting in fire weather concerns…
As the calendar dives deeper into autumn, colder storm systems are
beginning to impact parts of the country along with wintry weather
conditions. The Intermountain West and Rockies will face the brunt of next
Pacific-bred storm system ushering in below average temperatures, gusty
winds, and heavy mountain snowfall. A cold front marching southeastward
will mark the sharp transition toward cooler temperatures and increasing
snowfall potential. This frontal boundary is anticipated to cross the
Intermountain West between today and early Friday before traversing the
central Rockies and stalling over the southern High Plains by Saturday.
Heavy snowfall is likely in the higher terrain (mainly above 7000-8000
feet) of south-central Montana, western Wyoming, Utah, and southwest
Colorado. As the system slows forward progress and increasing moisture
content surges up the southern High Plains, the potential for heavy
rainfall exists across eastern New Mexico into southeast Colorado.
Training north-south oriented lines of showers and storms could contain
intense rainfall rates while remaining over similar locations for a few
hours. This setup could produce scattered areas of flash flooding,
especially for poor drainage locations and urban regions. A Slight Risk
(level 2/4) of Excessive Rainfall has been issued for this part of the
country in order to further highlight the flooding threat. Additionally,
gusty winds are possible in the central Great Basin and Southeast as the
strong frontal boundary sweeps through over the next few days, this may
also lead to a strong offshore wind event throughout California. Wind
Advisories have been issued for parts of Nevada, Arizona, and California,
as well as Red Flag Warnings for parts of central and northern California
in order to highlight the fire weather danger.
Fire weather concerns also exist throughout much of the central U.S. today
as strong southerly flow aids in producing above average temperatures and
low relative humidity. Red Flag Warnings span from Kansas to Minnesota and
reiterate the potential for fires to spread rapidly. These weather
conditions throughout the Plains and Midwest are in relation to a potent
high pressure system situated over the Ohio/Tennessee valleys that is
expected to settled over the East by the end of the week. Underneath this
high remains below average temperatures and for some places the first
frost or freeze of the season. Low temperatures are expected to drop into
the 30s and 40s for a majority of the eastern U.S. outside of the Florida
Peninsula, but even northern parts of the Sunshine State may need to break
out the sweaters the next few mornings. Temperatures will begin to
moderate by Saturday as afternoon highs into the 70s become more
widespread.
Elsewhere, a separate Pacific system moving inland over British Columbia
on Friday will surge precipitation chances into western Washington.
Rainfall amounts over 2 to 3 inches are possible in the commonly-damp
Olympic Peninsula and northern Cascades.
Snell
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php