From The Weather Channel:
“Winter Storm Elliott
Intensifying Into A Likely Bomb Cyclone With Snow, High Winds And Blizzard
Conditions”
Winter Storm Elliott is
intensifying into a likely bomb cyclone as it tracks through the Plains,
Midwest and Great Lakes with snow and strong winds, including blizzard
conditions for some. Elliott will also bring strong winds and a possible flash
freeze to parts of the Midwest, East and South.
Here's a look at where the
storm is now and what's to come.
Happening Now Snow is
falling right now from parts of Kansas and Oklahoma to Missouri, eastern Iowa,
Illinois, Wisconsin and Michigan. A separate area of snow, sleet and freezing
rain is spreading through interior parts of the Northeast. Minneapolis-St.
Paul received up to 8 inches of snow overnight. The Denver metro saw 3 to 6
inches of snowfall. The cold front's passage is being accompanied by
strong winds gusting to 50 mph (locally even higher) in the Plains. Blowing
snow is impacting travel even in areas where snow has ended because of the
strong winds. A major temperature drop is also spreading through the
central states. Blizzard warnings have been issued for parts of the
Northern Plains, upper Midwest and Great Lakes, as illustrated by the pink
polygons in the map below. Those warnings include Buffalo, New York, Des
Moines, Iowa, Grand Rapids, Michigan, and Pierre, South Dakota. Winter storm
warnings and winter weather advisories are in effect for a much larger area
that extends from the upper Midwest to the Great Lakes and mid-South. Among the
cities included are Chicago, Cleveland, Detroit, Indianapolis, Milwaukee, Minneapolis-St.
Paul, Nashville and Memphis. Travel should be avoided in many of these areas
since it could become difficult or impossible. That's not just because of the
snow, but also strong winds and extreme cold. Below, we'll step you
through the timing, snowfall forecast, wind forecast, and other impacts from
this storm, then we'll provide perspective on bomb cyclones and how this storm
lines up with other December and all-time Great Lakes storms.
Forecast Timing
Thursday-Thursday Night The
storm will continue to intensify in the Midwest with areas of snow and rain
changing quickly to snow as the arctic front races through. Strong winds
will spread from the Plains to the Midwest and South. Expect dangerous travel
conditions from the Central Plains to the upper Mississippi Valley and western
Great Lakes, with blizzard conditions in some areas, even in areas where snow
is no longer falling. In the interior Northeast, freezing rain, sleet
and snow early in the day will transition to rain in most areas by Thursday
afternoon, with the exception of northern New England and upstate New York.
Rain is expected along the Interstate 95 corridor.
Friday The storm will
reach its peak intensity with high winds, snow and blizzard conditions in parts
of the Great Lakes, from northern and eastern Wisconsin and far northeast
Illinois to parts of Michigan, northern Indiana, northern Ohio, western
Pennsylvania and western New York. Any rain or rain changing to snow in
the Northeast will be followed by bitterly cold air that could result a flash
freeze, making for icy conditions in spots. High winds are also
expected over much of the East as far south as Georgia and the Carolinas.
Saturday By Saturday,
the storm will move away into eastern Canada, but strong winds will likely
linger in much of the Great Lakes and upper Mississippi Valley. Those winds
blowing over the Great Lakes could produce bands of heavy lake-effect snow that
could last into Christmas Day in the eastern Great Lakes. Also,
lingering areas of blowing and drifting snow are expected outside the lake
snowbelts in the Midwest where snow fell the previous few days.
How Much Snow?
Plains, Midwest, Great Lakes More
than a foot of snow is likely in the western Great Lakes snowbelts, where winds
blowing over the lakes will enhance snowfall downwind of lakes Superior and
Michigan over the Upper Peninsula, western Lower Michigan and extreme northern
Indiana. Up to 6 inches of snow could fall in parts of Wisconsin,
northeast Illinois and much of the rest of Michigan outside the lake snowbelts.
Farther south, a widespread area from the Central Plains to the
mid-Mississippi and Ohio valleys has a chance of at least a few inches of snow.
And at least light snow totals might be enough to make roads slick as far south
as parts of Oklahoma, northern Arkansas and Tennessee.
Northeast In the
interior Northeast, snowfall totals generally less than 6 inches are expected,
with some accumulation possible Thursday before precipitation changes to rain,
then again after the cold front swings through Friday. Totals over 6
inches are possible in the high country of the central Appalachians,
Adirondacks, Green and White Mountains. Heavy snow is also expected in
the eastern Great Lakes snowbelts this weekend, with some one-foot totals
possible in the Lake Erie and Ontario snowbelts of northeast Ohio, northwest
Pennsylvania, western New York and upstate New York, including Buffalo and
Watertown.
High Wind Threat High
winds will be the most widespread impact from Elliott. Winds will continue to
increase in the Plains on Thursday, but the strongest winds from this storm
are expected Thursday night through Friday into early Saturday in the Midwest
and along the East Coast from New England to Georgia Friday. The
National Weather Service has issued high wind warnings for parts of upstate New
York and northern and eastern New England, including the Boston metro area. These
winds will be capable of downing tree limbs and knocking out power,
particularly where they combine with snow accumulations weighing down trees and
power lines in the Midwest and East. Plan ahead now for the potential for power
outages in cold weather if you live in these areas. Even areas of lower
snowfall totals may see dangerous reductions in visibility due to strong winds
combined with snow and also drifting snow on roads, especially in outlying
areas. The winds will also lead to areas of coastal flooding. Minor
to moderate coastal flooding is expected with Friday's late morning or early afternoon
high tide from the southern Delmarva Peninsula to parts of coastal New England,
including Long Island and the Jersey Shore. Lakeshore flooding is also
expected along the eastern shores of Lakes Erie and Ontario in western and
upstate New York Friday into Saturday night. In Buffalo, lake levels could
exceed 3 feet above flood stage, according to the NWS, a level that's been
reached only three other times since the mid-1970s. That could inundate
flood-prone areas near the lake such as the Old First Ward in South Buffalo.
Other Threats There are
two other things we could see with this storm that could be dangerous for your
drive. First, as the arctic cold front sweeps through the Plains,
Midwest and East, snow squalls could develop. These are bursts of snow,
but they're brief, typically lasting less than an hour. The reason they're dangerous
is they can quickly lower visibility and coat roads in a thin film of snow,
making them slippery. Multi-vehicle accidents can and do occur within
these snow squalls, particularly on major freeways with more traffic. Keep that
in mind, even if your area of the Midwest and East does not have heavy
accumulations of snow in the forecast. It could instead come down in these
short-lived bursts. Secondly,
there's the potential for a flash freeze. This occurs when rain soaks
pavement, then is followed quickly by an arctic cold front that ushers in
subfreezing air. That fast-arriving cold air would then turn any
lingering water on untreated roads into patches of ice, making travel slippery
and dangerous, particularly on bridges and overpasses. This is
certainly possible in parts of the Ohio Valley and East ahead of the cold front
Thursday into Friday.
Bomb Cyclone Perspective We
mentioned earlier that this winter storm could become a bomb cyclone. As
a rule of thumb, meteorologists refer to a strengthening low as "bombing
out" or undergoing bombogenesis if its minimum surface pressure drops by
at least 24 millibars in 24 hours or less, though that criteria also depends on
a storm's latitude. Meteorologists frequently discuss pressure in terms
of millibars, rather than inches of mercury. The reason this all matters
beyond just a geeky statistic is the lower the pressure in a storm, the more
intense it is. And the greater difference in pressure over an area, the
stronger the winds.
Winter Storm Elliott has the
potential to plunge to a pressure that could threaten December low-pressure
records in the Great Lakes, according to data compiled by NOAA Weather
Prediction Center meteorologist David Roth. For now, the latest ensemble model
forecasts do not bring Elliott's low to the level of what is considered the
all-time low-pressure record – the so-called "Cleveland Superbomb" of
late January 1978. Nevertheless, this combination of wind, snow, cold, snow
squalls and flash freezes will be a travel headache. If you reside or have
pre-Christmas travel plans in these areas, monitor the forecast closely and be
prepared to make alternate travel arrangements.
^ Millions of Americans will be impacted
across the US over this Christmas and Chanukah Storm. Hopefully, we will all
have power and heat during and afterwards. ^
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