Number two of a one-two punch of snowstorms is about to bear down
upon the region. Water vapor imagery shows a well defined vorticity
maximum moving through the Four Corners this afternoon. This area
will MOVE into the Southern Plains late tonight or early Monday
morning. Models are in very good agreement taking an intense upper-
level low across Arkansas and through extreme southeastern Missouri.
There is also a strong clustering in the ensembles and deterministic
models in taking the surface low just slightly north of the upper
low track. This represents a nearly ideal path for heavy snow from
southern Kansas, along the Kansas Turnpike and right into the Kansas
City metro area, and possibly points northeastward.
Given the
strength of the system, which is nearly 5 standard deviations lower
than the normal upper-level height pattern for this time of year,
widespread heavy snow is likely with a large swath of at least 6 to
10 inches. Within that broad swath there will be a narrower strip
with amounts likely in excess of 10 inches. Also, given the way the
storm may pivot to our south during the overnight and early Tuesday
time frame, we may see a period across the Kansas city area of a
sustained
6 to 9 hours of 2+ inch/hr snowfall rates. Intense
frontogenesis, nearly ideal snow growth with maximum omega values
right around -15C and ample moisture flowing into the system via a
well defined trowal, all lead to the likelihood of very intense
snowfall rates and at this time, the timing looks to have a great
impact on the Tuesday morning commute across the region. We could
potentially see 6 to 8 inches of snow through the Kansas City metro
from midnight to 6 am with several more inches added on later in the
morning.
Regarding the potential for mixed precipitation and/or freezing
rain, BUFR soundings from around the region, and particularly from
Pleasant Hill to Clinton indicate only a brief period of sleet or
freezing rain before the strong dynamics of the system overwhelm the
warm air advecting into the system. This will cut into snow amounts
in our extreme southern/southeastern zones but overall, ice
accumulations look minimal with temperatures near freezing in that
area. This would tend to limit ice accumulations overall and with
only a brief period of time when ice would be possible,
accumulations look very minimal in our forecast area.
The snow, when combined with the other aspect of this storm, strong
northerly to northwesterly winds of up to 30 mph, will make travel
Tuesday morning across western Missouri and eastern Kansas quite
dangerous. Whiteout conditions are very possible and roads that were
cleared may quickly drift over, especially with how high the snow is
packed from the previous storm. Wind will blow snow over the piled
snow and deposit it rather quickly on the other side. The one caveat
against the significant blowing and drifting of snow is that our snow
ratios will be near or slightly lower than our climatological normal
of 13:1. So the snow will likely be fairly wet, as opposed to
powdery, with a higher snow ratio.
The intense storm system will move into the Ohio Valley by Tuesday
night and conditions through the forecast area will improve from
Tuesday afternoon onward. Although we will still see snow, and
possibly moderate snow in northeastern Missouri later Tuesday
morning, the intensity will be not nearly as strong with an inch or
less expected Tuesday afternoon through Tuesday evening. Light snow
will persist through the night and into the day Wednesday, but
again, only minor additional accumulations, perhaps as much as inch
through the day Wednesday, are expected.
http://forecast.weather.gov/product....n=1&glossary=1