Chris's Corner - CHANGES ARE COMING AND NOT JUST IN WEATHER

It looks like it has an enhanced band right along I-70 in IL of 4-6". I know that's obviously not to be taken at face value, but I wonder if it's suggesting such banding somewhere within the CWA is likely.

Looks like the difference with the UKMET is that it is flatter initially at 300mb with a weaker outbound jet streak. The 300mb wave moves out ahead of the 500mb low fairly quick and leaves it in the left entrance region of the jet streak squashing the 500mb wave.

Nice, steady, light snow here in Mascoutah.

Flake size has increased drastically!

Pretty good in Mascoutah

Light dusting w/ light snow falling in rural Festus

Absolutely!

Snowing decent here now. The Euro looks pretty good for the whole cwa to my untrained eye. I would think the heaviest qpf would need adjusted 25-50 miles NW. It seems nearly every model wants to hug the axis tighter to the features than what would normally be seen.

A light dusting on the grass here. That EPS does look good as does the GEFS. I think everyone else crapped out for the night, lol. Overall I think trends are looking good for 72 hrs out.

It looks like the 6z NAM is quite nice for the area. I know we are still too far out for its reliability, but very consistent with its 00z run.

.LONG TERM... (Monday Night through Saturday)
Issued at 327 AM CST Sun Jan 22 2023

On Monday night, a closed upper low over the Desert Southwest will
begin its trek east and will be the focus of our forecast through
Wednesday. This upper low will move from West Texas on Tuesday
morning through the Mid-Mississippi Valley on Wednesday while the
associated upper trough becomes increasingly negatively tilted as
is moves into the region. Strong cyclonic vorticity advection will
support rapid cyclogenesis as the surface low moves from south
Texas toward the Lower Ohio River Valley. The cyclone deepen
further as it approaches our region, bolstered by ample jet level
divergence associated with coupled jet streaks. Just ahead of the
intensifying low, strong moist isentropic ascent along the warm
conveyor belt will push precipitation into our forecast area
beginning Tuesday evening. Precipitation will continue through
Wednesday morning as the frontogenetical band on the back side of
the low swings through forecast area, tapering off in the
afternoon.

Guidance continues to highlight surface temperatures near or just
above freezing throughout much of this event, with the rest of
the profile remaining below freezing. Despite surface temps a few
degrees freezing, I expect the combination of favorable profiles
above the surface and dynamic cooling associated with at least
moderate precipitation rates will allow much of the expected
precipitation to fall as snow.

As for amounts, ensemble mean QPF continues to range from around
0.25" in NE MO to about 0.75" in SE MO and southern IL where the
strongest forcing will be found. There is still some variability
amongst the ensembles, with roughly 0.4" separating the
reasonable low and high-end solutions (the 10th and 90th
percentiles), likely due to differences in the low track. Even in
the low end scenario, much of the area is likely to see at least
light snow accumulations. Our current forecast is close to the
ensemble mean, which utilizing a snow-to-liquid ratios just below
climatology, highlights advisory-level snow amounts (3-6"). The
higher end solutions would obviously push us into warning
criteria for portions of the area.

While some uncertainty remains in the snowfall forecast, at this
point I`m confident that we`ll see accumulating snowfall across
much of the area. Going further, there`s a better chance than not
that we`ll end up with at least an winter weather advisory across
portions the area, and there is a potential for significant
travel impacts, especially to Wednesday morning`s commute. I
anticipate the difference between the high and low end scenarios
to decrease over the coming days, and we should be able to narrow
our forecast as that occurs.

If the latest runs are to come to fruition, that's going to be way low. I know there are plenty of factors to consider and the potential for melting and compaction, but if the GFS/NAM are right this won't be weakening as it goes by. As always, the NWS is playing it conservative and will follow the data and update which is the smartest move. It will be interesting to see the 12z data as full sampling should occur by then. Maybe the Ukmet and Euro will trend stronger as well.

Had about 1/2 inch of snow on the ground when I went to bed ….. she gone ……lol

That snowfall forecast by the NWS only goes out to 12z Wed...hence the low amounts.