NZUS99 KGJT 010418 RRA
WRKDDP

GOES ALPW is showing the strong tap of moisture across the Southwest
and directed at the central Rockies this evening. The latest GJT
sounding did shows this moisture continues to be mainly elevated
above 500mb with the persistent inverted V profile still in place.
This explains the 45 to 50 mph gusts from virga/showers this
afternoon and evening. No matter what you look at...integrated
moisture transport vectors...PWAT anomoly...M-Climate QPF...PWAT
return intervals...this is as good of moisture tap as we have seen
in a long time. If this was truly winter season this would have
boosted the SWE profile upward. Not so say this storm won't produce
some impressive snow totals...it will just be limited to the highest
elevations due to limited cold air and low SLR...more Sierra Cement.
Various ensembles are showing QPF amounts in the 1.5 to 2.5 inch
range with this storm and as much as I have been wanted to brush
those numbers aside...they are looking more likely than not. Why?
Strong SW to W orographics as this trough approaches and swings
through...moderate QG forcing overhead with said trough and a
combination of mesoscale forcing and convection. A more organized
band of precipitation arcing from southeast Utah into west-central
Colorado associated with jet-forced frotogenesis looks to be one
reason the QPF amounts are bullseyed over the Unc-Grand Mesa-West
Elks area. Favorable orographics another reason...which will also
favor the fertile crescent of the San Juans. So overall this will be
a welcome storm for all even with the wintery impacts tonight and
tomorrow through the mountain corridors when snow has the best
chance of accumulating on road surfaces. As the PV lobe cuts in by
mid-day we go full convective and though precipitation rates in some
areas will be robust...the warmer temps and filtered sunshine is
expected to improve road conditions. So even with some impressive
snow amounts (15+ inches) still happy with the winter advisories for
expected impacts. The trough axis swings across the divide tomorrow
evening keeping some cool air advection/orographic showers over our
eastern terrain through sunrise. We get a short break Thursday
before the next trough...a colder system...moves through late
Thursday through Friday. Will continue watch trends with this system
and tackle it after this bigger event ends.

Freeze potential.

warming and drier beyond