Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 182156

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
356 PM MDT Sun Mar 18 2018

.SHORT TERM...(Tonight through Monday night)
Issued at 356 PM MDT Sun Mar 18 2018

Everyone knows convection is king...and the king has been holding
court over the 4 Corners region into W.Colorado today. This
convection is producing supercells but it has been helping produce
snow rates pushing 2 inches per hour. This was experiences by a
lot of places in SW.Colorado as the front pushed through and
helped release the instability for upright convection and heavy
wet snow was the result. Large scale ascent ahead of the main
upper low and the core of the low itself it also continue to bring
lightning strikes and most likely heavy precipitation bursts late
this afternoon from our southern CWA to the Front Range. There
will likely be some impressive strips of heavy snowfall that will
be reported but overall would say this storm probably under-
performed expectations. The focus for this storm is moving east of
the divide but the central and especially northern mountains
should still get a shot of precipitation through the evening. Cold
northerly flow in the moist dendritic zone should also keep some
of the north facing ranges accumulating snow through Monday
morning. Not convinced of a true Gorge event but it will be
something to monitor. Temperatures stay cool in the wake of this
storm to start the week. We will be starting WAA aloft as heights
increase to our West late tomorrow. Prior to this lapse rates
remain steep enough that some building mountain clouds may
continue to keep some isolated to widely scattered showers around
but this should be mainly near the divide and to the east. Some
high cloudiness will be moving overhead Monday night as the above
mentioned WAA works in aloft. Dry conditions expected however as
the atmosphere begins to stabilize as a result.

.LONG TERM...(Tuesday through Sunday)
Issued at 356 PM MDT Sun Mar 18 2018

A good warming trend will take place for the mid week period as
the ridge aloft settles over the High Plains with troughs along
each side of NOAM. What will be important for the upcoming week
will be a moderate atmospheric river forecast to hit the lower
half of the Left Coast Tuesday afternoon. Model ensembles suggest
over an inch of PWAT hitting SoCal with values of half this much
moving into the 4 Corners region by early Thursday. This is of
course very wet for mid March and will be the fuel for a late week
system to produce precipitation. Unfortunately QG fields and the
H500 pattern show energy ejecting from the Western trough is being
handled quite differently by the med to long range models. This
court jester is not willing to lean one way or the other attm or
especially use the GEM for a push off one side of the fence. It
would be sad to see this good push of moisture go to waste so hope
things can gel with the next few model runs and trend toward the
wetter Euro solution. Otherwise expect temperatures to push back
to near or above normal for the mid to late week period.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1059 AM MDT Sun Mar 18 2018

TAF sites will experience rain and snow over the next 12-18
hours. TAF sites in eastern Utah will see an end to showers by
21Z, but until then snow will bring MVFR CIGS and IFR VSBY to
KVEL and KCNY. The higher elevation TAF sites in western Colorado
will experience a occasional snow showers with a mix of rain and
snow at valley sites. This will result in periods of IFR/MVFR
CIGS and periods of IFR VSBY. In addition, a number of sites will
have CIGS below ILS breakpoints. Conditions improve late tonight with
showers ending. However, CIGS may linger below ILS breakpoints at


CO...Winter Weather Advisory until 6 AM MDT Monday for COZ009-012-018-

     Winter Weather Advisory until midnight MDT tonight for COZ003-

     Winter Weather Advisory until noon MDT Monday for COZ004-010-013.

UT...Winter Weather Advisory until 6 PM MDT this evening for UTZ023-



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