Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 231000
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
400 AM MDT Mon Apr 23 2018

.SHORT TERM...(Today through Tuesday)
Issued at 400 AM MDT Mon Apr 23 2018

A fast-moving trough will move from western UT into eastern UT
this morning, then through NW CO late this morning and afternoon.
This is an active little system that was producing thunderstorms
over NW UT early this morning. The trailing edge of the uplift
area will move along the northern UT and CO borders and kick off
isolated to scattered showers and a few thunderstorms.

The shorter range models are not in good agreement today for the
rest of eastern UT and western CO. The HRRR is much drier the day
for areas south of the Tavaputs and Flattops and seems to be
supported best by satellite imagery.

The cold front associated with this system appears to stay north
of or along the northwest CO border this afternoon then the short
range models all push it south between 00z and 03z and to the
mountains north of Gunnison by 12z Tuesday morning. A few inches
of snow is expected over the northern mountains and portions of
the central mountains, with a dusting over the SW mountains.

The front then seems to remain stationary and draped along the
Continental Divide Tuesday, affecting mainly eastern CO. This
moves most of the precipitation out of the forecast area.

.LONG TERM...(Tuesday night through Sunday)
Issued at 400 AM MDT Mon Apr 23 2018

A warm and mainly dry forecast is setting up for the latter half
of the week as high pressure dominates the E.Pac and the Western
States. Now trapped under this ridge will be a Rex Low that will
be slowly approaching the Left Coast toward the weekend. The
interesting part is how the northern stream and southern stream
will interact to pool moisture over the Southwest. Basically a
northern stream wave dropping through the Northern High Plains
Wednesday night into Thursday will force a deep cold front into
the Southern High Plains. This front will gather GoMex moisture
and merge it with moisture over the Southwest that will have
arrived with a subtropical wave to this region earlier Wednesday.
By the late week period lowering heights in the west will induce
return flow northward. The difluent flow ahead of the upstream
low will then try to utilize this moisture source to form a large
swath of precipitation oriented from Old Mexico to PacNW. QG
ascent is more organized with the GFS in the Southwest Friday PM
and as a result the convection is more organized into the 4
Corners Region. The southern extent of the QG ascent is not so
prolific in the Euro and arrives earlier Saturday so convection
potential is not fully utilized. So still a fly in the ointment
for this late week/weekend pattern. Overall however temperatures
will be warming Wednesday and stay in the above normal category
through the period.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 400 AM MDT Mon Apr 23 2018

VFR conditions will prevail for the next 24 hours at the TAF
sites, though KHDN, KEGE, and KASE may see a few showers and cigs
to ILS breakpoints last this morning through early this evening.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

SHORT TERM...CC
LONG TERM...15
AVIATION...CC



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