785
FXUS65 KGJT 171118
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
518 AM MDT Fri May 17 2024

.KEY MESSAGES...

- Warm and breezy conditions are expected through the weekend.
  Temperatures will remain at least 5 to 10 degrees above
  normal.

- A series of systems will bring daily showers and thunderstorms
  Saturday and Sunday afternoon. Gusty outflows and small hail
  will be the main concerns.

- Cooler, unsettled weather will prevail early next week before
  drier and warmer conditions return by midweek.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 308 AM MDT Fri May 17 2024

A downturn in excitement is expected today as the forecast area
remains under a weak, just barely noticeable, ridge of high
pressure. This will lead to quiet weather under mostly sunny
skies, though mid and high clouds will begin to increase later
on this afternoon. Upstream, a trough of low pressure will begin
to dig into the Intermountain West before pushing farther south
into the Northern Rockies by this evening. Flow aloft will
quickly be deflected to the west as a weak frontal boundary
straddles the Wyoming border, resulting in a gradual tightening
of the gradient during the day. Surface gusts of 25 to 35 mph
are still expected for areas north of I-70 this afternoon with
the southern tier generally maxing out at 30 mph. Even with the
passing clouds, humidities will hover in the low to mid teens
this afternoon. The front will begin to nudge into northeast
Utah and northwest Colorado tonight but, with a prevalent dry
layer at the surface, little to no shower activity is expected.
In fact, PWATs are anticipated to remain 70 to 90 percent of
normal into Saturday morning. On Saturday a shortwave will
slowly begin to push into southern California, helping to
deflect the Friday night cold front out of the area. Flow across
the southern two-thirds of the CWA will shift to the southwest
in response to the approaching trough on Saturday. PWATs will
exceed 150 percent of normal in this moist pattern which, when
paired with daytime heating and orographics, will fuel isolated
to scattered showers and storms throughout the day. Though the
higher terrain will be favored, some drift into the adjacent
valleys is expected. As noted previously, additional support
from the associated warm front will aid in storm development.
Similar to previous days, gusty outflow winds and even some
small hail will be the primary threats with convection.

Temperatures will remain unseasonably warm through the short
term period with today`s highs reaching 6 to 12 degrees above
the norm for mid May. The increase in clouds and storms on
Saturday will dampen highs a bit but values will remain 5 to 10
degrees above normal. Tonight`s lows will also be quite warm for
this time of year. With all of these warm temperatures, those
rivers will be rising. No areas of concern at the moment but
certainly something to keep in mind when recreating this
weekend.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 308 AM MDT Fri May 17 2024

The split flow pattern over the West breaks down Saturday night into
Sunday and once again the high latitudes drop across the US border
and spreads below normal heights into the mid latitudes.
The main trough looks to hang back to our West until the Tuesday
timeframe but even now the timing on this is off by half a day
between the global models. Either way Tuesday into the mid-week
period looks to be the coolest and wettest of the forecast with
highs dropping back to and below normal for a few days. Models are
still struggling with additional high latitude energy dropping into
the general trough over the NW CONUS through the end of the week.
The latest GFS is swinging a stronger piece of energy across the
Northern Rockies as early as Thursday while the EURO holds it back
off the PacNW Coast where it lingers into the weekend. Looking at
trends and ensemble clusters the former solution has been more
consistent as the latest EURO choice for the deterministic run is
drastically different than 12 hours ago. That said looks like
Thursday has good probability of being warmer and drier before
another cool down arrives late in the week as the system to the
North throws a cold front through our area. Moisture anomalies at
this point are not significant and this is reflected in only
moderate PoPs and a light QPF outcome late in the week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 517 AM MDT Fri May 17 2024

VFR conditions under mainly clear skies can be expected the next
24 hours...with a few afternoon gusts over 25 mph possible.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...None.
UT...None.

&&

$$

SHORT TERM...MMS
LONG TERM...15
AVIATION...TGJT