976
FXUS65 KGJT 162357
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
557 PM MDT Tue Jul 16 2024

.KEY MESSAGES...

- Temperatures are expected to remain a few degrees above normal
  with daily thunderstorm chances through the remainder of the
  week and into the weekend as moisture is recycled under the
  area of high pressure over the region.

- Threats from thunderstorms will mainly be from gusty outflow
  winds though a few storms will be capable of producing smaller
  hail and moderate to heavy rainfall rates. Overall flooding
  threats remain low.

- The combination of high based storms...gusty outflow winds and
  lightning will keep also keep a threat of new wildfire starts
  in the picture.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 317 PM MDT Tue Jul 16 2024

The SubTropical High will start to get a nudge back to the West
over the next 24 hours as low pressure digs through OH/TN
Valleys. This minor switch in West to Northwest flow will pull
in some drier air and it appears there will be a bit of a
downturn in convection for tomorrow. That said...this drier air
has been working into northern Utah and Colorado this afternoon
but there is plenty of convection thanks to a moderate shear
profile. The convective mode has remained multicell but a few of
the storms have been strong enough to throw out some
accumulating hail and modest to heavy rainfall rates. Overall
however gusty outflow winds remain the main threat past sunset
before a noticeable downturn in convection is indicated by most
models. The only caveat...PVU fields/current H2O imagery
show a wave moving through SW Utah attm which is triggering
storms to our West and this moves through overnight. Will the
drying trend counter this wave and keep things on the quiet
side likely not so there are some minimal pops on place. Maybe
not enough. Otherwise most of the convection looks to favor the
eastern high country of our CWA on Wednesday with a few storms
also favored again over the northern Utah mountains. With a
drier sounding the threat of storms with more wind and lightning
than rainfall will be the favored mode. Cloud cover will
continue to dictate overnight temperatures but the trend is a
bit cooler tonight with drier conditions forecast. Temperatures
tomorrow remain above normal and could gain a degree or two with
more sunshine in place.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 317 PM MDT Tue Jul 16 2024

The stubborn ridge of high pressure baking the West still shows no
signs of abating in the near term outlooks. Troughing in the north
Pacific and eastern Canada sandwich a persistent hot air mass here
in the West. Forecast challenges still exist for the coming days, as
pockets of monsoonal moisture work their way northward under the
ridge. Temperatures in our low valleys along the Utah/Colorado state
line will hover around 100 degrees, with a few spikes likely when
cloudless conditions allow. Elsewhere, lows and highs will run
around 5 degrees warmer than climatology through the period.
Temperature relief for many locales will come by way of afternoon
showers and thunderstorms. Storm coverage will continue to favor the
terrain, with model data showing some contraction of coverage
towards the weekend. Confidence in storm coverage is low. Outdoor
enthusiasts on the higher terrain will want to keep an eye to the
sky, as lightning will be a daily hazard this week. Strong outflow
winds and small hail will remain a concern as well. Saturday, models
begin to pinch off a clipper system dropping into the Plains that
threatens the ridge and knocks heights down. This could potentially
push our monsoonal tap out of the way. At the moment, I`d say our
northern counties see a break in storms this weekend if we get into
the expected drier northerly flow. This could push temperatures down
a bit for much of the eastern half of the CWA, while areas closer to
the remnant ridge out west will stay hot. This remains a tentative
forecast as models try to signal a pattern shift. For now, it looks
like a pattern shift on Monday and Tuesday to close out the long
term.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 553 PM MDT Tue Jul 16 2024

Showers and thunderstorms will wind down this evening on the
terrain. Gusty outflows, small hail, and TEMPO visibility and
ceiling reductions expected at mountain terminals. Otherwise,
VFR conditions are expected to return overnight. Scattered cloud
cover left over from showers will likely linger on some terrain
into the morning hours. Winds will remain terrain driven through
the TAF period with more showers and thunderstorms expected on
the terrain Wednesday afternoon.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...15
LONG TERM...LTB
AVIATION...TGJT