652
FXUS65 KGJT 101750
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1150 AM MDT Wed Jul 10 2024

.KEY MESSAGES...

- Temperatures will continue to climb into the weekend. Near
  record highs are expected by Friday and Saturday. Heat
  Advisories are in place for portions of eastern Utah and the
  Grand Valley.

- Afternoon showers and thunderstorms will develop on the
  terrain today and beyond.

- Temperatures remain elevated beyond the weekend, but some
  relief is expected from cloud cover and shower activity, as
  monsoonal moisture is forecast to return early next week.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 443 AM MDT Wed Jul 10 2024

Today will be hot and Thursday will be hotter. High pressure
centered over the Great Basin will continue to make things
uncomfortable for residents of the West Slope. Our southeast Utah
zones and the Grand Valley will eclipse the 100 degree mark today
and likely for the next few days in a row. We have issued a Heat
Advisory for our lower elevation zones in eastern Utah and the Grand
Valley for Friday and Saturday, where afternoon highs approaching
record levels and warmer night time lows will pose risks to
vulnerable populations and those working/playing outdoors, as well
as pets and livestock. Despite the hot and dry conditions, some
pockets of subtropical moisture continue to work their way into the
CWA. Afternoon showers and thunderstorms are expected to increase in
coverage west of the Divide today, favoring terrain. Gusty outflows
and small hail will be of concern around these storms, as they drift
off their source terrain and decay. Dry boundary layer conditions on
last evening`s Grand Junction sounding are expected to persist. An
ideal regime for some strong outflows. Afternoon highs today will
trend 5-10 degrees over climatology and tonight`s lows will trend
upward too, by around 5 degrees. As mentioned above, nothing much
changes Thursday, but the thermometer. 500 mb height rises will
intrude further and our low desert valleys will approach or surpass
the 100 degree mark again. Some of our upper valleys against the
Divide will climb into the mid and upper 90`s as well. Shower
coverage on the terrain will once again favor the slopes west of the
Divide, as well as the San Juans and Central Mountains. Gusty winds
and small hail remain a threat, but wetting rains will be hard to
come by. A few of these outflows will likely provide some relief to
those already weary of the warm conditions at the higher elevations.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 443 AM MDT Wed Jul 10 2024

High pressure becomes centered over Utah on Friday and nudges
overhead on Saturday. These two days will likely be the warmest of
the forecast period, and record high temperatures are possible.
Models show some moisture still trapped in the area especially south
of I-70. This will result in afternoon showers and storms mainly in
the higher terrain. The warm temperatures will keep rainfall amounts
on the low end, while dry low levels will promote gusty outflows.
Some of the adjacent valleys may experience a cool down from these
outflows. As the high shifts over the area on Saturday there looks
to be a slight uptick in the moisture. This may result in a few more
afternoon showers and storms. On Sunday the high may move just east
of the Divide and allow for a better moisture advection. This
adjustment also means highs cool down by a few degrees just based on
700 mb temperatures. Increased showers, clouds and the potential for
rain-cooled outflows could result in lower highs as well. Confidence
in the forecast decreases beyond this period. One reason is that
model solutions seem to be changing each cycle. Also, the models are
introducing the potential for a deep trough to drop into the central
US, which pushes the high pressure back to our west. Moisture
appears to still around for the most part and therefore temperatures
are closer to normal. If that high drifts west conditions may
eventually dry out, but that is towards the end of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1143 AM MDT Wed Jul 10 2024

Expect VFR conditions across the region outside any showers or
thunderstorms through the TAF period. Scattered cloud are
building on the terrain today, along with some scattered showers
and thunderstorms. The primary threats from these storms will
be 40-50 mph outflows winds and small hail. Included vicinity
showers and thunderstorms at the mountain terminals. Winds will
be generally light and terrain influenced outside of shower
activity. Showers will quickly diminish towards sunset.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Heat Advisory from 10 AM Friday to 9 PM MDT Saturday for
     COZ006.
UT...Heat Advisory from 10 AM Friday to 9 PM MDT Saturday for
     UTZ024-027-029.

&&

$$

SHORT TERM...LTB
LONG TERM...KJS
AVIATION...TGJT