804
FXUS65 KGJT 111747
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1147 AM MDT Thu Jul 11 2024

.KEY MESSAGES...

- Temperatures will continue to climb into the weekend. Near
  record highs are expected Friday and Saturday.

- Afternoon showers and thunderstorms will develop over higher
  terrain each day throughout the next 7 days with an increase
  in coverage expected early next week.

- 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 FRIDAY/...
Issued at 124 AM MDT Thu Jul 11 2024

There is not much change in the overall pattern today compared to
yesterday. The Great Basin high pressure continues to gradually
shift eastward so highs will come up and degree or two. There may be
a subtle drying to the environment due to that shift as well, but
not sure it will translate to much difference. Still expect showers
and storms to develop over the high terrain across the eastern half
of the area this afternoon. They will be capable of producing wind
gusts up to 45 mph as outflows expand and fan out after development.
Some of the stronger cells may produce small hail in spots. Motion
will be north to south once again. By sunset this activity will
dissipate. Lows increase tonight by a few degrees. Tomorrow the high
pressure begins to drift over Utah causing yet another increase in
temperatures by a few degrees. In fact, we may break some records as
the high pressure gets closer and eventually settles overhead. The
high will advect some drier into the northern mountains tomorrow so
expect less afternoon convection there. Diurnal showers and storms
will still develop mainly south of I-70 where moisture stays
sufficient. Once again small hail is possible and gusty outflow
winds are likely.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 124 AM MDT Thu Jul 11 2024

High pressure continues to drive the forecast for the foreseeable
future. This means above-normal temperatures are here to stay,
especially this weekend when triple-digit highs will be commonplace
in the valleys. On Saturday moisture is progged to be highest in the
southern mountains where the highest coverage of precipitation is
expected, but there may be enough moisture present to kick off
terrain-driven showers and storms further north as well. We continue
to see diurnal precipitation chances in the high terrain through
the forecast period. Coverage will likely increase on Monday as more
moisture begins to wrap around the high pressure center and into
eastern Utah and western Colorado. The GEFS and ECMWF ENS show this
increased mositure (125-150% of normal) sticking around through
midweek. Outflows could help initiate precipitation in the valleys
as well, but confidence in the location and coverage of outflow-
driven showers and storms is rather low at this time. Beyond midweek
we begin to see model guidance diverge. We will have to wait and see
how synoptic features across the CONUS develop and impact what
happens to the location of the high and the moisture feed into the
region.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1144 AM MDT Thu Jul 11 2024

Isolated showers and thunderstorms are expected to develop
across the higher terrain of western Colorado this afternoon
with gusty outflow winds 35 to 45 mph possible at times. Aside
from high terrain storms, VFR conditions are expected to persist
through the period.

&&

.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...KJS
LONG TERM...KAA
AVIATION...MDA