790
FXUS65 KGJT 030604
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1204 AM MDT Mon Jun 3 2024

.KEY MESSAGES...

- Showers and thunderstorms will fire over northern portions of
  the CWA today. Gusty winds and small hail expected from the
  stronger cells.

- Another round of convection expected Monday with the Flat Tops
  and northern mountains favored during the evening hours.

- Temperatures will remain above normal and into the coming
  week. The warmest temperatures of the season thus far will be
  Thursday and Friday at 10 to 15 degrees above normal.

- Major stem rivers will continue to show rises over the coming
  days thanks to warm surface temperatures.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 1217 PM MDT Sun Jun 2 2024

Convection has already started firing over the northern valleys
as expected. This convection is in response to an approaching
shortwave trough that is just to our west. As it moves through,
convection will increase though models have consistently placed
the convection over northern portions of the CWA. Limited
moisture will preclude most, if any, convection for areas south
though a quick popup can`t be completely ruled out. Forecast
soundings highlight dry lower levels across the area which is
also borne out with local obs reporting humidities in the teens.
This type of environment favors gusty surface winds and don`t
see that changing this afternoon. Some outflow winds from the
stronger cells will likely reach 40 to 50 mph, if not a bit
higher. Forecast DCAPE values range from 500 to over 1000 J/kg
in some spots so chances are increased for stronger downdrafts
associated with this convection. Along with the winds, some hail
will also be possible. Outside of the convection, the usual Cu
buildup over the higher terrain will occur along with some high
clouds moving overhead. Convection will die down later this
evening giving way to calm conditions.

The next shortwave trough to move in will move in from the
northwest. The base of the trough won`t move through until the
late evening hours on Monday so while northern portions of the
CWA might see a few showers/storms coverage will be minimal at
best. One thing many areas will see will be some gusty surface
winds ahead of the wave. Areas north of the San Juans will see
gusts of 25 to 35 mph with lower gusts south. Heading into the
evening hours, the northern mountains and Flat Tops are favored
to see some showers and a few storms. Like today, outside of the
showers/storms, look for some mid to high level clouds from mid
afternoon onwards. Warm temperatures remain.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 1217 PM MDT Sun Jun 2 2024

A weak but dry embedded wave may kick off a few more thunderstorms
across the northwest Colorado mountains on Tuesday afternoon but,
elsewhere, look for drier and warmer weather. A strong ridge of high
pressure will build across the Desert Southwest while a potent upper
level low dominates the eastern CONUS. Benign weather prevails for
Wednesday before the axis of the ridge begins to shift east of the
Divide as troughing elongates off the Aleutian Islands. Aiding in
the shift will be the presence of a cut off low centered off the
coast of Baja, helping to deflect that ridge axis by Thursday.
Guidance remains inconsistent regarding the weak advection of
subtropical moisture into the area underneath the ridge with the
latest NBM knocking back shower potential late in the week. For now,
the arrival of at least high-based moisture would bring some passing
clouds. This weekend will see the cut off low swing northeast into
the southwest CONUS but confidence on what impacts we will see
remains low. Overall, the long term will be quiet but by the time we
hit the weekend a shift towards more unsettled conditions is
possible.

As noted in prior discussions, the strong warming trend will be the
main highlight of the long term period. Under the building ridge
highs will climb to 10 to 15 degrees above normal and even approach
the lower triple digits in our desert valleys. Even with the ridge
axis shifting farther east later in the period highs will remain 5
to 10 degrees above normal through the weekend. Low temperatures
each night will also be unseasonably warm.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1146 PM MDT Sun Jun 2 2024

Expect VFR conditions and light winds through 18Z. Westerly
afternoon winds pick up after 18Z gusting 25-35 kts across the
northern areas, 15-25 kts across the southern areas with mid-
level ceilings generally along and north of the I-70 corridor.
Look for showers to kick off over the higher terrain of the
northern and central mountains early in the afternoon with
thunderstorms firing later in the afternoon as a frontal
boundary approaches. The fast moving front will pass west to
east along and north of the I-70 corridor starting about 23Z at
KVEL, moving east of KASE and the Divide by about 06Z with an
accompanying band of stronger thunderstorms. Expect a brief
period below ILS breakpoints at KRIL, KEGE and LASE through the
evening with the passing thunderstorms.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...TGR
LONG TERM...MMS
AVIATION...DB