-- Discussion containing changed information from previous version are highlighted. --
814
FXUS65 KGJT 131123
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
523 AM MDT Thu Jun 13 2024

.KEY MESSAGES...

- Hot temperatures remain in place today with highs reaching 10
  to 15 degrees above seasonal values. A few records may be tied
  or broken.

- A storm approaches the region tonight bringing showers and a
  few thunderstorms favoring the San Juan and central Colorado
  mountains Friday afternoon/evening.

- Temperatures cool off Friday but rebound Saturday and into
  next week. These temps, along with dry and breezy conditions
  from Sunday onwards, will potentially bring critical fire
  weather conditions.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 239 AM MDT Thu Jun 13 2024

The closed low that has been spinning off the southern
California coast over the last few days will finally get moving
today. This movement will push the dome of high pressure
centered over New Mexico a little eastward but not too much.
Like yesterday, we`ll see some gusty afternoon winds with hot
temperatures reaching the triple digits in the Grand Valley
across to Moab and down to the rest of southeastern Utah. Will
likely see a few highs tie or break previous records. Dry
conditions also remain in place as humidities will drop to the
single digits in those same areas. Critical fire weather
conditions will be briefly met for UT Zone 490 but won`t last
long enough to warrant any highlights. As fuels are still deemed
non- critical for CO Zones 200, 202 and 203...no highlights
needed there either though winds and humidities will reach Red
Flag criteria. For those interested, to issue Red Flag Warnings
we need humidities < 15%, wind speed/gusts > 25 mph, AND fuels
must be critical...these conditions must also occur for 3 hours
or greater. Lesson over.

As previously mentioned, the low will move inland today and this
movement will allow a marginal plume of moisture to move up
into our area this afternoon. This is reflected in an increase
in both specific humidities and PWATs. The end result will be
increasing mid and high level clouds this evening with some
showers overspreading the area overnight. With such dry
conditions in place, look for most precip to evaporate but a few
sprinkles can`t be ruled out.

Waking up Friday, we`ll all see plenty of clouds with showers
starting to increase for southern portions of the CWA. By noon,
the closed low will have opened up into an open wave and as it
moves across the CWA, will be the focus of precip. Coverage has
decreased considerably from previous model runs but we can still
expect some showers, maybe a storm or two, Friday afternoon and
evening. The southern half of the CWA will be favored for this
precip. The increased cloud cover will cause highs to drop
anywhere from 10 to 15 degrees from what we`ll see today. Won`t
last long though so enjoy it while it lasts.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 239 AM MDT Thu Jun 13 2024

Friday night will find us in the wake of a passing frontal boundary.
Residual showers will linger into the early morning hours of
Saturday on our terrain against the Continental Divide. Saturday
morning temperatures will take a brief pleasant dip across the
region, but rebound quickly by afternoon, reaching for triple digits
in our deserts and low elevation valleys. While a flattened ridge
sits to our west and south, weakly zonal flow will ripple through
the mountains Saturday afternoon. Favorable orographics should be
able to tap into some leftover surface moisture behind Friday`s
wave, along with afternoon instability and spark a shower and/or
thunderstorm or two on the terrain. The low pressure center tracking
across Canada will drag a frontal boundary across the Intermountain
West Saturday afternoon. The band of stronger winds aloft settles in
far enough south Saturday afternoon for some breezy conditions in
our northern counties, mostly north of the Colorado River and west
of the Continental Divide, where winds will gust around 30 mph. The
frontal boundary to our north never really budges on Sunday, as
another low pinches off in the PACNW. This will tighten gradients in
the southwest flow working across the Four Corners Sunday. Concerns
for critical fire weather conditions in our zones with susceptible
fuels will arise Sunday afternoon with wind gusts approaching 30+
mph across the region. This hot, dry, windy pattern sets up
residency into the new work week, as the PACNW low digs into the
Great Basin and keeps our southwesterly gradient winds anchored in
place. This, unfortunately, keeps moisture out of the picture and
might break the seal on our first fire products of the 2024 fire
season. The PACNW low lifts onto the northern Plains late Tuesday
and drags its trailing front across the CWA. Useful moisture looks
out of reach on this system at the moment. Models are consistent
with the southwesterly influence here on the West Slope ahead of
this system, but the evolution of the low to the north is in
question. For now, hot and dry to start the week will yield to
cooler and likely some cloudier conditions by Wednesday. Warm and
dry returns late next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
-- Changed Discussion --
Issued at 522 AM MDT Thu Jun 13 2024

VFR remains the rule today as high pressure remains overhead.
Another round of gusty west through southwest winds is expected
today reaching 20 to 30 mph at times. Clouds will increase in
the afternoon and evening hours as the next system approaches
from the southwest. Some midlevel ceilings are possible heading
towards Friday morning.
-- End Changed Discussion --

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...TGR
LONG TERM...LTB
AVIATION...TGJT