Area Forecast Discussion
Issued by NWS Grand Junction, CO

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169
FXUS65 KGJT 141610
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1010 AM MDT Sun Jul 14 2024

.KEY MESSAGES...

- The desert valleys of eastern Utah and the Grand Valley in
  western Colorado remains hot today with temperatures well
  above normal. Heat Advisories remain in place.

- An uptick in thunderstorm coverage this afternoon will lead
  to an elevated risk of fire starts. A Red Flag Warning has
  been issued for locations forecast to see the highest storm
  coverage.

- Temperatures remain seasonably warm with daily thunderstorm
  chances through the seven day forecast.

&&

.UPDATE...
Issued at 1010 AM MDT Sun Jul 14 2024

Based on latest model guidance and expected coverage area of dry
thunderstorms, decided to add UT487 and CO290 to the Red Flag
Warning for dry thunderstorms today. The remaining areas,
coverage remains isolated so did not include them in the Red
Flag Warning (need at least widely scattered).

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 403 AM MDT Sun Jul 14 2024

Water vapor satellite imagery early this morning showed the high
pressure system that has been responsible for the recent stretch of
unseasonably warm, dry conditions was located near the central
Colorado/New Mexico border. Increasing moisture was also apparent
across eastern Utah into western Colorado. Hi-res guidance shows
that PWAT values will gradually increase to 0.75-1" by early this
afternoon providing the first push of mositure into the region in
awhile. Despite more cloud cover today, temperatures are still
forecast to be 5 to 10 degrees warmer than seasonal normals. A Heat
Advisory remains in effect for the lower valleys until 9 PM this
evening. Temperatures cool slightly to kick off the new work week on
Monday, but some valley locations will still be flirting with triple-
digit highs.

Thunderstorm coverage in the mountains will also increase this
afternoon with renewed moisture present. Model soundings show that
precipitation will be fighting a very dry near-surface layer across
much of the forecast area. This means the threat for heavy rainfall
is on the lower side, but conditions will be favorable for gusty
outflow winds up to 50 mph. Frequent lightning will also pose an
elevated threat for fire starts given the very dry antecedent
conditions. Sensible weather conditions will be somewhat of a rinse
and repeat on Monday afternoon with more showers and storms rotating
around the high overhead.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 403 AM MDT Sun Jul 14 2024

High pressure remains centered south of the forecast area somewhere
over the central border between New Mexico and Arizona Monday night
where it will remain on Tuesday through Tuesday night. Moisture
levels appeared largely unchanged in model data, so diurnal
shower/thunderstorm on Tuesday should be similarly to Monday`s
activity. Positioning of the high brings modest drying in westerly
flow aloft for Wednesday resulting in reduced moist convection over
eastern Utah and westernmost Colorado, while the mountains of the
Continental Divide remain active. The downturn in activity will be
short lived as moisture pooled over the southern Plains is wrapped
back into the region by Thursday which is then recycled over the
area through the end of the week as the high slowly shifts west.
Moisture levels stay below 150% of normal through the period, so
expect excessive rainfall will be localized. Despite, the persistent
shower/thunderstorm activity, temperatures will continue to run
above normal, though aren`t likely to be as hot as they have been
over the past several days.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 533 AM MDT Sun Jul 14 2024

A few ongoing showers near KCNY early this morning, but this
activity is unlikely to bring showers to TAF sites before Sunday
afternoon. Expect showers and thunderstorms to develop over
higher terrain similar to Saturday with showers in the vicinity
of the mountain sites of KASE, KEGE, KTEX and KGUC with only
KTEX likely to experience a thunderstorm over the airport during
the afternoon. This is not to say that it`s not possible that
others won`t experience showers/thunderstorms, but just the
potential is too low to mention at this point. That said, expect
continued VFR conditions with no ceilings below ILS breakpoints
at all TAF sites through the next 24 hours. Winds will
generally be light and terrain driven, though outflow wind gusts
to 45 mph are possible.

&&

.FIRE WEATHER...
Issued at 1010 AM MDT Sun Jul 14 2024

The mix of dry fuels, a dry airmass near the surface, and
an upturn in thunderstorm coverage in the higher terrain will
lead to an elevated threat for dry thunderstorm fire starts this
afternoon. As a result, a Red Flag Warning has been issued for
locations most susceptible and where thunderstorm coverage is at
least widely scattered. However, any lightning strike could
lead to fire starts. While environmental winds are forecast to
be on the lighter side with high pressure overhead, gusty
outflow winds up to 50 mph are possible near showers and storms.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Red Flag Warning until 9 PM MDT this evening for COZ201-205-
     290>293.
     Heat Advisory until 9 PM MDT this evening for COZ006.
UT...Red Flag Warning until 9 PM MDT this evening for UTZ485>487-
     491.
     Heat Advisory until 9 PM MDT this evening for UTZ024-027-029.

&&

$$

UPDATE...MDA
SHORT TERM...KAA
LONG TERM...NL
AVIATION...TGJT
FIRE WEATHER...TGJT