936
FXUS65 KGJT 131143
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
543 AM MDT Mon Oct 13 2025

.KEY MESSAGES...

- Another round of highly anomalous moisture from TD Raymond
  moves up from the south today into Tuesday.

- A Flood Watch remains in effect for the southern San Juans and
  adjacent valleys. Total rainfall amounts in that area are 1-2
  inches with locally higher amounts upwards of 3-4 inches
  possible.

- Unsettled weather continues for much of the week as another
  system moves in from the west bringing more showers and storms
  to eastern Utah and western Colorado.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 521 AM MDT Mon Oct 13 2025

Models show good agreement with satellite imagery indicating the
initialized well for the 00Z run. The low pressure system
descending along the Pacific Northwest Coast is tracking slower
than the models predicted in earlier runs. This will have the effect
of keeping eastern Utah and Western Colorado in the moist southerly
to southwesterly flow longer, extending the period of rain possibly
through mid week. The limiting factor may be that the strong
southwest flow aloft just depletes all the remnant moisture from TD
Raymond before the low can eject to the northeast. Stay tuned on
this. Showers are already moving up into southwestern Colorado and
eastern Utah ahead of the main push of mositure later this morning.
CAMs models show numerous heavy rain showers with isolated
thunderstorms across the San Juans through the morning hours,and
scattered to widespread showers spreading north to I-70 with
isolated showers farther north by noon today. Convective activity
will become widespread across the region through the afternoon,
continuing through the overnight period. Though most of the heavy
rain will be confined to the southern face of the San Juans and the
valleys to the south, this push of moisture will be able to produce
localized heavy rain on the southwestern faces of any higher terrain
such as the Uncompahgre Plateau, the Grand Mesa, and the Elk and
West Elk Mountains. Though cloud cover will limit diurnal heating,
strong upper-level dynamics and increased shear set up through this
afternoon that may support stronger thunderstorm development across
southeastern Utah and the Four Corners area. Threats from these
storms will mostly be damaging winds over 60 mph, but can`t rule out
some large hail either.

Showers become more scattered across the region through Tuesday
morning, diminishing through the afternoon. As mentioned above, the
heavier rains could extend through the day Tuesday if the moist
plume doesn`t deplete. A Flood Watch is in effect from 6AM this
morning through noon tomorrow for the San Juan Mountains and the
valleys to the south for the increased risk of flooding and flash
flooding in these areas due to the heavy rains and saturated soils.
A Flood warning remains in effect through midnight tomorrow for the
area around and north of Vallecito Reservoir, and a River Flood
Warning remains in effect for the San Juan River in the Pagosa
Springs area through 2:30 PM this afternoon. Stay tuned for updates
on this latter warning as it may require an extension today with the
additional rains.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 521 AM MDT Mon Oct 13 2025

A broad area of high pressure will be anchored over eastern Texas at
the start of the long term period while an approaching closed low
will be over central California. Supporting this closed low will be
a robust jet streak of 110kts that will be moving over most of Utah.
For our area, we will be under the right exit region of a departing
jet streak which is cause for some concern. Divergence aloft will
aid in lift while southerly flow will keep favorable orographics
over the San Juans and with available moisture still above normal,
some heavier rain may be realized. The amount of rain seen recently
will only exacerbate the risk for more flash flooding in that area
as soils will remain close to being saturated. WPC has highlighted
this possibility with a marginal risk of flash flooding over the San
Juans and southern valleys from Wednesday morning through Thursday
morning. Will need to keep an eye on future model runs.

Aside from this rain, the closed low will lift to the northeast
during the day Wednesday and become more of an open wave. As it does
so it will drag a cold front across our area. Some showers and a few
storms will be possible Wednesday but as the best CAPE and steepest
lapse rates will stay over northern UT into WY, this convection
should stay isolated to scattered at best. Some gusty winds (30 to
40 mph in spots) will also be likely as the pressure gradient
tightens and some stronger winds aloft mix to the surface. As the
upper level trough pushes through on Thursday, some lingering
showers and a few storms may fire according to the NBM though other
deterministic models aren`t as gung ho.

Some light snow will also be possible as the front moves through
dropping snow levels from around 11 to 12K feet to 7 to 8K feet
Thursday into Friday. Minor snow accumulations are expected, mostly
less than inch, though the highest peaks of the eastern Uintas and
northern mountains may see an inch or two. Friday morning, much
drier air moves in as height rises indicate a ridge axis approaching
the area. This will also lead to efficient cooling overnight with
many northern and southern valley locations seeing lows dropping to
the upper 20s. Might need a few freeze products Friday morning to
account for this. Those height rises and ridge axis will lead to a
very pleasant, warm, and dry weekend. Finally.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 538 AM MDT Mon Oct 13 2025

Clouds have started filling in across the area with some very
isolated showers noted. Coverage for showers and a few storms
will only increase from here on out. Widespread VFR conditions
remain across the area presently but as the precipitation
continues to move in, ceilings will lower as will visibilities
under and near the heavier precipitation. As this occurs, MVFR
conditions will be possible, if not occasional IFR/LIFR, which
is covered by many PROB30 groups for all TAF sites. ILS
breakpoints will likely be met from time to time through the day
for similar reasons mentioned above. Mountain obscurations will
be common. Unsettled weather will continue through tommorrow.

&&

.HYDROLOGY...
Issued at 303 PM MDT Sun Oct 12 2025

The amount of precipitation some areas have received over the
past few days has been exceedingly impressive to say the least.
Looking at 72 hour totals (unofficially), most areas across the
San Juans received between 2 to 4 inches of rainfall with a few
spots reaching just over 5 inches. 1 to 2 inches was common
across central portions of Colorado with anywhere from a half to
1 inch for the northern valleys. Most of eastern Utah received
the same, a half to 1 inch of rain.

The Flood Watch continues for portions of the San Juans and
southern valleys as TD Raymond brings another surge of moisture
from the south Monday into Tuesday. Soil moisture in the watch
area is very high due to all of the rain therefore runoff will
be more efficient for this round. The estimated rainfall totals
did increase with this latest forecast package, so there is a
chance would could see similar impacts.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Flood Watch through Tuesday morning for COZ019-022-023.
UT...None.

&&

$$

SHORT TERM...DB
LONG TERM...TGR
AVIATION...TGJT
HYDROLOGY...TGJT