Flash Flood Warning 13, NWS Grand Junction, CO

Area Forecast Discussion
National Weather Service Grand Junction CO
1116 AM MDT Tue Aug 26 2025

.KEY MESSAGES...

- Widespread showers and thunderstorms are expected to continue
  today and beyond.

- Elevated risk today for flash flooding and debris flows in
  sensitive areas, especially over recent burn scars.

- Heavy rain becomes more localized Wednesday and flash flooding
  remains a concern, especially for recent burn scars.

- Temperatures will trend cooler this week thanks to rain and
  cloud cover.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 411 AM MDT Tue Aug 26 2025

A wet and active forecast continues to take shape this morning.
Water vapor imagery shows well stacked moisture at all levels across
the Great Basin, bleeding across the state line this morning.
Overnight showers have been persistent across eastern Utah and
western Colorado. Southwesterly upslope flow has produced showers
and thunderstorms all night on the eastern Tavaputs. Subsidence
under the upper ridge has been curbing intrusion into the Colorado
side of the terrain there. Although, that's changing at the time of
this discussion, with a few thunderstorms working along the Rio
Blanco/Garfield County border. Convective debris and cloud cover
look to linger into the morning hours today, perhaps inhibiting
convective initiation. PWAT's will trend 150-180 percent of seasonal
normal today. Available moisture won't be a problem. A southwesterly
jet streak nosing into the Great Basin will continue to push
moisture our way. Upper level forcing and afternoon heating should
lend a hand by mid day. Hi res models are developing some scattered
showers this afternoon, then a series of vorticity lobes ramps up
production this evening. All of this is expected to pose some
challenges for burn scars and already saturated soils. Given the
antecedent dry conditions around the region, parched dirt is
expected to mitigate impacts of heavy rain. However, this will all
depend on very localized weather patterns today. A Flash Flood Watch
remains in effect today and tonight for much of the region to
highlight potential for flooding. Temperatures will remain on the
cool side of climatology today thanks to clouds and rain. A few
sunny locales will surge up towards more summer-like conditions, but
that will be the exception for much of the area.

Showers will taper some by early Wednesday morning, but given the
location of the jet overhead, we will see nocturnal showers
continue. Much of this activity will likely convert to stratiform
precipitation, thereby squashing rates of accumulation. However,
there remains a threat for localized flooding to continue early
Wednesday, given the ample moisture supply and potential for
overnight convection. Leftover cloud cover will come back into play
Wednesday again. While PWAT's trend downward, a generous supply of
surface moisture will get worked on by orographics. A few of these
showers and thunderstorms will likely produce rain rates capable of
flooding on burn scars again. Flood concerns will be much more
localized Wednesday afternoon. Temperatures will remain consistent
again Wednesday afternoon, with the chance for additional sunshine
to destabilize us further.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 343 PM MDT Mon Aug 25 2025

A low amplitude upper-level ridge centered over Colorado sets
up for the latter half of the week. This puts eastern Utah and
western Colorado in a southwesterly flow pattern. A 50-60 knot
jet will keep moisture elevated through the extended forecast,
but PWAT anomalies begin to fall from south to north on
Wednesday as "drier" air begins to work in. With PWAT anomalies
falling from 175-200% to 125-150% of normal, convection will
become less widespread and favor the higher terrain. With the
region already primed for precipitation, chances are higher that
afternoon storms could move off the terrain and into adjacent
valleys (typically to the northeast). Stronger storms will
continue to be capable of producing frequent lightning and burn
scar flash flooding, but the frequency in which this occurs will
trend downward into the weekend.

Temperatures remain at or below seasonal normals through the
seven-day forecast and will be highly dependent on how much
cloud cover there is each day. In general, we'll see a decrease
in cloud cover heading into the weekend so temperatures will
warm a handful of degrees in return.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1115 AM MDT Tue Aug 26 2025

Showers will likely produce intermittentbreakpoint conditions
for the terminals with low ceilings and visibility. Gusty
outflow winds and small hail will remain a concern for aviators
too. Winds will remain light and terrain driven otherwise. Some
shower activity is expected to continue into tomorrow morning.

&&

.HYDROLOGY...
Issued at 411 AM MDT Tue Aug 26 2025

Flash flooding and debris flows adjacent to burn scars
continues to be a prominent concern as anomalously high moisture
makes its way through the region. Non-burn scar related mud and
rock slides have also been observed over the past couple days
as a result of the multiple days of rainfall. PWAT's surge
higher today. As a result, a Flash Flood Watch has been issued
for southeastern Utah and much of western Colorado. Flash
flooding will become more localized Wednesday, but remain a
threat due to potential for heavy rainfall.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Flood Watch through this evening for COZ003-006>014-017>023.
UT...Flood Watch through this evening for UTZ022-028-029.

&&

SHORT TERM...LTB
LONG TERM...KAA
AVIATION...TGJT
HYDROLOGY...TGJT

Hazardous Weather Outlook
National Weather Service Grand Junction CO
405 AM MDT Tue Aug 26 2025

COZ001>014-017>023-UTZ022>025-027>029-271015-
Lower Yampa River Basin-Central Yampa River Basin-
Roan and Tavaputs Plateaus-Elkhead and Park Mountains-
Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor-
Central Colorado River Basin-Grand and Battlement Mesas-
Gore and Elk Mountains/Central Mountain Valleys-
Central Gunnison and Uncompahgre River Basin-
West Elk and Sawatch Mountains-Flat Tops-Upper Gunnison River Valley-
Uncompahgre Plateau and Dallas Divide-Northwest San Juan Mountains-
Southwest San Juan Mountains-Paradox Valley/Lower Dolores River-
Four Corners/Upper Dolores River-Animas River Basin-
San Juan River Basin-Southeast Utah-Eastern Uinta Mountains-
Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat-
La Sal and Abajo Mountains-Canyonlands/Natural Bridges-
405 AM MDT Tue Aug 26 2025

This Hazardous Weather Outlook is for northwest Colorado, southwest
Colorado, west central Colorado, east central Utah, northeast Utah
and southeast Utah.

.DAY ONE...Today and tonight.

Widespread convection is expected this afternoon. Storms will be
capable of producing moderate to heavy rainfall, small hail, gusty
winds, and frequent lightning. Flash flooding and debris flows are
possible in sensitive areas, such as slot canyons and recent burn
scars. A Flash Flood Watch remains in effect for western Colorado and
southeast Utah.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Chances of widespread heavy rain, along with potential flash
flooding or debris flows, continue through the week. Temperatures
will run below normal.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected today or tonight, however
spotters are encouraged to relay rainfall amounts or any observed
flooding to the National Weather Service in Grand Junction.

Preliminary Local Storm Report
National Weather Service Grand Junction CO
907 AM MDT Tue Aug 26 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0850 AM     Rain             2 N Bondad              37.11N 107.88W
08/26/2025  M0.65 Inch       La Plata           CO   Mesonet

            Mesonet station DRG01 Durango.

0848 AM     Rain             41 NNE Elgin            39.55N 109.91W
08/26/2025  M0.68 Inch       Uintah             UT   Mesonet

            Mesonet station WHBU1 Wildhorse.

0848 AM     Rain             4 S Sawpit              37.93N 108.01W
08/26/2025  M0.56 Inch       San Miguel         CO   Mesonet

            Mesonet station GW1216 Sawpit.

0845 AM     Rain             Dolores                 37.47N 108.50W
08/26/2025  M0.59 Inch       Montezuma          CO   Mesonet

            Mesonet station DOLC2 Dolores.

&&

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