Flash Flood Warning 21, NWS Grand Junction, CO

989 
WGUS75 KGJT 062037
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
237 PM MDT Sat Sep 6 2025

COC103-062047-
/O.EXP.KGJT.FF.W.0021.000000T0000Z-250906T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Rio Blanco CO-
237 PM MDT Sat Sep 6 2025

...FLASH FLOOD WARNING FOR THE LEE BURN SCAR WILL EXPIRE AT 245 PM 
MDT THIS AFTERNOON FOR SOUTH CENTRAL RIO BLANCO COUNTY...

Excess runoff from heavy rain has ended over the warned area. If 
flooding has been observed...Please report it to your local law 
enforcement agency. Flooding is no longer expected to pose a threat. 
Please continue to heed remaining road closures.

&&

LAT...LON 3979 10810 3980 10809 3981 10810 3983 10809
      3980 10808 3983 10803 3982 10799 3982 10798
      3981 10797 3979 10798 3978 10796 3975 10796
      3974 10803 3970 10806 3975 10806 3975 10807
      3975 10808 3975 10810 3976 10809

$$

GF

Area Forecast Discussion
National Weather Service Grand Junction CO
1155 AM MDT Sat Sep 6 2025

.KEY MESSAGES...

- Showers and thunderstorms continue today with more widespread
  coverage.

- Higher rainfall rates could produce localized flash flooding
  today on burn scars and other sensitive locales.

- Temperatures will remain near the climatological mean before a
  warming trend Monday onwards.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 358 AM MDT Sat Sep 6 2025

Satellite imagery shows the ridge still extending north into British
Columbia dominating our weather pattern advecting much of the
extra-tropical moisture along its western flank up out of the
Great Basin into Idaho, Oregon and Washington. A shortwave
disturbance slowly working its way through the lower Great Basin
into southwestern Utah is keeping nocturnal thunderstorms going
in the Las Vegas area north to Richfield, UT. This shortwave
will track northeast across central eastern Utah and
northwestern Colorado this afternoon and early evening pulling
moisture out of northern Arizona into the Four Corners area and
drawing some of the extra-tropical moisture with it out of the
Great Basin into eastern Utah and Western Colorado to keep pwats
in the 0.7-0.8 range across the region for today. Skies are
clearing out across the region and to the west due to the
subsidence under the ridge as it shifts slightly eastward. This
opens the door to strong diurnal heating through the morning to
kick off convection early and to pump more energy into the
atmosphere for stronger convection through the afternoon. Look
for orographic showers to start building on the southern
mountains by mid morning, transitioning into thunderstorms by
noon as they spread to the northeast across the region. These
storms will continue to be slow moving due to the weak flow
aloft, but will track more to the east or southeast with the
westerly shift in the winds aloft. These storms continue to be
capable of producing heavy rain that will pose a greater threat
of flash flooding to the more east-west oriented valleys and
canyons where storm training is more probable. As the shortwave
moves through, convection will diminish from southwest to
northeast through the late afternoon into the evening with
lingering scattered showers over the central to northern
Colorado mountains into the overnight period before the
shortwave exits to the northeast.

Skies will clear out overnight behind the shortwave allowing for
diurnal heating to initiate convection Sunday over the southern
mountains taking advantage of moisture lingering in the area.
Another shortwave will work its way across the areas along and
north of the I-70 corridor Sunday afternoon and evening with yet
potential for a few stronger thunderstorms.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 336 PM MDT Fri Sep 5 2025

On Sunday the region will be under quasizonal flow aloft situated
on the northern periphery of a weak ridge. Dry air working in from
the west will start to decrease the coverage of convection across
the area. There should still be enough moisture for scattered
showers and storms. By Monday that dry air might only allow for
isolated showers. Meanwhile a deep low pressure will approach the
Pac NW keeping the southwesterly flow going. The models show a piece
of that energy breaking off, forming into a separate low and then
tracking over the Great Basin. Unfortunately, there are differences
with the timing and location of that secondary low. If that low
materializes it will cause a shift to southerly flow for our area.
This would pull some deep moisture in from New Mexico towards the
end of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1149 AM MDT Sat Sep 6 2025

Showers and thunderstorms will continue for eastern Utah and
western Colorado this afternoon. Included TEMPO conditions at
most terminals to account for spotty nature of storms.
Intermittent IFR ceilings and visibility are expected in heavier
showers. Gusty outflow winds will likely impact a few terminals
as storms decay. Small hail remains a threat too. Winds will
otherwise be light beneath the high pressure parked overhead.
Conditions will slowly improve this evening as drier air
infiltrates the region from west to east. VFR conditions are
expected across the majority of the region through Sunday
morning. A few clouds and showers will hang up along the Divide
in northern Colorado through the early morning hours of Sunday.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

SHORT TERM...DB
LONG TERM...KJS
AVIATION...TGJT

Hazardous Weather Outlook
National Weather Service Grand Junction CO
424 AM MDT Sat Sep 6 2025

COZ001>014-017>023-UTZ022>025-027>029-071030-
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-
424 AM MDT Sat Sep 6 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.

Expect widespread showers and thunderstorms across the region today.
Threats from these storms are gusty winds, lightning and periods of
heavy rain leading to localized flash flooding.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Showers and thunderstorms across the region again Sunday will be more
scattered as the region begins to somewhat dry out. These showers
and thunderstorms will become more isolated to scattered across the
region Monday through mid week. Late in the week looks to have
another uptick in showers and thunderstorms.

.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.