Flash Flood Watch 7, NWS Grand Junction, CO

173 
WGUS65 KGJT 032104
FFAGJT

Flood Watch
National Weather Service Grand Junction CO
304 PM MDT Sat Jul 3 2021

COZ008-010-013-032215-
/O.CAN.KGJT.FF.A.0007.000000T0000Z-210704T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central Colorado River Basin-Gore and Elk Mountains/Central Mountain
Valleys-Flat Tops-
304 PM MDT Sat Jul 3 2021

...FLASH FLOOD WATCH FOR THE GRIZZLY CREEK FIRE BURN AREA IS 
CANCELLED...

The Flash Flood Watch for portions of northwest Colorado and west 
central Colorado, including the following areas, in northwest 
Colorado, Flat Tops. In west central Colorado, Central Colorado 
River Basin and Gore and Elk Mountains/Central Mountain Valleys has 
been cancelled.

The Flood Watch is replaced with a Flood Warning.

$$

MAC

Area Forecast Discussion
National Weather Service Grand Junction CO
1147 AM MDT Sat Jul 3 2021

.SHORT TERM...(Today through Sunday)
Issued at 321 AM MDT Sat Jul 3 2021

Forecast models continue to suggest a slight downturn in the
coverage of convection the next few afternoons. This is not so
much as an influx of drier air but rather weak subsidence aloft
with high pressure settling over the Intermountain West. The
atmosphere remains conditionally unstable with isolated nocturnal
showers again popping up. There is a subtle jet aloft and the H2O
channels show quite a few boundaries interacting from earlier
convection. So I will go with that. The question is will these
boundaries force more convection than anticipated later
today...possibly. We will still have the threat of moderate to
heavy rainfall rates in the strongest storms but outflow winds are
becoming more of a threat as the lower part of the atmosphere
will be mixing out better in the hotter temperatures. Speaking
of...above normal temperatures are here to stay and the lower
desert valleys will be hitting the upper 90s to triple digits the
next few afternoons.

.LONG TERM...(Sunday night through Friday)
Issued at 321 AM MDT Sat Jul 3 2021

Attention then turns to a last chance for dynamically driven
precipitation before the upper level ridge anchors and strengthens
over the Four Corners. An upper level trough coming around the
western/northern periphery of the upper level ridge from central
CA will move across WY and northern CO Monday. Available moisture
will also increase along and ahead of this feature which will
result in greater coverage of showers/storms, especially north or
I-70 and over the mountains.

After the passage of this upper level trough, drier air and
increased subsidence under the strengthening ridge will result in
only isolated diurnal convection over the mountains and
temperatures rising a few degrees more. Confidence is medium to
high with this scenario as ensemble guidance shows precipitable
water values remaining below 0.75 of an inch and max temperatures
for GJT into the lower 100s, and lower to mid 90s for DRO, for
the last half of the week.&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1125 PM MDT Fri Jul 2 2021

Isolated showers or a thunderstorm will be possible through the
overnight hours with very low probability of impacts at the TAF
sites. More showers and storm will develop in the heat of the day
on Saturday but again the limited coverage will limit confidence
on impacts. So for now VFR rules continue.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1146 AM MDT Sat Jul 3 2021

Another round of afternoon thunderstorm can be expected. However
the coverage looks to be less than the past few days and
confidence not high of impacts at TAFs sites. Gusty outflow winds
would be the main concern. VFR will dominate the forecast over the
next 24 hours.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

SHORT TERM...15
LONG TERM...BM
AVIATION...TGJT

Hazardous Weather Outlook
National Weather Service Grand Junction CO
434 AM MDT Sat Jul 3 2021

COZ001>014-017>023-UTZ022>025-027>029-041045-
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-
434 AM MDT Sat Jul 3 2021

This hazardous weather outlook is for eastern Utah and western
Colorado.

.DAY ONE...Today and Tonight

Thunderstorm development will be possible mainly this afternoon
and evening. Gusty outflow winds and lightning will be the
primary threats.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Isolated to widely scattered thunderstorm development will be
possible through the weekend and into next week. Expect isolated
gusty winds and heavy downpours with the strongest cells.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.