Flash Flood Warning 38, NWS Grand Junction, CO

132 
WGUS75 KGJT 260655
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
1255 AM MDT Mon Jul 26 2021

COC077-UTC019-260730-
/O.CON.KGJT.FF.W.0038.000000T0000Z-210726T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mesa CO-Grand UT-
1255 AM MDT Mon Jul 26 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 AM MDT EARLY THIS 
MORNING FOR WESTERN MESA AND SOUTHEASTERN GRAND COUNTIES...

At 1255 AM MDT, Doppler radar indicated heavy rainfall from 
thunderstorms had fallen across the warned area. Between 0.5 and 1 
inch of rain has fallen. The expected rainfall rate is lessening at 
0.1 to 0.2 inches in 1 hour. Additional rainfall amounts up to 0.1 
inches are possible in the warned area.

HAZARD...Flash flooding caused by thunderstorms with heavy
         rainfall.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Gateway.

This includes the following highways...
	Colorado 141 between mile markers 106 and 113.

This includes the following streams and drainages...
  Bar A Creek, Taylor Creek, Dolores River, Waring Canyon, Onion 
  Creek, West Creek, John Brown Creek, Beaver Creek and Fisher Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3851 10914 3872 10930 3874 10897 3864 10890

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.1-0.2 INCHES IN 1 HOUR

$$

15

289 
WGUS75 KGJT 260730
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
130 AM MDT Mon Jul 26 2021

COC077-UTC019-260740-
/O.EXP.KGJT.FF.W.0038.000000T0000Z-210726T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mesa CO-Grand UT-
130 AM MDT Mon Jul 26 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 130 AM MDT EARLY THIS MORNING 
FOR WESTERN MESA AND SOUTHEASTERN GRAND COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3851 10914 3872 10930 3874 10897 3864 10890

$$

15

Area Forecast Discussion
National Weather Service Grand Junction CO
530 PM MDT Sun Jul 25 2021

.SHORT TERM...(Tonight through Monday night)
Issued at 206 PM MDT Sun Jul 25 2021

While an isolated shower or two continued into the morning hours,
thunderstorm activity was slower to redevelop this afternoon in
response to a broad swath of midlevel clouds over the central CWA.
However, convection has blossomed within the last hour with cells
beginning to produce lightning as well as rain rates of one to two
inches per hour. Steering flow aloft remains light so the threat
for localized flash flooding will continue through the evening
hours before activity transitions to stratiform. As has been the
trend over the last several days isolated showers will continue
overnight, favoring the southern zones in response to the
influence of the departing retrograding low.

Monday will see the center of the upper level ridge slowly
transition eastward and resettle over the CWA. PWATs will trim
back slightly across the northern tier of the forecast area
resulting in less storm coverage. Even so, PWATs will trend near
an inch in southwest Colorado with CAM guidance projecting
numerous showers and thunderstorms over the southern and central
Colorado mountains during the afternoon. The similar threats of
lightning, heavy rain and localized flooding can once again be
expected through Monday evening.

.LONG TERM...(Tuesday through Sunday)
Issued at 206 PM MDT Sun Jul 25 2021

On Tuesday, the high pressure aloft will become centered over the
Central Plains placing our area under weak south-southeast flow.
This is a favorable pattern for monsoon moisture to advect into the
CWA, and as a result widespread storms and the potential for heavy
rainfall will exist. The high pressure is expected to drift over the
Central and Southern Plains, but overall this shouldn't affect the
sensible weather through next weekend. There are hints in the models
that a remnant tropical low pressure from Mexico may get absorbed
into the flow around the high later in the week. This could enhance
or hinder convection depending on the timing and where it tracks
over the region. Although the general trend is that precipitation
coverage increases due to the remnant low. The consensus is for the
low to get steered towards the Four Corners and or Great Basin. One
thing different from this current high placement is that next week
convectively induced waves may form upstream (NM/AZ) and move over
our area overnight. This means nocturnal storms may be better
supported. The latest ensemble means in the 8 to 10 day period
maintains ridging placed over the Northern Rockies, with the
midlevel high centered over the Texas Panhandle.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 530 PM MDT Sun Jul 25 2021

Evening storms may produce heavy rainfall and lightning at most
TAF sites except KVEL and KHDN where a slightly drier airmass is
in place. VFR should prevail with temporary MVFR conditions
possible if a shower directly impacts the airfield. Expect similar
weather to play out from late Monday morning through the
afternoon.

&&

.HYDROLOGY...
Issued at 206 PM MDT Sun Jul 25 2021

The threat of heavy rainfall still exists with above normal
moisture remaining in the area. This will lead to localized
flooding today due to slow storm motion and the possibility of
training storms. Similar conditions are expected into the new
week. The most vulnerable areas will be burn scars and areas
which have received heavy rainfall the past few days and have
already experienced flooding or debris flows. The potential for
more widespread flooding returns by mid next week as the high
drifts towards the southern Plains, advecting additional pulses of
monsoonal moisture into the region. Please continue to remain up-
to-date on the latest forecast, particularly if travelling.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Flash Flood Watch until 8 PM MDT this evening for COZ008-010-013.

UT...None.

&&

SHORT TERM...MMS
LONG TERM...KJS
AVIATION...TGJT
HYDROLOGY...TGJT

Hazardous Weather Outlook
National Weather Service Grand Junction CO
528 AM MDT Sun Jul 25 2021

COZ001>014-017>023-UTZ022>025-027>029-261130-
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-
528 AM MDT Sun Jul 25 2021

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

.DAY ONE...Today and Tonight

Thunderstorm development will occur today especially over the
mountains by early afternoon. Lightning will be the main threat
along with gusty outflow winds. A few storms will be capable of
producing locally heavy rainfall which could lead to flooding.
Thunderstorms should dissipate by the early morning hours.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Daily scattered to numerous showers and thunderstorms can be
expected each day with monsoon moisture entrenched across the area.
Moderate to heavy rain and gusty winds will be the primary
threats with storms along with lightning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Special Weather Statement
National Weather Service Grand Junction CO
603 PM MDT Sun Jul 25 2021

UTZ025-260045-
Tavaputs Plateau UT-
603 PM MDT Sun Jul 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL UINTAH COUNTY UNTIL
645 PM MDT...

At 601 PM MDT, Doppler radar was tracking a strong thunderstorm 45
miles east of Sunnyside, or 49 miles northeast of Green River, moving
southwest at 15 mph.

Half inch  hail and winds in excess of 40 mph will be possible with
this storm.

This storm will remain over mainly rural areas of south central
Uintah County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall is also occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3966 10954 3953 10941 3937 10954 3943 10971
      3957 10976
TIME...MOT...LOC 0001Z 055DEG 13KT 3953 10955

MDM/NL

Special Weather Statement
National Weather Service Grand Junction CO
803 PM MDT Sun Jul 25 2021

COZ006-017-260245-
Uncompahgre Plateau/Dallas Divide CO-Grand Valley CO-
803 PM MDT Sun Jul 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL MESA COUNTY UNTIL
845 PM MDT...

At 802 PM MDT, Doppler radar was tracking a strong thunderstorm near
Fruita, or 11 miles west of Grand Junction, moving southeast at 10
mph.

Half inch  hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Glade Park and Redlands.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall is also occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3909 10888 3914 10880 3904 10863 3898 10871
      3895 10884
TIME...MOT...LOC 0202Z 318DEG 9KT 3907 10878

MDM/NL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
852 PM MDT SUN JUL 25 2021

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

0839 PM     TSTM WND GST     2 NW MONTROSE           38.50N 107.90W
07/25/2021  M48 MPH          MONTROSE           CO   ASOS

            ASOS STATION KMTJ MONTROSE RGNL AIRPORT.

&&

NL