Heat Advisory
URGENT - WEATHER MESSAGE
National Weather Service Rapid City SD
307 PM MDT Fri Jul 17 2026
SDZ001-002-012>014-025>027-030>032-041>044-046-047-049-072>078-
WYZ054>056-058>060-181215-
/O.CON.KUNR.HT.Y.0001.000000T0000Z-260720T0300Z/
Harding-Northern Perkins-Butte-Northern Meade Co Plains-Ziebach-
Northern Foothills-Rapid City-Southern Foothills-Custer Co Plains-
Pennington Co Plains-Haakon-Western Fall River-Northern Oglala
Lakota-Northern Jackson-Bennett-Mellette-Todd-Tripp-
Sturgis/Piedmont Foothills-Southern Meade Co Plains-Hermosa
Foothills-Eastern Fall River-Southern Oglala Lakota-Southern
Jackson-Southern Perkins-Northern Campbell-Southern Campbell-
Western Crook-Weston County Plains-Newcastle-Northeastern Crook-
Including the cities of Buffalo, Wasta, Milesville, Shadehill,
Hamill, Cherry Creek, Weston, Whitewood, Glad Valley, Osage, Rapid
City, Rozet, Oglala, Summerset, Quinn, Tuthill, Sharps Corner,
Ellsworth AFB, Pine Haven, Winner, Beulah, Smithwick, Upton, Long
Valley, Fairburn, Rosebud, Opal, Spearfish, Rumford, New Underwood,
Belvidere, Kadoka, Colome, Batesland, Bison, Piedmont, Howes, Caputa,
Fruitdale, South Eagle Butte, Martin, Cedar Butte, Belle Fourche,
Hermosa, Sturgis, Keyhole Reservoir, Witten, Ideal, Reva, Harrington,
Newell, Dupree, Wright, Belle Fourche Reservoir, Clareton, Saint
Francis, Box Elder, Buffalo Gap, Wall, Ardmore, Pine Ridge, Wanblee,
Recluse, Oelrichs, Wood, Mission, Potato Creek, Mud Butte, Provo,
White Owl, Rockyford, Devils Tower, Camp Crook, Hot Springs, Zeona,
Norris, Meadow, Edgemont, Newcastle, Scenic, Folsom, Wounded Knee,
Midland, Oral, Lemmon, Prairie City, Ludlow, White River, Saint Onge,
Rochelle, Ladner, Gillette, Red Owl, Elm Springs, Colony, Aladdin,
Hulett, Black Hawk, Enning, Porcupine, Faith, Moorcroft, Interior,
Parmelee, Allen, Usta, Philip, Manderson, Kyle, Cottonwood, Vale,
Union Center, Angostura Reservoir, Sorum, Tilford, Redig, and Hoover
307 PM MDT Fri Jul 17 2026 /407 PM CDT Fri Jul 17 2026/
...HEAT ADVISORY REMAINS IN EFFECT UNTIL 9 PM MDT /10 PM CDT/
SUNDAY...
* WHAT...Peak afternoon heat index values of 95 to 105.
* WHERE...Portions of northwestern, south central, and southwestern
South Dakota and northeast Wyoming.
* WHEN...Until 9 PM MDT /10 PM CDT/ Sunday.
* IMPACTS...Hot temperatures may cause heat illnesses.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
&&
$$
Wong
URGENT - WEATHER MESSAGE
National Weather Service Cheyenne WY
1212 PM MDT Fri Jul 17 2026
NEZ003-019>021-096-WYZ101-102-108-181200-
/O.NEW.KCYS.HT.Y.0002.260719T1800Z-260721T0000Z/
Box Butte County-Scotts Bluff County-Banner County-Morrill County-
Southern Sioux County-Converse County Lower Elevations-Niobrara
County-Goshen County-
Including the cities of Hemingford, Douglas, Harrisburg,
Alliance, Bridgeport, Redington, Agate, Bayard, Redbird, Angora,
Torrington, Gering, Glenrock, Bill, Deer Creek, Lusk, and
Scottsbluff
1212 PM MDT Fri Jul 17 2026
...HEAT ADVISORY IN EFFECT FROM NOON SUNDAY TO 6 PM MDT MONDAY...
* WHAT...Afternoon temperatures between the upper 90`s to low 100`s
with overnight lows in the mid 60`s to low 70`s.
* WHERE...In Nebraska, Banner County, Box Butte County, Morrill
County, Scotts Bluff County, and Southern Sioux County. In
Wyoming, Converse County Lower Elevations, Niobrara County, and
Goshen County.
* WHEN...From noon Sunday to 6 PM MDT Monday.
* IMPACTS...Hot temperatures and high humidity may cause heat
illnesses.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
&&
$$
CG
URGENT - WEATHER MESSAGE
National Weather Service Cheyenne WY
1212 PM MDT Fri Jul 17 2026
NEZ002-095-181200-
/O.NEW.KCYS.HT.Y.0002.260718T1800Z-260721T0000Z/
Dawes County-Northern Sioux County-
Including the cities of Chadron St Park, Chadron, and Harrison
1212 PM MDT Fri Jul 17 2026
...HEAT ADVISORY IN EFFECT FROM NOON SATURDAY TO 6 PM MDT MONDAY...
* WHAT...Afternoon temperatures between the upper 90`s to low 100`s
with overnight lows in the mid 60`s to low 70`s.
* WHERE...Dawes County and Northern Sioux County.
* WHEN...From noon Saturday to 6 PM MDT Monday.
* IMPACTS...Hot temperatures and high humidity may cause heat
illnesses.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Denver CO
1200 PM MDT Fri Jul 17 2026
COZ038>040-043-181245-
/O.NEW.KBOU.HT.Y.0002.260719T1600Z-260721T0300Z/
Larimer County Below 6000 Feet/Northwest Weld County-Boulder And
Jefferson Counties Below 6000 Feet/West Broomfield County-North
Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe
Counties/East Broomfield County-Central and South Weld County-
Including the cities of Fort Collins, Longmont, Fort Lupton,
Littleton, Boulder, Lakewood, Brighton, Eaton, Hereford, City of
Denver, Arvada, Golden, Nunn, Greeley, Denver International Airport,
Loveland, Highlands Ranch, Parker, Aurora, and Roggen
1200 PM MDT Fri Jul 17 2026
...HEAT ADVISORY IN EFFECT FROM 10 AM SUNDAY TO 9 PM MDT MONDAY...
* WHAT...High temperatures between 99-102 expected. Low temperatures
Sunday night will be between 69-71 in the Denver metro.
* WHERE...Fort Collins, Boulder and the western suburbs of Denver,
Denver, and Greeley.
* WHEN...From 10 AM Sunday to 9 PM MDT Monday.
* IMPACTS...Hot temperatures may cause heat illnesses.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
Take extra precautions when outside. Wear lightweight and loose
fitting clothing. Try to limit strenuous activities to early morning
or evening. Take action when you see symptoms of heat exhaustion and
heat stroke.
To reduce risk during outdoor work, the Occupational Safety and
Health Administration recommends scheduling frequent rest breaks in
shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an
emergency! Call 9 1 1.
&&
$$
For more information from the National Weather Service, visit
https://weather.gov/bou
22
Flood Advisory
Flood Advisory
National Weather Service Riverton WY
840 PM MDT Fri Jul 17 2026
WYC043-180415-
/O.CON.KRIW.FA.Y.0020.000000T0000Z-260718T0415Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washakie WY-
840 PM MDT Fri Jul 17 2026
...FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1015 PM MDT THIS EVENING...
* WHAT...Small stream flooding in normally dry creeks caused by
excessive rainfall is expected.
* WHERE...The east side of Worland along Slick Creek and the roadways
that cross Slick Creek.
* WHEN...Until 1015 PM MDT.
* IMPACTS...Rises in small streams and normally dry washes. Water
could go over roadways as culverts plug. Overflowing in poor
drainage areas.
* ADDITIONAL DETAILS...
- At 839 PM MDT, Doppler radar indicated heavy rain due to
thunderstorms. This will cause normally dry creeks (e.g. Slick
Creek) and small stream flooding. Between 1 and 2 inches of rain
have fallen upstream in the Slick Creek drainage.
- This includes the following streams and drainages...
Slick Creek all the way to the Bighorn River, Tenmile Creek, East
Fork Nowater Creek, Marconi Pit Drain, East Fork Sand Creek and
Sand Creek.
- Some locations that will experience flooding include...
Locations along Slick Creek.
- http://www.weather.gov/safety/flood
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don`t drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Remain alert for flooding even in locations not receiving rain.
Arroyos, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4396 10792 4400 10793 4407 10796 4408 10794
4402 10785 4403 10780 4399 10772 4395 10776
4393 10782
$$
TL
Flood Advisory
National Weather Service Billings MT
756 PM MDT Fri Jul 17 2026
MTC003-180500-
/O.NEW.KBYZ.FA.Y.0020.260718T0156Z-260718T0500Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Big Horn MT-
756 PM MDT Fri Jul 17 2026
...FLOOD ADVISORY IN EFFECT UNTIL 11 PM MDT THIS EVENING...
* WHAT...Flooding caused by excessive rainfall is expected.
* WHERE...Northwestern Big Horn County in south central Montana...
* WHEN...Until 1100 PM MDT.
* IMPACTS...Minor flooding in low-lying and poor drainage areas.
Rainfall will drain into the Bighorn River potentially causing
increases in flows.
* ADDITIONAL DETAILS...
- At 754 PM MDT, Doppler radar indicated heavy rain due to
thunderstorms. Minor flooding is ongoing or expected to begin
shortly in the advisory area. Between 1.5 and 2.5 inches of rain
have fallen.
- Additional rainfall amounts up to 0.5 inches are expected over
the area. This additional rain will result in minor flooding.
- Some locations that will experience flooding include...
Mainly rural areas of Northwestern Big Horn County.
- http://www.weather.gov/safety/flood
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don`t drown when encountering flooded roads. Most flood
deaths occur in vehicles. Do not drive on or attempt to cross flooded
roads, find an alternate route. Roads and driveways may be damaged or
washed out in places.
&&
LAT...LON 4554 10754 4555 10775 4566 10766 4564 10754
$$
Torgerson
Flood Watch
Flood Watch
National Weather Service Riverton WY
1033 AM MDT Fri Jul 17 2026
WYZ001-180400-
/O.EXA.KRIW.FA.A.0002.260717T1800Z-260718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yellowstone National Park-
Including the cities of Lake, Old Faithful, and Mammoth
1033 AM MDT Fri Jul 17 2026
...FLOOD WATCH IN EFFECT UNTIL 10 PM MDT THIS EVENING...
* WHAT...Flooding caused by excessive rainfall continues to be
possible.
* WHERE...A portion of northwest Wyoming, including the following
area, Yellowstone National Park.
* WHEN...Until 10 PM MDT this evening.
* IMPACTS...Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.
* ADDITIONAL DETAILS...
- Heavy rainfall from slow moving showers and thunderstorms may
bring local flooding.
- http://www.weather.gov/safety/flood
PRECAUTIONARY/PREPAREDNESS ACTIONS...
You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.
&&
$$
Flood Watch
National Weather Service Riverton WY
1033 AM MDT Fri Jul 17 2026
WYZ002>005-007-180400-
/O.CON.KRIW.FA.A.0002.260717T1800Z-260718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Absaroka Mountains-Cody Foothills-North Bighorn Basin-Southwest
Bighorn Basin-Owl Creek and Bridger Mountains-
Including the cities of Cody, Lovell, Clark, Shell, Meeteetse,
Greybull, Thermopolis, Powell, and Basin
1033 AM MDT Fri Jul 17 2026
...FLOOD WATCH REMAINS IN EFFECT UNTIL 10 PM MDT THIS EVENING...
* WHAT...Flooding caused by excessive rainfall continues to be
possible.
* WHERE...Portions of central and northwest Wyoming, including the
following areas, in central Wyoming, Owl Creek and Bridger
Mountains and Southwest Bighorn Basin. In northwest Wyoming,
Absaroka Mountains, Cody Foothills and North Bighorn Basin.
* WHEN...Until 10 PM MDT this evening.
* IMPACTS...Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.
* ADDITIONAL DETAILS...
- Heavy rainfall from slow moving showers and thunderstorms may
bring local flooding.
- http://www.weather.gov/safety/flood
PRECAUTIONARY/PREPAREDNESS ACTIONS...
You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.
&&
$$
Straub
Air Quality Alert
COC005-001-031-014-059-013-069-123-035-182200-
Arapahoe-Adams-Denver-Broomfield-Jefferson-Boulder-Larimer-
Weld-Douglas-
410 PM MDT Fri Jul 17 2026
...OZONE ACTION DAY ALERT FROM 400 PM FRIDAY UNTIL 400 PM
SATURDAY...
The Colorado Department of Public Health and Environment has
issued the following...
WHAT...Ozone Action Day Alert.
WHERE...Douglas, Jefferson, Denver, western Arapahoe, western
Adams, Broomfield, Boulder, Larimer, and Weld Counties
WHEN...400 PM Friday July 17 to 400 PM Saturday July 18
IMPACTS...Ozone Action Day Alert is now in effect for the Front
Range Urban Corridor. Hot and sunny weather will result in
concentrations of ozone reaching the Unhealthy for Sensitive
Groups category on Friday and Saturday. The highest concentrations
are most likely in the western portions of the Denver Metro area,
including the lower foothills. For Colorado air quality
conditions, forecasts, and advisories, visit:
https://www.colorado.gov/airquality/colorado_summary.aspx If
possible, please help us reduce ozone pollution by limiting
driving gas and diesel-powered vehicles until at least 4 p.m.
Saturday, July 18, 2026. Colorado is also addressing ozone
pollution through state policies. For more information about
health impacts and how ozone pollution forms in Colorado, visit:
https://cdphe.colorado.gov/ozone- pollution-and-your-health
HEALTH INFORMATION...Increasing likelihood of respiratory symptoms
and breathing discomfort in active children and adults and people
with lung disease, such as asthma. Active children and adults, and
people with lung disease, such as asthma, should reduce prolonged
or heavy outdoor exertion.
$$
Hydrologic Outlook
Hydrologic Outlook
COC007-029-033-045-051-053-067-077-081-083-085-091-103-107-111-113-
UTC019-037-200300-
Hydrologic Outlook
National Weather Service Grand Junction CO
435 PM MDT Fri Jul 17 2026
...RISK OF FLASH FLOODING AND DEBRIS FLOWS INCLUDING RECENT BURN
SCARS...
Anomalous moisture has become established across portions of
eastern Utah and western Colorado. Rainfall rates of 1-2 inches
per hour will be possible with the stronger storms. These rates
could lead to flash flooding and debris flows especially over
recent burn scars.
Storms over the last few days have helped prime lower levels of
the atmosphere and saturate the ground where rain was observed.
Several locations across southwest Colorado reported over 0.5
inches of rain within 30 minutes; which is more than sufficient
to create issues in our steep, rocky terrain that is already
susceptible to flash flooding. This environment also triggers
heightened awareness over recent (or actively burning) fires,
due to the burnt ground`s inability of absorbing moisture under
heavy rainfall. As such, we continue to emphasize the potential
for flash flooding and debris flows in this regime.
As a reminder: Keep an eye on our forecasts through the end of
the week and stay tuned for updated hydrology alerts if
visiting or if you reside below vulnerable terrain to flash
flooding and/or debris flows. Storms across the west develop
quickly, leaving little room for lead time in flashy terrain.
$$
KJS
