While some areas in western Colorado received above normal precipitation, above normal temperatures continued throughout the month of August. As a result, drought conditions in western Colorado persisted.
Every event with a place to put it; 21 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GJT wrote it up.
While some areas in western Colorado received above normal precipitation, above normal temperatures continued throughout the month of August. As a result, drought conditions in western Colorado persisted.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Junction, CO wrote its last area forecast discussion before the first event at Jul 31, 9:52 PM MST, 2 hours 8 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 1052 PM MDT Tue Jul 31 2018 .SHORT TERM...(Tonight through Wednesday night) Issued at 240 PM MDT Tue Jul 31 2018 With high pressure sitting to the west, the western slope is sitting on the eastern periphery of the high with a drier north to northwest flow overhead. There is no shower or thunderstorm development yet this afternoon with a few cumulus clouds forming over the southern ridges. Do not anticipate much in the way of precipitation due to the more stable atmosphere present today, helping to suppress the cumulus growth. A bit more cloud cover is anticipated tonight with an increase in high level moisture, so not expecting temperatures to be quite as cool as they were this morning. The morning started off a bit smokey as smoke from the wildfires in California is making its way around the high pressure and down into our CWA for widespread hazy and smokey skies. The several wildfires burning across our state are allowing for localized heavier smoke nearby, as seen on radar and satellite this afternoon. The HRRR smoke model shows this trend continuing through at least Wednesday night/Thursday morning, so kept smoke in the forecast through that period. Wednesday will be a transitional day as the high pressure begins slowly shifting eastward, allowing for a little more moisture to infiltrate from the west. Precipitable water (PW) values rise towards 0.75 inches across eastern Utah and extreme western Colorado, which will result in isolated to scattered thunderstorms over the higher terrain Wednesday afternoon. Storms are expected to be high based with gusty outflow winds and lightning the main concerns. A weak shortwave looks to rotate around the periphery of this high, which does remain to the west, but it seems that this shortwave will impact locations more downstream over the Front Range as it interacts with better moisture. Overall though, anticipating a mostly dry, smokey and hot day. Afternoon temperatures overall have been trending warmer than guidance in this type of regime, so inched those numbers a bit above statistical guidance. .LONG TERM...(Thursday through Tuesday) Issued at 240 PM MDT Tue Jul 31 2018 The high pressure ridge will begin a more eastward shift on Thursday as a trough pushes into the Pacific Northwest, allowing the flow to lay over to the west. This will also advect in better moisture as PW rises above 0.75 towards an inch near the Four Corners and eastern Utah. Anticipating a dry start to Thursday as the better moisture and associated stronger shortwave do not arrive until Thursday evening. This will carryover into Friday, which is looking like the better day in terms of thunderstorm chances and coverage, as well as better moisture, with PW values above an inch across portions of eastern Utah and western Colorado. The regime will transition on Thursday from drier, high based thunderstorms towards better chance of heavy rainers heading into Friday. The valleys even look to be impacted late Thursday into Friday as this better moisture push is supported by a more robust shortwave and better upper level support. Due to the heavy rain potential increasing for Friday, future shifts will have to look at potential for localized flash flooding on any recent burn scars. This is still a few days out so models can change, but something to keep in mind. Temperatures will be hot on Thursday and a bit cooler Friday due to increased clouds and showers. Still trended above guidance as periods of sun still expected to heat things up despite the increase, but it will not feel as noticeably hot. Confidence decreases this weekend into early next week as the models become out of phase with each other. Expecting enough residual moisture to hang around this weekend for afternoon storms focused over the higher terrain and drifting into some valleys late in the day with the high shifting a bit eastward but still having its influence over our region. An embedded shortwave looks to move through the flow late Sunday, for another potential uptick in storm activity through the evening. By early next week, the GFS is now indicating the high pressure building back to the west over the Great Basin, bringing much drier air into the region from the north-northwest which is quite the polar opposite from the model runs 24 hours ago. The EC, however, is still holding onto the ridge placement east of the divide with a decent continued push of moisture from the southwest. The trend so far this summer has been to shift the high back west after a decent moisture push so trending towards the drier forecast for next week, until models come into better agreement. Temperatures are also anticipated to make a rebound late this weekend into next week due to the drier trend. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1052 PM MDT Tue Jul 31 2018 Drier air in north-northwesterly flow will continue to bring widespread VFR conditions to the region through 12Z. Clouds will increase after 15Z with isolated showers and storms beginning to fire off over the higher terrain by 18Z as a weak disturbance moves through. Activity will continue through sunset. Areas of smoke and haze will persist through Wednesday, though VIS at TAF sites should remain at VFR conditions. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...MDA LONG TERM...MDA AVIATION...MMS
Hazardous Weather Outlook National Weather Service Grand Junction CO 635 AM MDT Tue Jul 31 2018 COZ001>014-017>023-UTZ022>025-027>029-011245- 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- 635 AM MDT Tue Jul 31 2018 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Dry weather will continue through midweek with an in thunderstorm activity over the higher terrain arriving by Wednesday as some moisture trickles back into the region. Friday will be the most active day for thunderstorms in the higher terrain with some gusty winds and heavy downpours possible. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
21 drought. Local standard time, as filed.
Exceptional (D4) drought conditions persisted through the end of the month.
Exceptional (D4) drought conditions persisted through the end of the month.
Extreme (D3) drought conditions persisted across the eastern portion of the zone through the end of the month while exceptional (D4) drought conditions remained over the far western portion of the zone.
Extreme (D3) drought conditions remained across the southeastern portion of the zone throughout the month while exceptional (D4) drought conditions remained across the rest of the zone.
Exceptional (D4) drought conditions remained across the far western portion of the zone and even inched further northeast by mid August. Meanwhile, extreme (D3) drought conditions persisted across the remainder of the zone through the end of the month.
Exceptional (D4) drought conditions persisted across all but the far northwest portion of the zone where extreme (D3) drought status continued through the end of the month.
Exceptional (D4) drought conditions expanded in mid August to include all but the northwest portion of the zone where extreme (D3) drought status continued through the end of the month.
Extreme (D3) drought conditions persisted through the end of the month and worsened to exceptional (D4) drought status in mid August across the southern portion of the zone.
Extreme (D3) drought conditions persisted across the zone through the end of the month.
Extreme (D3) drought conditions persisted through the end of the month and worsened to exceptional (D4) drought status across the far western portion of the zone in mid August.
Extreme (D3) drought conditions persisted through the end of the month and expanded to encompass the entirety of the zone by mid August.
Extreme (D3) drought conditions persisted across the zone through the end of the month.
Extreme (D3) drought conditions continued through the end of the month and expanded to encompass the entirety of the zone by mid August.
Extreme (D3) drought conditions continued across the zone through the end of the month.
Extreme (D3) drought conditions persisted across the far western portion of the zone through the end of the month and expanded to encompass almost the entirety of the zone by mid August.
Extreme (D3) drought conditions persisted across the far southwest portion of the zone through the end of the month and expanded to include the entirety of the zone by mid August.
Extreme (D3) drought conditions persisted across the far western portion of the zone through the end of the month and expanded to encompass the southern half of the zone by mid August.
Extreme (D3) drought conditions persisted across the far southern portion of the zone through the end of the month and expanded to encompass the entirety of the zone by mid August.
Severe (D2) drought conditions that had been in place since July worsened in mid August when the situation deteriorated to the extreme (D3) drought category across all but the far northern portion of the zone. The extreme drought conditions persisted through the end of the month.
Severe (D2) drought conditions that had been in place since July worsened in mid August when the situation deteriorated to the extreme (D3) drought category across the southern half of the zone. The extreme drought conditions persisted in that area through the end of the month.
Severe (D2) drought conditions that had been in place since the beginning of the month quickly deteriorated to the extreme (D3) drought category across the southern half of the zone by mid August. The extreme drought conditions persisted in that area through the end of the month.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2018Every state in 2018This day in weather historyWarnings in Colorado, August 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 774636, 774637, 774638, 774639, 774640, 774641, 774642, 774643, 774644, 774645, 774646, 774647, 774648, 774649, 774650, 774651, 774652, 774653, 774655, 774657, 774660.