A surge of subtropical moisture into the area resulted in some thunderstorms with heavy rainfall in northwest Colorado.
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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.
A surge of subtropical moisture into the area resulted in some thunderstorms with heavy rainfall in northwest Colorado.
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 Aug 3, 9:41 AM MST, 4 hours 19 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 1041 AM MDT WED AUG 3 2016 .SHORT TERM...(Today through Thursday) Issued at 228 AM MDT Wed Aug 3 2016 Mid to high level clouds remain over the southern half of the CWA this morning with a few showers down south thrown in for good measure. Today looks to be the start of the monsoonal push of moisture as latest mesoscale analysis indicating around 1.2 inches of PWAT for the four corners region. This moisture will be worked on by daytime heating and also a small perturbation which is currently over northeastern Arizona. H7 winds show a very weak area of low pressure in that area and this forcing is reflected in increased QPF from the NAM and GFS. This weak disturbance will approach the four corners region today and models show some enhanced QPF along with it. The 06Z NAM run really ratchets up preciptation for our southern areas starting around noontime and continuing through midnight. The GFS likes this solution too though not as robust. Felt it prudent to go with flash flood watch for this afternoon and evening for the San Juans, southeastern Utah and also our southern valleys. Ample moisture, slow moving storms and some forcing should all lend themselves for some heavy rainers through the day. Aside from the precipitation down south, a deep area of low pressure moving along the U.S. and Canadian border will drag a front through the northern Rockies and this front will just graze our area this evening. By the time it reaches our area, it will have weakened quite a bit but still looks to be the focus for some showers and storms though not as strong as those down south. Once the front/trough moves through, winds will switch to the northwest overnight and limit advecting moisture from the south for areas north of I-70. For Thursday then, moisture will continue to stream up from the south while the weak low also moves over the CWA. Add to the mix an upper level trough approaching from the Great Basin and all ingredients are in place for some heavy rainfall. At this point, the heaviest precip looks to fall over the four corners region during the day before transitioning to the San Juans and the mountains on our side of the Continental Divide in the afternoon and evening hours. A flash flood watch looks very likely but held off this morning to allow a model run or two to really nail down the specifics. It will also allow day shift to see how models do today with forecast precipitation. .LONG TERM...(Thursday night through Tuesday) Issued at 307 PM MDT Tue Aug 2 2016 Another shortwave moves through the region on Friday with widespread storm coverage spreading across much of the area. Steering flow remains light. That being said, potential exists for more widespread flash flooding, mainly areas south of I-70, due to deep moisture, added forcing/lift with disturbances, and light steering flow with very little storm motion. Some concerns are that there may be too much cloud cover due to the substantial increase in moisture, which would limit convective potential. Will issue a Special Weather Statement (SPS) to address this heightened potential and let later shifts hone in on the details before deciding on a possible Flash Flood Watch. Saturday through Tuesday...the upper low will remain positioned over the Pacific Northwest through Monday before it finally begins its eastward track through Idaho and Montana by Tuesday. Enough moisture will remain over the region for daily storms each afternoon and evening this weekend, beginning over the higher terrain with drift into some adjacent valleys. Disturbances will continually be ejected out from this upper low, but will not have a direct impact on our area, so expect most activity to die down by midnight. Drier air will slowly advect in from the west throughout this period. Expect a more significant downturn in convection Monday and Tuesday as the upper low tracks eastward along the U.S.-Canadian border, bringing much drier air in from the west, with focus for convection mainly over higher terrain of western Colorado. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1041 AM MDT Wed Aug 3 2016 The day will start off VFR conditions with conditions deteriorating throughout the afternoon and evening. Showers and thunderstorms will develop after 17Z and continue through 03Z Thursday for most areas. Some storms may linger all night especially over southeast Utah and southwest Colorado, impacting KTEX and KDRO. Storms will be slow moving with heavy rainfall and gusty winds from stronger storms, reducing cigs and vsby to MVFR/IFR at times. && .GJT Watches/Warnings/Advisories... CO...Flash Flood Watch through this evening for COZ018>023. UT...Flash Flood Watch through this evening for UTZ022-028-029. && SHORT TERM...TGR LONG TERM...MDA AVIATION...MDA
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
The national radar mosaic for the moment the first event began.
1 debris flow. Local standard time, as filed.
Heavy rainfall resulted in a mudslide across County Road 76.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2016Every state in 2016This day in weather historyWarnings in Colorado, August 2016
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: 683089.