Alert archive / Arizona / Flash Flood Watches in 2021
Flash Flood Watch 6, NWS Tucson, AZ
NWS Tucson, AZ issued this flash flood watch at Aug 17, 2021, 9:37 PM MST for 4 counties in Arizona. It took effect at Aug 18, 2021, 12:00 AM MST. It was in force for 20 hr.
The area
The counties it named.
The facts
- Issued
- Aug 17, 2021, 9:37 PM MST (04:37 UTC)
- In effect from
- Aug 18, 2021, 12:00 AM MST
- Expired
- Aug 18, 2021, 8:00 PM MST
- In force
- 20 hr
- Issued by
- NWS Tucson, AZ
- Flood severity
- None
Counties Cochise County, AZ, Graham County, AZ, Greenlee County, AZ, Pinal County, AZ
The radar
The Tucson radar (KEMX), 108 km from the middle of the area, began a volume at 04:39 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Tuscon, AZ (KTUS), launched 00:00Z, 4.6 hours before the alert went out and 101 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1326 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 1309 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- -13 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
640 WGUS65 KTWC 180437 FFATWC URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Tucson AZ 937 PM MST Tue Aug 17 2021 AZZ505-506-509>511-181245- /O.NEW.KTWC.FF.A.0006.210818T0700Z-210819T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ South Central Pinal County-Southeast Pinal County-Upper Gila River Valley-White Mountains of Graham and Greenlee Counties-Galiuro and Pinaleno Mountains- Including the cities of Picacho Peak State Park, Clifton, Mount Graham, Mammoth, Oracle, Hannagan Meadow, and Safford 937 PM MST Tue Aug 17 2021 ...FLASH FLOOD WATCH IN EFFECT THROUGH WEDNESDAY EVENING... The National Weather Service in Tucson has issued a * Flash Flood Watch for a portion of Southeast Arizona, including the following areas, Galiuro and Pinaleno Mountains, South Central Pinal County, Southeast Pinal County, Upper Gila River Valley and White Mountains of Graham and Greenlee Counties. * Through Wednesday evening. * A storm system moving southwest to northeast from Sonora Mexico will likely produce showers and thunderstorms later tonight into tomorrow afternoon or evening. Multiple rounds of showers and storms could lead to localized areas of 1 to 3 inches of rain. * Locally heavy rainfall combined with a saturated ground will likely result in flash flooding of washes, small streams, and poor drainage areas. Burn scars from past and more recent wildfires will be especially prone to flash flooding and debris flow. Flash flooding may also lead to significant mainstem river rises through Wednesday evening. This may result in some washes and rivers reaching flood stage. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ JRM
3 follow-up statements
006 WGUS65 KTWC 181127 FFATWC Flood Watch National Weather Service Tucson AZ 427 AM MST Wed Aug 18 2021 AZZ505-506-509>511-181930- /O.CON.KTWC.FF.A.0006.000000T0000Z-210819T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ South Central Pinal County-Southeast Pinal County-Upper Gila River Valley-White Mountains of Graham and Greenlee Counties-Galiuro and Pinaleno Mountains- Including the cities of Picacho Peak State Park, Clifton, Mount Graham, Mammoth, Oracle, Hannagan Meadow, and Safford 427 AM MST Wed Aug 18 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING... The Flash Flood Watch continues for * A portion of Southeast Arizona, including the following areas, Galiuro and Pinaleno Mountains, South Central Pinal County, Southeast Pinal County, Upper Gila River Valley and White Mountains of Graham and Greenlee Counties. * Through this evening. * A storm system moving southwest to northeast from Sonora Mexico will produce showers and thunderstorms this morning into this afternoon before ending this evening. Multiple rounds of showers and storms could lead to localized areas of 1 to 3 inches of rain. * Locally heavy rainfall combined with a saturated ground will likely result in flash flooding of washes, small streams, and poor drainage areas. Burn scars from past and more recent wildfires will be especially prone to flash flooding and debris flow. Flash flooding may also lead to significant mainstem river rises through Wednesday evening. This may result in some washes and rivers reaching flood stage. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
231 WGUS65 KTWC 181802 FFATWC Flood Watch National Weather Service Tucson AZ 1102 AM MST Wed Aug 18 2021 AZZ505-506-509>511-190300- /O.CON.KTWC.FF.A.0006.000000T0000Z-210819T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ South Central Pinal County-Southeast Pinal County-Upper Gila River Valley-White Mountains of Graham and Greenlee Counties-Galiuro and Pinaleno Mountains- Including the cities of Picacho Peak State Park, Clifton, Mount Graham, Mammoth, Oracle, Hannagan Meadow, and Safford 1102 AM MST Wed Aug 18 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 8 PM MST THIS EVENING... The Flash Flood Watch continues for * A portion of Southeast Arizona, including the following areas, Galiuro and Pinaleno Mountains, South Central Pinal County, Southeast Pinal County, Upper Gila River Valley and White Mountains of Graham and Greenlee Counties. * Until 8 PM MST this evening. * A storm system moving southwest to northeast from Sonora Mexico will produce showers and thunderstorms this morning into this afternoon before ending this evening. Multiple rounds of showers and storms could lead to localized areas of 1 to 3 inches of rain. * Locally heavy rainfall combined with a saturated ground will likely result in flash flooding of washes, small streams, and poor drainage areas. Burn scars from past and more recent wildfires will be especially prone to flash flooding and debris flow. Flash flooding may also lead to significant mainstem river rises through Wednesday evening. This may result in some washes and rivers reaching flood stage. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ WJM
620 WGUS65 KTWC 190301 FFATWC Flood Watch National Weather Service Tucson AZ 801 PM MST Wed Aug 18 2021 AZZ505-506-509>511-190415- /O.EXP.KTWC.FF.A.0006.000000T0000Z-210819T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ South Central Pinal County-Southeast Pinal County-Upper Gila River Valley-White Mountains of Graham and Greenlee Counties-Galiuro and Pinaleno Mountains- Including the cities of Picacho Peak State Park, Clifton, Mount Graham, Mammoth, Oracle, Hannagan Meadow, and Safford 801 PM MST Wed Aug 18 2021 ...FLASH FLOOD WATCH HAS EXPIRED... The Flash Flood Watch for a portion of Southeast Arizona, including the following areas, Galiuro and Pinaleno Mountains, South Central Pinal County, Southeast Pinal County, Upper Gila River Valley and White Mountains of Graham and Greenlee Counties has expired. Flooding is no longer expected to pose a threat, therefore the watch will be allowed to expire. Please continue to heed remaining road closures. $$ JRM
The office that day
Everything else NWS Tucson, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 7:18 PM MST | Severe Thunderstorm Warning | TWC | Pima | 42 min |
| Aug 17, 7:33 PM MST | Areal Flood Advisory | TWC | Pima | 4 min |
| Aug 17, 7:37 PM MST | Flash Flood Warning | TWC | Pima | 113 min |
| Aug 17, 7:44 PM MST | Areal Flood Advisory | TWC | Graham, Pima, Pinal | 3 hr |
Nearby
Flash Flood Watches in Arizona, 2021Every flash flood watch in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.