Alert archive / Arizona / Flash Flood Watches in 2021
Flash Flood Watch 4, NWS Tucson, AZ
NWS Tucson, AZ issued this flash flood watch at Jul 29, 2021, 2:06 PM MST for Pima County, Pinal County, Arizona. It took effect at Jul 30, 2021, 12:00 PM MST. It was in force for 17 hr.
The area
The counties it named.
The facts
- Issued
- Jul 29, 2021, 2:06 PM MST (21:06 UTC)
- In effect from
- Jul 30, 2021, 12:00 PM MST
- Expired
- Jul 31, 2021, 5:00 AM MST
- In force
- 17 hr
- Issued by
- NWS Tucson, AZ
- Flood severity
- None
Counties Pima County, AZ, Pinal County, AZ
The radar
The Phoenix radar (KIWA), 88 km from the middle of the area, began a volume at 21:05 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 12:00Z, 9.1 hours before the alert went out and 73 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
- 153 J/kg
- Mixed-layer CIN
- -305 J/kg
- Mixed-layer LCL
- 2293 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- -36 m²/s²
- 0-3 km storm-relative helicity
- 23 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
832 WGUS65 KTWC 292106 FFATWC URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Tucson AZ 206 PM MST Thu Jul 29 2021 AZZ501-502-300515- /O.NEW.KTWC.FF.A.0004.210730T1900Z-210731T1200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Western Pima County-Tohono O'odham Nation- Including the cities of Organ Pipe Cactus N.M., Sells, and Ajo 206 PM MST Thu Jul 29 2021 ...FLASH FLOOD WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY NIGHT... The National Weather Service in Tucson has issued a * Flash Flood Watch for a portion of Southeast Arizona, including the following areas, Tohono O'odham Nation and Western Pima County. * From Friday afternoon through late Friday night. * Additional showers and thunderstorms, some with very heavy downpours, will be likely again Friday afternoon and Friday night. Therefore, there will be an increased threat of flash flooding. Larger washes such as the Vamori and San Simon may experience high flows due to local runoff from heavy rains. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ JD
5 follow-up statements
946 WGUS65 KTWC 300448 FFATWC Flood Watch National Weather Service Tucson AZ 948 PM MST Thu Jul 29 2021 AZZ501-502-302100- /O.CON.KTWC.FF.A.0004.210730T1900Z-210731T1200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Western Pima County-Tohono O'odham Nation- Including the cities of Organ Pipe Cactus N.M., Sells, and Ajo 948 PM MST Thu Jul 29 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY NIGHT... The Flash Flood Watch continues for * A portion of Southeast Arizona, including the following areas, Tohono O'odham Nation and Western Pima County. * From Friday afternoon through late Friday night. * Additional showers and thunderstorms, some with very heavy downpours, will be likely again Friday afternoon and Friday night. Therefore, there will be an increased threat of flash flooding. Larger washes such as the Vamori and San Simon may experience high flows due to local runoff from heavy rains. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ RH
290 WGUS65 KTWC 300957 FFATWC Flood Watch National Weather Service Tucson AZ 257 AM MST Fri Jul 30 2021 AZZ501-502-311200- /O.CON.KTWC.FF.A.0004.210730T1900Z-210731T1200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Western Pima County-Tohono O'odham Nation- Including the cities of Organ Pipe Cactus N.M., Sells, and Ajo 257 AM MST Fri Jul 30 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT FROM NOON MST TODAY THROUGH LATE TONIGHT... The Flash Flood Watch continues for * A portion of Southeast Arizona, including the following areas, Tohono O'odham Nation and Western Pima County. * From Noon MST today through late tonight. * Additional showers and thunderstorms, some with very heavy downpours, will be likely again today and tonight. Therefore, there will be an increased threat of flash flooding. Larger washes such as the Vamori and San Simon may experience high flows due to local runoff from heavy rains. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ JRM
588 WGUS65 KTWC 302101 FFATWC Flood Watch National Weather Service Tucson AZ 201 PM MST Fri Jul 30 2021 AZZ501-502-310515- /O.CON.KTWC.FF.A.0004.000000T0000Z-210731T1200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Western Pima County-Tohono O'odham Nation- Including the cities of Organ Pipe Cactus N.M., Sells, and Ajo 201 PM MST Fri Jul 30 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH LATE TONIGHT... The Flash Flood Watch continues for * A portion of Southeast Arizona, including the following areas, Tohono O'odham Nation and Western Pima County. * Through late tonight. * Additional showers and thunderstorms, some with very heavy downpours, will be likely through tonight. Therefore, there will be an increased threat of flash flooding. Larger washes such as the Vamori and San Simon may experience high flows due to local runoff from heavy rains. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ JD
045 WGUS65 KTWC 310533 FFATWC Flood Watch National Weather Service Tucson AZ 1033 PM MST Fri Jul 30 2021 AZZ501-502-311200- /O.CON.KTWC.FF.A.0004.000000T0000Z-210731T1200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Western Pima County-Tohono O'odham Nation- Including the cities of Organ Pipe Cactus N.M., Sells, and Ajo 1033 PM MST Fri Jul 30 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 5 AM MST SATURDAY... The Flash Flood Watch continues for * A portion of Southeast Arizona, including the following areas, Tohono O'odham Nation and Western Pima County. * Until 5 AM MST Saturday. * Additional showers and thunderstorms, some with very heavy downpours, will be likely through tonight. Therefore, there will be an increased threat of flash flooding. Larger washes such as the Vamori and San Simon may experience high flows due to local runoff from heavy rains. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ WJM
372 WGUS65 KTWC 311150 FFATWC Flood Watch National Weather Service Tucson AZ 450 AM MST Sat Jul 31 2021 AZZ501-502-311300- /O.EXP.KTWC.FF.A.0004.000000T0000Z-210731T1200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Western Pima County-Tohono O'odham Nation- Including the cities of Organ Pipe Cactus N.M., Sells, and Ajo 450 AM MST Sat Jul 31 2021 ...FLASH FLOOD WATCH WILL EXPIRE AT 5 AM MST EARLY THIS MORNING... The Flash Flood Watch for a portion of Southeast Arizona, including the following areas, Tohono O'odham Nation and Western Pima County will expire at 5 AM MST early this morning. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures. $$ JRM
The office that day
Everything else NWS Tucson, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 8:12 PM MST | Areal Flood Advisory | TWC | Cochise | 63 min |
| Jul 29, 1:20 PM MST | Severe Thunderstorm Warning | TWC | Pima | 40 min |
| Jul 29, 1:55 PM MST | Areal Flood Advisory | TWC | Pima | 2 hr |
| Jul 29, 2:08 PM MST | Special Weather Statement | TWC | 37 min | |
| Jul 29, 2:42 PM MST | Flash Flood Warning | TWC | Pima | 2 hr |
| Jul 29, 2:44 PM MST | Special Weather Statement | TWC | Cochise | 61 min |
| Jul 29, 3:03 PM MST | Areal Flood Advisory | TWC | Cochise | 117 min |
| Jul 29, 3:10 PM MST | Special Weather Statement | TWC | Graham | 35 min |
| Jul 29, 4:54 PM MST | Areal Flood Advisory | TWC | Graham | 2 hr |
| Jul 29, 4:54 PM MST | Special Weather Statement | TWC | 36 min |
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.