Alert archive / Arizona / Flash Flood Watches in 2021

Flash Flood Watch 2, NWS Tucson, AZ

July 18, 20216 counties in Arizona

NWS Tucson, AZ issued this flash flood watch at Jul 18, 2021, 1:28 PM MST for 6 counties in Arizona. It was in force for 11 hr.

The area

The counties it named.

The facts

Issued: Jul 18, 2021, 1:28 PM MST (20:28 UTC)
Expired: Jul 19, 2021, 12:00 AM MST
In force: 11 hr
Issued by: NWS Tucson, AZ
Flood severity: None

Counties Cochise County, AZ, Graham County, AZ, Greenlee County, AZ, Pima County, AZ, Pinal County, AZ, Santa Cruz County, AZ

The radar

The Tucson radar (KEMX), 61 km from the middle of the area, began a volume at 20:30 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, 8.5 hours before the alert went out and 49 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1146 J/kg
Mixed-layer CIN: -124 J/kg
Mixed-layer LCL: 1485 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

590 
WGUS65 KTWC 182028
FFATWC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Tucson AZ
128 PM MST Sun Jul 18 2021

.Thunderstorms are will continue to develop through the afternoon 
east and south of Tucson and they are expected to continue into the 
evening. Soils are very wet due to recent rains across portions of 
the watch area enhancing the potential for flooding due to heavy 
rains.

AZZ503-506>509-511>514-190700-
/O.NEW.KTWC.FF.A.0002.210718T2028Z-210719T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Upper Santa Cruz River Valley/Altar Valley-Southeast Pinal County-
Upper San Pedro River Valley-Eastern Cochise County below 5000 feet-
Upper Gila River Valley-Galiuro and Pinaleno Mountains-Chiricahua
Mountains-Dragoon and Mule and Huachuca and Santa Rita Mountains-
Catalina and Rincon Mountains-
Including the cities of Sierra Vista, Nogales, Willcox, Clifton, 
Mount Lemmon, Douglas, Canelo Hills, Mount Graham, Mammoth, Madera 
Canyon, Summerhaven, Oracle, Bisbee, Safford, Chiricahua NM, and 
Benson
128 PM MST Sun Jul 18 2021

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MST TONIGHT...

The National Weather Service in Tucson has issued a

* Flash Flood Watch for a portion of Southeast Arizona, including 
  the following areas, Catalina and Rincon Mountains, Chiricahua 
  Mountains, Dragoon and Mule and Huachuca and Santa Rita Mountains, 
  Eastern Cochise County below 5000 feet, Galiuro and Pinaleno 
  Mountains, Southeast Pinal County, Upper Gila River Valley, Upper 
  San Pedro River Valley and Upper Santa Cruz River Valley/Altar 
  Valley.

* Until Midnight MST tonight.

* Thunderstorms are expected into the evening hours with the 
  potential to produce rainfall heavy enough to result in local 
  Flash Flooding.

* Potential for flooded washes and streams with fast moving water 
  resulting in flooded roads near washes and streams and at low 
  water crossings.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

CC

1 follow-up statement

279 
WGUS65 KTWC 190702
FFATWC

Flood Watch
National Weather Service Tucson AZ
1202 AM MST Mon Jul 19 2021

AZZ503-506>509-511>514-190815-
/O.EXP.KTWC.FF.A.0002.000000T0000Z-210719T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Upper Santa Cruz River Valley/Altar Valley-Southeast Pinal County-
Upper San Pedro River Valley-Eastern Cochise County below 5000 feet-
Upper Gila River Valley-Galiuro and Pinaleno Mountains-Chiricahua
Mountains-Dragoon and Mule and Huachuca and Santa Rita Mountains-
Catalina and Rincon Mountains-
Including the cities of Sierra Vista, Nogales, Willcox, Clifton, 
Mount Lemmon, Douglas, Canelo Hills, Mount Graham, Mammoth, Madera 
Canyon, Summerhaven, Oracle, Bisbee, Safford, Chiricahua NM, and 
Benson
1202 AM MST Mon Jul 19 2021

...FLASH FLOOD WATCH HAS EXPIRED...

The Flash Flood Watch for a portion of Southeast Arizona, including 
the following areas, Catalina and Rincon Mountains, Chiricahua 
Mountains, Dragoon and Mule and Huachuca and Santa Rita Mountains, 
Eastern Cochise County below 5000 feet, Galiuro and Pinaleno 
Mountains, Southeast Pinal County, Upper Gila River Valley, Upper 
San Pedro River Valley and Upper Santa Cruz River Valley/Altar 
Valley has expired.

The threat of heavy rainfall had ended. Although there will continue 
to be elevated flows in area washes and small streams, flooding is 
no longer expected to pose a threat. Please continue to heed 
remaining road closures.

$$

JD

The office that day

Everything else NWS Tucson, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 17, 6:50 PM MST	Special Weather Statement	TWC	Cochise	25 min
Jul 17, 8:04 PM MST	Special Weather Statement	TWC	Graham	41 min
Jul 17, 8:28 PM MST	Special Weather Statement	TWC	Cochise	32 min
Jul 18, 6:19 AM MST	Special Weather Statement	TWC	Santa Cruz	41 min
Jul 18, 7:55 AM MST	Areal Flood Advisory	TWC	Santa Cruz	3 hr
Jul 18, 11:57 AM MST	Areal Flood Advisory	TWC	Cochise	3 hr
Jul 18, 1:00 PM MST	Areal Flood Advisory	TWC	Graham	109 min
Jul 18, 2:36 PM MST	Areal Flood Advisory	TWC	Graham	3 hr
Jul 18, 3:05 PM MST	Severe Thunderstorm Warning	TWC	Graham	40 min
Jul 18, 3:36 PM MST	Areal Flood Advisory	TWC	Graham	114 min
Jul 18, 4:08 PM MST	Flash Flood Warning Considerable damage threat	TWC	Greenlee	112 min
Jul 18, 4:10 PM MST	Special Weather Statement	TWC		35 min
Jul 18, 4:16 PM MST	Areal Flood Advisory	TWC	Graham, Greenlee	119 min
Jul 18, 4:21 PM MST	Areal Flood Advisory	TWC	Graham	114 min
Jul 18, 4:36 PM MST	Flash Flood Warning Considerable damage threat	TWC	Graham, Greenlee	3 hr
Jul 18, 4:45 PM MST	Areal Flood Advisory	TWC	Cochise	2 hr
Jul 18, 4:50 PM MST	Severe Thunderstorm Warning	TWC	Cochise	40 min
Jul 18, 4:58 PM MST	Flash Flood Warning Considerable damage threat	TWC	Cochise	2 hr

Nearby

Flash Flood Watches in Arizona, 2021 Every 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.