Alert archive / Arizona / Flash Flood Warnings in 2018

Flash Flood Warning 22, NWS Tucson, AZ

August 20, 2018Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 20, 2018, 6:33 PM MST for Pima County, Arizona. It was in force for 2 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 20, 2018, 6:33 PM MST (01:33 UTC)
Expired: Aug 20, 2018, 9:00 PM MST
In force: 2 hr
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Flood severity: None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 29 km from the middle of the area, began a volume at 01:32 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.

What was reported inside it

Time	Report	Where	Remark
Aug 20, 7:25 PM MST	FLASH FLOOD	11 Sw Tucson, AZ	FLOODED ROADWAY WITH DEBRIS IN THE ROAD NEAR THE SAN XAVIER MISSION.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Tuscon, AZ (KDMA), launched 00:00Z, 1.6 hours before the alert went out and 15 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: 758 J/kg
Mixed-layer CIN: -59 J/kg
Mixed-layer LCL: 2841 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: -20 m²/s²
0-3 km storm-relative helicity: 26 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

630 
WGUS55 KTWC 210133
FFWTWC
AZC019-210400-
/O.NEW.KTWC.FF.W.0022.180821T0133Z-180821T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
633 PM MST MON AUG 20 2018

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  East central Pima County in southeastern Arizona...

* Until 900 PM MST.

* At 630 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area, especially to the southeast of 
  Tucson International Airport. Radar estimates indicate up to 2 
  inches of rain has occurred with flash flooding expected to begin 
  shortly. Some notable washes that will be impacted include Franco 
  Wash and Flato Wash. 

* Some locations that will experience flooding include...
  Tucson, Sahuarita, Summit, East Sahuarita, Drexel Heights, San
  Xavier Mission and Corona De Tucson.

This includes Interstate 19 between mile markers 48 and 57.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3204 11075 3191 11075 3198 11105 3210 11109
      3212 11097

$$

GL

2 follow-up statements

240 
WGUS75 KTWC 210235
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
735 PM MST MON AUG 20 2018

AZC019-210400-
/O.CON.KTWC.FF.W.0022.000000T0000Z-180821T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
735 PM MST MON AUG 20 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM MST FOR
EAST CENTRAL PIMA COUNTY...

At 733 PM MST, the public reported flash flooding from earlier 
thunderstorms near the San Xavier Mission. Flash Flooding is also 
possible especially in areas along the Franco Wash and Flato Wash to 
the east of Interstate 19. 

Some locations that will experience flooding include...
Tucson, Sahuarita, Summit, East Sahuarita, Drexel Heights, San Xavier
Mission and Corona De Tucson.

This includes Interstate 19 between mile markers 48 and 57.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3204 11075 3191 11075 3198 11105 3210 11109
      3212 11097

$$

GL

878 
WGUS75 KTWC 210351
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
851 PM MST MON AUG 20 2018

AZC019-210401-
/O.EXP.KTWC.FF.W.0022.000000T0000Z-180821T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
851 PM MST MON AUG 20 2018

...THE FLASH FLOOD WARNING FOR EAST CENTRAL PIMA COUNTY WILL EXPIRE
AT 900 PM MST...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3204 11075 3191 11075 3198 11105 3210 11109
      3212 11097

$$

GL

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 5:04 PM MST	Areal Flood Advisory	TWC	Pima, Santa Cruz	3 hr
Aug 20, 5:12 PM MST	Special Weather Statement	TWC	Santa Cruz	63 min
Aug 20, 5:31 PM MST	Special Weather Statement	TWC	Santa Cruz	29 min
Aug 20, 5:47 PM MST	Special Weather Statement	TWC		58 min
Aug 20, 5:55 PM MST	Severe Thunderstorm Warning	TWC	Pima	50 min
Aug 20, 5:57 PM MST	Severe Thunderstorm Warning	TWC	Pima	63 min
Aug 20, 6:11 PM MST	Dust Storm Advisory	TWC	Pima, Pinal	2 hr
Aug 20, 6:31 PM MST	Severe Thunderstorm Warning	TWC	Pima	59 min
Aug 20, 6:45 PM MST	Dust Storm Warning	TWC	Pima, Pinal	2 hr
Aug 20, 6:53 PM MST	Special Weather Statement	TWC	Pima	67 min
Aug 20, 7:04 PM MST	Areal Flood Advisory	TWC	Pima	2 hr
Aug 21, 4:01 AM MST	Areal Flood Advisory	TWC	Graham	3 hr
Aug 21, 4:10 AM MST	Special Weather Statement	TWC	Graham	50 min
Aug 21, 1:30 PM MST	Areal Flood Advisory	TWC	Cochise, Graham, Greenlee	3 hr
Aug 21, 2:39 PM MST	Flash Flood Warning	TWC	Graham	3 hr
Aug 21, 2:59 PM MST	Areal Flood Advisory	TWC	Graham, Greenlee	3 hr
Aug 21, 3:14 PM MST	Special Weather Statement	TWC	Greenlee	46 min
Aug 21, 4:02 PM MST	Areal Flood Advisory	TWC	Cochise	3 hr

Nearby

Flash Flood Warnings in Arizona, 2018 Every flash flood warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.