Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 53, NWS Flagstaff, AZ

July 19, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 19, 2021, 3:37 PM MST for Coconino County, Arizona. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 19, 2021, 3:37 PM MST (22:37 UTC)
Expired: Jul 19, 2021, 6:45 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 100 km from the middle of the area, began a volume at 22:36 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.6 hours before the alert went out and 23 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: 96 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 1290 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 68 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

884 
WGUS55 KFGZ 192237
FFWFGZ
AZC005-200145-
/O.NEW.KFGZ.FF.W.0053.210719T2237Z-210720T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
337 PM MST Mon Jul 19 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Coconino County in north central Arizona...

* Until 645 PM MST.

* At 336 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain in rural areas from 5 to 15 miles southeast of 
  WIlliams, including the upper portion of the Sycamore Canyon 
  drainage. Between 1.5 and 2.5 inches of rain have fallen. 
  Additional rainfall amounts of 0.25 to 0.5 inches are possible in 
  the warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  White Horse Lake Campground, Dogtown Lake Campground and Raymond 
  Boy Scout Camp.

This includes the following swimming holes...
Sycamore Falls, Lower Sycamore Falls "The Golden Pond" and Paradise 
Forks.

This includes the following streams and drainages...
  Sycamore Creek, Dogtown Wash and Hell Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3523 11211 3520 11203 3518 11199 3514 11197
      3511 11198 3509 11196 3509 11198 3512 11204
      3514 11218

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JJ

2 follow-up statements

967 
WGUS75 KFGZ 192356
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
456 PM MST Mon Jul 19 2021

AZC005-200145-
/O.CON.KFGZ.FF.W.0053.000000T0000Z-210720T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
456 PM MST Mon Jul 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM MST THIS 
EVENING FOR COCONINO COUNTY...

At 453 PM MST, Doppler radar indicated that heavy rain has ended 
over the warning area, over rural areas from 5 to 15 miles southeast 
of Williams, including the upper portion of the Sycamore Canyon 
drainage. Between 1.5 and 2.5 inches of rain fell earlier this 
afternoon. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  White Horse Lake Campground, Dogtown Lake Campground and Raymond 
  Boy Scout Camp.

This includes the following swimming holes...
Sycamore Falls, Lower Sycamore Falls "The Golden Pond" and Paradise 
Forks.

This includes the following streams and drainages...
  Sycamore Creek, Dogtown Wash and Hell Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3523 11211 3520 11203 3518 11199 3514 11197
      3511 11198 3509 11196 3509 11198 3512 11204
      3514 11218

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JJ

846 
WGUS75 KFGZ 200136
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
636 PM MST Mon Jul 19 2021

AZC005-200146-
/O.EXP.KFGZ.FF.W.0053.000000T0000Z-210720T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
636 PM MST Mon Jul 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 645 PM MST THIS EVENING FOR 
COCONINO COUNTY...

The heavy rain threat has ended south of Williams and flood waters 
will continue to recede over the next few hours. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3523 11211 3520 11203 3518 11199 3514 11197
      3511 11198 3509 11196 3509 11198 3512 11204
      3514 11218

$$

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 5:31 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	59 min
Jul 18, 5:43 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	24 min
Jul 18, 6:14 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 18, 6:21 PM MST	Special Weather Statement	FGZ		24 min
Jul 19, 1:48 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 19, 1:54 PM MST	Special Weather Statement	FGZ		51 min
Jul 19, 2:08 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	37 min
Jul 19, 2:30 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	2 hr
Jul 19, 3:07 PM MST	Special Weather Statement	FGZ		23 min
Jul 19, 3:28 PM MST	Special Weather Statement	FGZ		32 min
Jul 19, 4:01 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 19, 4:27 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	2 hr

Nearby

Flash Flood Warnings in Arizona, 2021 Every flash flood warning 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.