Alert archive / Arizona / Flash Flood Watches in 2020

Flash Flood Watch 2, NWS Phoenix, AZ

March 11, 20205 counties in Arizona; Imperial County, Riverside County, San Bernardino County, California

NWS Phoenix, AZ issued this flash flood watch at Mar 11, 2020, 3:59 AM MST for 5 counties in Arizona; Imperial County, Riverside County, San Bernardino County, California. It took effect at Mar 12, 2020, 11:00 AM MST. It was in force for 33 hr.

The area

The counties it named.

The facts

Issued
Mar 11, 2020, 3:59 AM MST (10:59 UTC)
In effect from
Mar 12, 2020, 11:00 AM MST
Expired
Mar 13, 2020, 8:00 PM MST
In force
33 hr
Issued by
NWS Phoenix, AZ
Flood severity
None

Counties Gila County, AZ, La Paz County, AZ, Maricopa County, AZ, Pinal County, AZ, Yuma County, AZ, Imperial County, CA, Riverside County, CA, San Bernardino County, CA

The radar

The Yuma radar (KYUX), 142 km from the middle of the area, began a volume at 11:02 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

Yuma Prvg Ground, AZ (K1Y7), launched 00:00Z, 11.0 hours before the alert went out and 128 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-pSkew-T log-p diagram, Yuma Prvg Ground, AZ at 00:00Z on 2020-03-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Yuma Prvg Ground, AZ at 00:00Z on 2020-03-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1704 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Phoenix, AZ wrote its last area forecast discussion before this flash flood watch went out at Mar 11, 3:46 AM MST, 13 minutes earlier.

Area forecast discussion, Mar 11, 3:46 AM MST, 13 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Mar 10, 7:04 PM MSTAreal Flood AdvisoryPSRYuma4 hr
Mar 10, 8:39 PM MSTAreal Flood AdvisoryPSRLa Paz4 hr
Mar 11, 10:06 AM MSTAreal Flood WarningPSRGila5 days
Mar 10, 6:50 PM MSTFlash Flood Warning Considerable damage threatPSRImperial4 hr
Mar 11, 6:25 AM MSTDense Fog AdvisoryPSRImperial4 hr

Nearby

Flash Flood Watches in Arizona, 2020Flash Flood Watches in California, 2020Every flash flood watch in 2020

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.