Alert archive / Arizona / Hard Freeze Warnings in 2018

Hard Freeze Warning 2, NWS Phoenix, AZ

December 27, 2018Gila County, Pinal County, Arizona

NWS Phoenix, AZ issued this hard freeze warning at Dec 27, 2018, 2:37 PM MST for Gila County, Pinal County, Arizona. It took effect at Dec 30, 2018, 12:00 AM MST. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Dec 27, 2018, 2:37 PM MST (21:37 UTC)
In effect from
Dec 30, 2018, 12:00 AM MST
Expired
Dec 30, 2018, 9:00 AM MST
In force
9 hr
Issued by
NWS Phoenix, AZ

Counties Gila County, AZ, Pinal County, AZ

The radar

The Phoenix radar (KIWA), 55 km from the middle of the area, began a volume at 21:35 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 (KDMA), launched 12:00Z, 9.6 hours before the alert went out and 132 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, Tuscon, AZ at 12:00Z on 2018-12-27Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tuscon, AZ at 12:00Z on 2018-12-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 79 square meters per square second.193958Sfc1 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
1324 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 27, 2:37 PM MSTFreeze WarningPSRLa Paz, Maricopa, Pinal, Yuma42 hr
Dec 27, 2:37 PM MSTFreeze WarningPSRLa Paz, Maricopa, Pinal, Yuma66 hr
Dec 27, 2:37 PM MSTHard Freeze WarningPSRGila, Pinal42 hr

Nearby

Hard Freeze Warnings in Arizona, 2018Every hard freeze 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.