Alert archive / Arizona / Hard Freeze Warnings in 2014

Hard Freeze Warning 3, NWS Tucson, AZ

December 27, 2014Pima County, Pinal County, Arizona

NWS Tucson, AZ issued this hard freeze warning at Dec 27, 2014, 2:29 AM MST for Pima County, Pinal County, Arizona. It took effect at Dec 28, 2014, 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, 2014, 2:29 AM MST (09:29 UTC)
In effect from
Dec 28, 2014, 12:00 AM MST
Expired
Dec 28, 2014, 9:00 AM MST
In force
9 hr
Issued by
NWS Tucson, AZ

Counties Pima County, AZ, Pinal County, AZ

The radar

The Phoenix radar (KIWA), 88 km from the middle of the area, began a volume at 09:32 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.

The nearest sounding before it

Tuscon, AZ (KDMA), launched 00:00Z, 9.5 hours before the alert went out and 73 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 00:00Z on 2014-12-27Temperature 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 00:00Z on 2014-12-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.1939587897Sfc1 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
2449 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Tucson, AZ wrote its last area forecast discussion before this hard freeze warning went out at Dec 27, 2:23 AM MST, 6 minutes earlier.

Area forecast discussion, Dec 27, 2:23 AM MST, 6 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
223 AM MST SAT DEC 27 2014

.SYNOPSIS...WIDESPREAD FREEZING TEMPERATURES WILL OCCUR THIS
MORNING AND AGAIN SATURDAY NIGHT INTO SUNDAY MORNING...WITH A
HARD FREEZE FOR MANY AREAS. TEMPERATURES WILL WARM UP SOME EARLY
NEXT WEEK BEFORE ANOTHER COLD AND WET SYSTEM MOVES IN MIDWEEK.
EXPECT WIDESPREAD VALLEY RAIN AND MOUNTAIN SNOW SHOWERS WEDNESDAY
NIGHT INTO THURSDAY...WITH SNOW POTENTIALLY REACHING THE VALLEY
FLOORS EAST OF TUCSON THURSDAY EVENING.

&&

.DISCUSSION...MOST OF THE CLOUD COVER FROM YESTERDAYS SYSTEM HAS
EXITED THE AREA...WHICH HAS ALLOWED FOR SOME COOLING TO TAKE
PLACE. MOST LOCATIONS THIS MORNING HAVE ALREADY NEARED OR DROPPED
BELOW FREEZING. THIS COOLING WILL CONTINUE OVER THE NEXT SEVERAL
HOURS SO MOST LOCATIONS WILL EXPERIENCE A GOOD FREEZE. A
FREEZE/HARD FREEZE WARNING ARE IN EFFECT FOR TUCSON AND AREAS
NORTH AND WEST OF THE CITY. NOT EXPECTING MUCH WARMER TEMPERATURES
TODAY COMPARED TO YESTERDAY...BESIDE SLIGHTLY COOLER OUT EAST.
COMBINE THIS WITH ANOTHER CLEAR TO MOSTLY CLEAR CONDITIONS TONIGHT
AND THERE SHOULD ANOTHER WIDESPREAD FREEZE SUNDAY MORNING. HAVE
ADDED A FREEZE WARNING FOR ZONES 502 AND 505 /THE TOHONO O'ODHAM
NATION AND WESTERN PINAL COUNTY/ AND A HARD FREEZE WARNING FOR
ZONES 504 AND 506.../TUCSON METRO...AND EASTERN PINAL COUNTY./ A
WARMING TREND WILL BEGIN SUNDAY WHICH SHOULD KEEP TEMPERATURE
MONDAY ABOVE WARNING CRITERIA FOR MOST LOCATIONS. THOUGH...TUCSON
WILL LIKELY BE NEAR FREEZING AGAIN. NEVERTHELESS...WILL HOLD OFF
ADDING ANY HEADLINES FOR MONDAY.

THEN FOCUS TURNS TO AN UPPER LEVEL TROUGH DIGGING ACROSS THE
WESTERN STATES EARLY WEEK. LATE TUESDAY INTO WEDNESDAY AN AREA OF
THIS TROUGH WILL CUT OFF. THIS WILL ALLOW FOR IT TO PICK UP SOME
ADDITIONAL MOISTURE BEFORE A PIECE OF ENERGY SLIDES AROUND IT AND
KICKS THRU THE REGION WEDNESDAY INTO THURSDAY. THE ASSOCIATED COLD
FRONT LOOKS TO MOVE THROUGH THE AREA AROUND THE TIME THE REGION
RINGS IN THE NEW YEAR. THIS SYSTEM IS QUITE COLD SO SHOULD SEE A
LOWER SNOW LEVELS THAN PREVIOUS SYSTEMS. ALSO...THE TIME OF THE
FROPA WILL ALLOW FOR ANOTHER LOWERING OF SNOW LEVELS DURING THE
EVENT. HAVE CONTINUED THE MENTION OF SNOW IN THE VALLEYS EAST OF
TUCSON THURSDAY. COULD SEE SOME SNOW MIXING INTO AREAS AROUND
TUCSON AS WELL THOUGH CONFIDENCE IS LOW AT THIS TIME.
NEVERTHELESS...SHOULD BE A WET BEGINNING TO THE NEW YEAR. THE
SYSTEM WILL EXIT THE AREA BY THE END OF THE WEEK WHICH WILL BRING
BACK THE CONCERN OF FREEZING TEMPERATURE TO AREA FOR FRIDAY AND
SATURDAY.

&&

.AVIATION...VALID THRU 28/12Z.
VFR WITH MOSTLY CLEAR SKIES IN A DRY NORTHERLY TO NORTHWESTERLY FLOW
ALOFT. NORMAL DIURNAL WIND TRENDS GENERALLY LESS THAN 10 KTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...SEASONABLY COOL AND DRY CONDITIONS WITH GENERALLY
LIGHT TERRAIN DRIVEN WINDS THROUGH MONDAY OR TUESDAY. A DEEP LOW
PRESSURE SYSTEM WILL THEN BRING A GOOD CHANCE OF VALLEY RAIN AND
MOUNTAIN SNOW BY LATE WEDNESDAY INTO THURSDAY. LOWER SNOW LEVELS ARE
POSSIBLE WITH THIS STORM. BREEZY TO WINDY CONDITIONS ARE EXPECTED
AHEAD OF THIS SYSTEM...DEVELOPING BY LATE TUESDAY AND STRENGTHENING
WEDNESDAY.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING UNTIL 9 AM MST THIS MORNING FOR AZZ504-506.

HARD FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM MST SUNDAY FOR
AZZ504-506.

FREEZE WARNING UNTIL 9 AM MST THIS MORNING FOR AZZ501-502-505.

FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM MST SUNDAY FOR
AZZ502-505.

&&

DISCUSSION...MEADOWS
FIRE WEATHER/AVIATION...MEYER

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 27, 2:29 AM MSTFreeze WarningTWCPima, Pinal31 hr

Nearby

Hard Freeze Warnings in Arizona, 2014Every hard freeze warning in 2014

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.