Alert archive / Arizona / Mesoscale Discussions in 2012

Mesoscale Discussion 1665

July 31, 2012Apache County, Navajo County, Arizona

The Storm Prediction Center issued this mesoscale discussion at Jul 31, 2012, 1:31 PM MST for Apache County, Navajo County, Arizona. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Jul 31, 2012, 1:31 PM MST (20:31 UTC)
Expired: Jul 31, 2012, 2:30 PM MST
In force: 59 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Apache County, AZ, Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 126 km from the middle of the area, began a volume at 20:30 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, 8.5 hours before the alert went out and 134 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: 209 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 818 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 121 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

870 
ACUS11 KWNS 312032
SWOMCD
SPC MCD 312031
AZZ000-312130-

MESOSCALE DISCUSSION 1665
NWS STORM PREDICTION CENTER NORMAN OK
0331 PM CDT TUE JUL 31 2012

AREAS AFFECTED...NERN AZ

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 312031Z - 312130Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...TSTM COVERAGE IS INCREASING ACROSS THE WHITE MTNS AND CO
PLATEAU OF NERN AZ THIS AFTERNOON...WITH A FEW OF THESE STORMS
CAPABLE OF PRODUCING MARGINALLY SVR HAIL AND STRONG-SVR WIND GUSTS.
DUE TO THE MARGINAL/ISOLATED NATURE OF THE THREAT...A WW IS NOT
CURRENTLY BEING CONSIDERED.

DISCUSSION...CONVECTION HAS INCREASED ACROSS NERN AZ THIS
AFTERNOON...PARTLY AIDED BY A MCV POSITIONED E OF PHX AND MOVING N
TOWARDS THE MOGOLLON RIM. SEVERAL OF THESE STORMS HAVE OCCASIONALLY
DISPLAYED THE POTENTIAL FOR AT LEAST SMALL HAIL. MODERATELY STRONG
MIDLEVEL SLY FLOW ALONG THE WRN PERIPHERY OF A SRN PLAINS
ANTICYCLONE...SAMPLED AT 20-30 KTS BY FSX VWP...IS SUFFICIENT FOR AT
LEAST MARGINAL STORM ORGANIZATION...LIKELY ENHANCING THE POTENTIAL
FOR HAIL. THE PRIMARY LIMITING FACTOR FOR A MORE ROBUST SVR THREAT
APPEARS TO BE WEAK INSTABILITY ACROSS THE AREA...DESPITE ADEQUATE
BOUNDARY LAYER MOISTURE...PRIMARILY OWING TO WARM MIDLEVEL
TEMPERATURES AND WEAK LAPSE RATES. A LOCALIZED STRONG WIND THREAT
COULD ALSO ACCOMPANY THE STRONGEST CONVECTIVE CORES WHERE STRONG
HEATING AND DEEP BOUNDARY LAYER MIXING HAS OCCURRED.

..ROGERS/CARBIN.. 07/31/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FGZ...

LAT...LON   34310925 33930975 34461119 35331172 36721177 36921085
            36910989 36340954 34310925

Nearby

Mesoscale Discussions in Arizona, 2012 Every mesoscale discussion in 2012

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.