Alert archive / Arizona / Mesoscale Discussions in 2011
Mesoscale Discussion 2156
The Storm Prediction Center issued this mesoscale discussion at Sep 10, 2011, 3:05 PM MST for 5 counties in Arizona. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 10, 2011, 3:05 PM MST (22:05 UTC)
- Expired
- Sep 10, 2011, 5:30 PM MST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Cochise County, AZ, Graham County, AZ, Pima County, AZ, Pinal County, AZ, Santa Cruz County, AZ
The radar
The Tucson radar (KEMX), 65 km from the middle of the area, began a volume at 22:07 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 (KTUS), launched 12:00Z, 10.1 hours before the alert went out and 45 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.
- Mixed-layer CAPE
- 306 J/kg
- Mixed-layer CIN
- -95 J/kg
- Mixed-layer LCL
- 1601 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 39 m²/s²
- 0-3 km storm-relative helicity
- 206 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.3
The text
As transmitted, in the capitals the NWS used until 2016.
480
ACUS11 KWNS 102205
SWOMCD
SPC MCD 102205
AZZ000-110030-
MESOSCALE DISCUSSION 2156
NWS STORM PREDICTION CENTER NORMAN OK
0505 PM CDT SAT SEP 10 2011
AREAS AFFECTED...AZ
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 102205Z - 110030Z
A COUPLE OF SEVERE HAIL AND/OR SEVERE WIND EVENTS WILL BE POSSIBLE
INTO THE EVENING HOURS IN A GENERALLY FOCUSED REGION OF SERN AZ.
GIVEN LIMITED AREAL EXTENT OF THIS THREAT...AND SOME UNCERTAINTY
REGARDING OVERALL DURATION/LONGEVITY...A WATCH IS NOT ANTICIPATED AT
THIS TIME.
RAPID AND ROBUST TSTM DEVELOPMENT HAS OCCURRED WITHIN THE LAST HOUR
OR SO ACROSS SRN PINAL AND WRN COCHISE COUNTIES OF ERN AZ AS STRONG
HEATING HAS ELIMINATED CONVECTIVE INHIBITION. TERRAIN INFLUENCES AND
APPROACH OF A LOW AMPLITUDE SHORT WAVE TROUGH EMANATING FROM THE
LARGER CLOSED LOW OFF THE COAST OF SRN CA ARE ALSO CONTRIBUTING TO
AN ENHANCEMENT IN BOTH MESOSCALE AND SYNOPTIC SCALE ASCENT ACROSS
THE REGION. A VERY UNSTABLE AIR MASS /MLCAPE TO 2000 J PER KG/
SHOULD CONTINUE TO FUEL A FEW INTENSE STORM UPDRAFTS. DEEP-LAYER
SHEAR IS SOMEWHAT MARGINAL FOR GREATER STORM ORGANIZATION GIVEN MID
LEVEL FLOW AOB 20KT. WHILE THIS SHOULD KEEP MOST ACTIVITY IN
MULTICELLULAR REALM...STRONGER SWLY FLOW EXISTS NEAR ANVIL LEVEL AND
IS EVIDENT IN MODEL DATA AND SUPPORTED BY RECENT VSBL SATL IMAGERY.
NOT ONLY WILL THIS ALLOW FOR AN EFFECTIVE EXHAUST MECHANISM FOR SOME
OF THE MORE INTENSE STORMS...BUT EFFECTIVE SHEAR IN THESE CASES
COULD BRIEFLY RESULT IN SUPERCELLULAR STRUCTURE AND ENHANCED
WIND/HAIL POTENTIAL.
BOTH THE LARGE HAIL AND DOWNBURST WIND THREAT WILL LIKELY BE
GREATEST OVER THE NEXT HOUR OR SO BEFORE STORM INTERACTIONS AND
INCREASE IN STORM COVERAGE ACT TO OVERTURN THE AIR MASS AND BEGIN TO
RESULT IN AN INCREASE IN INHIBITION.
..CARBIN.. 09/10/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...TWC...PSR...
LAT...LON 32311226 32611221 32821217 33091198 33341140 33331108
33451066 33260982 33050931 32790907 32470906 32080908
31840907 31450908 31340918 31341073 31751230 32311226SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 10, 2:41 PM MST | Mesoscale Discussion | SPC | Apache, Coconino, Navajo | 3 hr |
Nearby
Mesoscale Discussions in Arizona, 2011Every mesoscale discussion in 2011
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.