Alert archive / Arizona / Special Weather Statements in 2012
Special Weather Statement, NWS Phoenix, AZ
NWS Phoenix, AZ issued this special weather statement at Aug 21, 2012, 3:51 PM MST for La Paz County, Arizona. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2012, 3:51 PM MST (22:51 UTC)
- Expired
- Aug 21, 2012, 4:30 PM MST
- In force
- 39 min
- Issued by
- NWS Phoenix, AZ
County La Paz County, AZ
The radar
The Yuma radar (KYUX), 170 km from the middle of the area, began a volume at 22:52 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
Phoenix, AZ (KPSR), launched 12:00Z, 10.9 hours before the alert went out and 180 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
- 931 J/kg
- Mixed-layer CIN
- -180 J/kg
- Mixed-layer LCL
- 1715 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 20 m²/s²
- 0-3 km storm-relative helicity
- 35 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>What forecasters said that day
The local office's own words before this special weather statement 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 special weather statement went out at Aug 21, 2:45 PM MST, 1 hour 6 minutes earlier.
Area forecast discussion, Aug 21, 2:45 PM MST, 1 hour 6 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 245 PM MST TUE AUG 21 2012 .SYNOPSIS... UNUSUALLY HIGH MONSOON MOISTURE WILL PERSIST OVER THE REGION THROUGH THURSDAY...RESULTING IN REPEATED CHANCES OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION DURING THE MIDWEEK PERIOD...LEADING TO A SIGNIFICANT INCREASE IN COVERAGE AND INTENSITY OF THUNDERSTORMS... ESPECIALLY WEDNESDAY AFTERNOON AND EVENING. AFTER A BOUT OF SOMEWHAT COOLER WEATHER ASSOCIATED WITH THE ENHANCED THUNDERSTORM THREAT...A DRYING TREND WITH REBOUND TO NEAR AVERAGE TEMPERATURES CAN BE EXPECTED THIS WEEKEND. && .DISCUSSION... CONVECTION FIRING NICELY OVER THE HIGHER TERRAIN OF NORTHERN AND EASTERN ARIZONA EARLY THIS AFTERNOON...AS SEEN IN THE LATEST IR AND VISIBLE SATELLITE LOOPS. PLENTY OF MOISTURE IS IN PLACE ACROSS THE STATE WITH MOUNTAIN PWAT NEAR 1 INCH...AND DESERT VALUES APPROACHING 2 INCHES. GOOD AMOUNTS OF MLCAPE ON THE SOUNDINGS AS WELL. AT 2 PM SURFACE DEWPOINTS OVER THE LOWER DESERT REMAINED HIGH AND RANGED FROM THE MID 60S TO ABOUT 70. UPPER HIGH HAS SHIFTED TOWARDS THE SOUTHEAST AND STEERING FLOW OVER THE LOWER CENTRAL/SWRN DESERTS HAS BECOME SOUTH/SOUTHWEST. THIS IS NOT A GOOD DIRECTION IN TERMS OF GETTING HIGHER TERRAIN STORMS INTO THE DESERTS. WE WILL BE LOOKING FOR OUTFLOW BOUNDARIES TO MOVE INTO THE CENTRAL DESERTS FROM THE NORTHEAST AND SOUTHEAST LATER THIS AFTERNOON AND EVENING...AND BOUNDARY INTERACTION WILL DRIVE NEW STORM DEVELOPMENT. RAISED POPS INTO THE CHANCE CATEGORY TONIGHT FOR SOUTH CENTRAL AZ...INCLUDING THE GREATER PHOENIX AREA...TO ACCOUNT FOR THIS POSSIBILITY. GUIDANCE HAS MOSTLY RESOLVED THE TIMING ISSUES WITH THE PACIFIC LOW PRESSURE SYSTEM THAT IS FORECAST TO MOVE INLAND OVER SOUTHEAST CALIFORNIA WEDNESDAY...AND BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO THE DESERTS WED AFTERNOON THRU THE DAY ON THURSDAY. BEST TIMING WINDOW APPEARS TO BE WEDNESDAY EVENING INTO THE MORNING HOURS THURSDAY...AS THE BEST DYNAMICS WILL COMBINE WITH COPIOUS MOISTURE AND GOOD INSTABILITY TO GENERATE STORMS WITH HEAVY RAIN...SMALL HAIL AND STRONG GUSTY WINDS. BY 5 PM WEDNESDAY THE UPPER LOW WILL BE MOVING INLAND ACROSS SOUTHEAST CALIFORNIA CENTERED JUST NORTHWEST OF JOSHUA TREE NP. INCREASING DIFLUENCE ALOFT...SHEAR AND PVA ASSOCIATED WITH THE LOW...IN ADDITION THE THE PRESENCE OF THE RIGHT REAR QUADRANT OF AN UPPER JET WILL ALL AID IN THUNDERSTORM FORMATION AND INTENSIFICATION. PWAT VALUES IN EXCESS OF 2 INCHES ARE FORECAST OVER MUCH OF THE LOWER AZ DESERTS...ALONG WITH 850MB DEWPOINTS IN EXCESS OF 14C. MLCAPE VALUES WILL BE WELL IN EXCESS OF 1000 J/KG. IT ADDS UP TO A POTENTIALLY VERY ACTIVE PERIOD...CONVECTIVELY SPEAKING...STARTING LATE WED AFTERNOON AND CONTINUING PAST MIDNIGHT. POPS ATTM RANGE FROM 40 TO 60 PERCENT OVER MOST OF THE CWA...HIGHEST OVER SOUTH CENTRAL ARIZONA. GFS AND ECMWF BOTH CALL FOR THE UPPER LOW CENTER TO PUSH INTO FAR NWRN AZ DURING THE MORNING HOURS ON THURSDAY. THIS MEANS THAT WE WILL BE VERY UNSETTLED OVERNIGHT WEDNESDAY NIGHT...WITH POPS REMAINING IN THE GOOD CHANCE TO EVEN LIKELY CATEGORIES ALL NIGHT LONG. EXPECT SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED THUNDERSTORMS TO PERSIST INTO THE MORNING THURSDAY. LATEST MRA MOS GUIDANCE SHOWED SOME EYE OPENING VALUES...80 PERCENT CHANCE FOR PHOENIX OVERNIGHT...AND 100 PERCENT AT DEER VALLEY. WE MAY NEED TO RAISE POPS SOME MORE FOR WED NIGHT SHOULD MODELS CONTINUE TO DISPLAY GOOD CONSISTENCY WITH THE HANDLING OF THIS LOW. ALTHOUGH THE BEST DYNAMICS...SHEAR...DIFLUENCE...WILL MOVE THROUGH NORTHERN ARIZONA THURSDAY...WE WILL CARRY A CONTINUED CHANCE FOR SHOWERS AND STORMS ALL DAY...PRIMARILY FROM MARICOPA COUNTY EASTWARD. BETTER CHANCE FOR MEASURABLE RAIN WILL PROBABLY BE IN THE MORNING HOURS...BUT AS MID LEVELS DRY DURING THE AFTERNOON...THE THREAT FOR SEVERE WEATHER WILL INCREASE. HIGH TEMPERATURES WILL FALL A FEW DEGREES WEDNESDAY...DOWN BELOW NORMAL AND TOWARDS 100 OVER THE CENTRAL DESERTS...THEN WILL PLUNGE SEVERAL MORE DEGREES THURSDAY AS THE LOW MOVES ACROSS THE STATE. DEPENDING ON HOW MUCH CONVECTION AND PRECIP WE SEE OVER THE CENTRAL DESERTS WEDNESDAY NIGHT...THE LOWER ATMOSPHERE COULD BE VERY WORKED OVER AND HIGHS WEDNESDAY MAY STRUGGLE TO EVEN REACH THE LOW 90S. WILL NOT GO THAT LOW...BUT WILL KEEP THE HIGHS IN THE MID 90S...WITH A HIGH OF 96 FORECAST FOR PHOENIX. BEYOND THURSDAY...MODELS ARE STILL IN GOOD AGREEMENT DEPICTING DEEPER WESTERLY FLOW AND A GRADUAL DRYING TREND. OUTSIDE OF HIGHER TERRAIN LOCATIONS EAST OF PHOENIX...SEE LITTLE IMPETUS FOR PRECIPITATION WITH MONSOON ACTIVITY SHIFTING ALMOST EXCLUSIVELY INTO NEW MEXICO. HAVE KEPT POPS ON THE VERY LOW SIDE THROUGH THE BEGINNING OF NEXT WEEK...WITH TEMPERATURES STEADILY WARMING BACK TO...AND POSSIBLY ABOVE AVERAGE. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL... DEBRIS CLOUDS FROM YESTERDAY'S THUNDERSTORMS KEEPING SCT-BKN MID-HIGH LEVEL CIGS IN PLACE ACROSS THE PHX AREA TODAY. ISOLATED SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP TO THE EAST AND NORTH OF THE TERMINALS THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW AT THIS TIME TO INTRODUCE THEM IN THE TAFS...AT THIS TIME. SOUTHWESTERLY FLOW ALOFT TO RESULT IN LONGER-THEN-USUAL PERIODS OF WESTERLY WINDS AT THE TAF SITES. INPUT VCSH INTO TAFS STARTING MID-MORNING WEDNESDAY AS UPPER TROF APPROACHES FROM THE WEST...WITH AN ACTIVE TS PERIOD LIKELY ON WED AFTERNOON. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... PERSISTENT SOUTHERLY WINDS AT 10-15 KNOTS THROUGH MUCH OF THE PERIOD WITH PERIODS OF HIGH CLOUDS. WIDELY ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE IN THE REGION...BUT NOT LIKELY TO AFFECT AIRFIELDS. SOME INCREASE IN CLOUDS IS EXPECTED FROM THIS EVENING ONWARD INTO WED MORNING. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... PERSISTENT WESTERLY FLOW ALOFT IS EXPECTED TO PUSH DRIER AIR INTO THE REGION THROUGH THE PERIOD. THIS WILL REDUCE THE AVAILABLE MOISTURE AND THUNDERSTORM ACTIVITY SUBSTANTIALLY FROM FRIDAY ONWARD INTO EARLY NEXT WEEK. THUNDERSTORM ACTIVITY IS EXPECTED TO BE REDUCED TO JUST SOME ISOLATED CELLS OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX EACH AFTERNOON AND EVENING. NIGHTTIME RELATIVE HUMIDITY RECOVERIES ARE EXPECTED TO FALL INTO THE FAIR TO GOOD RANGE EACH DAY. WINDS WILL REMAIN ON THE LIGHT SIDE AND GENERALLY FOLLOW NORMAL DIURNAL PATTERNS....EXCEPT NEAR THUNDERSTORMS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...CB/MO AVIATION...PERCHA/KUHLMAN FIRE WEATHER...PERCHA
Hazardous weather outlook, Aug 21, 4:48 AM MST, 11 hours 3 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PHOENIX AZ 448 AM MST TUE AUG 21 2012 AZZ021>023-026>028-221215- WEST CENTRAL DESERTS-NORTHWEST MARICOPA COUNTY-GREATER PHOENIX AREA- SOUTHWEST DESERTS-SOUTHWEST MARICOPA COUNTY- NORTHWEST AND NORTH CENTRAL PINAL COUNTY- 448 AM MST TUE AUG 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH-CENTRAL ARIZONA...SOUTHWEST ARIZONA AND WEST-CENTRAL ARIZONA. .DAY ONE...TODAY AND TONIGHT. THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING. THE PRIMARY HAZARDS ARE LOCALLY HEAVY RAINFALL AND FLOODING...AS WELL AS ISOLATED DAMAGING WIND GUSTS AND BLOWING DUST. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE WEDNESDAY AND THURSDAY. DAILY HAZARDS WILL INCLUDE LIGHTNING...GUSTY WINDS...LOCALIZED BLOWING DUST...AND PERIODS OF HEAVY RAIN POTENTIALLY LEADING TO FLOODING. THE MOST ACTIVE DAY WITH AN ORGANIZED SEVERE WEATHER THREAT LOOKS TO BE WEDNESDAY...WITH POSSIBLE STRONG DAMAGING WIND GUSTS AND LARGE HAIL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY AND WEDNESDAY. AZZ024-221215- SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS- 448 AM MST TUE AUG 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST-CENTRAL ARIZONA. .DAY ONE...TODAY AND TONIGHT. SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY. THE PRIMARY HAZARDS ARE GUSTY WINDS AND PERIODS OF HEAVY RAINFALL LEADING TO FLASH FLOODING OF LOW LYING AREAS AND NORMALLY DRY WASHES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. THERE WILL BE A CONTINUED CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH THURSDAY...WITH LESSER CHANCES BY THE END OF THE WEEK AND WEEKEND. THE PRIMARY THREATS WILL BE LIGHTNING...GUSTY WINDS...AND HEAVY RAINFALL POTENTIALLY LEADING TO FLOODING. THE MOST ACTIVE DAY WITH AN ORGANIZED SEVERE WEATHER THREAT LOOKS TO BE WEDNESDAY...WITH POSSIBLE STRONG DAMAGING WIND GUSTS AND LARGE HAIL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY AND WEDNESDAY. AZZ020-025-CAZ030>033-221215- LOWER COLORADO RIVER VALLEY AZ-YUMA/MARTINEZ LAKE AND VICINITY- JOSHUA TREE NATIONAL PARK-LOWER COLORADO RIVER VALLEY CA- RIVERSIDE COUNTY/EASTERN DESERTS-IMPERIAL COUNTY- 448 AM MST TUE AUG 21 2012 /448 AM PDT TUE AUG 21 2012/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR EXTREME SOUTHWEST ARIZONA...EXTREME WEST-CENTRAL ARIZONA...EXTREME SOUTHEAST CALIFORNIA AND SOUTHEAST CALIFORNIA. .DAY ONE...TODAY AND TONIGHT. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON AND EVENING. THE PRIMARY THREATS WILL BE LOCALLY HEAVY RAINFALL AND FLOODING...ALONG WITH GUSTY WINDS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. THERE IS A CHANCE OF THUNDERSTORMS WEDNESDAY...WITH LOCALLY HEAVY RAINFALL AND FLOODING...POSSIBLE STRONG DAMAGING WIND GUSTS...AND LARGE HAIL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED WEDNESDAY. NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX
In the hours before
Special weather statement, Aug 21, 2:17 PM MST, 1 hour 34 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PHOENIX AZ 217 PM MST TUE AUG 21 2012 AZZ024-212200- GILA AZ- 217 PM MST TUE AUG 21 2012 ...SIGNIFICANT WEATHER ADVISORY... THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR... SOUTH CENTRAL GILA COUNTY IN EAST CENTRAL ARIZONA UNTIL 300 PM MST AT 215 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A STRONG THUNDERSTORM NEAR GLOBE...MOVING NORTHEAST AT 5 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING. LOCATIONS IMPACTED INCLUDE... CUTTER... LAT...LON 3360 11061 3338 11047 3327 11079 3343 11090 TIME...MOT...LOC 2118Z 242DEG 6KT 3339 11075 HIRSCH
Special weather statement, Aug 21, 3:51 PM MST, 0 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PHOENIX AZ 351 PM MST TUE AUG 21 2012 AZZ021-212330- LA PAZ AZ- 351 PM MST TUE AUG 21 2012 ...SIGNIFICANT WEATHER ADVISORY... THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR... CENTRAL LA PAZ COUNTY IN WEST CENTRAL ARIZONA UNTIL 430 PM MST AT 348 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A STRONG THUNDERSTORM 7 MILES NORTHWEST OF VICKSBURG...MOVING NORTHEAST AT 5 MPH. LOCALLY DENSE BLOWING DUST...PERIODS OF BRIEF HEAVY RAIN AND WIND GUSTS UP TO 45 TO 55 MPH ARE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... RURAL CENTRAL LA PAZ COUNTY... STATE ROUTE 72 BETWEEN VICKSBURG JUNCTION AND BOUSE... SOME UNSECURED OBJECTS WILL BE BLOWN AROUND...TREE LIMBS COULD BE SNAPPED OFF...AND ISOLATED POWER OUTAGES WILL BE POSSIBLE. SEEK SHELTER INDOORS UNTIL THE STORM PASSES. LAT...LON 3398 11388 3388 11366 3372 11382 3377 11396 TIME...MOT...LOC 2250Z 206DEG 5KT 3380 11384 NOLTE
The office that day
Everything else NWS Phoenix, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 5:05 PM MST | Special Weather Statement | PSR | 55 min | |
| Aug 20, 5:43 PM MST | Special Weather Statement | PSR | La Paz | 47 min |
| Aug 20, 6:01 PM MST | Flash Flood Warning | PSR | La Paz | 89 min |
| Aug 20, 6:42 PM MST | Special Weather Statement | PSR | Maricopa | 33 min |
| Aug 20, 6:53 PM MST | Special Weather Statement | PSR | 37 min | |
| Aug 20, 6:57 PM MST | Areal Flood Advisory | PSR | Maricopa | 62 min |
| Aug 20, 7:01 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 59 min |
| Aug 20, 7:11 PM MST | Blowing Dust Advisory | PSR | 81 min | |
| Aug 20, 7:21 PM MST | Flash Flood Warning | PSR | Maricopa | 114 min |
| Aug 21, 2:17 PM MST | Special Weather Statement | PSR | Gila | 43 min |
| Aug 21, 4:18 PM MST | Areal Flood Advisory | PSR | Gila | 117 min |
| Aug 21, 4:42 PM MST | Areal Flood Advisory | PSR | La Paz | 93 min |
Nearby
Special Weather Statements in Arizona, 2012Every special weather statement 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.