A wet Pacific storm system produced isolated thunderstorms across south central Arizona during the evening hours on December 22nd. Some of these storms generated gusty and damaging winds, in addition to locally heavy rainfall.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PSR wrote it up.
A wet Pacific storm system produced isolated thunderstorms across south central Arizona during the evening hours on December 22nd. Some of these storms generated gusty and damaging winds, in addition to locally heavy rainfall.
The local office's own words before the first event, 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 the first event at Dec 22, 8:15 PM MST, 2 hours 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 815 PM MST WED DEC 22 2010 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE FROM WEST TO EAST ACROSS THE REGION THROUGH THURSDAY MORNING. THIS WILL RESULT IN NUMEROUS RAIN SHOWERS AND SLIGHT CHANCE OF THUNDERSTORMS. THE RAIN MAY BE HEAVY AT TIMES WITH THE BEST CHANCE OF FLOODING OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THIS EVENING. CONDITIONS WILL DRY OUT ON THURSDAY... FOLLOWED BY A WARMING TREND LEADING TO ABOVE NORMAL TEMPERATURES SATURDAY AND SUNDAY. A WEAK WEATHER SYSTEM EARLY NEXT WEEK WILL BRING SLIGHT COOLING WITH LITTLE CHANGE THROUGH WEDNESDAY. && .DISCUSSION... THE STRONG PACIFIC LOW PRESSURE SYSTEM JUST OFF THE SOUTHERN CA COAST WED MORNING...WAS ACCELERATING INLAND THIS EVENING AND HEADING TOWARD NORTHERN AZ...CROSSING NORTHERN AZ BETWEEN MIDNIGHT AND 5AM MST. MOST UPPER LEVEL DYNAMICS/UPPER LEVEL STORM SUPPORT WILL DEVELOP OVER NORTHERN AZ...CENTERED AROUND THE GRAND CANYON AIRPORT BY 2 AM MST. MOST RAINFALL ON WEDNESDAY OCCURRED IN OUR SOUTHEAST CA PORTION OF THE FORECAST AREA...BUT SINCE 6 PM MST... RAIN AND OR RAIN SHOWERS HAD DEVELOP IN AND AROUND THE GREATER PHOENIX AREA. ONE CONCERN LATE THIS AFTERNOON/EARLY EVENING WAS THE THREAT OF STRONG DOWNBURST WINDS NEAR THE COLORADO RIVER. A LOW LEVEL JET... NEARLY 35 KNOTS AT 6 THSD FT...HAD THE POTENTIAL TO BE PUSHED DOWN OR DIRECTED TOWARD THE SURFACE FROM CONVECTIVE DOWNDRAFTS. WE DID SEE A FEW DOWNBURST WIND SIGNATURES TO 37 KNOTS/43 MPH OVER MEXICO 30 MILES SOUTHWEST OF YUMA...AND ISOLATED DOWNBURSTS JUST WEST OF THE COLORADO RIVER VALLEY IN THE REMOTE SOUTHEAST CA DESERTS. OTHERWISE...PLOT DATA SHOWED A RICH 850/700 MB MOISTURE PLUME NOSING INTO SOUTHWEST AZ AT 00Z/5 PM MST...AND JUST ABOUT INTO THE PHOENIX AREA. UNFORTUNATELY STRONG UPPER LEVEL DYNAMICS/STORM SUPPORT WILL BE DIRECTED INTO NORTHERN AZ TONIGHT...HOWEVER THE PHOENIX AREA SHOULD BE CLIPPED A LITTLE BY MIDNIGHT. THE INFERENCE HERE IS... HEAVIEST RAINFALL ON THE SOUTH CENTRAL DESERTS...INCLUDING PHOENIX WILL OCCUR BETWEEN 11 PM AND 2 AM MST. THERE COULD EVEN BE AN ISOLATED THUNDERSTORM WITH GUSTY WINDS. HOWEVER...THE HEAVIEST RAIN SHOULD OCCUR OVER THE UPSLOPE MOUNTAIN AREAS JUST TO THE NORTH NORTH AND EAST OF PHOENIX WHERE BETWEEN 1 AND 1.25 INCH STORM TOTALS ARE POSSIBLE. UP TO 1/2 INCH IN THE DESERT VALLEYS ARE ALSO POSSIBLE. AGAIN THE FAST MOVING NATURE OF THE LOW PRESSURE SYSTEM WILL TAKE IT EAST OF THE FORECAST AREA...SOUTHEAST CA TO SOUTH CENTRAL AZ INCLUDING PHOENIX...BY EARLY THURSDAY MORNING. RAIN CHANCES WILL PRETTY MUCH END IN SOUTHEAST CA/FAR SOUTHWEST AZ SHORTLY AFTER MIDNIGHT...THEN END IN THE PHOENIX AREA...LETS SAY AROUND 8 AM. THE THREAT FOR WIDESPREAD HEAVY RAIN HAS ENDED IN SOUTHEAST CA AND PORTIONS OF FAR SOUTHWEST AZ. WILL GO AHEAD AND DROP THE FLASH FLOOD WATCH FOR PORTIONS OF SOUTHEAST CA AND THE COLORADO RIVER VALLEY... BUT CONTINUE IT ACROSS EASTERN LA PAZ...EASTERN YUMA...AND NORTHWEST MARICOPA COUNTIES UNTIL 11 PM MST. CURRENT FORECASTS LOOK VERY GOOD FOR THE REMAINDER OF TONIGHT INTO THURSDAY MORNING. NO UPDATES PLANNED. PORTIONS OF PREVIOUS DISCUSSION BELOW STILL APPLY. PREVIOUS DISCUSSION... ONSET OF SIGNIFICANT PRECIP STILL LOOKS TO BE AFTER DARK TONIGHT. SHOWERS OVER OUR FORECAST AREA HAVE BEEN MOST WIDESPREAD OVER SOUTHEAST CALIFORNIA WITH A DOWNWARD TREND NOTED OVER JOSHUA TREE NATIONAL PARK. THUS WILL LET THE FLASH FLOOD WATCH THERE EXPIRE. CONVECTIVE SHOWERS HAVE DEVELOPED OVER IMPERIAL COUNTY THOUGH WITH A BRIEF LIGHTNING STRIKE NOTED FROM THE NLDN DATA. ANTICIPATE ANY DEEP CONVECTION TO REMAIN ISOLATED BUT IF IT FORMS...THERE IS SUFFICIENT VERTICAL WIND SHEAR THIS AFTERNOON AND EVENING FOR ORGANIZED STORM STRUCTURES TO TAKE SHAPE CREATING THE POTENTIAL FOR HAIL AND STRONG WINDS. WILL KEEP THE FLASH FLOOD WATCH AS IS SINCE MOST OF THE PRECIP OVER OUR ARIZONA ZONES HAS YET TO HAPPEN. PRECIP WILL TAPER OFF FROM WEST TO EAST TONIGHT WITH A LINGERING SLIGHT CHANCE OF RAIN OVER ZONE 24 THURSDAY AFTERNOON. ANTICIPATE ANOTHER QUARTER TO HALF INCH OF PRECIP YET OVER THE LOWER DESERTS OF SOUTHEAST CALIFORNIA WITH HALF TO ONE INCH AMOUNTS ON AVERAGE OVER THE ARIZONA ZONES TONIGHT INTO THURSDAY MORNING WITH ISOLATED HIGHER AMOUNTS POSSIBLE. MODELS INDICATE THAT DEW POINTS IN THE LOW LEVELS WILL DECREASE OVERNIGHT OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA SUCH THAT FOG WILL NOT BE AN ISSUE. HOWEVER...ANTICIPATE THAT THERE WILL BE ENOUGH RADIATIONAL COOLING AND LINGERING SURFACE MOISTURE TO PRODUCE SOME PATCHY FOG OVER MUCH OF THE LOWER DESERTS THURSDAY MORNING. NOT CONFIDENT IT WILL BE DENSE ENOUGH TO MERIT AN ADVISORY. THE SYSTEM WILL CONTINUE TO MOVE EASTWARD THURSDAY WITH A RIDGE QUICK ON ITS HEELS. ANTICIPATE TEMPS ON THE SOUTH-CENTRAL DESERTS THURSDAY TO BE COOLER THAN TODAY DUE TO COOL AIR LEFT BEHIND BY THE FRONT. ELSEWHERE THERE WILL BE LITTLE CHANGE. THE RIDGE AXIS WILL PEAK OVER THE INTERIOR WEST...INCLUDING ARIZONA...ON SATURDAY LEADING TO A WARMING TREND FRIDAY AND SATURDAY. MADE ONLY SUBTLE CHANGES TO PREVIOUSLY FORECASTED TEMPS. SUNDAY THROUGH WEDNESDAY...A NORTHEAST PACIFIC TROUGH MOVES INLAND SATURDAY NIGHT AND SUNDAY BUT WEAKENS RAPIDLY AS IT ENCOUNTERS THE HIGH AMPLITUDE RIDGE. BOTH GFS AND ECMWF AGREE THAT A SPLIT IN THE FLOW DEVELOPS OVER CALIFORNIA ON MONDAY WITH A MINOR TROUGH DEVELOPING OVER ARIZONA AND NORTHWEST MEXICO. WHILE THERE ARE DIFFERENCES BETWEEN THE TWO...NEITHER OF THEM DEPICT A STRONG ENOUGH SYSTEM TO INTRODUCE POPS AT THIS TIME...JUST CLOUDINESS. FOR TUESDAY AND WEDNESDAY THERE IS EITHER DRY NORTHWESTERLY FLOW PER THE GFS OR LESS DRY SOUTHWESTERLY FLOW AHEAD OF ANOTHER WEAK TROUGH PER THE ECMWF. EITHER WAY...TEMP TRENDS LOOK TO BE FLAT AFTER SUBTLE COOLING MONDAY. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX AND KIWA AIRFIELDS... MVFR AT TIMES ARE EXPECTED WITH RAIN AND OR RAIN SHOWERS. CIGS AOB 5000FT ARE LIKELY AT BOTH SITES NEAR 12Z...BUT VSBYS SHOULD REMAIN 6SM OR GREATER. THERE IS A POSSIBILITY OF CIGS DROPPING TO 3000FT AT PHX WITHIN THE HEAVIEST SHOWERS. RAIN WILL TAPER OFF AROUND 12Z THU WITH A FEW LINGERING SHOWERS POSSIBLE UNTIL 15Z. SKIES WILL GRADUALLY CLEAR THROUGH THE DAY THURSDAY. AT THIS POINT WILL LEAVE FOG OUT OF THE FORECAST AS PRECIP WILL BE LINGERING TOO LONG AND CLOUD COVER SHOULD BE TOO THICK FOR FOG FORMATION. SKIES BECOMING SCT 8 THSD AGL BY 18Z THU. SE CALIFORNIA AND SW ARIZONA...INCLUDING KIPL AND KBLH AIRFIELDS... AREAS OF MVFR CIGS/VSBYS WITH WITH SHOWERS THROUGH 06Z. SKIES BECOMING 4 TO 8 THSD SCT-BKN BETWEEN 06Z THU AND 09Z THU. AFT 09Z THU SCT CLOUDS BASED NEAR 6 THSD AGL. PATCHY AREAS OF 2-4 MILES IN FOG BETWEEN 10Z THU AND 14Z THU. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... WARMER AND DRIER CONDITIONS ARE EXPECTED FRIDAY THROUGH THE WEEKEND AS HIGH PRESSURE RETURNS TO THE AREA. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...FLASH FLOOD WATCH THROUGH 11 PM MST AZZ021-022-026. CA...NONE. && NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX DISCUSSION...VASQUEZ/AJ AVIATION...VASQUEZ FIRE WEATHER...MEYERS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PHOENIX AZ 421 AM MST WED DEC 22 2010 CAZ030-231130- JOSHUA TREE NATIONAL PARK- 321 AM PST WED DEC 22 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST CALIFORNIA. .DAY ONE...TODAY AND TONIGHT A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS AFTERNOON. HEAVY RAINFALL WITH AMOUNTS UP TO 4 TENTHS OF AN INCH PER HOUR...WITH TOTAL AMOUNTS OF AN INCH OR MORE MAY OCCUR OVER HIGHER TERRAIN. ROADS AND LOW SPOTS MAY HAVE CONSIDERABLE RUNOFF...WITH FLOODING POSSIBLE INTO THIS AFTERNOON. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY NO WEATHER HAZARDS ARE EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. AZZ020>022-025-026-CAZ031>033-231130- LOWER COLORADO RIVER VALLEY AZ-WEST CENTRAL DESERTS- NORTHWEST MARICOPA COUNTY-YUMA/MARTINEZ LAKE AND VICINITY- SOUTHWEST DESERTS-LOWER COLORADO RIVER VALLEY CA- RIVERSIDE COUNTY/EASTERN DESERTS-IMPERIAL COUNTY- 421 AM MST WED DEC 22 2010 /321 AM PST WED DEC 22 2010/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EXTREME SOUTHWEST ARIZONA...EXTREME WEST-CENTRAL ARIZONA...SOUTH-CENTRAL ARIZONA... SOUTHWEST ARIZONA...WEST-CENTRAL ARIZONA AND EXTREME SOUTHEAST CALIFORNIA. .DAY ONE...TODAY AND TONIGHT A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING. HEAVY RAINFALL WITH AMOUNTS UP TO A QUARTER INCH PER HOUR...WITH TOTAL AMOUNTS OF AN INCH OR MORE MAY OCCUR OVER HIGHER TERRAIN. ROADS AND LOW SPOTS MAY HAVE CONSIDERABLE RUNOFF...WITH FLOODING POSSIBLE INTO THIS EVENING. ISOLATED THUNDERSTORMS WITH DANGEROUS LIGHTNING AND BRIEF GUSTY WINDS ARE ALSO EXPECTED. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY CLEARING SKIES WITH PATCHY FOG IS FORECAST BY EARLY THURSDAY MORNING. VISIBILITY MAY BE REDUCED TO LESS THAN ONE MILE. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. SPOTTER ACTIVATION MAY BECOME NECESSARY LATER TODAY. AZZ023-024-027-028-231130- GREATER PHOENIX AREA- SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS- SOUTHWEST MARICOPA COUNTY-NORTHWEST AND NORTH CENTRAL PINAL COUNTY- 421 AM MST WED DEC 22 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST-CENTRAL ARIZONA AND SOUTH-CENTRAL ARIZONA. .DAY ONE...TODAY AND TONIGHT SHOWERS WILL SPREAD ACROSS THE AREA AND BECOME WIDESPREAD THIS AFTERNOON. LOCALLY HEAVY RAIN WITH TOTAL AMOUNTS BETWEEN A HALF INCH AND ONE INCH ARE EXPECTED. HIGHWAYS WILL BECOME SLIPPERY WITH SOME STANDING WATER IN LOW SPOTS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY NO WEATHER HAZARDS ARE EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
816 PM MST WED DEC 22 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0813 PM HEAVY RAIN 2 S GLENDALE 33.55N 112.20W
12/22/2010 E5.00 INCH MARICOPA AZ TRAINED SPOTTER
SPOTTER REPORTED LOCALIZED FLOODING OF AN UNDERPASS,
CURB-TO-CURB ACCUMULATED WATER.
&&
CDEWEYThe Phoenix radar (KIWA), 55 km away, was scanning. The volume nearest the first event began at 05:52 UTC.
1 thunderstorm wind. Local standard time, as filed.
Gusty thunderstorm winds, estimated to be 50 knots, blew down a 12 inch diameter tree in north central Phoenix. Other small tree limbs were blown down, and some shingles were blown off of a roof.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2010Every state in 2010This day in weather historyWarnings in Arizona, December 2010
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 277808.