1 flood, as filed by the National Weather Service.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 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 4, 3:00 AM MST, 6 hours earlier.
AZZ020>028-CAZ030>033-041745- SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 300 AM MST TUE DEC 4 2001 .SYNOPSIS... A LOW PRESSURE SYSTEM AND ITS ASSOCIATED COLD FRONT...MOVING IN FROM THE EASTERN PACIFIC...WILL BRING BREEZY CONDITIONS...INCREASED CLOUD COVER AND A CHANCE FOR SHOWERS TO SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA TODAY AND TONIGHT. THE CLOUDS AND SHOWERS WILL DECREASE FROM THE WEST WITH TIME...WITH SOUTHEAST CALIFORNIA AND THE FAR WEST DESERTS EXPECTED TO BECOME PARTLY CLOUDY BY THIS AFTERNOON. THIS WEATHER SYSTEM WILL ALSO BRING COOLER TEMPERATURES...WITH DAYTIME HIGHS EXPECTED TO BE BELOW NORMAL TODAY AND WEDNESDAY. HIGH PRESSURE IS FORECAST TO REBUILD OVER THE AREA BY THE END OF THE WEEK... BRINGING FAIR WEATHER AND ABOVE-NORMAL TEMPERATURES ONCE AGAIN. .DISCUSSION... COLD UPPER LEVEL LOW PRESSURE TROF NOW ALONG SERN CA STARTING TO PUSH INLAND OVER SERN CA AND APPROACH AZ...WITH THE ASSOCD FRONTAL BAND NOW INTO FAR WRN AZ. PER 88D DOPPLER RADAR IMAGERY...SCT MAINLY LIGHT SHOWERS HAVE DEVELOPED IN VICINITY OF THE FRONT...WITH SOME FURTHER BACK TOWARDS THE LOW OVER SERN CA. H5 TEMPS ARE NEAR MINUS 30C NEAR THE LOW CENTER...ALONG THE SERN CA COAST. A LOOK AT THE 00Z SAN DIEGO RAOB SHOWED THAT MARINE LAYER HAD DEEPENED TO JUST OVER 700MB...AND AS SUCH THIS LOW TO MID LVL MSTR HAS BEEN SPREADING OVER THE COASTAL RANGES AND INTO SERN CA AND SWRN AZ...AND INCREASING THE MOISTURE AVAILABLE TO THIS SYSTEM. SHORT TERM MODELS NOW HAVE COME INTO PRETTY GOOD AGREEMENT WITH THE TIMING OF THIS SHORT WAVE...PUTTING THE TROF AXIS INTO CNTRL AZ BY 18Z...THEN PUSHING THE LOW OUT OF AZ AND INTO NM BY ABT 12Z WED. RATHER IMPRESSIVE DYNAMICS WITH THIS SYSTEM...WITH H7 UVVS FORECAST TO BE OVER 6 MICROBARS/SEC OVR SCNTRL AZ THIS MORNING...THO THE STRONGEST FORCING DOES APPEAR TO BE FOCUSED OVER NRN AZ. TROF IS MOVING THROUGH AZ IN A SOMEWHAT POSITIVE TILT FASHION...RATHER PROGRESSIVLY...AND JET DYNAMICS ARE NOT THAT SUBSTANTIAL FOR OUR CWA AS SRN AZ NOT IN A FRONT LEFT QUAD OF THE UPPER JET...RATHER THE RIGHT REAR QUAD...AS THE JET LIFTS OUT ON THE FRONT SIDE OF THE TROF TODAY. STILL...SHOULD BE SUFFICIENT DYNAMICS COMBINED WITH DECENT MOISTURE TO GIVE SCATTERED SHOWERS TO MOST OF THE CWA TODAY...AND SOME LOCATIONS COULD SEE OVER ONE TENTH OF AN INCH OF RAIN. FAVORED UPSLOPE AREAS IN OUR NORTHERN CWA...MOSTLY N OF PHX...COULD EVEN SEE OVER ONE QUARTER INCH TODAY. GIVEN THE COLD AIR ALOFT WITH THIS PASSING TROF...AND THE EFFECTS OF THE FRONTAL PASSAGE...COULD SEE ISOLD THUNDERSTORMS DEVELOP DURING THE DAY...THO MODELS ALL SUGGEST THAT THE ONLY NEGATIVE LIFTED INDICES WILL BE WELL NORTH OF OUR CWA. WILL KEEP THE SLIGHT CHANCE FOR THUNDERSTORMS MENTIONED IN THE ZONES TODAY AND EARLY THIS EVENING THO. TONIGHT SHOULD SEE THE SYSTEM EXIT TO OUR EAST...WITH SKIES OVER THE WRN ZONES BECOMING MOSTLY CLEAR EARLY. PHX EAST SHOULD STILL SEE SCT EVENING SHOWERS...ALONG WITH A POSSIBLE THUNDERSTORM...WITH ZONE 24 THE LAST TO CLEAR OUT. EXPECT SHOWERS TO LAST IN SRN GILA COUNTY UNTIL MIDNIGHT OR A BIT BEYOND. OF COURSE...BREEZY AND COOLER WEATHER WILL ACCOMPANY THIS TROF...WITH DESERT HIGHS EXPECTED TO DROP INTO THE UPPER 50S TO LOW 60S...THO THE ACTUAL NUMBERS WILL DEPEND ON HOW SUBSTANTIAL THE CLOUDS AND SHOWERS ARE. WILL GO WITH 62 FOR PHX...BUT THIS COULD BE A BIT WARM IF SHOWERS PERSIST INTO THE EARLY EVENING. ALTHOUGH THICKNESSES ARE PROGGED TO RISE OVER 100M FROM THIS AFTN TO WED AFTN...FEEL TEMPS WILL NOT WARM MUCH...AND THUS WILL NOT MENTION ANY TEMP TREND FOR WED...WITH READINGS TO STAY BELOW NORMAL. REST OF THE FORECAST LOOKS DRY WITH A WARMING TREND THU INTO SAT. NO CHANGES PLANNED TO THE PACKAGE BEYOND THE SECOND PERIOD. 11 .PSR...NONE
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Locally heavy rainfall, with amounts up to 1.4 inches, spread across much of the East Valley during the day. Minor street flooding was reported as well as pea-size hail in Ahwatukee and Chandler.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2001Every state in 2001This day in weather historyWarnings in Arizona, December 2001
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: 5276394.