This storm system originated over central Pacific Ocean and was able to tap into the subtropical air which produced valley rain and heavy snow in the mountains on the 7th. 25 inches to 1 inch around southeast Arizona.
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The episode as NWS TWC wrote it up.
This storm system originated over central Pacific Ocean and was able to tap into the subtropical air which produced valley rain and heavy snow in the mountains on the 7th. The main precipitation band produced valley rain in amounts ranging from .25 inches to 1 inch around southeast Arizona. This caused some minor street flooding in the Tucson Metro area. Snow levels fluctuated between 5500 and 6500 feet with significant accumulation above 7000 feet. By the afternoon on the 7th, the system moved east and the dry slot helped organize lines of low topped storms. Several spotters reported small hail and gusty winds. There was also a report of a funnel cloud from Ryan Airfield.
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 Tucson, AZ wrote its last area forecast discussion before the first event at Mar 7, 2:20 PM MST, 33 minutes earlier.
SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
220 PM MST WED MAR 7 2001
SYNOPSIS...THE WINTER STORM OVER SOUTHERN ARIZONA WILL EXIT THE AREA
OVERNIGHT...ALLOWING HIGH PRESSURE TO MOVE IN FROM THE WEST COAST
FOR THE END OF THE WEEK. ANOTHER WINTER STORM APPROACHING THE
PACIFIC NORTHWEST WILL DROP INTO ARIZONA LATE SATURDAY INTO
SUNDAY...BRINGING ANOTHER THREAT OF RAIN AND MOUNTAIN SNOW...AS WELL
AS LOWER SNOW LEVELS.
DISCUSSION...STORM SYSTEM GOING PRETTY MUCH AS PLANNED. PRECIP BAND
IS STILL PRETTY IMPRESSIVE, BUT IT'S GETTING MORE FRAGMENTED AS
UPPER LOW BEGINS TO SHEAR A LITTLE. FURTHER W, LOW-TOPPED SHOWERS
WERE REDEVELOPING IN THE DRY SLOT AND COULD GIVE US A FEW HEADACHES
THIS AFTERNOON IN THE FORM OF THUNDER AND MAYBE EVEN A LITTLE HAIL.
CURRENT HEADLINE TIMING LOOKS GOOD, WITH ZONES 33/34 EXPIRING AT 4PM
AND THE E CONTINUING INTO THE EVENING. WE'LL LET THE FLOOD ADVISORY
DIE AT 4PM AS WELL, ALTHOUGH GRAHAM/COCHISE COUNTIES WILL HAVE TO BE
WATCHED FOR A COUPLE OF HOURS. WITH A LITTLE CLEARING OVERNIGHT, FOG
COULD BECOME A REAL PROBLEM. HOWEVER, WITH LINGERING CYCLONIC
CURVATURE IN THE LOW AND MID LEVELS, THE MOISTURE COULD JUST AS
EASILY LIFT INTO A STRATUS DECK. WE'LL USE PATCHY FOG FOR NOW SINCE
EVEN IF WE FORM STRATUS, ELEVATIONS LYING IN THE CLOUD DECK WILL
SOCK IN. AFTER THAT, IT LOOKS LIKE A QUIET END OF THE WEEK, WITH FRI
BEING THE BEST DAY AS UPPER LOW DROPPING DOWN THE W COAST ALLOWS A
RIDGE TO BEEF UP OVER AZ.
I WISH THE PACJET PROJECT WAS STILL GOING OFF THE W COAST. I WAS
FULLY PREPARED TO UP TO "LIKELY" WORDING SUN, BUT NOW THE 12Z AVN IS
GOING TOWARD THE ECMWF AND TAKING THE UPPER LOW MUCH FURTHER N THAN
THE MRF/UKMET/CANADIAN. IF THAT HAPPENS, SE AZ WILL GET MORE WIND
AND LESS PRECIP. EVEN THOUGH I DON'T COMPLETELY BUY THIS PROGRESSIVE
TREND, I NOW HAVE JUST ENOUGH DOUBT TO HOLD ON THE MORE CERTAIN
WORDING. I'M ALSO GOING TO BE HEDGY AND OMIT "MOUNTAIN SNOW" WORDING
IN THE E CWA SINCE ANY PRECIP WE GET MAY REACH VALLEY FLOORS. EVEN
WITH THIS FURTHER N TRAJECTORY, AVN HAS SNOW LEVELS DROPPING TO 3KFT
AND 500MB TEMPS TO BELOW -25C. MOST ENSEMBLE MEMBERS AND THE
OPERATIONAL AVN/MRF LEAVE SOME ENERGY BACK OVER US ON MON. EVEN IF
IT THE MORE PROGRESSIVE TREND COMES TO PASS, THE LINGERING SHEAR
AXIS OVER US WARRANTS KEEPING A CHANCE IN THE E CWA EARLY MON.
PYTLAK
.TWC..i.HEAVY SNOW WARNING THIS EVENING ABOVE 7000FT ZONES 19/30
SNOW ADVISORY THIS EVENING ABOVE 7000FT ZONE 35.The Tucson radar (KEMX), 112 km away, was scanning. The volume nearest the first event began at 21:50 UTC.
1 funnel cloud. Local standard time, as filed.
A trained spotter reported a cold air funnel cloud 5 miles west of Ryan Airfield.
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, March 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: 5235277.