3 hail, 1 tornado, as filed by the National Weather Service.
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 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 San Francisco Bay Area, CA wrote its last area forecast discussion before the first event at Dec 20, 3:00 PM PST, 1 hour 20 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
300 PM PST THU DEC 20 2001
THE CUTOFF LOW IS TRACKING EWD WITH THE CENTER HEADED FOR PT ARENA
WHICH WOULD VERIFY THE ETA FORECAST...THE AVN HAD IT COMING ONSHORE
NEAR PT REYES. EITHER WAY ITS ON TRACK TO MAKE LANFDALL SHORTLY
AFTER 00Z. SHOWERS AND TSTMS HAVE BEEN WIDESPREAD...WE JUST HAD A
HEFTY BOOMER HERE IN MRY WITH SMALL HAIL...LOTS OF LIGHTNING...AND
TORRENTIAL DOWNPOURS. THE SHOWERS AND STORMS SHOULD CONTINUE INTO
EARLY EVE BUT WILL DECREASE AFTER THAT AS THE CUTOFF TRACKS INLAND
AND DAYTIME HEATING ENDS. EXPECT SHOWERS TO END BY ABOUT DAWN...
PROBABLY LAST HERE IN MRY COUNTY WHERE THEY OFTEN PERSIST IN MOVING
ONSHORE IN THE POST TROF CYCLONIC NWLY FLOW.
THE NEXT STORM IS MOVING RAPIDLY EWD WITH ITS VORTCENTER NEAR
43/165 AT 21Z. ITS REALLY MOTORING AND WILL PROBABLY COME ASHORE SAT
AM. THE MODELS VARY WIDELY IN ITS PROJECTED INTENSITY. THE CANADIAN
IS QUITE WET FOR OUR WHOLE DISTRICT ON SAT. THE AVN ALSO SPREADS
RAIN ACROSS THE DISTRICT. THE ETA IS SLOWER AND CONFINES THE RAIN TO
THE N BAY WHILE THE UK FORECASTS THE SYSTEM TO FIZZLE OUT WITH
VIRTUALLY NO EFFECT ON OUR REGION. BLENDING THE MODELS WILL BRING
RAIN INTO THE N BAY CATEGORICALLY ON SAT...TAPERING TO A CHANCE IN
MRY COUNTY.
THE MODELS FORECAST ANOTHER SHORTWAVE TO MOVE ASHORE ABOUT 12Z TUE.
THE UK AND AVN INDICATE THAT IT WILL BE NEGATIVELY TILTED AND
DIFFLUENT...BUT WEAK. FOR NOW WILL FORECAST A CHANCE OF RAIN FOR
XMAS AND AWAIT FURTHER DEVELOPMENTS.
STS 9048 SFO 9027 SJC/LVK 9016 MRY 8004. MARKKANEN
.SFO...TNGT..SCA...PT ARENA TO PT PIEDRAS BLANCAS AND SFO/MRY BAYS.
HVY SURF ADVY...PT ARENA TO PT PIEDRAS BLANCAS AND
MRY BAY.The San Francisco radar (KMUX), 23 km away, was scanning. The volume nearest the first event began at 00:20 UTC.
3 hail, 1 tornado. Local standard time, as filed.
From the same storm system 3/4 inch hail was reported covering the ground 2 nm n of Watsonville. The hail damaged a large greenhouse. In a separate report there was golf ball sized hail reported in the same area.
A minor tornado was spawned from a line of convection across the Monterey bay that went ashore near Watsonville CA. The storm downed a power line by snapping off four poles, destroyed a green house and some trailers, then about a half a mile to the east tore the off off a barn as well as downing some mateure ( 5 feet in diameter) euclyptus trees.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2001Every state in 2001This day in weather historyThe tornado archive for California, 2001Warnings in California, 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: 5273774, 5273773, 5273775, 5273776.