Severe Thunderstorm Warning 4, NWS San Francisco Bay Area, CA

Issued

Dec 20, 2001, 7:00 PM PST (03:00 UTC)

Expired

Dec 20, 2001, 7:30 PM PST

In force

30 min

Issued by

NWS San Francisco Bay Area, CA

Area

Whole counties; the outline is the Mesonet’s reconstruction

Counties Santa Clara County, CA, Santa Cruz County, CA

714 
WUUS56 KMTR 210301
SVRSFO
CAC085-087-210330-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
700 PM PST THU DEC 20 2001

THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO BAY AREA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTH CENTRAL SANTA CLARA COUNTY IN WESTERN CALIFORNIA
  THIS INCLUDES THE CITIES OF...MORGAN HILL...GILROY
  SOUTHEASTERN SANTA CRUZ COUNTY IN WESTERN CALIFORNIA

* UNTIL 730 PM PST

* AT 657 PM PST...WEATHER SPOTTERS REPORTED LARGE HAIL   
  ABOUT 2 MILES NORTHEAST OF WATSONVILLE...MOVING NORTHEAST AT 20 
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  3 MILES NORTHWEST OF GILROY AT 720 PM PST
  6 MILES SOUTHEAST OF MORGAN HILL AT 730 PM PST

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS IN
EXCESS OF 55 MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN SAN FRANCISCO BAY AREA.

LAT...LON 3696 12187 3690 12180 3708 12137 3724 12157

NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this severe thunderstorm warning went out at Dec 20, 3:00 PM PST, 4 hours 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.

Severe Thunderstorm Warnings in California, 2001Every severe thunderstorm warning in 2001

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.