Severe Thunderstorm Warning 6, NWS Sacramento, CA

522 
WWUS56 KSTO 050240
SVSSTO

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SACRAMENTO CA
740 PM PDT MON JUN 4 2012

CAC103-050250-
/O.EXP.KSTO.SV.W.0006.000000T0000Z-120605T0245Z/
TEHAMA CA-
740 PM PDT MON JUN 4 2012

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN TEHAMA COUNTY WILL
EXPIRE AT 745 PM PDT...

LAT...LON 4036 12242 4031 12219 4012 12229 3994 12244
      4007 12269
TIME...MOT...LOC 0240Z 220DEG 14KT 4037 12221

$$

CS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
349 PM PDT MON JUN 4 2012

.SHORT TERM DISCUSSION...

UNUSUAL...BUT NOT UNPRECEDENTED...JUNE WX FOR INTERIOR NORCAL TODAY
WITH A MINUS 3 STANDARD DEVIATION 500 MBS HEIGHT ANOMALY...AND A PW
PLUME UP TO 175% PERCENT OF NORMAL AFFECTING THE AREA. THE FRONTAL
PRECIP HAS MOVED INTO THE SIERRA NEVADA WITH GENERALLY STRATIFORM
PRECIP...BUT ALSO A LINE OF STRONGER CELLS ALONG THE FRONT. TO
THE W OVER THE COASTAL RANGE...CONVECTIVE CELLS ARE BEGINNING TO
DEVELOP WITH A FEW +/- CG STRIKES AS THE 500 MBS HEIGHT ANOMALY
APPROACHES THE AREA. DARKENING IN THE WATER VAPOR IMAGERY
INDICATES A STRONG VORT MAX JUST OFF THE SFO COAST WHICH IS
FORECAST TO MOVE INLAND OVER THE SFO BAY AREA BY 00Z TUE AND THEN
NEWD TOWARDS THE CA/OR/NV BORDER OVERNITE. THIS IS FOLLOWED BY
SHEARED VORTICITY ON THE BACKSIDE OF THE UPPER TROF WHICH MOVES NEWD
ACROSS NORCAL ON TUE. LAPSE RATES FROM BUFKIT DATA ARE FORECAST TO
STEEPEN TO >7 DEG/KM AFTER 00Z...SO THE BEST CHANCE OF THUNDER IN
THE VALLEY STILL LOOKS TO BE IN THE EARLY EVENING HRS. THE BETTER
0-1 KM AND 0-6 KM SHEAR VALUES ARE FORECAST TO BE OVER THE N END
OF THE SAC VALLEY DURING THE EARLY EVENING HOURS AS WELL...AND ARE
FORECAST TO REACH THE MINIMAL VALUES FOR WEAK ROTATING CELLS. THE
STRONGEST CONVERGENCE AND TERRAIN FORCING IS ALSO EXPECTED TO BE
IN THE NRN SAC VLY AS THE UP VALLEY FLOW INCREASES WITH THE
APPROACHING VORT MAX/UPPER TROF. WRF CAPES ARE ALSO MAXIMIZED OVER
THE NRN ZONES. IF HEATING WAS STRONGER TODAY...WE WOULD HAVE
STRONGER INSTABILITY...BUT THE CLOUD COVER SHOULD REMAIN THICK
ENOUGH TODAY TO LIMIT DIFFERENTIAL HEATING...THE DOWNSIDE FOR
TODAY'S CONVECTIVE THREAT.

WITH THE APPROACHING TROF/VORT MAX...PRESSURE GRADIENTS WILL ALSO
INCREASE THROUGH 00Z AND A PERIOD OF GUSTY ONSHORE AND UP VALLEY WINDS
ARE OCCURRING AHEAD OF THE VORT MAX/UPPER TROF THIS AFTERNOON AND
MAY ALSO OCCUR IN THE WAKE OF THE VORT MAX EARLY THIS EVENING.
SOME OF THE NUMERICAL GUIDANCE IS INDICATING THE POTENTIAL FOR
WIND ADVSRY CRITERIA WINDS FROM LAKE CO...THROUGH THE CARQUINEZ
AND INTO THE SRN SAC AND NRN SAN JOAQUIN VALLEY. TERRAIN FORCING
HAS RESULTED IN WIND ADVISORY WINDS IN THE NRN SAC VLY...WHICH MAY
ALSO DEVELOP OVER THE CENTRAL SAC VLY AT TIMES THROUGH EARLY
EVENING AS THE TROF PROGRESSES INLAND.

WE DECIDED TO GO AHEAD WITH THE SNOW ADVISORY FOR THE SIERNEV AS
SNOW LEVELS LOWER OVERNITE AS THE TROF MOVES INLAND. OUR SNOW
TOTAL GRID HAS ABOUT 4-5 INCHES OF ACCUMULATING SNOW OVER THE HIGHER
TERRAIN...MAINLY ABOVE 6000 FEET. THE SNOW LEVEL MAY LOWER TO 5000
TO 5500 FT EARLY TUE MORNING...BUT LITTLE QPF IS EXPECTED TO FALL
TUE MORNING. WITH THE TROF AXIS STILL NOT EAST OF THE SIERNEV BY 12Z
TUE...PRECIP IS LIKELY TO CONTINUE OVER THE SIERNEV FOR MOST OF
THE NITE...ALTHOUGH THE HRRR/WRF INDICATE A DECREASE IN PRECIP
THIS EVENING AFTER FROPA.

ANY LINGERING SHOWERS OVER THE NRN ZONES SHOULD END ON TUE AS DRIER
NWLY FLOW DEVELOPS OVER NORCAL BEHIND THE DEPARTING TROF. TUE WILL
BE ANOTHER COOL DAY WITH HIGHS IN THE LOW 70S IN THE VALLEY SOME
10-20 DEG BELOW NORMAL...COOL FOR PRIMARY ELECTION DAY IN NORCAL.
WEAK SHORT WAVE RIDGING BUILDS OVER THE AREA ON WED AND MAX TEMPS
SHOULD WARM INTO THE LOW TO MID 80S...CLOSER TO NORMAL.

THE FLOW TRANSITIONS TO CYCLONIC ON THU AS THE NEXT GOA UPPER LOW
APPROACHES THE B.C. COAST. CLOUD COVER IS FORECAST TO SPREAD ACROSS
THE NRN ZONES...N OF THE I-80 CORRIDOR...WITH A SLIGHT CHANCE OF
SHOWERS ACROSS THE NRN MTNS. THIS SHOULD RESULT IN LOWER MAX TEMPS
ACROSS THE N ON THU. ONSHORE GRADIENTS SHOULD INCREASE DURING THE
DAY RESULTING IN A DELTA BREEZE...BUT TOO LATE IN THE DAY TO LOWER
MAX TEMPS AWAY FROM THE DELTA.     JHM

.EXTENDED DISCUSSION (FRIDAY THROUGH MONDAY)

A LARGE UPPER LEVEL TROUGH IS FORECAST TO SLOWLY PROPAGATE ACROSS
THE PACIFIC NORTHWEST BY LATE THURSDAY...WITH BROAD TROUGHING
CONTINUING INTO THE WEEKEND. HIGH TEMPERATURES ARE FORECAST TO
DROP A FEW DEGREES AS THE TROUGH APPROACHES NORCAL. THERE IS A
SLIGHT CHANCE OF PRECIPITATION FOR FAR NORTHERN SHASTA
COUNTY...ALTHOUGH MODELS SUGGEST MOST OF THE PRECIP WILL REMAIN
NORTH OF THE REGION. BREEZY NORTH WINDS ARE POSSIBLE FOR THE
VALLEY FOR THE WEEKEND AS THE LOW MOVES EASTWARD. WARMING IN TEMPS
MAY RETURN BY THE END OF THE WEEKEND AND INTO EARLY NEXT
WEEK...HOWEVER THERE IS SOME MODEL UNCERTAINTY BY THIS POINT. SLH

&&

.AVIATION...

THE BAND OF SHOWERS WILL CONTINUE TO PUSH EASTWARD ACROSS THE VALLEY
AND INTO THE MOUNTAINS THROUGH THIS AFTERNOON. -SHRA CONDITIONS IN THE
NORTHERN SAN JOAQUIN VALLEY WILL CONTINUE TO PROPAGATE INTO THE
FOOTHILLS BY 00Z. ISOLATED THUNDERSTORMS WILL SPREAD ACROSS THE
VALLEY FROM THE NORTH AND PROPAGATE EASTWARD...MOSTLY IN THE
NORTHERN SACRAMENTO VALLEY. VFR/MVFR CIGS WILL BECOME MAINLY VFR
FOR THE VALLEY...EXCEPT LOCAL MVFR/IFR CONDITIONS WILL BE POSSIBLE
DURING THUNDERSTORMS. BREEZY SOUTHWEST WINDS WILL BRING SPEEDS UP TO
10-15 KTS WITH LOCAL GUSTS UP TO 25 KTS THROUGH 03Z...THEN DECREASING.

FOR MOUNTAINS...IFR/LIFR CONDITIONS ARE EXPECTED OVER THE SIERRA
AS RAIN SHOWERS PERSIST THROUGH THE EVENING. RAIN IS FORECAST TO
TURN TO SNOW AS SNOW LEVELS LOWER TO 5500-6500 FT. MODERATE TO
STRONG SW WINDS TODAY INTO TONIGHT WITH RIDGETOP GUSTS UP TO 50
KTS. SLH

&&

.STO WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM PDT TUESDAY ABOVE 6000 FEET
FOR THE WEST SLOPE NORTHERN SIERRA NEVADA...WESTERN PLUMAS
COUNTY/LASSEN PARK.

WIND ADVISORY UNTIL 9 PM PDT THIS EVENING CARQUINEZ STRAIT AND
DELTA...CLEAR LAKE/SOUTHERN LAKE COUNTY...NORTHERN SAN JOAQUIN
VALLEY...SOUTHERN SACRAMENTO VALLEY.

WIND ADVISORY UNTIL 8 PM PDT THIS EVENING CENTRAL SACRAMENTO
VALLEY...NORTHERN SACRAMENTO VALLEY.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
524 AM PDT MON JUN 4 2012

CAZ013>019-063-064-066>069-051400-
SHASTA LAKE AREA/NORTHERN SHASTA COUNTY-
BURNEY BASIN/EASTERN SHASTA COUNTY-NORTHERN SACRAMENTO VALLEY-
CENTRAL SACRAMENTO VALLEY-SOUTHERN SACRAMENTO VALLEY-
CARQUINEZ STRAIT AND DELTA-NORTHERN SAN JOAQUIN VALLEY-
MOUNTAINS SOUTHWESTERN SHASTA TO NORTHERN LAKE COUNTIES-
CLEAR LAKE/SOUTHERN LAKE COUNTY-MOTHERLODE-
EAST FOOTHILLS/NORTH SACRAMENTO VALLEY-
WESTERN PLUMAS COUNTY/LASSEN PARK-WEST SLOPE NORTHERN SIERRA NEVADA-
524 AM PDT MON JUN 4 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

A STRONG LATE-SEASON WEATHER SYSTEM WILL SPREAD SHOWERS INLAND
ACROSS THE REGION TODAY ALONG WITH BRINGING GUSTY SOUTHWEST WINDS TO
THE HIGHER ELEVATIONS AND MUCH COOLER TEMPERATURES. SIGNIFICANT
RAINFALL OF OVER AN INCH WILL BE POSSIBLE IN THE NORTHERN SIERRA
NEVADA ALONG WITH SNOWFALL ACCUMULATION OF UP TO 4 INCHES ALONG THE
CREST. STRONG THUNDERSTORMS WILL BE POSSIBLE IN THE SACRAMENTO
VALLEY AND FOOTHILLS LATE THIS AFTERNOON AND THIS EVENING POSSIBLY
ACCOMPANIED BY GUSTY WINDS...HAIL AND EVEN A BRIEF TORNADO. WEATHER
SPOTTERS FROM COLUSA...SUTTER AND YUBA COUNTIES NORTHWARD TO SHASTA
COUNTY SHOULD BE PREPARED FOR POSSIBLE ACTIVATION THIS AFTERNOON.

* SPECIAL WEATHER STATEMENT..SEE WWUS86 KSTO - SPSSTO FOR DETAILS *

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

SHOWERS WILL TAPER OFF ACROSS THE REGION TUESDAY...OTHERWISE NO
HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

THE LATEST WEATHER INFORMATION IS AVAILABLE ON THE INTERNET AT
(LOWER CASE): HTTP://WWW.WRH.NOAA.GOV/STO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
503 PM PDT MON JUN 04 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0435 PM     HAIL             3 WNW REDDING           40.59N 122.42W
06/04/2012  E0.75 INCH       SHASTA             CA   TRAINED SPOTTER

            HAIL COVERING ROAD AND STOPPING TRAFFIC. HAIL NEAR DIME
            SIZED.

&&

DVCLEAVE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
511 PM PDT MON JUN 04 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0430 PM     HAIL             3 WSW REDDING           40.56N 122.41W
06/04/2012  M0.75 INCH       SHASTA             CA   TRAINED SPOTTER

0450 PM     HAIL             5 WNW PALO CEDRO        40.59N 122.33W
06/04/2012  M0.75 INCH       SHASTA             CA   TRAINED SPOTTER

            HAIL COVERED THE GROUND

&&

DVCLEAVE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
528 PM PDT MON JUN 04 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0510 PM     HAIL             10 SW ANDERSON          40.33N 122.40W
06/04/2012  E1.00 INCH       TEHAMA             CA   TRAINED SPOTTER

            SPOTTER REPORTED HAIL FALLING BETWEEN DIME AND QUARTER
            SIZE. HAIL ALSO COVERING THE GROUND.

&&

DRP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
602 PM PDT MON JUN 04 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0545 PM     HAIL             9 NNW RED BLUFF         40.30N 122.30W
06/04/2012  E1.00 INCH       TEHAMA             CA   TRAINED SPOTTER

            HAIL BETWEEN DIME AND QUARTER SIZE. HAIL COVERING THE
            GROUND.

&&

DRP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
614 PM PDT MON JUN 04 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0558 PM     HAIL             11 NNW RED BLUFF        40.31N 122.33W
06/04/2012  E0.50 INCH       TEHAMA             CA   TRAINED SPOTTER

            HAIL TWO INCHES DEEP COVERING THE GROUND. TRAFFIC SLOWED
            TO A CRAWL IN RESIDENT AREA.

&&

DRP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SACRAMENTO CA
630 PM PDT MON JUN 04 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0628 PM     HAIL             11 NNW RED BLUFF        40.31N 122.35W
06/04/2012  E1.00 INCH       TEHAMA             CA   TRAINED SPOTTER

            HAIL SIZES OF 5/8 INCH TO 1 INCH IN SIZE. 2 INCHES OF
            HAIL DEPTH ACCUMULATED ON GROUND SO FAR. SMALL BRANCHES
            DOWN.

&&

SLH