Lightning Strike and Winter Weather in California, March 17 to 18, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
310 AM PST FRI MAR 17 2006

.SHORT TERM...FOR THE CENTRAL CALIFORNIA INTERIOR...THE RADAR
COMPOSITE LOOP SHOWS A BAND OF RAIN SAGGING SOUTHEAST INTO MERCED
COUNTY THIS MORNING. A STRONG SOUTHWEST FLOW ALOFT HAS SLOWED THE
PROGRESS OF THE RAIN BAND...BUT IT REMAINS ON TRACK TO REACH FRESNO
AROUND SUNRISE...THEN CONTINUE TO DROP SOUTH DURING THE DAY...AND
REACH THE KERN COUNTY MOUNTAINS AND DESERTS BY THIS AFTERNOON.

THE SYSTEM LOOKS LESS THAN IMPRESSIVE ON THE GOES SATELLITE LOOP.
THE UPPER-LEVEL LOW IS JUST WEST OF PORTLAND...WITH THE TROUGH AXIS
OFFSHORE ALONG 128W. A VORTICITY LOBE IS DROPPING INTO THE TROUGH...
AND WILL PUSH INTO THE CENTRAL CALIFORNIA LATER THIS MORNING. THE
00Z MODELS ARE IN GOOD AGREEMENT WITH THE TROUGH AXIS MOVING INTO
THE HANFORD WARNING/FORECAST AREA THIS AFTERNOON...THEN EAST OF THE
REGION BY 06Z SATURDAY. THE MODELS CLOSE OFF A LOW IN THE BASE OF
THE TROUGH...OVER THE SOUTHERN PART OF THE FORECAST AREA...TONIGHT
BUT EJECT IT EAST INTO SOUTHERN NEVADA BY 00Z SUNDAY...SETTING UP A
DRY NORTHERLY FLOW ALOFT OVER THE CENTRAL CALIFORNIA INTERIOR
SATURDAY NIGHT.

1000-500-MB THICKNESSES ARE FORECAST TO FALL TO 5400 METERS BY 00Z
SATURDAY...AND 5340 METERS BY 12Z SATURDAY. 700-MB TEMPERATURES OVER
THE HANFORD WARNING/FORECAST AREA FALL TO -8 C TO -10 C BY 00Z
SATURDAY...WITH -10 C OVER MOST OF THE REGION BY 12Z SATURDAY. THIS
WOULD PLACE THE SNOW LEVEL BETWEEN 3000-3500 FEET. HOWEVER...THE NAM
HAS TRENDED WARMER THAN THE GFS AT 850 MB THE LAST FEW RUNS...AND
DOES NOT DROP 850-MB TEMPERATURES BELOW FREEZING THROUGH THE PERIOD.
IF THE NAM IS CORRECT...SNOW LEVELS SATURDAY COULD BE HIGHER THAN
CURRENTLY FORECAST.

IN TERMS OF THE CONVECTIVE POTENTIAL TODAY...THE 06Z WS-ETA HAS
SURFACE COMPUTED CAPES OF 400+ JOULES/KG OVER THE WEST SIDE OF THE
SAN JOAQUIN VALLEY AT 00Z SATURDAY...WITH LIFTED INDEXES OF -1 TO -2
AND 500-MB TEMPERATURES OF -28 C. BOTH THE CAPES AND LIFTED INDEXES
ARE SLIGHTLY MORE STABLE THAN HAD BEEN FORECASTED BY THE WS-ETA RUN
FOR 16/06Z...BUT STILL FAVOR ISOLATED AFTERNOON THUNDERSTORMS. THE
SPC CONVECTIVE OUTLOOK FOR TODAY CONTINUES TO HAVE NEARLY ALL OF
CALIFORNIA IN A GENERAL RISK CATEGORY.

FOR SATURDAY...THE SPC DAY-2 OUTLOOK HAS A GENERAL RISK OF
THUNDERSTORMS SOUTH OF FRESNO COUNTY. THE 06Z WS-ETA FORECASTS
500-MB TEMPERATURES OVER THE HANFORD WARNING/FORECAST AREA OF AROUND
-26 C AT 00Z SUNDAY. THIS IS 4 C WARMER THAN THE 16/06Z SOLUTION...
REFLECTING THE WARMING TREND THE ETA/NAM SUITE HAS SHOWN. SURFACE
COMPUTED CAPES ARE DOWN AS WELL...WITH ISOLATED 300 JOULES/KG ONLY
IN WESTERN MERCED AND KERN COUNTIES. LIKEWISE...LIFTED INDEXES ALSO
ARE NEGATIVE ONLY OVER WESTERN MERCED AND KERN COUNTIES. WILL KEEP
THE MENTION OF ISOLATED THUNDERSTORMS FOR THE SAN JOAQUIN VALLEY AND
THE SIERRA FOOTHILLS SATURDAY AFTERNOON FOR NOW...BUT CONFIDENCE IS
WEAK DUE TO THE DIFFERENCES BETWEEN THE NAM AND THE GFS.

THE MODELS ARE IN AGREEMENT WITH THE TROUGH MOVING INTO THE GREAT
BASIN SATURDAY NIGHT AND SUNDAY...AS AN UPPER-LEVEL SHORT-WAVE RIDGE
BUILDS OFF THE CALIFORNIA COAST. THIS WILL BRING DRY WEATHER TO THE
REGION SUNDAY WITH WARMER TEMPERATURES.

.LONG TERM...FOR SUNDAY NIGHT THROUGH THURSDAY...THE MEDIUM RANGE
MODELS ARE ACTUALLY IN FAIRLY GOOD AGREEMENT THIS MORNING FOR
ONCE...AND THE ENSEMBLE MEMBERS ARE IN FAIRLY GOOD AGREEMENT THROUGH
D7 SO CONFIDENCE FOR THIS PERIOD IS IMPROVED. THE CONSENSUAL
AGREEMENT IS THAT THE SHORT WAVE RIDGE OVER CA ON SUNDAY NIGHT WILL
BREAK DOWN BY MONDAY AS A FAST MOVING UPPER LOW CENTER APPROACHES
THE WESTERN CONUS COAST. THE LOW IS EXPECTED TO RAPIDLY CROSS NORCAL
MONDAY NIGHT AND EARLY TUESDAY...WHICH IS A FASTER TIMING THAN WHAT
THE GFS WAS INDICATING YDAY. SINCE THERE IS GOOD MODEL AGREEMENT
WITH THE FASTER TIMING...HAVE BOUGHT INTO THIS IDEA AND HAVE
INCREASED POPS FOR MONDAY NIGHT THROUGH TUESDAY. THE MODELS ARE ALSO
MOVING THIS LOW EAST OF OUR AREA BY MIDWEEK. AFTER SOME RESIDUAL
SHOWERS TUESDAY NIGHT...A FAIRLY STRONG DRY UPPER RIDGE IS EXPECTED
TO BUILD INTO CA ON WEDNESDAY AND REMAIN THE MAIN WEATHER FEATURE
OVER CA THROUGH THE END OF THE WEEK...PROVIDING OUR AREA WITH A
WARMING TREND AND MOST LIKELY SEVERAL DAYS OF DRY WEATHER AS THE
MODEL CONSENSUS IS INDICATING THAT THIS RIDGE WILL HAVE A HIGHER
AMPLITUDE TO IT THAN THE WESTERN CONUS HAS OBSERVED WITH ANY RIDGING
IN OVER THREE WEEKS.

&&

.AVIATION...MAINLY MVFR CONDITIONS WITH AREAS OF IFR IN MOUNTAIN
OBSCURATIONS...WILL SPREAD SOUTHWARD ACROSS THE SOUTHERN SIERRA
NEVADA AND TEHACHAPI MOUNTAINS TODAY AS A MOIST FRONTAL BAND CROSSES
THE AREA. MVFR AND AREAS OF IFR CONTINUING THROUGH TONIGHT ACROSS
THE THE SOUTHERN SIERRA NEVADA AND TEHACHAPI MOUNTAINS TONIGHT IN
SHOWERS AND MOUNTAIN OBSCURATIONS. ELSEWHERE...GENERALLY VFR
CONDITIONS WILL PREVAIL THROUGH 12Z SATURDAY IN THE CENTRAL AND
SOUTH SAN JOAQUIN VALLEY AND KERN DESERTS WITH LOCAL MVFR CEILINGS
IN HEAVIER SHOWERS THIS AFTERNOON AND EVENING. FOR SPECIFIC
DETAILS...PLEASE REFER TO TAFS FOR KMCE...KFAT AND KBFL.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...A SNOW ADVISORY IS IN EFFECT FOR
     THE SOUTHERN SIERRA NEVADA...FROM YOSEMITE TO KINGS CANYON...
     THROUGH 4 AM SATURDAY MORNING.

&&

WWW.WEATHER.GOV/HANFORD /USE ALL LOWER CASE/

SANGER/DS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
252 AM PST FRI MAR 17 2006

CAZ089>095-097>099-171700-
WEST CENTRAL SAN JOAQUIN VALLEY-EAST CENTRAL SAN JOAQUIN VALLEY-
SOUTHWESTERN SAN JOAQUIN VALLEY-SOUTHEASTERN SAN JOAQUIN VALLEY-
MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS-TULARE COUNTY FOOTHILLS-
KERN COUNTY MOUNTAINS-TULARE COUNTY MOUNTAINS-INDIAN WELLS VALLEY-
SOUTHEASTERN KERN COUNTY DESERT-
252 AM PST FRI MAR 17 2006

...ANOTHER WINTER STORM HEADING THIS WAY...

A STORM SYSTEM ORIGINATING IN THE GULF OF ALASKA WILL BRING
COLDER WEATHER TO THE CENTRAL CALIFORNIA INTERIOR TODAY THROUGH
SATURDAY...WITH RAIN AND HIGHER ELEVATION SNOW.

PRECIPITATION WILL DEVELOP AS FAR SOUTH AS FRESNO BY DAYBREAK...THEN
SPREAD SOUTH INTO KERN COUNTY DURING THE DAY. SNOW LEVELS WILL START
OUT BETWEEN 4500 AND 5500 FEET TONIGHT...LOWER THROUGH THE DAY...AND
BOTTOM OUT BETWEEN 2500 AND 3000 FEET EARLY SATURDAY MORNING.

THIS STORM HAS THE POTENTIAL TO BRING SEVERAL INCHES OF SNOW ABOVE
3000 FEET BY SATURDAY MORNING...AND UP TO A FOOT OR MORE OF NEW SNOW
TO THE SIERRA SUMMITS.

IN THE KERN COUNTY MOUNTAINS...THERE IS A POSSIBILITY OF A SMALL
ACCUMULATION OF SNOW AND ICE ON THE GRAPEVINE AND TEHACHAPI PASS
TONIGHT INTO SATURDAY MORNING. ALSO...STRONG AND GUSTY WINDS MAY
HAMPER TRAVEL THROUGH AND BELOW THE MOUNTAIN PASSES TODAY THROUGH
SATURDAY.

ADDITIONALLY...AS A COLD AND UNSTABLE AIRMASS MOVES INTO CENTRAL
CALIFORNIA...ISOLATED AFTERNOON THUNDERSTORMS MAY OCCUR IN THE
SAN JOAQUIN VALLEY BOTH TODAY AND SATURDAY.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE NEWS SOURCE...
FOR FURTHER INFORMATION ON THIS WINTER STORM.

WWW.WEATHER.GOV/HANFORD /USE ALL LOWER CASE/

SANGER