Flash Flood Warning 11, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
925 PM PST SAT JAN 26 2008

.SYNOPSIS...RAIN AND STRONG WINDS FROM A POWERFUL WINTER STORM WILL
SPREAD ACROSS SOUTHERN CALIFORNIA TONIGHT. THE RAIN WILL CHANGE OVER
TO SHOWERS AND THUNDERSTORMS ON SUNDAY AND CONTINUE INTO MONDAY
BEFORE ENDING. SNOW LEVELS WILL LOWER SUNDAY AND HEAVY SNOW WILL
MAKE TRAVEL DIFFICULT IN THE MOUNTAINS SUNDAY EVENING. COOL WEATHER
AND INTERMITTENT SHOWERS WILL PREVAIL THROUGH THE MIDDLE OF NEXT
WEEK.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

LIGHT RAIN IS SLOWLY SATURATING THE LOWEST 4000 FEET THIS EVENING.
SO INSTEAD OF ACCUMULATING PRECIP THIS EVENING...MOST OF THIS RAIN
HAS GONE INTO SATURATING THE LOWER LAYERS. THIS MAY TREND THE TOTAL
PRECIP AMOUNTS FOR TONIGHT DOWNWARD SLIGHTLY...BY ABOUT A HALF INCH.
HOWEVER...THE TIME PERIOD OF ANTICIPATED HEAVIER RAIN IS FORECAST
BETWEEN 06-12Z.

POSITIVE TILT UPPER LOW CENTERED 600 MILES SOUTHWEST OF PT
CONCEPTION STARTING TO MOVE TO THE EAST THIS EVENING. WIND FLOW
AROUND THIS LOW HAS BACKED QUITE A BIT THE PAST 6 HOURS. THE AMSU
PRECIPITABLE WATER LOOP SHOWS A SURGE OF HIGH PW WEST OF BAJA HAD
MOVED NNW AND WAS JUST OFF THE SOCAL COAST AT 0108Z. THE WARM
SUBTROPICAL CONNECTION HAS PUSHED THE FREEZING LEVEL UPWARD TO 8000
FEET. AT 730 PM THE TEMP AT MT BALDY WAS 34F AT 8000 FEET.

THE FIRST SHORTWAVE PINWHEELING AROUND THE UPPER LOW WILL TRACK
ACROSS THE REGION BETWEEN 06Z-12Z. THE INTERACTION OF THIS VORTICITY
MAX AND THE INCREASING MOIST SOUTHERLY WARM CONVEYOR BELT WILL BRING
A BURST A MODERATE TO HEAVY RAIN TONIGHT. TRAJECTORIES REMAIN
FAVORABLE FOR SOCAL TO BE IN THE DIRECT LINE OF THIS DEEP LAYER
MOISTURE TONIGHT...SO STILL ANTICIPATE MODERATE TO LOCALLY HEAVY
RAIN FOR A TIME TONIGHT. BUT LOWER PRECIP AMOUNTS APPEAR
LIKELY...AND WILL LOWER THE RAIN TOTALS DOWN TO AN INCH WEST OF THE
MOUNTAINS BY SUNDAY MORNING...AND 1.5 TO 2.5 INCHES OVER THE
FOOTHILLS AND ON THE SOUTH FACING MOUNTAIN SLOPES.

850 MB WINDS CONTINUE TO IMPRESS. SOUTHEAST WINDS VEER SOUTH TONIGHT
AHEAD OF THE SHORT WAVE AND PEAK AT 50 KTS...SUPPORTING THE GALE
WARNINGS AND WIND ADVISORIES. THE WINDS SHIFT SOUTHWEST SUNDAY BUT
REMAIN QUITE STRONG UNTIL SUNDAY NIGHT.

BETWEEN 12Z-15Z SUNDAY...A MID LEVEL DRY SLOT FILLS IN BEHIND THE
COLD FRONT. THIS WILL MARK THE END OF THE STEADY RAIN AND TURN THE
PRECIP MORE SHOWERY IN NATURE. RAPID DESTABILIZATION FOLLOWS SUNDAY
AFTERNOON AND EVENING WHEN AN EVEN STRONGER VORT MAX ROUNDS THE BASE
OF THE UPPER LOW POWERED BY A 140 KT 300 MB JET. FACTOR IN COLD CORE
500 MB TEMPS OF -24C WITH LIFTED INDICES OF -4...AND THUNDERSTORMS
ARE A GOOD BET. ADDITIONAL PRECIP FROM THIS SECOND SHORTWAVE WILL BE
LESS UNIFORM BUT AN ADDITIONAL TWO INCHES WILL FALL ON THE COASTAL
SLOPES AND FOOTHILLS...WITH AN ADDITIONAL INCH WEST OF THE MTNS.

THE HIGH SNOW LEVELS TONIGHT WILL FALL TO 5000 FEET BY SUNDAY
AFTERNOON...THEN LOWER TO NEAR 4000 FEET SUNDAY NIGHT. WITH THE
STRONG INSTABILITY IN PLACE...THUNDERSNOW IS POSSIBLE IN THE MTNS
THROUGH SUNDAY EVENING. HEAVY SNOWBURSTS AND STRONG WINDS COULD
CAUSE WHITEOUT CONDITIONS AT TIMES. FOR THE SAN DIEGO COUNTY
MOUNTAINS... HEAVY SNOWFALL IS NOT EXPECTED UNTIL LATE ON SUN OR SUN
NIGHT WHEN THE COLDER AIR LOWERS THE SNOW LEVELS.

THE STRONG SOUTH WINDS TONIGHT WILL SHIFT WEST SUNDAY. SOME OF THE
STRONG JET ENERGY ALOFT WILL TRANSLATE TOWARD THE SURFACE SUNDAY
AFTERNOON RESULTING IN STRONG WINDS THROUGH SUNDAY
EVENING...ESPECIALLY IN THE MTNS.

MOIST WESTERLY FLOW WILL KEEP PRECIPITATION GOING ON THE WEST SLOPES
MON...BUT IT SHOULD TAPER OFF ELSEWHERE. SEE LATEST FFASGX FOR
DETAILS.

&&

.AVIATION...
270500Z...CLOUD BASES WILL GRADUALLY LOWER THE NEXT FEW HOURS...FROM
MOSTLY OVER 8000 FT MSL TO ABOUT 3000 FT. AFTER 08Z...CLOUD BASES
SHOULD LOWER BELOW 3000 FT MSL IN HEAVIER RAIN WITH LOCAL CIGS BELOW
1000 FT MSL. VSBYS WILL BE 2-4 MILES AT TIMES. MTN OBSCURATIONS WILL
BECOME WIDESPREAD OVERNIGHT. AROUND 15Z SUN...RAIN RATES WILL
DECREASE AND RESULT IN SOME IMPROVEMENTS IN VSBYS AND CIGS...THOUGH
THE NEXT WAVE LATE SUN COULD BRING ANOTHER INCREASE IN PRECIP AND
CORRESPONDING DECREASE IN VSBYS/CIGS.

GUSTY SOUTH TO SOUTHEAST WINDS SHOULD ALSO BE EXPECTED OVERNIGHT AT
COASTAL AIRPORTS SUCH AS KSAN AND KSNA. LOCAL GUSTS COULD EXCEED 30
KNOTS AT KSAN AFTER 09Z. THE WIND SHOULD BECOME MORE SOUTHWESTERLY
ON SUNDAY BUT REMAIN GUSTY THROUGH SUNDAY NIGHT.

&&

.MARINE...
270500Z...WINDS WILL CONTINUE TO INCREASE OVER THE COASTAL WATERS
OVERNIGHT AND CONTINUE SUNDAY MORNING. WINDS ARE EXPECTED TO BE 25
TO 30 KT WITH GUSTS TO 35 TO 40 KT. LOCAL GALE FORCE WINDS ARE
POSSIBLE...THOUGH MOST WINDS WILL FALL SHORT OF GALE WARNING
CRITERIA. AFTER A SLIGHT DECREASE IN THE WIND SUNDAY MORNING...THE
WIND SHOULD SPIKE AGAIN WITH THE NEXT WAVE LATE IN THE DAY. AN
UNSTABLE AIR MASS WILL MOVE OVER SUNDAY AND BRING A CHANCE OF
THUNDERSTORMS AND THE CHANCE OF FUNNEL CLOUDS OR WATERSPOUTS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH SUNDAY EVENING. SEE LAXFFASGX.

     WINTER STORM WARNING FOR THE SAN BERNARDINO AND RIVERSIDE
     COUNTY MOUNTAINS TONIGHT THROUGH MONDAY MORNING. SEE LAXWSWSGX.

     WINTER STORM WATCH FOR THE SAN DIEGO COUNTY MOUNTAINS
     BEGINNING LATE ON SUNDAY THROUGH MONDAY MORNING. SEE LAXWSWSGX.

     WIND ADVISORY ALL AREAS EXCEPT THE DESERTS. SEE LAXNPWSGX.

PZ...GALE WARNING UNTIL 7 AM PST SUNDAY.

     MARINE WEATHER STATEMENT. SEE LAXMWSSGX.

&&

PUBLIC...MOEDE
AVIATION/MARINE...MAXWELL

NWS ON THE WEB AT WEATHER.GOV/SANDIEGO

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN DIEGO CA
400 PM PST SAT JAN 26 2008

CAZ042-043-048-050-055-056-057-058-060-061-062-271200-
ORANGE COUNTY COASTAL AREAS-
SAN DIEGO COUNTY COASTAL AREAS-
SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-
SAN DIEGO COUNTY VALLEYS-
SAN BERNARDINO COUNTY MOUNTAINS-
RIVERSIDE COUNTY MOUNTAINS-
SANTA ANA MOUNTAINS AND FOOTHILLS-
SAN DIEGO COUNTY MOUNTAINS-
APPLE AND LUCERNE VALLEYS-
COACHELLA VALLEY-
SAN DIEGO COUNTY DESERTS-
400 PM PST SAT JAN 26 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ALL OF EXTREME SOUTHWESTERN
CALIFORNIA.

A STRONG PACIFIC LOW PRESSURE SYSTEM WILL BRING HEAVY RAIN...VERY
STRONG WINDS AND MOUNTAIN SNOW THROUGH SUNDAY NIGHT.

.DAY ONE... TONIGHT.

* FLASH FLOOD WATCH REMAINS IN EFFECT TONIGHT. HEAVY RAIN COULD
  CAUSE DEBRIS FLOWS...ESPECIALLY IN THE BURN AREAS.
  SEE LAXFFASGX FOR DETAILS.

* A WINTER STORM WARNING IS IN EFFECT FOR THE SAN BERNARDINO AND
  RIVERSIDE COUNTY MOUNTAINS TONIGHT THROUGH MONDAY MORNING. SEE
  LAXWSWSGX.

* VERY STRONG WINDS ACROSS ALL AREAS TONIGHT. SMALL CRAFT ADVISORIES
  AND GALE WARNINGS ARE IN EFFECT. SEE LAXCWFSGX. WIND ADVISORY ON
  LAND SEE LAXNPWSGX.

* POSSIBLE THUNDERSTORMS AND WATERSPOUTS OVER THE COASTAL WATERS.
  SEE LAXMWSSGX.

.DAYS TWO THROUGH SEVEN... SUNDAY THROUGH FRIDAY.

* HEAVY RAIN CONTINUES INTO SUNDAY MORNING WITH FLASH FLOODING
  AND DEBRIS FLOWS...ESPECIALLY IN THE BURN AREAS. SEE LAXFFASGX
  FOR DETAILS.

* A WINTER STORM WARNING IS IN EFFECT FOR THE SAN BERNARDINO AND
  RIVERSIDE COUNTY MOUNTAINS SUNDAY THROUGH MONDAY MORNING.   SEE
  LAXWSWSGX.

* A WINTER STORM WATCH IS IN EFFECT FOR THE SAN DIEGO COUNTY
  MOUNTAINS FOR SUNDAY NIGHT AND MONDAY MORNING. SEE LAXWSWSGX.

* VERY STRONG WINDS ACROSS ALL AREAS SUNDAY. SMALL CRAFT ADVISORIES
  AND GALE WARNINGS ARE IN EFFECT. SEE LAXCWFSGX. WIND ADVISORY ON
  LAND THROUGH SUNDAY. SEE LAXNPWSGX.

* POSSIBLE THUNDERSTORMS AND WATERSPOUTS OVER THE COASTAL WATERS.
  SUNDAY. SEE LAXMWSSGX.

.SPOTTER INFORMATION STATEMENT...

THE SKYWARN WEATHER SPOTTER NETWORK WILL BE ACTIVATED FOR THIS
SIGNIFICANT WEATHER EVENT.

MOEDE