Flash Flood Warning 3, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PST FRI JAN 4 2008

.SYNOPSIS...A STRONG WINTER STORM WILL SPREAD RAIN FROM NORTH TO
SOUTH ACROSS THE REGION TONIGHT. THE RAIN WILL BE HEAVY AT
TIMES...AND A FLASH FLOOD WATCH IS IN EFFECT FOR MOST AREAS. THE
RAIN CHANGES TO SHOWERS SATURDAY...WITH ON AND OFF SHOWERS
CONTINUING THROUGH SUNDAY NIGHT. SNOW LEVELS WILL GRADUALLY LOWER TO
5000 FEET THROUGH THE WEEKEND...AND SEVERAL INCHES OF SNOW WILL
ACCUMULATION AT THE HIGHER ELEVATION. STRONG...POTENTIALLY DAMAGING
WINDS ARE EXPECTED TONIGHT THROUGH SATURDAY MORNING. DRIER WEATHER
IS PROJECTED FOR MONDAY AND TUESDAY.

&&

.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.

HEAVY RAIN ARRIVED IN THE SAN BERNARDINO MOUNTAINS THIS EVENING WITH
RAIN RATES OF A HALF-INCH PER HOUR AT LYTLE CREEK ON THE LOWER
COASTAL SLOPES. RAIN EXTENDED ALL THE WAY BACK TO VENTURA
COUNTY...MOVING WEST TO EAST. THE SBD MTNS ARE IN FOR A 6 TO 8 HOUR
PERIOD OF MODERATE TO HEAVY RAIN TRAINING OVER THE SAME AREAS
THROUGH 12Z. FLASH FLOOD WARNINGS HAVE BEEN ISSUED.

THE RAIN WAS MOVING WEST TO EAST THIS EVENING...BUT WILL SLOWLY SAG
SOUTH OVERNIGHT AS THE TROUGH DIGS DOWN THE COAST...BRINGING
MODERATE TO HEAVY RAIN TO ORANGE AND RIVERSIDE COUNTY BETWEEN 06Z
AND 12Z. THE HEAVIEST RAIN WILL REACH NORTHERN SAN DIEGO BTWN 08Z
AND 12Z...THE SPREAD INTO SOUTHERN SAN DIEGO COUNTY BTWN 12-15Z.

STRONG OROGRAPHICS ARE ALREADY IN PLACE. BUT THE BEST TERRAIN
INDUCED LIFT IS STILL YET TO ARRIVE. THE 850 MB LLJ CORE OF 50KT
TRACKS OVER THE AREA BTWN 06-12Z...THE TIME FRAME FOR THE HEAVIEST
RAINS AND MOST INTENSE RAIN RATES. HEAVIEST RAIN WILL FALL ON THE
SBD MTNS AND FOOTHILLS...AND THERE ARE CONCERNS THAT RADAR ECHOES
TRAINING OVER THE MTNS COULD BRING RAIN AMOUNTS IN EXCESS OF 12
INCHES IN PLACES LIKE LYTLE CREEK. ORANGE COUNTY MTNS ARE ALSO AN
AREA OF CONCERN TONIGHT.

RIVERSIDE AND SAN DIEGO COUNTY WILL SEE SHORTER DURATIONS OF OPTIMAL
OROGRAPHICS AND HEAVY RAINFALL. WHILE 4 TO 8 INCHES AMOUNTS IN THE
MTNS ARE IMPRESSIVE AND WILL CAUSE FLOODING/MUDSLIDE PROBLEMS...THE
HEAVIEST RAINS WILL FALL OVER SBD AND ORANGE COUNTY MTNS.

2 TO 4 INCHES AMTS IN THE INLAND EMPIRE AND COASTAL ORANGE COUNTY
LOOK ON TARGET...WITH 5 INCHES POSSIBLE NEAR THE FOOTHILLS. SAN
DIEGO COUNTY COASTS AND VALLEYS WILL SEE LESSER AMTS DUE TO THE
SHORTER DURATION OF MODERATE TO HEAVY RAINS...FROM 1 TO 2 INCHES.
DESERT RAINFALL ALL DEPENDS ON HOW MUCH MOISTURE MAKES IT OVER THE
MTNS...AND A HALF INCH TO INCH IS POSSIBLE IN THE HIGH DESERTS WITH
HALF AN INCH OR LESS IN THE LOWER DESERTS.

THE UPPER SUPPORT AND STRONGEST OROGRAPHICS SHIFT EAST EARLY
SATURDAY. THE WIDESPREAD HEAVY RAINS WILL END IN SBD AND ORANGE
COUNTIES BTWN 12-15Z...BTWN 15-18Z IN RIVERSIDE...AND FROM 18Z-21Z
IN SAN DIEGO.

POST FRONTAL INSTABILITY WILL BRING OFF AND ON SHOWERS SATURDAY
NIGHT THROUGH SUNDAY MORNING. SUNDAY AFTERNOON ANOTHER POTENT LITTLE
SHORT WAVE WILL BRING ANOTHER ROUND OF HEAVIER PRECIP SUNDAY
EVENING. SHOWERS WILL TAPER OFF MONDAY.

THE SNOW LEVEL WAS AT 6500 FEET THIS EVENING...A LITTLE LOWER THAN
ORIGINALLY THOUGHT. IT SHOULD STAY THERE OR RISE SLIGHTLY OVERNIGHT
IN THE WARM SOUTHWEST PREFRONTAL WINDS. COLD AIR ADVECTION LATER
TONIGHT AND SATURDAY WILL LOWER SNOW LEVELS DOWN TO 6000 FEET
SATURDAY AFTERNOON...THEN DOWN TO 5000 FT SUNDAY NIGHT WITH THAT
COLDER SHORTWAVE. MOST SIGNIFICANT SNOW FALL WILL FALL AT THE
HIGHEST ELEVATIONS FOR THE SAN BERNARDINO AND RIVERSIDE COUNTY
MOUNTAINS.

RIDGING AND DRY WEATHER BUILD IN MONDAY INTO TUESDAY. ANOTHER FAST
MOVING SHORT WAVE LOOKS STRONG ENOUGH FOR A CHANCE OF RAIN TUESDAY
NIGHT INTO WEDNESDAY MORNING.

&&

.LONG TERM (TUE-FRI)...MOIST WLY FLOW WILL CONTINUE PARTLY CLOUDY
SKIES. WEAK RIDGING TUE WILL BRING A LITTLE WARMING. A SHORT WAVE
TROUGH COULD BRING A FEW LIGHT SHOWERS TUE NIGHT INTO WED MORNING.
MORE RIDGING WED AFTERNOON INTO THU WITH POSSIBLY ANOTHER SHORT WAVE
FRI WITH ANOTHER SMALL CHANCE OF PRECIP. HOWEVER...MODEL HAVE BEEN
INCONSISTENT AND PRECIP CHANCE TOO SMALL TO MENTION AT THIS TIME.

&&

.AVIATION...
050430Z...A COLD FRONT WILL CONTINUE TO MOVE THROUGH TONIGHT INTO
SATURDAY MORNING AND PRODUCE HEAVY RAIN AT TIMES. THE RAIN WILL
TAPER OFF LATE MORNING FROM THE NORTHWEST...BECOMING SHOWERS BY
SATURDAY AFTERNOON AND NIGHT. BASES WILL BE MOSTLY 1000 TO 2500 FT
OVERNIGHT INTO SATURDAY MORNING. TOPS WILL BE TO 25000 FT OR HIGHER.
BASES WILL LOWER TO 500 TO 1000 FT IN HEAVY RAIN WITH LOCALLY LOWER
BASES TO 200 FT. VSBY WILL LOWER TO 1-2SM IN THE MORE MODERATE
SHOWERS...AND DOWN TO 1/2SM TO 1/4SM IN HEAVY RAIN. HIGHER TERRAIN
OBSCURED. CONDITIONS ARE EXPECTED TO IMPROVE LATE MORNING SATURDAY
WITH BASES RISING TO AROUND 2500 FEET MSL OR HIGHER AND VSBY MOSTLY
ABOVE 7SM. SOME PERIODS OF SHOWERS AND LOWER CLOUDS AND VISIBILITIES
WILL STILL BE POSSIBLE AT TIMES.

&&

.MARINE...
050430Z...A STRONG COLD FRONT WILL CONTINUE TO MOVE THROUGH THE
REGION THROUGH SATURDAY MORNING. THEN MORE PERIODS OF RAIN WILL MOVE
THROUGH THE AREA THROUGH MONDAY. THUNDERSTORMS AND WATERSPOUTS WILL
BE POSSIBLE DURING THIS PERIOD OF INCLEMENT WEATHER. A HIGH SURF
ADVISORY CONTINUES FOR SATURDAY THROUGH TUESDAY MORNING. A NORTHWEST
SWELL WILL INCREASE TO 4 TO 6 FT TONIGHT AND THEN TO 5 TO 7 FEET
SATURDAY.  SWELLS WILL THEN RISE A BIT HIGHER SUNDAY AND MONDAY.
SOUTH WINDS WILL BECOME STRONG AND GUSTY THROUGH SATURDAY MORNING
WITH PERIODS OF STRONG WINDS THROUGH MONDAY. SEAS WILL BE CHAOTIC
THROUGH MONDAY AT TIMES. WHEN THE WINDS DECREASE SATURDAY AFTERNOON
THROUGH SUNDAY...THE SEAS WILL BE AROUND 10 FT OR HIGHER AND
HAZARDOUS SEAS WILL BE THE REASON FOR THE SMALL CRAFT ADVISORY WHEN
WINDS DROP BELOW 25 KT.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...

FLASH FLOOD WATCH FROM THROUGH SATURDAY AFTERNOON FOR THE
MOUNTAINS...INLAND VALLEYS AND COASTAL AREAS. SEE LAXFFASGX.

HIGH WIND WARNINGS AND WIND ADVISORIES FOR MTNS...VALLEYS AND
COASTAL ZONES UNTIL 2 PM SATURDAY. SEE LAXNPWSGX.

SMALL CRAFT ADVISORY UNTIL 2 AM PST MONDAY. SEE LAXCWFSGX.

HIGH SURF ADVISORY 6 AM SATURDAY UNTIL TUESDAY AFTERNOON. SEE
LAXCFWSGX.

SPECIAL WEATHER STATEMENT. SEE LAXSPSSGX.

&&

PUBLIC...MOEDE
AVIATION...SMALL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN DIEGO CA
545 PM PST FRI JAN 4 2008

CAZ042-043-048-050-055>058-060>062-PZZ750-775-051200-
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-
COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
30 NM-
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING 30 TO
60 NM OUT INCLUDING SAN CLEMENTE ISLAND-
545 PM PST FRI JAN 4 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
CALIFORNIA AND PZ.

.DAY ONE...TONIGHT

A PACIFIC STORM WILL BRING HEAVY RAIN...FLOODING AND STRONG WINDS.

SEE LAXFFASGX...LAXNPWSGX AND LAXCWFSGX OR DETAILS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

RAIN TAPERING TO SHOWERS SATURDAY. SCATTERED SHOWERS SATURDAY NIGHT
AND SUNDAY BECOMING MORE WIDESPREAD SUNDAY EVENING. HIGH SURF INTO
TUESDAY.

SEE LAXFFASGX...LAXNPWSGX...LAXCWFSGX AND LAXCFWSGX FOR DETAILS.

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION HAS BEEN
REQUESTED.

MOEDE