Flash Flood Watch 1, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
920 AM PST WED FEB 26 2014

.SYNOPSIS...
WIDESPREAD LOW CLOUDS OVER THE COASTAL AREAS AND INLAND VALLEYS ARE
CLEARING THIS MORNING...WITH HIGH TEMPERATURES NEAR SEASONAL
AVERAGES THIS AFTERNOON. ELSEWHERE...VARIABLE HIGH CLOUDS INCREASING
LATE TODAY. GUSTY SOUTHWEST TO WEST WINDS WILL INCREASE OVER THE
MOUNTAINS AND ON ADJACENT DESERT AREAS THROUGH TONIGHT...DECREASING
THURSDAY MORNING. MOSTLY LIGHT RAIN SHOWERS WILL MOVE IN FROM THE
WEST TONIGHT AND LINGER INTO THURSDAY MORNING. A STRONG PACIFIC
STORM WILL BRING LOWER TEMPERATURES...PRECIPITATION AND STRONG WINDS
FRIDAY THROUGH SATURDAY...WITH HEAVY RAIN AT TIMES AND HEAVY SNOW
OVER THE HIGHER MOUNTAINS. SHOWERS WILL END SUNDAY AFTERNOON. HIGH
PRESSURE WILL BRING A RETURN TO FAIR WEATHER AND SEASONAL
TEMPERATURES NEXT WEEK.

&&

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

THIS MORNING...LOW CLOUDS THAT COVERED THE COASTAL AREAS AND INLAND
VALLEYS EARLIER THIS MORNING ARE CLEARING FROM WEST TO EAST EVEN AS
HIGH CLOUDS MOVE IN FROM THE WEST AHEAD OF A LOW PRESSURE TROUGH
APPROACHING THE CAL COAST. LIGHT PRECIP AHEAD OF THE TROUGH IS
ALREADY FALLING OVER AREAS TO OUR NORTH.

TONIGHT AND THURSDAY...THE TROUGH WILL MOVE INLAND LATE TONIGHT INTO
THU MORNING. IT WILL BRING INCREASING CLOUDS...LOWER TEMPS...STRONG
SOUTHWEST TO WEST WINDS...AND PERIODS OF MOSTLY LIGHT SHOWERS. WINDS
WILL INCREASE OVER THE MOUNTAINS AND ON DESERT SLOPES LATE TONIGHT
INTO THURSDAY WITH GUSTS MOSTLY LESS THAN 45 MPH...WITH ISOLATED
STRONGER GUSTS AT TIMES. PRECIP AMOUNTS WILL BE MOSTLY ONE QUARTER
INCH OR LESS NEAR THE COAST AND ONE QUARTER TO ONE HALF INCH ON THE
COASTAL MOUNTAIN SLOPES...WITH LOCALLY GREATER AMOUNTS POSSIBLE.
RAINFALL AMOUNTS WILL FAVOR THE NORTHERN AREAS...DECREASING
SOUTHWARD INTO SAN DIEGO COUNTY. SNOW LEVELS WILL REMAIN ABOVE 6500
FT AND A FEW INCHES OF SNOW ARE POSSIBLE AT THE HIGHEST ELEVATIONS
OF THE SAN BERNARDINO AND RIVERSIDE COUNTY MTNS.

FRI THROUGH SUN...A STRONG PACIFIC LOW PRESSURE SYSTEM WILL MOVE
THROUGH SOCAL. IT WILL BRING LOWER TEMPS...STRONG AND GUSTY SW
WINDS...WIDESPREAD RAIN HEAVY AT TIMES...PERIODS OF HEAVY SNOW AND A
CHANCE OF TSTMS LATE FRI THROUGH SAT. DAYTIME TEMPS WEST OF THE MTNS
WILL BE MOSTLY IN THE 50S TO LOW 60S. WINDS WILL INCREASE OUT OF THE
S TO SW LATE THU NIGHT/EARLY FRI MORNING...PEAKING FRI AFTERNOON AS
THE COLD FRONT MOVES IN. STRONG WINDS WILL CONTINUE INTO SAT BEFORE
WEAKENING SAT AFTERNOON. LIGHT RAIN WILL MOVE IN THU
NIGHT...BECOMING PROGRESSIVELY HEAVIER WITH TIME...BEFORE BECOMING
SHOWERS FRI AFTERNOON. STRONG OROGRAPHIC ENHANCEMENT WILL RESULT IN
HEAVY RAINFALL ALONG THE COASTAL SLOPES FRI MORNING...AND SOME OF
THOSE AREAS WILL LIKELY EXPERIENCE FLASH FLOODING AND/OR MUD AND
DEBRIS FLOWS. DURING AND AFTER COLD FRONTAL PASSAGE SHOWERS AND
POSSIBLE TSTMS WILL CONTINUE THROUGH SAT. THE THREAT OF TSTMS WILL
DIMINISH BY SAT NIGHT BUT SHOWERS WILL LIKELY LINGER INTO SUN NIGHT.
SNOW LEVELS WILL START OUT AT AROUND 7000 FT THU NIGHT THEN LOWER TO
AROUND 6000 FT BY FRI EVENING...LOWERING TO BETWEEN 5000 TO 5500 FT
BY SAT MORNING.

FOR MORE DETAILS...PLEASE SEE OUR SPECIAL WEATHER STATEMENT.
LAXSPSSGX.

FAIR AND WARMER WEATHER RETURNS FOR MON THROUGH WED...WITH DAYTIME
TEMPS A FEW DEGREES ABOVE SEASONAL AVERAGES UNDER A HIGH PRESSURE
RIDGE.

&&

.AVIATION...
261600Z...COASTS/VALLEYS/COASTAL MTN SLOPES...BKN-OVC STRATUS...WITH
BASES 3500-4500 FT MSL AND TOPS AROUND 5000 FT MSL...FILLS THE
COASTAL BASIN...REMAINING THROUGH 16-18Z...WITH COASTAL MTN SLOPES
OBSCURED IN CLDS. AFT 16Z...STRATUS BCMG SCT-FEW BETWEEN 2500-4500
FT MSL...WITH SCT-BKN CLDS AOA 15000 FT MSL. STRATUS GRADUALLY BCMG
BKN-OVC IN THE 2000-5000 FT MSL LYR AFT 27/00Z. OVERNIGHT THRU THURS
MORNING...MERGING CLOUD LYRS 2000-15000 FT MSL WITH EMBEDDED
-SHRA...AREAS OF VIS 3-5SM...AND MTN OBSCURATION DUE TO CLDS/SHRA.

DESERT MTN SLOPES/DESERTS...SCT-BKN CLDS AOA 15000 FT MSL AND
UNRESTRICTED VIS THROUGH TONIGHT. W WINDS 20-25 KT WITH GUSTS 35-40
KT OVER MTN RIDGES...DESERT SLOPES AND ADJACENT DESERTS WILL BRING
MOD-STG UDDFS/LLWS OVER AND E OF THE MTNS AFTER 27/0000 UTC. VERY
LITTLE TO NO PRECIPITATION EXPECTED FOR THE DESERTS TONIGHT.

&&

.MARINE...
A MODERATELY-SIZED WNW SWELL WILL ARRIVE TODAY...PEAK AT 7 FEET/15
SECONDS AT THE SAN CLEMENTE BASIN BUOY THURSDAY...AND LOWER
THEREAFTER. THIS SWELL WILL LIKELY BRING WIDESPREAD 4-6 FOOT SURF
WITH LOCAL SETS TO 8 FEET...ALONG WITH STRONG RIP CURRENTS.

A STRONG PACIFIC STORM WILL BRING STRONG SOUTH TO SOUTHWEST
WINDS...PERIODS OF MODERATE TO HEAVY RAIN...POSSIBLE THUNDERSTORMS
WITH WATERSPOUTS...AND LARGE ROUGH SEAS TO THE COASTAL WATERS FRIDAY
AND SATURDAY. THE MARINE WEATHER STATEMENT CONTAINS MORE INFORMATION
ON THE THUNDERSTORM AND WATERSPOUT THREAT. WINDS COULD APPROACH GALE
FORCE WITH THE COLD FRONTAL PASSAGE FRIDAY AFTERNOON/EVENING...SO A
GALE WATCH IS IN EFFECT. WINDS WILL WEAKEN SATURDAY AFTERNOON INTO
SUNDAY. WAVE WATCH 3 CONTINUES TO SHOW 10-15 FOOT SEAS WITH PERIODS
OF 10-15 SECONDS WITH THIS STORM SYSTEM. STRONG WINDS WILL RESULT IN
WAVES BUT SURF WILL LIKELY STILL REACH 7-10 FEET FRIDAY AFTERNOON
THRU SUNDAY MORNING. THE COMBINATION OF HIGH SURF...HIGH TIDES OF
6.5-6.8 FEET...AND STRONG ONSHORE WINDS MAY PRODUCE MINOR COASTAL
FLOODING. A BEACH HAZARDS STATEMENT DESCRIBES THESE HAZARDS. SURF
AND SEA CONDITIONS WILL BEGIN TO IMPROVE BY SUNDAY AFTERNOON.

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. STAY TUNED FOR
ANY ACTIVATION POSSIBILITIES FRIDAY THROUGH SATURDAY NIGHT.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...BEACH HAZARDS STATEMENT FROM LATE THURSDAY NIGHT THROUGH SUNDAY
     AFTERNOON FOR THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO
     COUNTY COASTAL AREAS.

     WINTER STORM WATCH FROM FRIDAY MORNING THROUGH LATE SATURDAY
     NIGHT ABOVE 6000 FEET FOR THE RIVERSIDE COUNTY MOUNTAINS...
     SAN BERNARDINO COUNTY MOUNTAINS.

PZ...GALE WATCH FROM LATE THURSDAY NIGHT THROUGH LATE FRIDAY NIGHT
     FOR THE 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.

&&

PUBLIC...PG
AVIATION/MARINE...TS