Flood Potential Outlook
Issued by NWS San Diego, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3
000
FGUS76 KSGX 142111
ESFSGX
CAZ043-048-050-055>058-060>062-065-552-554-152115-

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SAN DIEGO CA
111 PM PST Tue Feb 14 2017

...STRONG PACIFIC STORM TO IMPACT SOUTHERN CALIFORNIA FRIDAY
AND SATURDAY...

CONFIDENCE IS BUILDING FOR ANOTHER LARGE RAIN EVENT ACROSS FAR
SOUTHWESTERN CALIFORNIA FOR FRIDAY AND SATURDAY FEBRUARY 17TH AND
18TH. THIS IS THE RESULT OF AN INTENSIFYING LOW PRESSURE CENTER
WITH A GOOD TAP ON MOISTURE FROM THE SUBTROPICS.

AS THIS STORM DEVELOPS...THE TYPICAL RAINFALL PATTERN OF MOUNTAIN
SHADOWING...WITH MORE IN THE MOUNTAINS THAN ON THE COAST IS NOT
EXPECTED. INSTEAD...HEAVIER AMOUNTS ARE FORECAST OVER NORTHERN
AREAS...WITH LESS TO THE SOUTH. A VERY STRONG SOUTHERLY WIND IS
FORECAST OVER THE AREA BY FRIDAY EVENING. THIS WILL FAVOR HEAVY
RAINFALL RATES OVER ORANGE COUNTY AND THE SAN BERNARDINO MOUNTAINS.
MODERATE TO LOCALLY HEAVY RAINFALL RATES ARE POSSIBLE SOUTH ACROSS
RIVERSIDE AND SAN DIEGO COUNTIES LATE FRI NIGHT INTO EARLY SATURDAY
AS WELL...BUT TOTALS SHOULD BE LESS. HIGH SNOW LEVELS WILL AUGMENT
RUNOFF FROM THE MOUNTAIN SLOPES.

...THOSE AREAS WITH THE GREATEST POTENTIAL FOR FLOODING INCLUDE ALL
OF ORANGE COUNTY INCLUDING THE SANTA ANA MOUNTAINS...THE CAJON PASS
AREA AND THE BLUE CUT FIRE BURN SCAR...AND THE UPPER MOJAVE RIVER
BASIN...


SOME PRELIMINARY 2-DAY FORECAST RAINFALL TOTALS FOR FRIDAY
AND SATURDAY IN INCHES...

ORANGE COUNTY..............3 to 5
SAN BERNARDINO MOUNTAINS...2 TO 7
SAN DIEGO COUNTY...........1.5 TO 3
RIVERSIDE COUNTY...........2 TO 4
UPPER DESERTS..............1 to 3
LOWER DESERTS..............0.5 to 1

AQUIFERS BELOW OUR MAIN STEM RIVERS HAVE FILLED SUFFICIENTLY SO THAT
THE COMING RAIN WILL LIKLEY RESULT IN SIGNIFICANT FLOWS IN ALL
RIVERS AND STREAMS. THE ATMOSPHERIC DEPTH OF MOISTURE WILL BE
SUFFICIENT FOR SIGNIFICANT ACCUMULATIONS EAST OF THE MOUNTAINS...SO
NORMALLY DRY WASHES MAY FLOW IN THE LOWER DESERTS AS WELL FOR A TIME.

THE SANTA MARGARITA...SAN DIEGO...WHITEWATER...MOJAVE...AND TIJUANA
RIVERS WILL RECORD SIGNIFICANT FLOWS. THE FASTER RESPONDING RIVERS
LIKE THE SAN DIEGO AND THE SANTA MARGARITA MAY REACH MONITOR OR
FLOOD STAGE EARLY SATURDAY.

ONCE THE SOILS BECOME SATURATED...FLOODING WILL BECOME MORE LIKELY
AT LOW-WATER CROSSINGS...NEAR STREAM BANKS...IN POORLY DRAINED URBAN
AREAS...AND BELOW RECENT BURN SCARS. ROCK SLIDES MAY CLOSE RURAL
HIGHWAYS THROUGH STEEP TERRAIN. THE BLUE-CUT FIRE BURN SCAR WILL
BE PARTICULARLY SUSCEPTIBLE TO MUD AND DEBRIS FLOWS.

WATERSHEDS LIKE THE WHITEWATER THROUGH THE COACHELLA VALLEY...AND
THE TIJUANA ARE PRONE TO SOME FLOODING EVEN WITH THE LOWER RAINFALL
TOTALS EXPECTED THERE.

WATCH FOR LAXRVSSGX ISSUANCES FOR RIVER FORECAST LEVELS IN THE
COMING DAYS...OR CHECK THE WEB AT:
WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=SGX AND WATCH FOR UPDATES AND
POSSIBLE WATCHES AND WARNINGS AT WEATHER.GOV/SANDIEGO AS WE GET
CLOSER TO THE EVENT.

$$

JAD



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.