HYDROLOGIC OUTLOOK
Warning Issue Date: 1152 AM PST WED DEC 09 2009
MORE RAIN AND SNOW EXPECTED TO ARRIVE THIS WEEKEND ACROSS
SOUTHERN CALIFORNIA...
A MOIST PACIFIC FLOW WILL BRING SEVERAL DISTURBANCES THROUGH
SOUTHERN CALIFORNIA FRIDAY THROUGH SUNDAY. LIGHT TO MODERATE AMOUNTS
OF RAIN ARE EXPECTED WITH THE FIRST SYSTEM ON FRIDAY...WHILE AREAS
OF HEAVIER RAIN AND POSSIBLE SNOW ARE POSSIBLE LATE SATURDAY INTO
SUNDAY.
AT THIS TIME IT IS TOO EARLY TO DETERMINE EXACT TIMING AND AMOUNTS
OF PRECIPITATION THAT WILL FALL...BUT THE GROUND WILL QUICKLY
BECOME SATURATED...ESPECIALLY IN SAN DIEGO COUNTY DUE TO THE HEAVY
RAIN THAT FELL ON MONDAY. A MODERATE RAIN ON FRIDAY...AND ANY
SUBSEQUENT SHOWERS...PRIOR TO THE SYSTEM LATER IN THE WEEKEND
WOULD MAKE FLOODING OF NORMALLY DRY WASHES...CREEKS...AND STREAMS
INCREASINGLY LIKELY...SHOULD HEAVY RAIN DEVELOP.
AT THIS TIME THE STORM SYSTEM CURRENTLY FORECAST FOR LATE SATURDAY
INTO SUNDAY LOOKS STRONG ENOUGH FOR POSSIBLE HEAVY RAIN. IT WOULD
ALSO BE COLD ENOUGH FOR HEAVY SNOW AT RESORT LEVELS IN THE
SAN BERNARDINO MOUNTAINS. PRELIMINARY PRECIPITATION ESTIMATES ARE
FOR ONE...TO AROUND THREE INCHES ON THE WETTER COASTAL SLOPES.
RAINFALL OF SEVERAL INCHES WOULD BE ENOUGH FOR RIVERS TO RISE
ENOUGH TO FLOOD LOW-LYING...TYPICALLY FLOOD PRONE AREAS. EVEN
THOUGH HEAVY RAIN IS NOT CURRENTLY FORECAST FOR SAN DIEGO COUNTY...
A SLIGHT SHIFT TO THE SOUTH IN THE STORM TRACK WOULD MAKE IT
POSSIBLE. OF MAIN CONCERN WOULD BE THE SOUTH COAST NEAR THE
TIJUANA RIVER...AND THE SAN DIEGO RIVER...WHERE LOW-WATER
CROSSINGS WOULD NEED TO BE BARRICADED.
HEAVY RAINFALL ON RECENT BURN AREAS COULD RESULT IN LIFE-
THREATENING DEBRIS FLOWS. A FLASH FLOOD WATCH MAY BE NEEDED IN
THESE AREAS BY SATURDAY.
PERSONS LIVING IN AND CLOSE TO RECENTLY BURNED AREAS OR IN LOW-
LYING AREAS SUBJECT TO RIVER AND STREAM FLOODING SHOULD KEEP
ABREAST OF LATER FORECASTS. AND LISTEN TO NOAA WEATHER RADIO FOR
UPDATES.
$$
JAD
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