AREA FORECAST DISCUSSION
NWS SAN DIEGO
AFDSAN 825 PM PST SUN JAN 4 2004
.SYNOPSIS...DEVELOPING HIGH PRESSURE ALOFT AND WEAK OFFSHORE FLOW WILL
KEEP THE WEATHER FAIR THROUGH TUESDAY EXCEPT FOR HIGH CLOUDS AT TIMES
AND LOCALLY GUSTY WINDS THROUGH AND BELOW MOUNTAIN CANYONS AND
PASSES. IT WILL BE COLD TONIGHT WITH FROST ADVISORIES FOR THE INLAND
VALLEYS AND FREEZE WARNINGS FOR THE SOUTHERN DESERTS. WEAK UPPER
LEVEL LOW PRESSURE WILL BRING MORE CLOUDS AND COOLER DAYS TOWARD MID
WEEK FOLLOWED BY HIGH PRESSURE TOWARD THE END OF THE WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES.
SKIES WERE CLEAR...AND THE HIGH CLOUDS APPROACHING FROM THE
NORTHWEST DO NOT LOOK VERY THICK...SO MOST INLAND VALLEYS SHOULD SEE
LOW TEMPS AT OR A BIT BELOW FREEZING...AND A FEW LOWER DESERT
LOCATIONS...LIKE THERMAL...COULD GET BELOW 28...WHERE DEW POINTS ARE
AROUND 10-15. WINDS SHOULD NOT BE TOO STRONG AS THE ONT ACARS SHOWS
ALL WINDS BELOW 6000 FT...THE DIVIDING LINE BETWEEN E/NE WINDS BELOW
AND N/NW WINDS ABOVE...BELOW 10 KNOTS. ENOUGH COLD AIR ADVECTION
EXISTS TO BRING SOME OF THE 8000-FT N WINDS TO 25 KNOTS TO THE
SURFACE...BUT VERY LOCALLY.
OTHERWISE...RH VALUES WILL GRADUALLY INCREASE ALOFT THROUGH TUESDAY
TO BRING MORE HIGH CLOUDS...BUT SURFACE RH VALUES WILL STAY LOW AT
LEAST UNTIL LATE TUE OR WED WHEN VERY WEAK ONSHORE FLOW DEVELOPS. A
LOT OF MID-HIGH LEVEL MOISTURE WILL DRIFT OVER THE AREA...SO BY WED
WE MAY BE QUITE CLOUDY...BUT DYNAMICS AND LOW LEVEL MOISTURE WILL
PROBABLY BE TOO FAR NORTH FOR US TO SEE MORE THAN A FEW SPRINKLES.
AFTER THAT...WE WILL BE PRONE TO VERY WEAK SHORTWAVES ZIPPING
THROUGH THE MOSTLY W FLOW TO BRING A FEW CLOUDS...BUT OTHERWISE
GRADUAL RIDGING WILL OCCUR...SO WE SHOULD HAVE A WARMING TREND INTO
THE WEEKEND.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...FREEZE WARNING AND FROST ADVISORY
TONIGHT...SEE LAXNPWSGX.
&&
$$
MAXWELL