Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 270430
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
830 PM PST WED NOV 26 2014

.SYNOPSIS...
VERY WARM AGAIN THURSDAY WITH HIGH PRESSURE ALOFT AND WEAK OFFSHORE
FLOW. INCREASING ONSHORE FLOW WILL BRING A COOLING TREND FRIDAY
THROUGH SUNDAY AND A RETURN OF NIGHT AND MORNING COASTAL AND VALLEY
LOW CLOUDS AND FOG. TUESDAY THROUGH WEDNESDAY OF NEXT WEEK...A
PACIFIC LOW PRESSURE SYSTEM COULD BRING MODERATE TO HEAVY
PRECIPITATION.

&&

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

THE WEST COAST RIDGE AND WEAK OFFSHORE FLOW BROUGHT ANOTHER VERY
WARM DAY TODAY WITH COASTAL AND VALLEYS HIGHS IN THE 80S. A FEW
STATIONS ECLIPSED 90 IN THE INLAND EMPIRE. THE NATIONS HIGH WAS 95
AT UC RIVERSIDE. RECORD HIGHS WERE BROKEN TODAY AND MORE ARE LIKELY
TOMORROW. RECORDS THAT ARE WITHIN REACH THURSDAY INCLUDE SANTA ANA
(86)...SAN DIEGO (83)...RIVERSIDE (89) AND EL CAJON (87).

AN ACTIVE PACIFIC JET WILL SEND WAVES OF ENERGY TOWARD THE WEST
COAST THAT WILL FLATTEN THE RIDGE AND BRING COOLING FRIDAY THROUGH
SUNDAY. A SHALLOW MARINE LAYER FRIDAY MORNING WILL STEADILY DEEPEN
THROUGH SUNDAY SENDING LOW CLOUDS AND FOG A LITTLE FARTHER INLAND
EACH NIGHT. PROGRESSIVELY COOLER THROUGH THE WEEKEND WITH LOWER
HEIGHTS AND STRONGER ONSHORE FLOW. THE MODELS SHOW A WEAK SHORTWAVE
TROUGH ZIPPING ACROSS SOUTH-CENTRAL CA WHICH THE ECMWF INDICATES
COULD SQUEEZE OUT SOME VERY LIGHT PRECIPITATION OVER SOUTHERN
CALIFORNIA...BUT THE 00Z GFS THIS EVENING REMAINS DRY AND WILL HOLD
TO THAT SOLUTION FOR NOW.

LONG RANGE OUTLOOK MONDAY INTO WEDNESDAY...MODELS TRENDING A LITTLE
SLOWER WITH THE PACIFIC TROUGH THAT WILL LIKELY BRING MODERATE TO
HEAVY PRECIPITATION. SUBTROPICAL MOISTURE AHEAD OF THE SYSTEM TAKES
AIM AT THE SOUTHWEST WITH THE 00Z GFS SHOWING A PLUME OF 1.5"
PRECIPITABLE WATER TUESDAY MORNING. WIDESPREAD BENEFICIAL RAINS
WOULD RESULT WITH THIS SCENARIO. THE AIRMASS WILL REMAIN QUITE WARM
AND SNOW LEVELS WILL REMAIN AROUND 9000-11000 FEET. THE TROUGH
PASSES TUESDAY NIGHT WITH THE RAIN TURNING TO SHOWERS WEDNESDAY.
COLD AIR ADVECTION WILL LOWER SNOW LEVELS TO AROUND 7000 FEET BY
EARLY WEDNESDAY MORNING.

.FROM PREVIOUS DISCUSSION...

PRECIPITATION TOTALS FOR THE SYSTEM STILL LOOK LIKE THEY WILL BE
SIGNIFICANT...WITH 1-2 INCHES AT THE COAST...2-3 INCHES IN THE
VALLEYS...3-4 INCHES OR GREATER IN THE MOUNTAINS...AND LESS THAN AN
INCH IN THE DESERTS. WITH GOOD SOUTH TO SOUTHWEST FLOW AT 850 MB
AHEAD OF THE COLD FRONT PASSAGE ON TUESDAY...THE HEAVIEST
PRECIPITATION MAY FOCUS OVER THE SOUTHERLY FACING SAN BERNARDINO
COUNTY MOUNTAINS. THE 12Z GFS BRINGS THE TROUGH AXIS THROUGH THE
AREA WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON...WITH PRECIPITATION
ENDING WEDNESDAY EVENING. THE AMOUNT OF SNOW THAT FALLS WILL LARGELY
DEPEND ON HOW MUCH PRECIPITATION OCCURS AFTER THE COLD AIR MOVES IN.

&&

.AVIATION...
270330Z...OTHER THAN INCREASING HIGH CLOUDS THURSDAY...MOSTLY CLEAR
SKIES WITH UNRESTRICTED VIS WILL CONTINUE THROUGH AT LEAST THURSDAY
EVENING.

&&

.MARINE...
730 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SUNDAY.
SOME SHOWERS AHEAD OF THE PACIFIC STORM SYSTEM COULD MOVE INTO THE
COASTAL SUNDAY NIGHT AND MONDAY...BUT STRONG WINDS ARE NOT EXPECTED
UNTIL AT LEAST AFTER MONDAY.

&&

.FIRE WEATHER...
WEAK OFFSHORE WINDS TONIGHT AND THURSDAY. VERY WARM THURSDAY WITH
HIGH TEMPERATURES 10-20 DEGREES ABOVE AVERAGE AND MINIMUM HUMIDITY
IN THE SINGLE DIGITS/LOW TEENS. ONSHORE FLOW WILL START TO RETURN
LATE THURSDAY NIGHT INTO FRIDAY WITH COOLING AND INCREASING HUMIDITY
THROUGH THE WEEKEND AS A TROUGH APPROACHES THE WEST COAST. THIS
TROUGH WILL BRING A GOOD CHANCE FOR SIGNIFICANT WETTING
PRECIPITATION EARLY NEXT WEEKEND.

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC/FIRE WEATHER...MOEDE
AVIATION/MARINE...MAXWELL










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