Area Forecast Discussion
Issued by NWS San Diego, CA

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448
FXUS66 KSGX 111713
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
913 AM PST THU FEB 11 2016

.SYNOPSIS...
FAIR WEATHER WITH TEMPERATURES LOWERING BY A FEW DEGREES EACH DAY
THROUGH SATURDAY AS THE RIDGE OF HIGH PRESSURE WEAKENS...ALTHOUGH
TEMPERATURES WILL STILL BE MUCH ABOVE NORMAL. ANOTHER WARM-UP
EXPECTED SUNDAY THROUGH TUESDAY AS THE RIDGE RE-BUILDS AND STRONGER
OFFSHORE FLOW MOVES IN. LOCALLY STRONG AND GUSTY NORTHEAST TO EAST
WINDS POSSIBLE IN THE PASSES...CANYONS AND COASTAL FOOTHILLS SUNDAY
AND MONDAY DUE TO STRONGER SURFACE HIGH PRESSURE OVER THE GREAT
BASIN. BY NEXT WEDNESDAY...THE RIDGE WILL WEAKEN AND ONSHORE FLOW
RETURNS...RESULTING IN DECREASING TEMPERATURES. A LOW PRESSURE
TROUGH MAY BRING SOME SHOWERS TO THE REGION ON THURSDAY.

&&

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

MORNING WATER VAPOR SATELLITE SHOWS A RIDGE OVER SOUTHERN
CALIFORNIA...WITH A LARGE TROUGH SOUTH OF THE ALEUTIAN ISLANDS.
MEANWHILE...VISIBLE SATELLITE SHOWS CLEAR SKIES ACROSS THE FORECAST
AREA...WITH SOME HIGH CLOUDS OVER SANTA BARBARA AND VENTURA
COUNTIES. A FEW PATCHES OF MARINE LAYER STRATUS CAN ALSO BE SEEN FAR
OFFSHORE. OFFSHORE PRESSURE GRADIENTS FROM SAN DIEGO TO TONOPAH ARE
CURRENTLY AT 9.9 MB...WHICH IS 1.1 MB WEAKER THAN 24 HOURS AGO.
RIGHT NOW...SIMILAR TO YESTERDAY...THERE ARE JUST SOME OFFSHORE
BREEZES IN THE PASSES/CANYONS AND THE COASTAL FOOTHILLS IN THE 20-30
MPH GUST RANGE. THE 12Z MIRAMAR SOUNDING SHOWS THAT THE 500 MB
HEIGHTS AND 850 MB TEMPERATURES ARE A LITTLE LOWER THAN
YESTERDAY...WHICH INDICATES A WEAKENING RIDGE AND SLIGHTLY COOLER
AIR MASS. ALTHOUGH MOST LOCATIONS WILL LIKELY BE A FEW DEGREES LOWER
THAN YESTERDAY...IT WILL STILL BE VERY WARM...WITH HIGHS REACHING 10-
20 DEGREES ABOVE NORMAL. IN THE INLAND COASTAL AREAS...VALLEYS AND
LOWER DESERTS...EXPECT HIGHS IN THE MID-TO-UPPER 80S AND LOCALLY 90
DEGREES...MID-TO-UPPER 70S AT THE BEACHES AND HIGH DESERTS...70S AT
THE LOWER MOUNTAIN SLOPES...AND THE LOW 60S AT THE HIGH ELEVATIONS.
A FEW STATIONS MAY REACH RECORD HIGH TEMPERATURES ONCE AGAIN...BUT
NOT AS MANY AS THE PREVIOUS 2 DAYS.

THE RIDGE WILL GRADUALLY WEAKEN THROUGH SATURDAY AS A TROUGH MOVES
BY TO THE NORTH...RESULTING IN SLOW COOLING FRIDAY AND
SATURDAY...ALTHOUGH DAY-TIME HIGHS SATURDAY WILL STILL BE 10-15
DEGREES ABOVE NORMAL. WEAK OFFSHORE FLOW WILL CONTINUE TO BRING 20-
30 MPH GUSTS IN THE PASSES/CANYONS AND COASTAL FOOTHILLS.

LOOK FOR ANOTHER WARM-UP SUNDAY THROUGH TUESDAY AS A RIDGE BUILDS
OVER SOUTHERN CALIFORNIA ONCE AGAIN. STRENGTHENING SURFACE HIGH
PRESSURE OVER THE GREAT BASIN RESULTS IN STRONGER OFFSHORE
GRADIENTS...HELPING TO PRODUCE THE WARMING TREND. THE OFFSHORE
PRESSURE GRADIENTS REACH ABOUT 10 MB FROM SAN DIEGO TO TONOPAH AND
FROM SAN DIEGO TO SALT LAKE CITY SUNDAY AND MONDAY...WITH MARGINAL
UPPER SUPPORT OF 10-20 KT NORTHEASTERLY WINDS AT 850 MB. THUS...WE
SHOULD SEE SOME GUSTIER NORTHEAST TO EAST WINDS SUNDAY AND MONDAY AT
AROUND 15-25 MPH WITH GUSTS OF 35-45 MPH IN THE PASSES/CANYONS AND
COASTAL FOOTHILLS...BUT IT DOES NOT LOOK AT THE MOMENT LIKE IT WILL
BE MUCH STRONGER THAN THAT. GRADIENTS START TO WEAKEN TUESDAY...WITH
WEAK OFFSHORE FLOW THAT DAY. LOOK FOR DAY-TIME HIGHS TO REACH 10-20
DEGREES...AND LOCALLY 25 DEGREES...ABOVE NORMAL DURING THAT TIME
PERIOD...AND THE CHANCE FOR MORE RECORDS TO BE BROKEN. SKIES WILL
CONTINUE TO BE MOSTLY CLEAR EXCEPT FOR SOME PASSING HIGH CLOUDS AT
TIMES.

THE LONG RANGE MODELS CONTINUE TO SHOW THE RIDGE WEAKENING ON
WEDNESDAY WITH ONSHORE FLOW RETURNING AS A TROUGH APPROACHES THE
WEST COAST...RESULTING IN COOLING CONDITIONS. THE TROUGH LIKELY
MOVES INLAND THURSDAY...BUT MODELS DIFFER ON THE AMPLITUDE OF THE
TROUGH AND PRECIPITATION CHANCES. THE 12Z GFS HAS A MUCH WEAKER
TROUGH AND KEEPS THE PRECIPITATION TO OUR NORTH...WHILE THE 00Z
ECMWF HAS A DEEPER TROUGH WITH A DECENT AMOUNT OF PRECIPITATION OVER
SOUTHERN CALIFORNIA.

&&

.AVIATION...
111600Z...FEW-SCT CLOUDS AOA 20000 FT MSL AND UNRESTRICTED VIS
THROUGH FRIDAY MORNING.

&&

.MARINE...
800 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH TUESDAY.

&&

.BEACHES...
800 AM...A LONG-PERIOD SWELL FROM 290 DEGREES WILL ARRIVE LATE
THURSDAY AND SLOWLY BUILD THROUGH THE DAY FRIDAY...PEAKING SATURDAY
AT 9 FT/18 SEC. THIS WILL GENERATE ELEVATED TO HIGH SURF OF 4 TO 7
FEET AND STRONG RIP CURRENTS FRIDAY THROUGH SUNDAY. LOCAL HIGHER
SETS ARE POSSIBLE NORTH OF NEWPORT BEACH AND SOUTH OF DEL MAR. SWELL
AND SURF WILL SUBSIDE ON MONDAY. A BEACH HAZARDS STATEMENT HAS BEEN
ISSUED FOR 10 AM FRI THROUGH 8 PM SUNDAY...BUT WILL LIKELY BE
UPGRADED LATER THIS AFTERNOON TO A HIGH SURF ADVISORY FOR THAT SAME
TIME PERIOD.

&&

.FIRE WEATHER...
LIGHT OFFSHORE WINDS WILL CONTINUE THROUGH NEXT TUESDAY...ALTHOUGH
SUNDAY AND MONDAY WILL HAVE A LITTLE STRONGER OFFSHORE WINDS WITH
NORTHEAST TO EAST WINDS OF 15-25 MPH AND GUSTS 35-45 MPH IN THE
FAVORED PASSES/CANYONS AND COASTAL FOOTHILLS. THE OFFSHORE FLOW WILL
COMBINE WITH VERY WARM CONDITIONS AND MINIMUM RELATIVE HUMIDITIES IN
THE SINGLE DIGITS TO TEENS TO CREATE ELEVATED FIRE
DANGER...PARTICULARLY ON SUNDAY AND MONDAY. OVERNIGHT HUMIDITY
RECOVERIES LOOK TO BE POOR TO LOCALLY MODERATE. EVEN THOUGH FUELS
HAVE BEEN DRYING THE LAST SEVERAL DAYS...THE WINDS SUNDAY AND MONDAY
AT THE MOMENT DO NOT APPEAR TO BE STRONG OR WIDESPREAD ENOUGH TO
PRODUCE RED FLAG CONDITIONS.

HUMIDITY WILL START TO INCREASE WEDNESDAY AS ONSHORE FLOW RETURNS
AND A TROUGH APPROACHES FROM THE PACIFIC. THIS TROUGH COULD PRODUCE
WETTING RAINS LATE IN THE WEEK.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...BEACH HAZARDS STATEMENT FROM FRIDAY MORNING THROUGH SUNDAY
     EVENING FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY
     COASTAL AREAS.

PZ...NONE.
&&

$$

PUBLIC/FIRE WEATHER...HARRISON
AVIATION/MARINE/BEACHES...TS



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