589
FXUS66 KSGX 201137
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
337 AM PST FRI DEC 20 2024
SYNOPSIS
AREAS OF LOW CLOUDS AND DENSE FOG WILL CONTINUE NEAR THE COAST
THROUGH LATER THIS MORNING AS TEMPERATURES SUBTLY LOWER INTO THE
WEEKEND WEST OF THE MOUNTAINS. A TROUGH OF LOW PRESSURE WILL MOVE
INTO THE REGION TUESDAY, BRINGING ELEVATED WINDS TO THE MOUNTAINS
AND DESERTS AND A CHANCE OF LIGHT SHOWERS ALONG AND WEST OF THE
MOUNTAINS. DRY AND FAIR WEATHER WILL RETURN FOR THE CHRISTMAS
HOLIDAY WITH A MINOR CHANCE OF SHOWERS LATER IN THE WEEK AS
ANOTHER WEAK TROUGH MOVES THROUGH SOCAL.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
FOG CONTINUES TO HUG OUR COASTAL AREAS THIS MORNING, WITH THE SAN
DIEGO AIRPORT SOCKED IN WITH VISIBILITY AT THIS HOUR NEAR 1/16TH
OF A MILE...PEA SOUP! EXPECT CLOUDS AND VISIBILITY TO CLEAR BY MID
TO LATE FRIDAY MORNING. LIGHT OFFSHORE FLOW WILL KEEP THE MARINE
LAYER THIN AND UNCHANGED THROUGH THE MORNING HOURS, LEADING TO
CONTINUED FOGGY CONDITIONS. SOME HINTS OF ONSHORE FLOW RETURN BY
FRIDAY AFTERNOON, WHICH MAY HELP LIFT THE MARINE LAYER A BIT MORE
BY SATURDAY MORNING, THOUGH FOGGY CONDITIONS STILL HAVE THE CHANCE
TO OCCUR ONCE AGAIN. KEEP AN EYE OUT FOR TRAVEL DELAYS, ESPECIALLY
IF TRAVELING DURING THE MORNING AND EVENING HOURS.
AS ONSHORE FLOW SUBTLY INCREASES TODAY, VALLEYS WEST OF THE
MOUNTAINS WILL SEE HIGHS IN THE 70S INSTEAD 80S LIKE YESTERDAY.
A TROUGHING REGIME HAS SET UP ACROSS CALIFORNIA, BRINGING WET
WEATHER TO NORCAL AND FURTHER COOLING INTO OUR REGION. THIS
COOLING WILL SPREADING FURTHER INTO THE WESTERN VALLEYS BY THE
WEEKEND WITH LOWER 70S EXPECTED BY SUNDAY. OTHER COMMUNITIES
ACROSS THE COAST, MOUNTAINS AND DESERTS WILL SEE SIMILAR
TEMPERATURE READINGS INTO THE WEEKEND: HIGHS NEAR 80 IN THE LOWER
DESERTS, NEAR 70 IN THE HIGH DESERT, AND MID 60S ALONG THE
BEACHES.
NORCAL WILL TRY TO SHARE A LITTLE BIT OF THE WEALTH AS ANOTHER
TROUGH MOVES INTO OUR REGION ON CHRISTMAS EVE. THE FORECAST
REMAINS CONSISTENT IN TERMS OF TIMING, WITH INCREASED CHANCES FOR
LIGHT SHOWERS TO MOVE INTO THE AREA FROM NORTH TO SOUTH TUESDAY
AFTERNOON THROUGH THE OVERNIGHT HOURS. MODEL TRENDS HAVE SHOWN A
SLIGHT DRYING TREND OVERALL, INDICATING OUR CONTINUED THINKING
THAT WHATEVER FALLS WILL BE LIGHT. COASTAL FACING SLOPES HAVE THE
HIGHEST CHANCE OF PRECIPITATION WITH TOTALS NEAR ONE TENTH OF AN
INCH, OTHER AREAS WEST OF THE MOUNTAINS A FEW HUNDREDTHS. AS THE
SYSTEM MOVES THROUGH, WEST WINDS WILL INCREASE ACROSS THE LEEWARD
SIDE OF THE MOUNTAINS INTO THE DESERTS OVERNIGHT WITH GUSTS 20 TO
LOCALLY 40 MPH. OVERALL, LOOKS LIKE SANTA'S JOURNEY INTO SOCAL
WILL BE A BIT CLOUDY AND BREEZY, YET MAGICAL.
TEMPERATURES WILL COOL FURTHEST BY WEDNESDAY AS THE TROUGH PASSES
OVER THE AREA. LOWER DESERT LOCATIONS WILL BE STICKING INTO THE
70S WITH WIDESPREAD 60S WEST OF THE MOUNTAINS. SIMILAR
TEMPERATURES CAN BE EXPECTED THROUGH THE END OF THE WEEK AS THE
TROUGHING PATTERN REMAINS. ANOTHER WAVE MAY DIG DEEP ENOUGH
THROUGH THE REGION BY THURSDAY AFTERNOON OR EVENING, BRINGING
ANOTHER MINOR CHANCE FOR PRECIPITATION SO NBM CHANCES LOOK GOOD
FOR THIS TIME PERIOD. OTHERWISE, MUCH OF OUR AREA WILL REMAIN DRY
THROUGH THE UPCOMING WEEK.
AVIATION
201100Z....COASTS/VALLEYS...VERY LOW CLOUDS (BASES 100-200FT MSL,
TOPPED TO 400FT MSL) AND AREAS OF DENSE FOG (VIS LESS THAN 1 MILE)
THAT PUSHED ASHORE LATE LAST NIGHT IS STARTING TO SLIDE BACK WEST AT
THIS HOUR WITH LIGHT OFFSHORE FLOW. VERY SIMILARLY TO LAST NIGHT,
CLEARING WILL BE MAXIMIZED IN NORTHERN SAN DIEGO COUNTY AND SOUTHERN
ORANGE COUNTY WITH MORE STUBBORN CLOUDS LINGERING IN NORTHERN
ORANGE/SOUTHERN SAN DIEGO COUNTIES (INCLUDING KSAN AND KSNA) THROUGH
ABOUT 13-16Z FRIDAY MORNING. WHILE CLEAR SKIES IS ANTICIPATED AFTER
16Z, ISOLATED BKN CIGS/FOG MAY LINGER NEAR THE BEACHES INTO FRIDAY
AFTERNOON. MORE LOW STRATUS/FOG WILL DEVELOP AND SPREAD INLAND AFTER
00Z SATURDAY, WITH SLIGHTLY HIGHER BASES/VIS NEAR THE COAST BUT
LIKELY MORE INLAND EXTENT AND LOWER VIS FOR THE INLAND
VALLEYS/HIGHER TERRAIN.
MOUNTAINS/DESERTS
MOSTLY CLEAR SKIES AND UNRESTRICTED VIS WILL
PREVAIL THROUGH EARLY SATURDAY MORNING.
MARINE
DENSE FOG WITH VISIBILITY BELOW 1 NM AT TIMES WILL CONTINUE THROUGH
FRIDAY MORNING, LIFTING GRADUALLY LATE IN THE MORNING. LONG PERIOD
WEST SWELL WILL GENERATE SEAS OF 8-11 FEET SUNDAY THROUGH WEDNESDAY,
HIGHEST IN THE OUTER COASTAL WATERS AND NEAR SAN CLEMENTE ISLAND.
BEACHES
A SERIES OF 16-19 SECOND PERIOD WEST-NORTHWESTERLY SWELLS (280-290
DEGREES) BEGINNING SUNDAY WILL BRING HIGH SURF OF 8-12 FEET WITH
LOCALLY HIGHER SETS TO SAN DIEGO COUNTY BEACHES WHILE ORANGE COUNTY
BEACHES WILL HAVE SURF CLOSER TO 4-8 FEET WITH LOCALLY HIGHER WAVES
TO 10 FEET ON MORE WEST-FACING BEACHES. A HIGH SURF ADVISORY IS IN
EFFECT FROM EARLY SUNDAY MORNING THROUGH WEDNESDAY MORNING. THERE
WILL BE A HIGH RISK OF STRONG RIP CURRENTS AND DANGEROUS SWIMMING
CONDITIONS. ADDITIONALLY, DESPITE RELATIVELY LOW ASTRONOMICAL TIDES,
NUISANCE TO MINOR INSTANCES OF COASTAL FLOODING IS POSSIBLE SUNDAY-
WEDNESDAY DUE TO THE HIGH SURF.
REINFORCING LONG PERIOD SWELLS MAY MAINTAIN ELEVATED/HIGH SURF THE
SECOND HALF OF NEXT WEEK, THOUGH WITH SURF SLIGHTLY LOWER THAN EARLY
IN THE WEEK.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...DENSE FOG ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
HIGH SURF ADVISORY FROM 10 PM SATURDAY TO 4 AM PST WEDNESDAY FOR
ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
PZ...NONE.
PUBLIC...APR
AVIATION/MARINE...MUNYAN
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