050
FXUS66 KSGX 042117
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
117 PM PST TUE NOV 4 2025
SYNOPSIS
LOW CLOUDS AND PATCHY FOG WILL FILL MUCH OF THE COASTAL
BASIN THIS EVENING INTO WEDNESDAY MORNING AS A TROUGH OF LOW
PRESSURE MOVES CLOSER TO THE AREA. THIS WILL ALSO LEAD TO SLIGHTLY
COOLER CONDITIONS FOR INLAND VALLEYS ALONG WITH WINDIER WEATHER
ACROSS THE MOUNTAINS AND DESERTS BY WEDNESDAY AND THURSDAY. AN AREA
OF HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA BY FRIDAY THROUGH
THE WEEKEND LEADING TO A WARMING TREND. A LOW PRESSURE SYSTEM WILL
MOVE CLOSER TO OUR REGION BY EARLY TO THE MIDDLE PART OF NEXT WEEK,
LEADING TO COOLER WEATHER AND THE POTENTIAL FOR RAIN SHOWERS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MOSTLY CLEAR SKIES WILL CONTINUE THROUGH THE AFTERNOON AS HIGH
TEMPERATURES STAY NEAR AVERAGE WEST OF THE MOUNTAINS AND AROUND 5
DEGREES ABOVE AVERAGE IN THE MTS/DESERTS. A TROUGH OF LOW PRESSURE
WILL CONTINUE TO MOVE CLOSER TO NORTHERN CALIFORNIA AND THE PACIFIC
NORTHWEST INTO WEDNESDAY. THIS WILL HELP DEEPEN THE MARINE LAYER
FURTHER TONIGHT INTO WEDNESDAY MORNING, FILLING MUCH OF THE COASTAL
BASIN WITH LOW CLOUDS AND FOG ACROSS HIGHER TERRAIN INTO THE INLAND
EMPIRE. THE TROUGH AXIS WILL PUSH THROUGH NORTHERN CALIFORNIA ON
WEDNESDAY, BRINGING FURTHER COOLING INTO THE INLAND VALLEYS WITH
HIGHS MOSTLY IN THE 70S AND 80S ACROSS THE LOWER DESERTS. THE
PASSING SYSTEM WILL ALSO TIGHTEN THE PRESSURE GRADIENT, LEADING TO
ELEVATED WEST/SOUTHWEST WINDS ACROSS THE MOUNTAINS AND DESERTS.
THERE IS HIGH CONFIDENCE IN WIDESPREAD WIND GUSTS 25 TO LOCALLY OVER
45 MPH ACROSS DESERT SLOPE PASSES. UPPER LEVEL FLOW ALOFT BECOMES
MORE ZONAL BY THURSDAY, WHICH WILL HELP EASE THE WINDS, BUT MAINTAIN
A SIMILAR TEMPERATURE PICTURE TO WEDNESDAY.
SPECTACULAR MODEL AGREEMENT IS SEEN ACROSS GLOBAL MODELS ON HIGH
PRESSURE TO OUR SOUTH TODAY BEGINNING TO BUILD ACROSS THE DESERT
SOUTHWEST BY FRIDAY INTO THE WEEKEND. MODELS PROJECT THE PRESSURE
GRADIENT TURNING WEAKLY OFFSHORE BY THIS TIME PERIOD AS THE RIDGE
AND ASSOCIATED SURFACE HIGH AMPLIFY OVER THE GREAT BASIN BY SUNDAY.
THIS WILL BRING IN LIGHT SANTA ANA WINDS MAINLY OUT OF THE EAST W
THROUGH THE MOUNTAIN PASSES AND WESTERN VALLEYS. THE FORECAST WAS
SLIGHTLY MODIFIED TO INCREASE TEMPERATURES A FEW DEGREES ABOVE NBM
GUIDANCE FOR SATURDAY AND SUNDAY FOR WESTERN VALLEYS AS THE OFFSHORE
FLOW BECOMES STRONGEST. CHANCES ARE AROUND 30-50% TO SEE HIGHS OVER
90 DEGREES ACROSS THE INLAND EMPIRE AND FOOTHILLS OF SAN DIEGO
COUNTY.
MODELS ARE IN BETTER AGREEMENT OF THE AN AMPLIFIED TROUGH DEVELOPING
OFFSHORE BY EARLY NEXT WEEK, WHERE A CUTOFF LOW WILL FORM SOMEWHERE
OVER THE PACIFIC DUE WEST OF CALIFORNIA. CONFIDENCE BECOMES LOWER ON
WHERE THE EXACT PATH OF SYSTEM WILL GO AND IF/WHEN IT WILL BRING
PRECIPITATION TO OUR REGION, ESPECIALLY HOW FAST THE SYSTEM MOVES.
THE FORECAST LOOKS DRY THROUGH AT LEAST NEXT TUESDAY WHERE
TEMPERATURES WILL BEGIN TO COOL OFF AS THE SYSTEM MOVES CLOSER TO
OUR AREA. THE WRINKLE IN THIS STORY IS THAT ANOTHER TROUGH TO NORTH
WILL LIKELY MOVE INTO THE WEST COAST BY THE MIDDLE OF NEXT WEEK.
THIS WILL BRING US A COOLER WEATHER PATTERN CHANGE BUT HOW FAR SOUTH
THIS GOES WILL DETERMINE ON IF WE CAN SEE ANY RAINFALL. ENSEMBLES
ARE STARTING TO HONE IN ON WEDNESDAY BEING THE EARLIEST DAY TO SEE
RAIN, WHILE SOME DO NOT POINT TO ANY RAIN UNTIL LATE THURSDAY OR
FRIDAY OF NEXT WEEK.
AVIATION...042030Z...COASTS/VALLEYS
COMPLETELY CLEAR AND VFR
THROUGH THE AFTERNOON. LOW CLOUDS DEVELOP AGAIN THIS EVENING
GENERALLY AROUND 02-03Z WED. BASES WILL COME IN AROUND 1100-1600FT
MSL AND PUSH AROUND 15 TO 20 MILES INLAND OVERNIGHT. BASES RISE A
BIT THROUGH THE NIGHT CLOSE TO OR ABOVE 2000FT MSL GENERALLY AFTER
13Z. VIS REDUCTIONS 0-5SM FOR INLAND VALLEYS AND COASTAL SLOPES WITH
LOCALIZED PATCHY DRIZZLE. CLOUDS BEGIN TO CLEAR EAST TO WEST,
APPROACHING THE COASTLINE AROUND 17Z.
MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS TODAY AND
TONIGHT. INCREASING HIGH CLOUDS AOA 20,000FT MSL ON WEDNESDAY.
SOUTHWEST WINDS IN THE DESERTS AND OVER THE MOUNTAINS WITH SURFACE
GUSTS 35 TO 40 KNOTS LATE WEDNESDAY MORNING AND INTO THE AFTERNOON.
MARINE
ONSHORE WINDS MAY APPROACH 20 KNOTS IN THE OUTER COASTAL WATERS NEAR
SAN CLEMENTE ISLAND THURSDAY AFTERNOON AND EVENING. OTHERWISE, NO
HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.
BEACHES
LONG PERIOD (15-16 SEC) WEST-NORTHWEST (290 DEGREE) SWELL WILL
ARRIVE THURSDAY, PEAK THURSDAY NIGHT, AND GRADUALLY DIMINISH
FRIDAY. SURF OF 4-7 FEET IS EXPECTED, LOCALLY HIGHER ON WEST-
FACING BEACHES WITH A HIGH RIP CURRENT RISK. KING TIDES WILL
COINCIDE WITH THE ELEVATED SURF TO CREATE MINOR TIDAL OVERFLOW IN
PARKING LOTS AND ALONG SIDEWALKS BOTH THURSDAY AND FRIDAY.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...APR
AVIATION/MARINE...ZUBER
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