252
FXUS66 KSGX 210900
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
200 AM PDT SUN JUN 21 2026
SYNOPSIS
BELOW AVERAGE TEMPERATURES WITH MARINE LAYER LOW CLOUDS AND FOG
REACHING INTO PORTIONS OF THE VALLEYS THIS WEEKEND. FOR THE FIRST
HALF OF THE WEEK, WIDESPREAD MODERATE TO AREAS OF MAJOR HEATRISK
POSSIBLE FOR THE DESERTS AND WIDESPREAD MINOR TO LOCALLY MODERATE
HEATRISK FOR INLAND ORANGE COUNTY, VALLEYS, AND MOUNTAINS. THE
MARINE LAYER WILL BECOME SHALLOWER NEXT WEEK, STAYING CONFINED TO
COASTAL LOCATIONS. GRADUAL COOLING EXPECTED FOR THE SECOND HALF OF
THE WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THAI MORNING...THE MARINE LAYER REMAINS ABOUT 3,000 FT DEEP WITH
LOW-ZONAL FLOW OVER SOCAL AND WEAK TROUGHING JUST TO OUR NORTH.
LOW CLOUDS ARE INCREASING IN COVERAGE OVER THE COASTAL AREAS AND
VALLEYS OF SAN DIEGO COUNTY. THE CLOUD COVERAGE SEEMS TO BE
EXPANDING IN A SIMILAR PATTERN TO YESTERDAY (FRIDAY) MORNING. THE
SATURATED LAYER IS RELATIVELY THIN AND THE INVERSION WEAK SO
CLEARING WILL LIKELY BE AS EARLY THIS MORNING AS YESTERDAY
MORNING.
A WARMING TREND WILL CONTINUE INTO THURSDAY AS HIGH PRESSURE
BUILDS OVER THE WESTERN STATES. WED AND THU WILL LIKELY BE THE
WARMEST DAYS WITH THE CENTER OF THE UPPER HIGH OVER NORTHERN MEXICO.
DAYTIME HIGH TEMPERATURES ON THOSE DAYS WILL LIKELY BE 5 TO 10
DEGREES ABOVE AVERAGE FOR INLAND LOCATIONS WITH LOCALIZED AREAS
OF MODERATE HEATRISK AWAY FROM THE COAST, AND AREAS OF MAJOR
HEATRISK IN THE LOW DESERT. MOST MODEL SOLUTIONS CONTINUE TO SHOW
AN INFLUX OF MID-LEVEL MOISTURE FROM THE SOUTH AROUND THE MIDDLE
OF THE WEEK. IF THIS BRINGS SIGNIFICANT CLOUD COVER, IT COULD
SUPPRESS TEMPERATURES DURING THE DAYTIME AND INHIBIT RADIATION
COOLING AT NIGHT - AT LEAST ON WED AND THU. THE POSSIBILITY OF
SHOWERS AND/OR TSTMS CAN'T BE RULED OUT FOR WED AFTERNOON BUT AT
THIS TIME, THE PROBABILITY IS 15 PERCENT OR LESS. THE MARINE LAYER
WILL BE SHALLOWER AND OVERNIGHT LOW CLOUDS MAY BE PATCHY AND
DISRUPTED BY THE MOISTURE ALOFT.
BEYOND THE MIDDLE OF THE WEEK...MODEL SOLUTIONS ARE COMING INTO
BETTER AGREEMENT WITH RESPECT TO A LOW PRESSURE SYSTEM MOVING
INLAND TO OUR NORTH, WITH A CLOSED UPPER LOW OVER WA STATE BY NEXT
SATURDAY MORNING. A MAJORITY OF ENSEMBLE MEMBERS NOW SHOW THE
RIDGE OF HIGH PRESSURE BEGINNING TO WEAKEN AND SHIFT EAST BY
THURSDAY AS A LOW PRESSURE TROUGH APPROACHES THE WEST COAST. THIS
WILL RESULT IN A COOLING TREND BEGINNING ON FRIDAY WITH NEXT
SUNDAY BEING THE COOLEST DAY OVERALL. HIGH TEMPERATURES WILL BE
WITHIN A DEGREE OR 2 OF NORMAL IN THE COASTAL AREAS AND LOW
DESERTS WHILE IN THE VALLEYS, MTNS AND HIGH DESERT DAYTIME HIGH
TEMPS WILL BE ANYWHERE FROM 3 TO 11 DEGREES BELOW NORMAL. THE
MARINE LAYER WILL AGAIN DEEPEN WITH LOW CLOUDS SPREADING INLAND TO
THE COASTAL MTN SLOPES DURING THE NIGHTS AND MORNINGS.
AVIATION
210530Z...COAST/VALLEYS...LOW CLOUDS ARE MEANDERING IN ALONG THE SAN
DIEGO COAST AND INTO THE ADJACENT VALLEY. LOW CLOUDS WITH CIGS 1500-
2000FT MSL WILL INCREASE IN COVERAGE OVER THE NEXT FEW HOURS,
SPREADING NORTH INTO OC AFTER 09-10Z. THE INLAND EMPIRE WILL GET
SOME LOW CLOUDS BUT NOT EXPECTING THEM TO FILL IN ALL THE WAY TO THE
FOOTHILLS. LOW CLOUDS WILL SCATTER OUT OF INLAND LOCATIONS AFTER 16-
17Z. LOW CLOUDS WITH SLIGHTLY LOWER BASES WILL REFORM AFTER 03Z
MONDAY.
MOUNTAINS/DESERTS...VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
WESTERLY WIND GUSTS OF 25-40 KTS WILL CONTINUE THIS EVENING ALONG
DESERT SLOPES AND LOCALLY INTO DESERTS. LOCAL VIS REDUCTIONS 4-6 SM
IN BLDU DURING PERIODS OF STRONG GUSTS AND MODERATE UP/DOWNDRAFTS IN
LEE OF MTNS. WINDS WILL SLOWLY DIMINISH THROUGH 12Z SUN. WESTERLY
WINDS OF SIMILAR STRENGTH WILL RETURN FOR THE SAME AREAS AFTER 18Z.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH THURSDAY.
BEACHES
ELEVATED SURF AND STRONG RIP CURRENTS ARE SET TO CONTINUE THROUGH
THIS WEEKEND WITH A PERSISTENT LONG PERIOD SOUTHWESTERLY SWELL. SURF
OF 3-5 FEET WITH LOCAL SETS TO 6 FEET ARE EXPECTED AT SOUTHWEST-
FACING BEACHES. EXPECT LOCALLY HAZARDOUS SWIMMING CONDITIONS WITH
HIGH RIP CURRENT AND LONGSHORE CURRENT RISK. SEE THE BEACH HAZARDS
STATEMENT FOR MORE DETAILS.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR ORANGE COUNTY
COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
PZ...NONE.
PUBLIC...PG
AVIATION/MARINE/BEACHES...VILLAFANE
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