836
FXUS66 KSGX 202349
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
449 PM PDT MON JUL 20 2026
SYNOPSIS
INCREASE IN BOTH HIGH AND LOW TEMPERATURES EXPECTED FOR THE MIDDLE
OF THE WEEK INTO EARLY NEXT WEEK. THIS WILL BRING WIDESPREAD
MODERATE TO AREAS MAJOR HEATRISK AWAY FROM THE COAST. SHOWER AND
THUNDERSTORM CHANCES ARE SLIM TO NONE FOR THE FIRST HALF OF THE
WEEK. SHOWER AND THUNDERSTORM CHANCES FOR THURSDAY AND FRIDAY
REMAIN IN THE FORECAST, BUT HAVE DECREASED OVER THE PAST FEW
FORECAST CYCLES. THROUGH THE WEEK THE MARINE LAYER WILL REMAIN
MOSTLY CONFINED TO THE COAST.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
WIDESPREAD HIGH CLOUD COVERAGE IS BEING OBSERVED AT 12 PM ON
VISIBLE SATELLITE. LIGHT RADAR RETURNS ARE BEING OBSERVED IN THE
DESERTS AND MOUNTAINS, ALTHOUGH ONLY AN ISOLATED HUNDREDTH OF RAIN
HAS BEEN OBSERVED IN AREA RAIN GAUGES. ANY ADDITIONAL RAIN THAT
FALLS SHOULD JUST BE A FEW SPRINKLES AND WILL NOT HAVE ANY
IMPACTS. SHOWERS CHANCES CONTINUE TO LOOK UNLIKELY THROUGH
WEDNESDAY.
THE WEATHER PATTERN THIS WEEK WILL BE MAINLY INFLUENCED BY BROAD
UPPER LEVEL RIDGING ACROSS THE SOUTHWEST UNITED STATES. TODAY AND
TUESDAY WILL SEE MINOR DAY TO DAY CHANGES IN TEMPERATURES WITH HIGHS
REMAINING NEAR TO SLIGHTLY ABOVE NORMAL AS THE HIGH DRIFTS EAST OVER
THE MIDWEST. STARTING WEDNESDAY, THE UPPER LEVEL HIGH IS FORECAST TO
SHIFT SOUTH AND WEST MORE OVER NEW MEXICO AND TEXAS WHICH IS WHEN IT
WILL BEGIN TO HAVE MORE OF AN INFLUENCE ON OUR WEATHER. HIGHS ON
WEDNESDAY WILL BE 5 TO 10 DEGREES WARMER THAN TUESDAY FOR INLAND
LOCATIONS AND A FEW DEGREES WARMER ALONG THE COAST. CONDITIONS WILL
CONTINUE TO WARM THURSDAY THROUGH THE UPCOMING WEEKEND AS THE UPPER
LEVEL HIGH'S POSITION MOVES MORE WEST OVER ARIZONA/NEVADA.
FOR THE MIDDLE OF THE WEEK THROUGH THE UPCOMING WEEKEND, BOTH HIGH
AND LOW TEMPERATURES WILL BE RUNNING 5 TO 10 DEGREES ABOVE AVERAGE.
THE COMBINATION OF ELEVATED HIGH AND LOW TEMPERATURES WILL LIMIT THE
ABILITY TO RECOVER FROM HEAT OVERNIGHT AND ALLOW FOR CONDITIONS TO
QUICKLY WARM ONCE THE SUN RISES. WIDESPREAD MODERATE TO LOCALLY
MODERATE HEATRISK IS EXPECTED IN INLAND ORANGE COUNTY, SAN DIEGO
VALLEYS, INLAND EMPIRE, AND AREA MOUNTAINS. MAJOR HEATRISK IS
EXPECTED IN THE DESERTS. MAJOR HEATRISK INDICATES THAT THE
GENERAL POPULATION MAY BE IMPACTED BY THE HEAT IF PRECAUTIONS ARE
NOT TAKEN.
WHILE THERE REMAINS CHANCES OF SHOWERS AND THUNDERSTORMS IN THE
MOUNTAINS THURSDAY AND FRIDAY AFTERNOONS, CHANCES ARE CONTINUING TO
DECREASE OVER THE LAST FEW FORECAST CYCLES. GUIDANCE IS ALSO
INDICATING A DECREASE IN PRECIPITABLE WATER VALUES, WITH THE GFS
INDICATING A MORE NOTABLE DECREASE THAN THE ECMWF ENSEMBLE GUIDANCE.
LESS OF A MOISTURE INFLUX WOULD ALLOW FOR A GREATER WARMING, WHILE
MORE MOISTURE WOULD PUT A LIMIT ON HOW WARM HIGHS WILL GET IT WOULD
ALSO INCREASE HUMIDITY WHICH WOULD MAKE CONDITIONS MUGGIER.
AVIATION
210000Z....COAST/VALLEYS...SCT-BKN MID-HIGH LEVEL (12-15 KFT) CLOUDS
REMAINING THROUGH THE EVENING. THESE WILL SEVERELY LIMIT LOW CLOUD
FORMATION FOR MOST OF THE EVENING, WITH PATCHY LOW CLOUDS EXPECTED
TO FORM ALONG THE COASTS AFTER 07Z. LOW CONFIDENCE EXISTS FOR LONG
DURATION CIGS AT ANY OF THE MAJOR COASTAL TAF SITES (KSAN/KCRQ/KSNA)
OVERNIGHT, BUT KSAN DOES HAVE THE HIGHEST CHANCE (~60%) FOR
RELATIVELY PERSISTENT CIGS NEAR 0900-1200FT MSL BETWEEN 11Z-15Z
TUESDAY MORNING. ANY PATCHY CLOUDS THAT REMAIN IN PLACE OVERNIGHT
WILL CLEAR BACK OUT TO THE COAST BY 15-16Z.
MOUNTAINS/DESERTS...SCT-BKN CLOUDS 12-15 KFT MSL. WEST WINDS GUSTING
10-25 KTS ALONG DESERT SLOPES AND UP TO 35 KTS THROUGH THE BANNING
PASS EXPECTED FROM THROUGH 06Z TUE.
MARINE
THERE IS ABOUT A 70% CHANCE FOR NW WIND GUSTS TO EXCEED 20 KTS IN
THE OUTER WATERS NEAR SAN CLEMENTE ISLAND WEDNESDAY AFTERNOON, AND A
60% CHANCE THURSDAY AFTERNOON. ADDITIONALLY, A MIXED SWELL WILL
CAUSE STEEP AND CHOPPY SEAS DURING THE DAY THURSDAY, ESPECIALLY IN
THE OUTER WATERS.
BEACHES
SOUTHERLY SWELL OF 4-5 FT WITH A PERIOD OF 11-13 SECONDS WILL
CONTINUE TO BRING ELEVATED TO HIGH SURF AND STRONG RIP AND LONGSHORE
CURRENTS THROUGH TUESDAY. SURF 4-7 FEET WITH SETS TO 8 FEET IS
EXPECTED THROUGH TUESDAY, WITH THE HIGHEST SURF FOCUSED ON SOUTH AND
SOUTHWEST FACING BEACHES OF ORANGE COUNTY. A HIGH SURF ADVISORY
REMAINS IN EFFECT UNTIL 11 PM TUESDAY.
THE SOUTHERLY SWELL AND SURF FALLS THROUGH THE DAY ON TUESDAY,
REMAINING LOWER INTO WEDNESDAY. ANOTHER ROUND OF ELEVATED SOUTHERLY
SWELL FROM A TROPICAL CYCLONE WELL OFF THE COAST IS EXPECTED
THURSDAY THROUGH THE END OF THE WEEK. THIS SWELL IS EXPECTED TO BE
AROUND 4-5 FT WITH A PERIOD OF ABOUT 15 SECONDS WHICH WOULD ONCE
AGAIN BRING HIGH SURF OF 6-8 FEET, ESPECIALLY FOR SOUTH-SOUTHWEST
FACING BEACHES.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HIGH SURF ADVISORY UNTIL 11 PM PDT TUESDAY FOR ORANGE COUNTY
COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
HEAT ADVISORY FROM 10 AM WEDNESDAY TO 8 PM PDT MONDAY FOR ORANGE
COUNTY INLAND AREAS-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY MOUNTAINS-
SAN DIEGO COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
EXTREME HEAT WATCH FROM WEDNESDAY MORNING THROUGH MONDAY EVENING
FOR APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-SAN DIEGO
COUNTY DESERTS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE/BEACHES...MUNYAN
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