268
FXUS66 KSGX 271138
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
438 AM PDT MON JUL 27 2026
SYNOPSIS
A GRADUAL COOLING TREND BEGINS TODAY AND WILL CONTINUE THROUGH
WEDNESDAY, BRINGING TEMPERATURES AROUND 5 DEGREES ABOVE AVERAGE
BY MIDWEEK. THE UPPER LEVEL RIDGE WILL SHIFT WEST AGAIN TOWARDS
THE END OF THE WEEK AND RESTRENGTHEN WITH INCREASING CONFIDENCE
THAT THIS SETUP COULD PROVIDE US WITH THE HOTTEST TEMPERATURES OF
THIS SUMMER THUS FAR, ESPECIALLY BY SATURDAY. SOME MONSOONAL
MOISTURE TRANSITING OVER THE REGION BY LATER IN THE WEEK AND INTO
THE UPCOMING WEEKEND MAY ALSO PROVIDE A SLIGHT CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS FOR OUR MOUNTAINS AND DESERTS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
TODAY THROUGH TOMORROW NIGHT...
THE LATEST GOES NIGHT FOG AT 4:30 AM REVEALS THAT MOST OF THE
COASTAL AREAS AND INLAND STRETCHING UP TO 15 MILES IN SOME AREAS
WITHIN SAN DIEGO AND ORANGE COUNTIES HAVE BEEN INUNDATED WITH LOW
CLOUDS AND OVERCAST SKIES. THESE CLOUDS MAY MAKE IT INTO THE
SOUTHERN PORTION OF THE IE, NAMELY THE TEMECULA/MURRIETA AREA,
OTHERWISE THESE LOW CLOUDS WILL LIKELY REMAIN IN PLACE THROUGH
SUNRISE, THEN GIVEN HOW SHALLOW THE INVERSION IS WITH THE LATEST
NKX 12Z SOUNDING, ALLUDING TO A SHALLOW MARINE LAYER, ALSO GIVES
CONFIDENCE TO A RELATIVELY QUICK MIXING AND SCATTER OUT OF THESE
CLOUDS WITHIN THE FIRST COUPLE OF HOURS AFTER SUNRISE OCCURS.
THE RIDGE IS BEGINNING TO SHIFT A LITTLE FURTHER EAST TODAY AS
THERE WILL BE FURTHER INFLUENCE BY AN AREA OF TROUGHING UPSTREAM,
WHICH IS GOING TO CONTINUE TO USHER IN RELATIVELY DRIER AIR INTO
THE MID LEVELS, AND LIKELY LIMIT THE CHANCE OF ANY THUNDERSTORM
DEVELOPMENT THIS AFTERNOON AS THE MID-LEVEL MOISTURE BECOMES MORE
SUPPRESSED AND CONFINED OVER ARIZONA. THIS TROUGHING WILL ALSO
ALLOW FOR A VERY GRADUAL COOLING TO TAKE PLACE TODAY THROUGH
TOMORROW, ALTHOUGH HIGHS WILL STILL BE RUNNING AROUND 5 TO 10
DEGREES ABOVE AVERAGE FOR MOST LOCATIONS. THE MARINE LAYER WILL
LIKELY STRUGGLE AGAIN TO DEVELOP TONIGHT, AND REMAIN MOSTLY IN
PLACE ALONG THE COASTAL AREAS OF SAN DIEGO COUNTY, THEN SLOWLY
EXTEND FURTHER INTO SOME OF THE INLAND AREAS CLOSER TO DAYBREAK.
WEDNESDAY THROUGH THE UPCOMING WEEKEND...
SLIGHT COOLING WILL CONTINUE THROUGH WEDNESDAY, THEN THE TROUGHING
UPSTREAM WILL BEGIN TO WEAKEN AND ALLOW FOR THE UPPER LEVEL RIDGE TO
FURTHER STRENGTHEN AND EXPAND BACK TOWARDS THE WEST. THIS WILL ALLOW
FOR TEMPERATURES TO INCREASE AGAIN WELL BACK ABOVE THE SEASONAL
AVERAGE FOR THIS TIME OF YEAR, BY AS MUCH AS 15 DEGREES FOR SOME
LOCATIONS, ESPECIALLY WITHIN THE INLAND EMPIRE. BY SATURDAY, THERE
COULD BE SEVERAL LOCATIONS WITHIN THE IE TOPPING OUT AROUND 110 AND
ABOVE, AND LIKELY WARRANTING THE ISSUANCE OF MORE HEAT PRODUCTS AT
THAT TIME. IF PLANNING TO BE OUTDOORS FOR THIS UPCOMING WEEKEND, IT
WOULD BE WISE TO PREPARE FOR THIS HEAT BY ENSURING THAT THERE ARE
PLENTY OF DRINKING FLUIDS, AS THE COMBINATION OF THE INCREASE
HEAT COULD PUT THOSE SENSITIVE TO HEAT AS RISK OF DEHYDRATION.
THERE WILL ALSO BE A BETTER PUSH OF MONSOONAL WAVES TRANSITIONING
AROUND THE PLATEAU HIGH LOCATED AROUND THE FOUR CORNERS REGION BY
LATER THIS WEEK, WHICH WILL ALLOW FOR INFLUXES OF MID-LEVEL
MOISTURE TO MOVE IN OVER THE REGION AND POSSIBLY ALLOW FOR A FEW
SHOWERS AND AFTERNOON DEVELOPMENT OF THUNDERSTORMS OVER THE
MOUNTAINS AND DESERTS, YET THIS WILL ALL BE DECIDED ON THE TIMING
OF THESE PULSES OF MOISTURE AS THEY TRANSITION OVER OUR AREA.
OTHERWISE, HOT AND DRY CONDITIONS WILL CONTINUE TO BE THE CASE
INTO THE UPCOMING WEEKEND.
AVIATION
271130Z....COAST/VALLEYS...LOW CLOUDS BASED 0600-1000 FT MSL HAVE
DEVELOPED AND PUSHED INLAND, UP TO AROUND 15 MILES IN SOME AREAS.
VIS REDUCED ALONG ELEVATED COASTAL TERRAIN AND LOCALLY IN
ELEVATED VALLEYS UP TO 15 MILES INLAND. LOW CLOUDS MOSTLY SCATTER
16-17Z. 30% CHANCE THAT BRIEF CIGS POSSIBLE AT THE IMMEDIATE COAST
AFTER 21Z AS LOW CLOUDS BEGIN REDEVELOPING EARLY. OTHERWISE, VFR
CONDITIONS PREVAIL MONDAY AFTERNOON UNTIL ANOTHER ROUND OF LOW
CLOUDS PUSH INLAND LIKELY AFTER 04Z TUE., WITH SIMILAR BASES
INITIALLY, AND THEN SLIGHTLY LOWERING THROUGHOUT THE REST OF THE
FORECAST PERIOD AS THEY FILL IN ALONG THE COAST. LOW CLOUDS BEGIN
TO SCATTER FROM THE INLAND TO THE COAST BEGINNING AROUND 16-17Z
TUE.
MOUNTAINS/DESERTS...VFR PREVAILS WITH FEW-BKN MID-LEVEL CLOUDS
AROUND 10-15K FT MSL WILL CONTINUE TO SCATTER THROUGHOUT THE DAY AND
MOVE OUT BY LATER THIS EVENING. CU/TCU DEVELOPMENT POSSIBLE OVER THE
MOUNTAINS THIS AFTERNOON, ALTHOUGH CHANCES OF PRECIPITATION WILL BE
VERY MINIMAL.
MARINE
CALM CONDITIONS INTO THE EARLY HALF OF NEXT WEEK WITH WAVES 3 TO 5
FEET AND AFTERNOON WIND GUSTS NEAR 15 KTS OR LESS THROUGH TUESDAY.
WAVES INCREASE IN THE OUTER WATERS MID TO LATE WEEK WITH WAVES
EXPECTED AROUND 5 TO 7 FEET.
BEACHES
A PERSISTENT LONG-PERIOD SOUTHWESTERLY SWELL (2-3 FEET AT 17-19
SECONDS) KEEPS SURF ELEVATED AT AROUND 3-5 FEET WITH SETS TO 6 FEET
INTO WEDNESDAY. BY WEDNESDAY AFTERNOON/EVENING, A MUCH HIGHER
AMPLITUDE SWELL ASSOCIATED WITH HURRICANE GENEVIEVE IS SET TO BUILD.
SOME UNCERTAINTY EXISTS IN EXACTLY HOW STRONG THIS SWELL WILL BE AS
IT DEPENDS ON THE STRENGTH AND TRACK OF GENEVIEVE, BUT CURRENT
GUIDANCE SUGGESTS THE SWELL COULD BE AROUND 5-7 FEET, WITH A PERIOD
AROUND 14 SECONDS. SHOULD THIS COME TO FRUITION, BREAKING WAVES OF 9-
11 FEET ARE POSSIBLE FOR SOUTH-SOUTHWEST FACING BEACHES FOR THURSDAY
AND FRIDAY.
IN ADDITION TO ELEVATED SURF, TIDES ARE EXPECTED TO INCREASE TO A
HEIGHT OF 6.0 TO 6.5 FEET MLLW BY FOR THIS EVENING'S HIGH TIDE AND
CONTINUE AT THAT HEIGHT THROUGH MOST OF THE WEEK. THE COMBINATION OF
SURF AND TIDES WILL LIKELY RESULT IN AT LEAST MINOR TIDAL OVERFLOW
DURING THE EVENING HIGH TIDES. MORE NOTABLE COASTAL FLOODING IS
POSSIBLE WHEN THE HIGH TIDES COMBINE WITH THE ELEVATED SURF BROUGHT
WITH GENEVIEVE'S SWELL LATER THIS WEEK. IT IS WORTH NOTING, THAT
WITH THE EFFECTS FROM THIS YEAR'S EL NINO, OBSERVED TIDES HAVE BEEN
CONSISTENTLY ABOUT 0.3-0.5 FEET BELOW MANY BASELINE PREDICTIONS.
A BEACH HAZARD STATEMENT REMAINS IN EFFECT THROUGH 6PM WEDNESDAY DUE
TO THE ELEVATED SURF, RIP CURRENT RISK, AND CONCERN FOR MINOR TIDAL
OVERFLOW. ADDITIONAL PRODUCTS FOR COASTAL FLOODING AND HIGH SURF ARE
LOOKING INCREASINGLY LIKELY FOR LATER THIS 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 THROUGH WEDNESDAY AFTERNOON FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORANGE COUNTY
COASTAL AREAS-ORANGE COUNTY INLAND AREAS-RIVERSIDE COUNTY
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO
COUNTY COASTAL AREAS-SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO
COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
EXTREME HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR APPLE AND
LUCERNE VALLEYS-COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-
SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...STEWEY
AVIATION/MARINE/BEACHES...STEWEY
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