276
FXUS66 KSGX 212029
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
129 PM PDT SUN JUN 21 2026
SYNOPSIS
WARMING TREND FOR THE FIRST HALF OF THE WEEK BRINGS 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 FOR WEDNESDAY. THE MARINE LAYER
WILL BECOME SHALLOWER THROUGH MIDWEEK, STAYING CONFINED TO
COASTAL LOCATIONS. A FEW STRAY SHOWERS/STORMS ARE POSSIBLE OVER
THE MOUNTAINS ON WEDNESDAY. GRADUAL COOLING EXPECTED FOR THE
SECOND HALF OF THE WEEK WITH THE MARINE LAYER BECOMING DEEPER.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
CURRENT SATELLITE AND 500MB ANALYSIS REVEALS LARGELY ZONAL FLOW
ALOFT AND A WEAK UPPER RIDGE ACROSS NORTHERN MEXICO, WITH MARINE
LAYER CLOUDS CLEARING OUT TO THE COASTS FOR THE DAY. TEMPERATURES
EARLY THIS AFTERNOON ARE RUNNING NEAR TO SLIGHTLY WARMER THAN
YESTERDAY, BUT IS STILL COMING IN 5-10 DEGREES BELOW NORMAL FOR MOST
ACROSS THE REGION. HOWEVER, TODAY LOOKS TO BE THE COOLEST DAY OF THE
NEXT SEVERAL AS MODEL GUIDANCE REMAINS CONSISTENT IN THE UPPER LEVEL
RIDGE STRENGTHENING AND SLIDING NORTHWARD OVER THE NEXT FEW DAYS,
BECOMING CENTERED NEAR EL PASO BY TUESDAY AFTERNOON. THE PLACEMENT
OF THIS RIDGE ALSO ESTABLISHES SOUTHEASTERLY FLOW ALOFT, ALLOWING
FOR AN INFLUX OF MID LEVEL MOISTURE INTO THE AREA. THE RIDGE AND THE
MOISTURE WILL LIKELY SERVE TO LIMIT THE VERTICAL DEPTH AND INLAND
EXTENT OF THE MARINE LAYER THROUGH MIDWEEK. THE MAIN CONSEQUENCE
WILL BE THE NOTABLE WARMING TREND, THAT TAKES AFTERNOON TEMPERATURES
5-10 DEGREES ABOVE NORMAL BY WEDNESDAY. MORE IMPORTANTLY, THE
MOISTURE WILL INHIBIT OVERNIGHT COOLING, LEADING TO MILD NIGHTS,
WITH LOW TEMPERATURES RUNNING 5-10 DEGREES ABOVE NORMAL AS WELL AND
LIMITING OVERNIGHT RELIEF FROM HE WARM DAYTIME TEMPERATURES. THIS
BRINGS AREAS OF MODERATE HEATRISK INTO THE INLAND VALLEYS ON
WEDNESDAY, WITH LOCALLY MAJOR HEATRISK FOR THE DESERTS.
ADDITIONALLY, THE INCREASED MID LEVEL MOISTURE COULD SUPPORT THE
DEVELOPMENT OF A FEW SHOWERS/STORMS OVER THE MOUNTAINS TUESDAY OR
MORESO WEDNESDAY AFTERNOON. A WEAK SHORTWAVE ROUNDING THE WESTERN
PERIPHERY OF THE RIDGE TUESDAY INTO WEDNESDAY MAY PROVIDE ENOUGH
SYNOPTIC SUPPORT FOR UPDRAFTS TO OVERCOME INHIBITING CLOUD COVER AND
DRY AIR ABOVE THE MOIST LAYER, BUT THESE ARE 2 MAIN FACTORS THAT
WILL LIKELY KEEP ANY IMPACTS FROM THESE PRECIPITATION CHANCES LITTLE
TO NONE.
ENSEMBLES CONTINUE TO PUSH A LONGWAVE TROUGH INTO THE PACIFIC
NORTHWEST FOR THURSDAY INTO FRIDAY, WHICH SHOULD HELP WEAKEN THE
RIDGE AND NUDGE IT SOUTH/EAST AS WELL AS KICK OUT THE MID LEVEL
MOISTURE. THIS RESULTS IN A COOLING TREND INTO THE WEEKEND WITH THE
MARINE LAYER DEEPENING AGAIN. TEMPERATURES RETURN TO NEAR AVERAGE
FOR THURS/FRI WITH THE POTENTIAL FOR AFTERNOON HIGHS 10 DEGREES OR
MORE BELOW NORMAL FOR THE WEEKEND.
AVIATION
211800Z...COAST/VALLEYS...LINGERING LOW LEVEL CLOUDS ALONG THE COAST
WILL CLEAR OFFSHORE BY 19Z. LOW CLOUDS REFORM AND MOVE INTO SD
COASTAL REGIONS AFTER 03Z AT 1700-2200 FT MSL, THEN INTO INLAND
SD/ORANGE COUNTY AFTER 06Z. THERE IS A 30-40% CHANCE FOR CLOUDS TO
REACH INTO THE SOUTHERN AND NORTHWEST PORTIONS OF THE INLAND EMPIRE,
INCLUDING VCNTY KONT, 11-16Z MONDAY. CIGS LIKELY TO LOWER SLIGHTLY
OVERNIGHT TO 1500-2000 FT MSL, THEN SCATTER OUT 16-18Z MON.
MOUNTAINS/DESERTS...VFR CONDITIONS WITH PERIODS OF UPPER LEVEL
CLOUDS AOA 20K FT EXPECTED THROUGH THE TAF PERIOD. WESTERLY WIND
GUSTS OF 25-40 KTS ALONG DESERT SLOPES AND LOCALLY INTO DESERTS
EXPECTED THROUGH ABOUT 06Z THIS EVENING. LOCAL VIS REDUCTIONS 4-6 SM
IN BLDU DURING PERIODS OF STRONG GUSTS AND MODERATE UP/DOWNDRAFTS IN
LEE OF MTNS.
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.
SGX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT UNTIL 11 PM PDT THIS EVENING FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
PZ...NONE.
PUBLIC...MUNYAN
AVIATION/MARINE/BEACHES...CSP
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