554
FXUS66 KSGX 010928
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
228 AM PDT FRI AUG 1 2025
SYNOPSIS
TEMPERATURES NEAR AVERAGE AND NIGHT AND MORNING LOW CLOUDS EACH
DAY ALONG THE COAST AND WESTERN VALLEYS THROUGH TUESDAY. HIGH
PRESSURE OVER THE DESERT SOUTHWEST MAY STRENGTHEN BY THE MIDDLE OF
NEXT WEEK, BRINGING A WARMING TREND WITH TEMPERATURES NEAR 5 TO
10 DEGREES ABOVE AVERAGE AWAY FROM THE COAST. THERE IS THE
POTENTIAL FOR MONSOON MOISTURE TO RETURN LATE IN THE WEEK, BUT
PRECIPITATION CHANCES REMAIN BELOW 10%.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
LOW CLOUDS HAVE SPREAD INTO THE WESTERN VALLEYS THIS MORNING WHILE
SKIES REMAIN CLEAR ELSEWHERE. CLOUDS WILL CLEAR BACK TO THE COAST
BY LATE MORNING. NOT MUCH EXCITEMENT TODAY WITH HIGH TEMPERATURES
NEAR NORMAL AND TYPICAL SEA BREEZES IN THE AFTERNOON, STRONGEST
THROUGH THE PASSES.
AN UPPER LEVEL HIGH CENTERED NEAR SOUTHERN ARIZONA WILL GRADUALLY
SHIFT WESTWARD INTO SATURDAY, THEN SLOWLY WEAKEN IN RESPONSE TO AN
UPPER LEVEL TROUGH MOVING INLAND TO THE NORTH. OVERALL DAILY
TEMPERATURE FLUCTUATIONS WILL REMAIN MINIMAL INTO EARLY NEXT WEEK,
GENERALLY IN THE MID 70S IN THE COASTAL AREAS, MID 80S TO MID 90S
FOR INLAND ORANGE COUNTY AND VALLEYS - LOCALLY INTO THE UPPER 90S
IN THE INLAND EMPIRE, UPPER 90S TO AROUND 100 IN THE HIGH DESERT,
AND AROUND 109-113 IN THE LOW DESERTS. THE MARINE LAYER WILL BE
SLIGHTLY MORE SHALLOW WITH NIGHT AND MORNING LOW CLOUDS CONFINED
TO THE COASTAL AREAS AND FAR WESTERN VALLEYS.
FOR THE LATTER HALF OF NEXT WEEK, A STRONGER UPPER LEVEL HIGH IS
FORECAST TO POSITION ITSELF OVER NM/AZ. THIS WILL BRING MORE
SIGNIFICANT WARMING FOR WEDNESDAY THROUGH FRIDAY, ESPECIALLY FOR
INLAND AREAS. THURSDAY IS CURRENTLY FORECAST TO BE THE HOTTEST
DAY, WHEN THE CHANCE OF HIGH TEMPERATURES EXCEEDING 100 DEGREES IS
AROUND 60% FOR THE INLAND VALLEYS OF SAN DIEGO COUNTY, 70-90% IN
THE INLAND EMPIRE, AND 90-100% FOR MUCH OF THE HIGH DESERT.
CHANCES OF HIGH TEMPERATURES EXCEEDING 115 ARE AROUND 40-70%.
GLOBAL ENSEMBLES SHOW AN INCREASE IN PRECIPITABLE WATER ASSOCIATED
WITH THE MONSOON NEXT WEEK, THOUGH THE MAIN PLUME OF MOISTURE
REMAINS TO OUR EAST. AT THIS POINT MOISTURE AND INSTABILITY LOOK
TOO MARGINAL FOR ANY SHOWER OR THUNDERSTORM THREAT WITH
PRECIPITATION CHANCES REMAINING BELOW 10%. IF WE DO GET ANY LOW-
LEVEL MOISTURE SURGES INTO THE LOWER DESERTS, THAT COULD IMPACT
(LOWER) THE HIGH TEMPERATURES, THOUGH IT JUST END UP BEING
SLIGHTLY LESS HOT BUT SIGNIFICANTLY MORE HUMID. A SHALLOW MARINE
LAYER REMAINING IN PLACE WILL MODERATE TEMPERATURES NEAR THE COAST
THROUGH THIS PERIOD WITH NIGHT AND MORNING LOW CLOUDS CONTINUING
ACROSS THE COASTAL AREAS.
AVIATION
010900Z...COASTS/WESTERN VALLEYS...LOW CLOUDS WITH BASES 900-1400
FEET HAVE MOVED INLAND AROUND 10-15 MILES. FOG IS DEVELOPING WITH
VIS 0-5SM OVER HIGHER TERRAIN AND LOCALLY IN VALLEYS AROUND AND
WEST OF I-15. SCATTER OUT THIS MORNING 16-17Z. OTHERWISE, VFR
CONDITIONS FRIDAY AFTERNOON WITH LOW CLOUDS REDEVELOPING AT THE
COAST 03Z SAT WITH SIMILAR BASES.
INLAND VALLEYS/MOUNTAINS/DESERTS...MOSTLY CLEAR WITH VFR
CONDITIONS THROUGH EARLY SATURDAY.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH MONDAY.
BEACHES
FOR BEACHES AND HARBORS...SMALL WATER LEVEL FLUCTUATIONS WILL
CONTINUE PERIODICALLY FROM THE DIMINISHING TSUNAMI.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...SS
AVIATION/MARINE/BEACHES...WESTERINK
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