591
FXUS66 KSGX 051158
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
458 AM PDT SUN APR 5 2026
SYNOPSIS
WARM AND DRY TODAY. TEMPERATURES WILL FLUCTUATE A FEW DEGREES
EACH DAY THROUGH WEDNESDAY, REMAINING AROUND 5 TO 10 DEGREES ABOVE
NORMAL. PATCHY FOG IS POSSIBLE THIS MORNING ALONG THE COAST,
FOLLOWED BY MORE WIDESPREAD NIGHT AND MORNING LOW CLOUDS THE
REMAINDER OF THE WEEK. MUCH COOLER WITH INCREASING CHANCES OF
PRECIPITATION AND GUSTY ONSHORE WINDS THURSDAY THROUGH SATURDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..AVIATION/MARINE DISCUSSION UPDATED
SURFACE DEW POINTS HAVE INCREASED INTO THE MID 50S ALONG PARTS OF
THE COAST THIS MORNING, BUT SO FAR NO FOG DEVELOPMENT IS EVIDENT
ON SATELLITE IMAGERY. SURFACE PRESSURE GRADIENTS ARE VERY WEAKLY
OFFSHORE, AROUND -0.2 MB SAN-DAG, AND TRENDING ONSHORE, WHICH MAY
ALLOW FOR PATCHY FOG TO FORM ALONG THE COAST LATER THIS MORNING.
OTHERWISE SCATTERED HIGH CLOUDS TO OUR SOUTHWEST WILL BEGIN TO
SPREAD INTO THE REGION LATER THIS AFTERNOON. WITH THE RETURN OF
ONSHORE FLOW, SOME COOLING WILL OCCUR WEST OF THE MOUNTAINS TODAY
WITH MINOR WARMING IN THE DESERTS. HIGH TEMPERATURES WILL BE
AROUND 10 DEGREES ABOVE NORMAL ACROSS MUCH OF THE AREA - IN THE
80S IN THE VALLEYS AND HIGH DESERT AND 90S IN THE LOW DESERT.
THE UPPER LEVEL RIDGE WILL CONTINUE TO SHIFT EAST AND BREAK DOWN
ON MONDAY WITH A WEAK SHORT WAVE TROUGH MOVING ACROSS SO CAL. THIS
IS FOLLOWED BY WEAK TRANSITORY RIDGING ON TUESDAY, WHICH WEAKENS
ON WEDNESDAY. MINOR DAILY FLUCTUATIONS IN TEMPERATURES WILL OCCUR
WITH HIGHS AROUND 5-10 DEGREES ABOVE NORMAL. MORE PERSISTENT
ONSHORE FLOW WILL ALLOW THE MARINE LAYER TO BECOME MORE
ESTABLISHED, WITH MORE WIDESPREAD LOW CLOUDS AND FOG ACROSS THE
COASTAL AREAS AND WESTERN VALLEYS EACH NIGHT AND MORNING,
POTENTIALLY EXTENDING INTO THE FAR WEST AND SOUTHERN PARTS OF THE
INLAND EMPIRE BY WEDNESDAY MORNING.
THERE IS STILL A LOT OF UNCERTAINTY IN THE TIMING OF THE UPPER
TROUGH LATER IN THE WEEK, THOUGH ENSEMBLE CONSENSUS HAS TRENDED
SLOWER WITH ITS ARRIVAL. AROUND 26% OF THE ENSEMBLE SPACE,
COMPRISED MOSTLY OF THE GEFS, IS FASTER WITH THE EASTWARD
PROGRESSION OF THE UPPER LOW, BRINGING IN LIGHT PRECIPITATION AS
EARLY AS THURSDAY. BY FRIDAY, ALL ENSEMBLE MEMBERS HAVE THE LOW IN
A POSITION THAT WOULD BRING US PRECIPITATION, THOUGH AGAIN THE
GEFS WITH ITS FASTER TRACK WOULD PUT THE BULK OF THE PRECIPITATION
ON FRIDAY, WHILE THE SLOWER EC AND CANADIAN ENSEMBLES ARE FOCUSED
MORE AROUND LATE FRIDAY INTO SATURDAY. THERE REMAINS CONSIDERABLE
SPREAD IN PRECIPITATION AMOUNTS AS WELL. NBM MEAN ACCUMULATIONS
FOR THE 48 HR PERIOD FROM 5 AM FRIDAY THROUGH 5 AM SUNDAY HAS
AROUND 0.25-0.50 INCH FOR THE MOUNTAINS WESTWARD WITH LOCAL
AMOUNTS NEAR 0.75 INCH ON THE COASTAL SLOPES, AROUND 0.10-0.20
INCH FOR THE HIGH DESERT, AND LESS THAN 0.10 INCH IN THE LOW
DESERT. NBM SNOW LEVEL RANGES FROM AROUND 7000-8000 FT FRIDAY AND
SATURDAY. IN ADDITION TO PRECIPITATION, GUSTY SOUTHWEST TO WEST
WINDS AND MUCH COOLER CONDITIONS ARE EXPECTED LATE IN THE WEEK
WITH HIGH TEMPERATURES AROUND 5 TO 10 DEGREES BELOW NORMAL BY
SATURDAY.
AVIATION
051200Z...GENERALLY VFR WITH INCREASING CLOUDS AOA 15K FT TODAY. LOW
CHANCE (20%) FOR LOW CLOUDS 400-800 FT MSL TO BRIEFLY IMPACT COASTAL
SITES THROUGH 15Z THIS MORNING, BUT HIGHER CONFIDENCE IS IN
CONTINUED VFR CONDITIONS AS WEAK OFFSHORE WINDS KEEP CONDITIONS DRY.
HIGHER CONFIDENCE IN MORE WIDESPREAD LOW CLOUDS 800-1200 FT MSL
SPREADING INLAND TONIGHT AFTER 08Z, VIS RESTRICTIONS 2-5 SM OVER
HIGHER VALLEY TERRAIN.
MARINE
NO HAZARDOUS MARINE CONDITIONS EXPECTED THROUGH THURSDAY. WINDS AND
SEAS MAY INCREASE LATE WEEK DUE TO AN INCOMING WEATHER SYSTEM. LOW
CONFIDENCE IN DETAILS AT THIS POINT.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...SS
AVIATION/MARINE...CSP
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