036
FXUS66 KSGX 210353
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
853 PM PDT SUN APR 20 2025
SYNOPSIS
DRY AND WARMER THROUGH EARLY WEEK WITH HIGH TEMPERATURES AROUND
OR SLIGHTLY ABOVE NORMAL MONDAY AND TUESDAY. GRADUAL COOLING
FOLLOWS WEDNESDAY THROUGH SATURDAY. MORNING LOW CLOUDS AND FOG
CONTINUING EACH DAY THROUGH NEXT WEEK, BECOMING MORE WIDESPREAD
TOWARDS THE MIDDLE OF THE WEEK AS THE MARINE LAYER DEEPENS.
AFTERNOON AND EVENING WINDS WILL STRENGTHEN SLIGHTLY ACROSS THE
MOUNTAINS AND DESERTS FOR THE LATTER HALF OF THE WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE
NO SIGNIFICANT UPDATES FROM THE PREVIOUS FORECAST PACKAGE. MILD
WEATHER EXPECTED BOTH TOMORROW AND TUESDAY WITH HIGHS NEAR TO
SLIGHTLY ABOVE NORMAL AND TYPICAL PATCHY MORNING FOG AND LOW
CLOUDS. FORECAST MODELS STILL INDICATE A SERIES OF SHORTWAVE
TROUGHS WILL MOVE ACROSS MID TO LATE WEEK, WITH COOLING
TEMPERATURES AND A DEEPENING MARINE LAYER PREVAILING INTO THE
WEEKEND. HIGHS FALL TO AROUND 5 DEGREES BELOW NORMAL FOR
EVERYWHERE WEST OF THE MOUNTAINS BY WEDNESDAY, AND WIDESPREAD
5-15 DEGREES BELOW NORMAL BY FRIDAY. SOME UNCERTAINTY REMAINS
WITH THE UPPER LEVEL PATTERN INTO THE WEEKEND AND ANY ASSOCIATED
PRECIPITATION CHANCES, BUT TRENDS CONTINUE TO FAVOR A DRIER
SOLUTION.
PREVIOUS DISCUSSION FROM 127 PM
SHORT TERM
BESIDES SOME VERY THIN CIRRUS (UPPER LEVEL CLOUDS), CLEAR SKIES
ARE PRESENT ACROSS THE REGION, WITH AFTERNOON HIGH TEMPERATURES
NEAR TO SLIGHTLY ABOVE AVERAGE. EXCELLENT WEATHER, IN THIS
FORECASTER'S OPINION, TO EAT FAR TOO MUCH CHOCOLATE. THE MARINE
CLOUD LAYER WILL REDEVELOP LATE THIS EVENING, LIKELY PATCHY AT
FIRST BEFORE BECOMING MORE WIDESPREAD IN THE SMALL HOURS OF MONDAY
MORNING. THESE CLOUDS WILL CLEAR MONDAY MORNING AT A SIMILAR TIME
TO THIS MORNING, FOLLOWED BY ANOTHER MOSTLY SUNNY DAY.
FOR THE NEXT WEEK, WEAKLY CYCLONIC FLOW WILL BE IN PLACE ALOFT,
WITH A SERIES OF WEAK SHORTWAVES BRINGING COOLING TEMPERATURES, A
DEEPENING MARINE LAYER, AND BRISKER AFTERNOON AND EVENING BREEZES
(MOSTLY IN THE MOUNTAINS AND DESERTS). MONDAY WILL SEE
TEMPERATURES SIMILAR TO TODAY, WITH SLIGHT COOLING ALONG THE COAST
AND SLIGHT WARMING FOR THE DESERTS, AND STRONGER AFTERNOON AND
EVENING BREEZES COMPARED TO TODAY IN THE MOUNTAINS AND DESERTS.
RINSE AND REPEAT TUESDAY WITH ANOTHER DEGREE OR TWO DROP IN HIGH
TEMPERATURES FOR THE COASTS AND VALLEYS, AND DEGREE OR TWO RISE
FOR THE MOUNTAINS AND DESERTS.
THE COOLING TREND THAT STARTED ALONG THE COAST WILL THEN SPREAD
INLAND FOR THE REST OF THE WEEK, WITH SLIGHTLY TO ABOUT 10 DEGREE
BELOW AVERAGE TEMPERATURES THROUGH MOST OF THE REGION BY THU-FRI.
MARINE LAYER LOW CLOUDS WILL GET PROGRESSIVELY DEEPER AND FURTHER
INLAND EACH NIGHT, WITH AREAS OF DRIZZLE UNDER THE MARINE LAYER
POSSIBLE (MOST LIKELY EARLY FRIDAY MORNING) BUT WITH OTHERWISE
VERY LIKELY DRY WEATHER. AFTERNOON AND EVENING BREEZES WILL
STRENGTHEN SLIGHTLY AGAIN IN THE MOUNTAINS AND DESERTS MID TO LATE
WEEK.
LONG TERM
SOME DEGREE OF LARGE-SCALE CYCLONIC FLOW CONTINUES TO BE LIKELY
FOR AT LEAST THE FIRST PART OF THE WEEKEND, MEANING COOLER
TEMPERATURES WOULD CONTINUE. GLOBAL ENSEMBLE MEMBERS ARE SPLIT ON
WHEN A LOW PRESSURE SYSTEM WILL MOVE INTO (AND OUT OF) THE GREAT
BASIN. THE EARLIER/FASTER TRACKING MODELS INDICATE RIDGING (AND
WARMING) STARTING SUNDAY, WHILE OTHERS INDICATE CONTINUED COOL
WEATHER WITH A DEEPER MARINE LAYER THROUGH THE WEEKEND AND PERHAPS
MONDAY. MODELS ARE IN BETTER AGREEMENT IN AT LEAST A WEAK RIDGE
WITH WARMER TEMPERATURES LOCALLY BY EARLY THE NEXT WEEK.
AVIATION
210330Z....COASTS/VALLEYS...BKN LOW CLOUDS WILL CONTINUE TO FILL IN
THIS EVENING WITH BASES NEAR 600-1200 FT MSL. LOW CLOUDS WILL MOVE
ABOUT 10 MILES INLAND OVERNIGHT. THERE IS A 15-20% CHANCE OF LOW
CLOUDS REACHING KONT, MOST LIKELY 13Z-16Z. OTHERWISE, SCT-BKN HIGH
CLOUDS OVERSPREADING THE REGION OVERNIGHT, LESS WIDESPREAD DURING
THE DAY MONDAY. LOCAL VIS RESTRICTIONS 2-4SM NEAR HIGHER COASTAL
TERRAIN AND IN THE VALLEYS. LOW CLOUDS AND VIS RESTRICTIONS EXPECTED
TO CLEAR TO THE BEACHES 16-18Z MON.
MOUNTAINS/DESERTS...SCT HIGH CLOUDS OVERNIGHT, LESS WIDESPREAD ON
MONDAY WITH UNRESTRICTED VIS THROUGH THE PERIOD.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH FRIDAY.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...ZUBER
AVIATION/MARINE...APR
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