246
FXUS66 KSGX 161822
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1022 AM PST SUN FEB 16 2025
SYNOPSIS
DRY WEATHER IS EXPECTED THROUGH THE WEEK. WEAK OFFSHORE FLOW AND
HIGH PRESSURE WILL BRING WARMER WEATHER TODAY. A BRIEF COOLING
TREND IS EXPECTED MONDAY AND TUESDAY WITH INCREASED ONSHORE FLOW,
THEN MINOR WARMING AND ANOTHER ROUND OF WEAK OFFSHORE FLOW FOR THE
MIDDLE TO LATTER PART OF NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE: THERE WILL BE A RESURGENCE OF THE MARINE LAYER BY LATER
THIS EVENING AND THROUGH TONIGHT WITH THE RETURN OF ONSHORE FLOW
AND THE FORMATION OF A WEAK COASTAL EDDY GOING INTO THE EARLY
MORNING HOURS TOMORROW JUST NORTH OF CATALINA ISLAND AND THEN
DROPPING SOUTHWARD. DUE TO THIS, THERE COULD ALSO BE SOME PATCHY
AREAS OF FOG DEVELOPING ALONG SOME OF THE COASTAL AREAS AS BASES
WILL BE GENERALLY AROUND 700 TO 1500 FEET MSL.
LATEST MODEL GUIDANCE KEEPS A MAJOR SHORTWAVE TROUGH MOVING TO THE
NORTH OF THE REGION FROM MONDAY THROUGH TUESDAY. THIS WILL NOT ONLY
RESULT IN A COOLING TREND THROUGH THE MID PART OF THE WORK WEEK
(WITH THE EXCEPTION OF THE DESERTS), BUT ALSO ALLOW FOR SOME
THICKENING OF THE MARINE LAYER WITH DRIZZLE BEING POSSIBLE DUE TO
THE FORMATION OF ANOTHER MORE WELL-PRONOUNCED COASTAL EDDY. IN
ADDITION, THERE WILL BE INCREASING WINDS FOR THE MOUNTAINS AND
DESERTS BY LATER IN THE EVENING ON MONDAY THROUGH TUESDAY MORNING,
WITH GUSTS FROM 40 TO 50 MPH BEING POSSIBLE ACROSS SOME OF THE
HIGHER TERRAIN.
LOOKING BEYOND TUESDAY, THERE LOOKS TO BE A FURTHER DRYING AND
WARMING TREND TOWARDS THE END OF THE WEEK AND INTO NEXT WEEKEND
AS THE RIDGE REMAINS IN PLACE. MODELS HAVE ALSO TRENDED TOWARDS
ANOTHER SHORTWAVE TROUGH PASSING TO THE NORTHEAST ON THURSDAY,
WHICH WILL ALLOW FOR SOME WEAK OFFSHORE WINDS IN ITS WAKE ON
FRIDAY.
(PREVIOUS DISCUSSION SUBMITTED AT 219 AM):
SCATTERED HIGH CLOUDS CONTINUE TO MOVE ACROSS THE REGION OVER THE
TOP OF AN UPPER LEVEL RIDGE TO OUR SOUTHWEST. WEAK OFFSHORE FLOW
TODAY WILL MAINTAIN WARMER AND DRY WEATHER, DESPITE THE RIDGE
FLATTENING IN RESPONSE TO AN UPPER LEVEL TROUGH MOVING INLAND
ACROSS THE PAC NW. HIGHS TODAY WILL BE AROUND 3-8 DEGREES ABOVE
NORMAL.
ONSHORE FLOW WILL RETURN BY THIS AFTERNOON, STRENGTHENING INTO
MONDAY AS THE TROUGH ALONG THE WEST COAST AMPLIFIES SLIGHTLY IN
RESPONSE TO SEVERAL SHORT WAVES MOVING INLAND TO OUR NORTH. THIS
WILL RESULT IN MINOR COOLING FOR MOST AREAS, WITH A FEW DEGREES OF
WARMING ACROSS THE LOW DESERTS. BREEZY WEST WINDS WILL DEVELOP
ACROSS THE DESERT MOUNTAIN SLOPES, DESERTS, AND BLOW THE PASSES
MONDAY AFTERNOON AND EVENING WHEN PEAK GUSTS OF 30-40 MPH ARE
EXPECTED. MARINE LAYER LOW CLOUDS MAY DEVELOP NEAR THE COASTAL
AREAS AS EARLY AS TONIGHT, THOUGH COVERAGE MAY BE PATCHY WITH A
CONTINUATION OF HIGH CLOUDS MOVING OVER THE REGION. A DEEPER, MORE
ORGANIZED MARINE LAYER IS EXPECTED MONDAY NIGHT INTO TUESDAY WITH
LOW CLOUDS EXTENDING INTO THE INLAND VALLEYS. AROUND 20% OFF THE
EPS MEMBERS HAVE LIGHT PRECIPITATION TUESDAY MORNING WITH LITTLE
ACCUMULATION, THOUGH THE GEFS IS DECIDEDLY DRY. MIGHT HAVE SOME
PATCHY MARINE LAYER DRIZZLE AT BEST, AND THAT IS OUR ONLY CHANCE
OF PRECIPITATION THE ENTIRE WEEK.
SURFACE PRESSURE GRADIENTS QUICKLY TURN OFFSHORE BY LATE
TUESDAY MORNING AS THE UPPER TROUGH PROGRESSES INLAND FOR SOME
LOCALLY BREEZY NORTH WINDS THROUGH THE PASSES. COLD AIR ADVECTION
FROM THE NORTH WILL RESULT IN MINOR COOLING IN THE MOUNTAINS AND
DESERTS, WITH LITTLE CHANGE IN THE COASTAL AREAS AND VALLEYS. WEAK
UPPER RIDGING BEGINS TO MOVE IN FROM THE WEST ON WEDNESDAY FOR
CONTINUED WARMING AND A RETURN OF ONSHORE FLOW. BEYOND THURSDAY,
ENSEMBLE SOLUTIONS VARY WITH THE TRACK OF THE NEXT SET OF UPPER
LEVEL TROUGHS THAT MOVE THROUGH THE PAC NW AND SOMEWHERE INTO THE
GREAT BASIN/DESERT SOUTHWEST. THIS WILL HAVE IMPLICATIONS ON HOW
STRONG ANY OFFSHORE FLOW IS AS WELL AS HOW MUCH WARMING WE'LL SEE.
FOR THURSDAY, ONLY 27% OF THE MEMBERS BRING THE WAVE FAR ENOUGH
SOUTH AND WEST FOR RELATIVELY STRONGER (WEAK TO MODERATE) SANTA
ANA WINDS YET COOLER WEATHER HERE, WHILE THE REMAINING 73% WOULD
RESULT IN WARMER AND LESS BREEZY WEATHER. THIS CONTINUES INTO
FRIDAY, WHEN ABOUT 45% OF THE MEMBERS KEEP A TROUGH SOMEWHERE
AROUND THE SOUTHWEST (STRONGER OFFSHORE FLOW AND COOLER), WHILE
THE REST HAVE A RIDGE BUILDING IN (WARMER AND LESS WINDY). BY
SATURDAY, THE WARMER SOLUTIONS ARE THE VAST MAJORITY, WHILE ONLY
15% MAINTAIN THE TROUGHING/COOLER PATTERN, SIMILAR TO THE
DETERMINISTIC GFS. NBM MAINTAINS COOLER WEATHER WITH HIGHS NEAR
NORMAL THROUGH FRIDAY, FOLLOWED BY MORE SIGNIFICANT WARMING NEXT
WEEKEND AS THE RIDGE BECOMES THE MORE DOMINANT SOLUTION.
AVIATION
161000Z...HIGH CLOUDS AT/ABOVE 20,000FT MSL WILL CONTINUE TO STREAM
OVERHEAD IN FROM THE NORTHWEST THROUGH THE DAY WITH VFR CONDITIONS
PREVAILING THROUGH THIS EVENING. THE MARINE LAYER LOOKS TO SLOWLY
REBUILD BEGINNING TONIGHT, ALBEIT CLOUDS SHOULD BE QUITE PATCHY.
THERE IS ABOUT A 20-40% CHANCE OF SEEING CIGS FROM THESE CLOUDS
BETWEEN 09-15Z MONDAY MORNING. IF CIGS DO OCCUR, BASES WILL BE
QUITE LOW, AROUND 500-1000FT MSL, AND WOULD BE ACCOMPANIED BY PATCHY
FOG WHICH MAY REDUCE VIS TO 2-4 SM ALONG THE COASTS.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE ANTICIPATED THROUGH THURSDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
UPDATE: STEWEY
PUBLIC...SS
AVIATION/MARINE...MUNYAN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page