767
FXUS66 KSGX 170534
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
934 PM PST MON DEC 16 2024
SYNOPSIS
FAIR AND WARMER WEATHER WILL PREVAIL THIS WEEK WITH THE WARMEST DAYS
WEDNESDAY AND THURSDAY. WEAK TO MODERATE SANTA ANA WINDS WILL
DEVELOP TUESDAY AND CONTINUE THROUGH WEDNESDAY, WITH WEAKER WINDS
THURSDAY THROUGH SATURDAY. A COOLING TREND WILL OCCUR FRIDAY
THROUGH SUNDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
NO SIGNIFICANT CHANGES TO THE FORECAST THIS EVENING AS HIGH CLOUDS
MOVE OVER THE AREA. A MID WEEK SANTA ANA LIKE EVENT IS STILL
EXPECTED, BUT THE INTENSITY OF IT WILL NOT BE AS WIDESPREAD AS THE
PREVIOUS EVENT.
PREVIOUS DISCUSSION FROM 1:30 PM DECEMBER 16TH 2024...
SKIES WERE MOSTLY SUNNY EXCEPT FOR A FEW HIGH CLOUDS AT EARLY
AFTERNOON. AFTER A CHILLY START THIS MORNING, TEMPERATURES WERE IN
THE UPPER 60S TO MID 70S WEST OF THE MOUNTAINS AND MOSTLY MID 70S IN
THE LOWER DESERTS. BOUNDARY LAYER MOISTURE INCREASES SOMEWHAT NEAR
THE COAST OVERNIGHT WHICH COULD LEAD TO PATCHY LOW CLOUDS AND FOG
NEAR THE IMMEDIATE COAST/COASTAL WATERS, BUT NOTHING WIDESPREAD.
A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE PAC NW AND NORTHERN
CALIFORNIA THE REST OF TODAY, BUT DRY ZONAL FLOW WILL PREVAIL IN
SOUTHERN CALIFORNIA. THE TROUGH WILL RAPIDLY MOVE EAST TO THE
NORTHERN/CENTRAL ROCKIES AND PLAINS TUESDAY AND DEEPEN, WHILE A
RIDGE WILL DEVELOP OVER THE WEST COAST. OFFSHORE FLOW WILL DEVELOP,
MOSTLY DRIVEN BY A DISTANT SURFACE HIGH OVER THE ID/WY BORDER, WITH
UP TO 20 MB MSLP GRADIENT TO SAN DIEGO. THIS, COMBINED WITH MODERATE
COLD AIR ADVECTION AROUND 850 MB WILL BRING MODERATE NORTHEASTERLY
WINDS TO THE REGION. THIS WILL BE PRIMARILY AN MSLP GRADIENT DRIVEN
WIND SO MOUNTAIN WAVE ACTIVITY WILL BE MORE LIMITED. PEAK GUSTS
SHOULD BE 35-50 MPH IN MOST OF THE WINDIER AREAS, SUCH AS FROM CAJON
PASS SOUTH THROUGH A RIBBON OF THE INLAND EMPIRE AND TO THE SANTA
ANA MOUNTAINS, PLUS A FEW LOCATIONS ON THE WESTERN SLOPES OF THE SAN
DIEGO COUNTY MOUNTAINS. HUMIDITY WILL BE LOW MOST OF THIS WEEK, WITH
LOWEST HUMIDITY 10-20 PERCENT WEDNESDAY.
THE UPPER HIGH WILL SHIFT EAST TO THE ROCKIES/PLAINS LATE IN THE
WEEK WITH A BROAD DEEP TROUGH OVER THE NE PACIFIC. THAT TROUGH WILL
BRING PRECIPITATION TO MUCH OF THE WEST COAST, BUT AGAIN WE WILL BE
TOO FAR SOUTH WITH THIS ROUND. REGARDLESS, WE WILL HAVE A GRADUAL
COOLING TREND FRIDAY-SUNDAY. LONGER-TERM GUIDANCE FOR THE WEEK OF
XMAS HAS THE STORM TRACK MOSTLY STAYING TO OUR NORTH, BUT AROUND 30-
40% OF ENSEMBLE MEMBERS HAVE AT LEAST A SMALL AMOUNT OF PRECIP IN
OUR AREA AROUND XMAS.
AVIATION
170515Z....COASTS/VALLEYS...MOSTLY CLEAR WITH UNRESTRICTED VIS
THROUGH LATE TONIGHT. PATCHY LOW CLOUDS WITH BASES 500-900FT MSL
POSSIBLE OVER THE NEARSHORE WATERS 07Z-09Z, BUT BUT CIG IMPACTS ARE
UNLIKELY AT COASTAL TAF SITES.
NORTHEAST TO EAST WINDS GUSTING 25-35 KTS WITH WEAK TO MODERATE
UP/DOWNDRAFTS AND LLWS OVER AND WEST OF THE MTNS, VCNTY KONT, KSBD
AND KSNA AFTER 17Z.
MOUNTAINS/DESERTS...SCT-BKN CLOUDS AT OR ABOVE 25,000 FT MSL WITH
UNRESTRICTED VIS THROUGH TUESDAY AFTERNOON.
MARINE
NORTHWEST WINDS WITH ISOLATED GUSTS 20-25 KTS NEAR SAN CLEMENTE
ISLAND, TAPERING OFF TUESDAY MORNING. OTHERWISE, NO HAZARDOUS MARINE
WEATHER EXPECTED THROUGH SATURDAY.
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...SUK
AVIATION/MARINE...PG
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