644
FXUS66 KSGX 171700
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
900 AM PST TUE DEC 17 2024
SYNOPSIS
WARMER THROUGH THE MIDDLE OF THIS WEEK WITH WEAK TO MODERATE
STRENGTH SANTA ANA WINDS PEAKING FOR TONIGHT INTO WEDNESDAY
MORNING. THEN GRADUALLY COOLER THROUGH THE WEEKEND, BUT WITH
SUNDAY HIGH TEMPERATURES STILL AS MUCH AS 8 TO 12 DEGREES ABOVE
AVERAGE FOR THE MOUNTAINS, DESERTS, AND INLAND VALLEYS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MORNING UPDATE
HIGH CLOUDS CONTINUE TO STREAM OVER THE REGION THIS MORNING AS AN
AREA OF MOISTURE ACROSS NORTHERN CALIFORNIA LIFTS FURTHER NORTH
AND EAST. AS IT DOES SO, A RIDGE OFF THE PACIFIC WILL STRENGTHEN
TODAY KNOCKING OUR TEMPERATURES A FEW DEGREES HIGHER THAN
YESTERDAY ACROSS THE REGION. 60S WILL ARRIVE THIS AFTERNOON FOR
THE HIGH DESERT, PORTIONS OF THE MOUNTAINS AND THE BEACHES WITH
70S FOR VALLEY REGIONS.
SANTA ANA WINDS HAVE BEGUN FOR AREAS NEAR THE CAJON PASS THIS
MORNING WITH LOCAL GUSTS OVER 35 MPH. THE FORECAST REMAINS ON
TRACK FOR THESE WINDS TO PEAK OVERNIGHT LOCALLY OVER 50 MPH IN
WIND PRONE AREAS. ELEVATED FIRE WEATHER CONDITIONS WILL CONTINUE
ACROSS THE REGION THROUGH TODAY INTO WEDNESDAY AFTERNOON; PLEASE
SEE THE FIRE WEATHER DISCUSSION BELOW FOR FURTHER DETAILS. WEDNESDAY
WILL ALSO BE THE WARMEST DAY OVER THE NEXT WEEK FOR MANY, WHERE
NBM SHOWS NEAR A 20-50% CHANCE OF SOME INLAND VALLEYS REACHING 85
DEGREES.
PREVIOUS DISCUSSION (307 AM TUESDAY)...
SHORT TERM (TODAY THROUGH THURSDAY)
OFFSHORE FLOW AND HIGH PRESSURE ALOFT WILL BRING WARMING FOR TODAY
AND WEDNESDAY. WEDNESDAY WILL BE THE WARMEST DAY FOR THE COAST
AND WESTERN VALLEYS WITH WEDNESDAY AND THURSDAY THE WARMEST DAYS
FOR INLAND AREAS. WITH THE WARMING, HIGH TEMPERATURES ON WEDNESDAY
FOR THE VALLEYS AND INLAND COASTAL AREAS WILL BE AS MUCH AS 15 TO
20 DEGREES ABOVE AVERAGE, INTO THE LOWER TO MID 80S FOR PORTIONS
OF THOSE AREAS.
GUSTY NORTHERLY SANTA ANA WINDS WILL SPREAD INTO PORTIONS OF
ORANGE AND SOUTHWESTERN SAN BERNARDINO COUNTIES THIS AFTERNOON,
THEN SPREAD SOUTHWARD INTO PORTIONS OF RIVERSIDE AND SAN DIEGO
COUNTIES FOR THIS EVENING AS THE THE WINDS BECOME MORE
NORTHEASTERLY. THE WINDS WILL CONTINUE INTO WEDNESDAY MORNING,
THEN GRADUALLY WEAKEN FOR WEDNESDAY AFTERNOON AND EVENING.
THE STRONGER GUSTS ALONG AND BELOW THE COASTAL SLOPES OF THE SAN
BERNARDINO COUNTY MOUNTAINS AND ALONG AND BELOW THE COASTAL SLOPES
OF THE SANTA ANA MOUNTAINS ARE EXPECTED TO REACH 40 TO 50 MPH,
WITH THE STRONGER GUSTS ALONG AND BELOW THE COASTAL SLOPES OF THE
MOUNTAINS IN RIVERSIDE AND SAN DIEGO COUNTIES TO 30 TO 40 MPH.
LONG TERM (FRIDAY THROUGH MONDAY)
HIGH PRESSURE ALOFT WILL REMAIN ACROSS SOUTHERN CALIFORNIA THROUGH
THE WEEKEND WITH LOW PRESSURE SYSTEMS MOVING INLAND TO THE NORTH
BRINGING GENERALLY WEAK ONSHORE FLOW TO SOUTHERN CALIFORNIA. THIS
WILL SPREAD COOLING INLAND THROUGH THE WEEKEND, BUT WITH SUNDAY
HIGH TEMPERATURES STILL AROUND 8 TO 12 DEGREES ABOVE AVERAGE FOR
THE MOUNTAINS, DESERTS, AND INLAND VALLEYS, MOSTLY IN THE LOWER TO
MID 70S FOR THE INLAND VALLEYS AND AROUND 80 FOR THE LOWER
DESERTS.
SOME TIME AROUND THE EARLY TO MIDDLE PART OF NEXT WEEK, A LOW
PRESSURE SYSTEM MOVING QUICKLY INLAND THROUGH CALIFORNIA COULD
BRING SOME GUSTY SOUTHWEST TO WEST WINDS TO THE MOUNTAINS AND
DESERTS AND A CHANCE FOR MOSTLY LIGHT PRECIPITATION. NBM DAILY
CHANCES FOR MEASURABLE PRECIPITATION ARE MOSTLY LESS THAN 25
PERCENT AND HIGHEST ON TUESDAY.
AVIATION
171630Z....COASTS/VALLEYS...VARIABLE HIGH CLOUDS THROUGH TOMORROW.
STRONGER OFFSHORE FLOW OVERNIGHT AND LLWS FOR AREAS WEST OF THE
MOUNTAINS VCNTY KONT, KSBD AND KSNA AFTER 18Z TODAY. LOW CLOUDS
DEVELOP OFFSHORE TONIGHT WITH BASES NEAR 600FT MSL, BUT ARE UNLIKELY
TO MOVE INLAND WITH ONLY A 5-10% CHANCE OF A CIG AT KSAN FOR
WEDNESDAY MORNING.
MOUNTAINS/DESERTS
NORTHEAST TO EAST WINDS GUSTING 25-35 KTS WITH
WEAK TO MODERATE UP/DOWNDRAFTS OVER THE MOUNTAINS. BLDU POSSIBLE AND
MAY BRIEFLY REDUCE VIS DOWN TO 3SM. STRONGER SURFACE WINDS THROUGH
MOUNTAIN PASSES.
MARINE
NO HAZARDOUS MARINE WEATHER CONDITIONS ARE EXPECTED THROUGH
SATURDAY.
FIRE WEATHER...
GUSTY NORTHERLY SANTA ANA WINDS WILL SPREAD INTO PORTIONS OF
ORANGE AND SOUTHWESTERN SAN BERNARDINO COUNTIES THIS AFTERNOON,
THEN SPREAD SOUTHWARD INTO PORTIONS OF RIVERSIDE AND SAN DIEGO
COUNTIES FOR THIS EVENING AS THE THE WINDS BECOME MORE
NORTHEASTERLY. THE WINDS WILL CONTINUE INTO WEDNESDAY MORNING,
THEN GRADUALLY WEAKEN FOR WEDNESDAY AFTERNOON AND EVENING.
THE STRONGER GUSTS ALONG AND BELOW THE COASTAL SLOPES OF THE SAN
BERNARDINO COUNTY MOUNTAINS AND ALONG AND BELOW THE COASTAL SLOPES
OF THE SANTA ANA MOUNTAINS ARE EXPECTED TO REACH 40 TO 50 MPH,
WITH THE STRONGER GUSTS ALONG AND BELOW THE COASTAL SLOPES OF THE
MOUNTAINS IN RIVERSIDE AND SAN DIEGO COUNTIES TO 30 TO 40 MPH.
THE LOWEST HUMIDITY ON WEDNESDAY FOR THE VALLEYS, INLAND COASTAL
AREAS, AND COASTAL SLOPES OF THE MOUNTAINS WILL FALL TO 10 TO 15
PERCENT. ONLY ISOLATED AREAS IN EITHER TIME OR SPACE MIGHT
BRIEFLY REACH RED FLAG CRITERIA FOR WEDNESDAY AFTERNOON WITH THE
MOST LIKELY LOCATIONS FOR THAT TO OCCUR BEING IN THE INLAND
EMPIRE BELOW THE CAJON PASS AND BANNING PASS.
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...APR/17
AVIATION/MARINE...ZUBER
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