025  
FXUS66 KSGX 171107  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
307 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...  
   
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
 
 
171030Z....VARIABLE HIGH CLOUDS TODAY AND TONIGHT.  
 
NEAR COAST...PATCHY LOW CLOUDS WITH BASES 500-900 FEET MSL ARE  
POSSIBLE THROUGH 15Z, 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.  
 

 
   
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/FIRE WEATHER...17  
AVIATION/MARINE...MM  
 
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