000
FXUS66 KSGX 051711
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1000 AM PDT SUN AUG 5 2018

.SYNOPSIS...
HIGH PRESSURE ALOFT WILL STRENGTHEN MONDAY AND TUESDAY AND BRING 
VERY HOT WEATHER TO MOST INLAND LOCATIONS. AN INCREASE IN THE 
EASTERLY FLOW WILL BRING SOME MOISTURE BACK TO SOUTHERN CALIFORNIA 
STARTING WEDNESDAY AND BRING SLIGHT CHANCES OF THUNDERSTORMS TO THE 
MOUNTAINS AND DESERTS THROUGH NEXT WEEKEND. ONSHORE FLOW AND A 
SHALLOW MARINE LAYER WILL BRING PATCHY COASTAL LOW CLOUDS TONIGHT 
AND EARLY MONDAY, THEN AGAIN NEXT WEEKEND.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

STRATUS HAS CLEARED TO THE BEACHES, WITH SUNNY SKIES OVER LAND AT 
MID-MORNING. THE NKX SOUNDING THIS MORNING WAS RELATIVELY UNCHANGED 
FROM SATURDAY EXCEPT THAT TEMPERATURES LOWERED A BIT BELOW THE 1000-
FOOT DEEP MARINE INVERSION, WHICH WAS REFLECTED BY THE TEMPERATURES 
THIS MORNING NEAR THE COAST. OVERALL, HIGH TEMPERATURES TODAY WILL 
BE SIMILAR TO THOSE SATURDAY, EXCEPT FOR THE SLIGHT COOLING AT THE 
COAST.

THE HIGH PRESSURE SYSTEM CENTERED OVER THE AZ/NM BORDER WILL 
CONTINUE TO EXPAND, INCLUDING OVER SOCAL, WITH RISING HEIGHTS AND 
TEMPERATURES ALOFT MONDAY. MODELS HAVE BEEN FAIRLY CONSISTENT WITH 
28-30 DEG C TEMPS AT 850 MB, AND WEAK ONSHORE FLOW FROM THE COASTAL 
WATERS TO THE CONVERGENCE AREA OVER THE MOUNTAIN CRESTS DEVELOPING 
EACH DAY. THE ONSHORE FLOW WILL MODERATE TEMPS NEAR THE COAST BUT 
WILL ONLY HAVE A SLIGHT EFFECT IN THE VALLEYS WHERE TEMPS COULD 
REACH AS HIGH AS AROUND 110-112 IN HOTTEST PARTS OF THE INLAND 
EMPIRE. LOWER DESERTS ARE ALREADY VERY HOT AND WILL PROBABLY ONLY 
ADD A DEGREE OR TWO MON/TUE VERSUS THE WEEKEND MAX TEMPS. THE 
EXCESSIVE HEAT WATCH WILL BE UPGRADED TO AN EXCESSIVE HEAT WARNING 
FOR MON/TUE FOR PARTS OF THE AREA, THOUGH WITH EXPECTED TEMPS MORE 
IN THE 97-103 RANGE IN THE SAN DIEGO COUNTY VALLEYS, A HEAT ADVISORY 
IS LIKELY TO BE ISSUED THERE. LOCAL WRF SHOWS LINGERING MARINE LAYER 
MOISTURE THROUGH MONDAY MORNING, WHICH WILL BRING COASTAL 
STRATUS/FOG LATE TONIGHT/EARLY MONDAY, AND WITH A SHALLOWER MARINE 
LAYER, THERE COULD BE SOME DENSE FOG OVER HIGHER COASTAL TERRAIN. 
STRATUS/FOG LOOKS UNLIKELY MONDAY NIGHT/TUESDAY AND PROBABLY WILL BE 
PATCHY AT BEST AFTER THAT UNTIL NEXT WEEKEND.

MODEL PROFILES AND MOS CONTINUE TO SHOW ABOUT 5 DEGREES OF COOLING 
WEDNESDAY, PARTLY DUE TO MONSOONAL MOISTURE FROM THE SOUTHEAST, 
WHICH COULD PRODUCE A FEW AFTERNOON/EARLY EVENING THUNDERSTORMS OVER 
THE MOUNTAINS AND DESERTS. ALSO, STRONGER ONSHORE FLOW WILL DEVELOP, 
WHICH WILL ASSIST WITH COOLING WEST OF THE MOUNTAINS. HOWEVER, TEMPS 
WILL REMAIN GENERALLY 5-10 DEG F ABOVE NORMAL MOST OF THE SECOND 
HALF OF THE WEEK, WITH SOME FURTHER COOLING NEXT WEEKEND. MODELS 
CONTINUE TO HAVE TROPICAL DEPRESSION 11, LIKELY COUPLED WITH ANOTHER 
TROPICAL SYSTEM, MOVING NORTHWEST OFF THE BAJA CALIFORNIA WEST COAST 
NEXT WEEKEND, BUT THIS APPEARS UNLIKELY TO ADD EXTRA MOISTURE OVER 
SO-CAL, THOUGH THAT COULD CHANGE IF THE TRACK ENDS UP FARTHER 
EAST/NORTHEAST.

&&

.AVIATION... 
051530Z...COAST/VALLEYS...AREAS OF LOW CLOUDS REMAIN AT THIS HOUR, 
WITH BASES 800-1100 FT MSL AND TOPS TO 1400 FT MSL. LOW CLOUDS 
SHOULD BE MOSTLY SCT BY 18Z BUT PATCHES COULD LINGER AT THE BEACHES 
INTO THE AFTERNOON. LOW CLOUDS INCREASING IN COVERAGE ALONG THE 
COAST AFTER 06Z MONDAY, WITH BASES 500-1000 FT MSL. OTHERWISE CLEAR 
WITH UNRESTRICTED VIS THROUGH MONDAY MORNING.

MOUNTAINS/DESERTS...MOSTLY CLEAR SKIES WITH UNRESTRICTED VISIBILITY 
THROUGH MONDAY.

&&

.MARINE...
NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH THURSDAY.

&&

.FIRE WEATHER...
INLAND DRYING WILL CONTINUE THROUGH MONDAY WITH LOWEST DAYTIME 
HUMIDITIES OF 5 TO 10 PERCENT TODAY IN THE MOUNTAINS AND DESERTS, 
SPREADING INTO THE INLAND VALLEYS ON MONDAY. THERE MAY BE SOME 
SLIGHT RECOVERY FOR THESE AREAS ON TUESDAY WITH A GREATER RECOVERY 
WEDNESDAY THROUGH NEXT WEEKEND AS SOME MONSOONAL MOISTURE RETURNS 
AND ONSHORE FLOW STRENGTHENS A LITTLE. THE LOW HUMIDITIES COMBINED 
WITH GUSTY SOUTHWEST TO WINDS TO 30 MPH WILL CAUSE NEAR CRITICAL 
FIRE WEATHER CONDITIONS THIS AFTERNOON AND EVENING FROM THE MOUNTAIN 
RIDGE TOPS INTO THE DESERT. THE HIGHEST TEMPERATURES FOR THE WEEK 
ARE EXPECTED ON MONDAY AND TUESDAY, BUT ABOVE AVERAGE TEMPERATURES 
ARE EXPECTED TO CONTINUE INTO NEXT WEEKEND.

&&

.SKYWARN... 
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...EXCESSIVE HEAT WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING 
     FOR APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-ORANGE 
     COUNTY INLAND AREAS-RIVERSIDE COUNTY MOUNTAINS-SAN 
     BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE 
     COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS-
     SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SAN 
     GORGONIO PASS NEAR BANNING-SANTA ANA MOUNTAINS AND 
     FOOTHILLS.

PZ...NONE.

&&

$$

PUBLIC/FIRE WEATHER...MAXWELL
AVIATION/MARINE...PG

  US Dept of Commerce
  National Oceanic and Atmospheric Administration
  National Weather Service
  1325 East West Highway
  Silver Spring, MD 20910
  Page Author: NWSChat Administration Team
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy  
Freedom of Information Act (FOIA)  
About Us  
Career Opportunities