000
FXUS66 KSGX 171625
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
925 AM PDT SAT AUG 17 2019

.SYNOPSIS...
COOLER WEATHER THIS WEEKEND WILL TURN VERY HOT INLAND NEXT WEEK 
AS HIGH PRESSURE BUILDS OVER THE SOUTHWEST. AT THE SAME TIME, 
COASTAL LOW CLOUDS MAKING AN APPEARANCE IN THE VALLEYS DURING 
NIGHTS AND MORNINGS WILL RETREAT TO THE COAST.

&&

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

LOW PRESSURE ALOFT FINALLY MADE ITS PRESENCE FELT AT THE SURFACE
OVERNIGHT AS THE MARINE LAYER DEEPENED CONSIDERABLY. A MARINE
LAYER THAT WAS AROUND 1200 FEET DEEP FRIDAY MORNING QUICKLY
DEEPENED TO ABOUT 2200 FEET THIS MORNING. THAT ALLOWED LOW CLOUDS
TO MOVE AS FAR INLAND AS SAN BERNARDINO AND HEMET, AND NEARLY 
FILL THE ENTIRE COASTAL BASIN. TODAY WILL BE MOSTLY SUNNY AS MANY
OF THOSE CLOUDS HAVE ALREADY CLEARED. A SIMILAR MARINE LAYER AND 
LOW CLOUD COVERAGE IS EXPECTED TONIGHT INTO SUNDAY. THE LOW 
PRESSURE ALOFT WILL LIFT OUT AND HIGH PRESSURE FROM THE EAST WILL 
GRADUALLY PRESS DOWN OVER THE SOUTHWEST. THAT WILL BRING US A 
NOTABLE WARMING TREND STARTING MONDAY THAT WILL PEAK IN A HEAT 
WAVE WEDNESDAY AND THURSDAY VERY SIMILAR TO THE ONE WE HAD THIS 
PAST WEEK. HIGH TEMPERATURES THIS WEEKEND WILL COME IN BELOW 
AVERAGE, BUT WILL CLIMB ABOVE AVERAGE INLAND BY TUESDAY AND 5-10 
DEGREES ABOVE AVERAGE ON WEDNESDAY AND THURSDAY, THE PROJECTED 
HOTTEST DAYS. THE HIGH PRESSURE ALOFT WEAKENS EVER SO SLIGHTLY 
THURSDAY INTO NEXT WEEKEND. TEMPS WILL BEGIN A MODEST DECREASE, 
ALTHOUGH IT WILL STILL BE PLENTY HOT INLAND. MONSOON MOISTURE 
BEGINS TO SHOW ITSELF TOWARD NEXT WEEKEND, BUT NOTHING TO REALLY 
FORECAST ABOUT YET.

&&

.AVIATION...
171530Z...COAST/VALLEYS...AT 15Z, WIDESPREAD LOW CLOUDS WITH BASES 
AROUND 1500 FT MSL AND TOPS TO 2500 FT MSL, EXTENDING UP TO 30 MI 
INLAND AFFECTING ALL TAF SITES WEST OF THE MTNS. LOCAL VIS 1-3 MILES 
WHERE CLOUDS AND TERRAIN INTERSECT. EXPECT CLEARING AT KONT AND KSBD 
AROUND 16Z, AND AT COASTAL TAF SITES BETWEEN 17Z AND 18Z. LOW CLOUDS 
LIKELY RETURNING TO COASTAL TAF SITES BETWEEN 03Z AND 06Z WITH BKN-
OVC BASES AROUND 1500 FT MSL AND TOPS TO 2500 FT MSL, SPREADING UP 
TO 30 MILES INLAND OVERNIGHT. CIGS AND REDUCED VIS COULD REACH KONT 
AND KSBD BETWEEN 12Z AND 15Z SUNDAY.

MOUNTAINS/DESERTS...SCT CLOUDS AT OR ABV 20000 FT MSL AND 
UNRESTRICTED VIS THROUGH SUNDAY. W WINDS GUSTING 25-40 KT OVER MTN 
CRESTS AND THROUGH PASSES, PRODUCING WEAK TO MDT UP/DOWNDRAFTS AND 
LLWS OVER AND EAST OF THE MTNS BETWEEN 19Z SAT AND 12Z SUN. NO 
IMPACTS EXPECTED AT KPSP AND KTRM.

&&

.MARINE... 
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH WEDNESDAY. 

&&

.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 TUESDAY MORNING THROUGH THURSDAY 
     EVENING FOR APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-SAN 
     DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR BANNING.

PZ...NONE.

&&

$$

PUBLIC...MM
AVIATION/MARINE...PG

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