Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 051023
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
323 AM PDT WED AUG 5 2015

.SYNOPSIS...

HIGH PRESSURE ALOFT WILL BRING ANOTHER HOT DAY FOR INLAND
LOCATIONS TODAY...WHILE THE SEA BREEZE MODERATES TEMPERATURES
ALONG THE COAST. LOW PRESSURE OFF THE CALIFORNIA COAST WILL MOVE
INLAND THIS WEEKEND...BRINGING COOLER WEATHER THURSDAY THROUGH
SATURDAY... WITH INCREASING COASTAL CLOUDS DURING THE NIGHTS AND
MORNINGS. THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS THURSDAY
FOR JUST ABOUT ANY LOCATION ACROSS THE REGION. HIGHER PRESSURE
RETURNS NEXT WEEK FOR ANOTHER MODEST WARMING TREND AND LESS
COASTAL CLOUDS.

&&

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

THE MARINE INVERSION HAS WEAKENED OVER THE LAST 24 HOURS AS HIGH
PRESSURE STRENGTHENS OVER THE REGION. SCATTERED STRATUS NEAR THE
COAST...AND THIN HIGH CLOUDS PASSING OVER ORANGE COUNTY AND INTO
RIVERSIDE AND SAN BERNARDINO COUNTIES THIS MORNING...OTHERWISE IT
WILL BE MOSTLY CLEAR TODAY OVER OUR AREA.

TODAY WILL BE THE HOTTEST DAY DURING OUR RECENT "MINI-HEATWAVE"
OVER THE INLAND REGIONS. UPPER HIGH PRESSURE WILL STRENGTHEN TO
ABOUT 596 DM OVER THE DESERT SW. THE HEAT ADVISORY CONTINUES FOR
THE LOWER DESERT ELEVATIONS OF SAN DIEGO AND RIVERSIDE COUNTIES
THROUGH THIS EVENING WHERE TEMPERATURES WILL BE ABOUT 10 DEGREES
ABOVE NORMAL.

LATE TONIGHT ALL OF THE HI RES SHORT TERM MODELS BRING A WEAK
EASTERN WAVE NORTH FROM BAJA MEXICO WITH A BAND OF ELEVATED
INSTABILITY AND SOME MID LEVEL MOISTURE. ALTHOUGH THE MODELS ARE
IN AGREEMENT TO DEVELOP THIS FEATURE AND THEN MOVE IT NORTH OVER
OUR AREA ON THURSDAY...WE HAVE LOW CONFIDENCE IN TIMING AND
GEOGRAPHIC COVERAGE DUE TO SOME DISAGREEMENTS IN THE FINER
DETAILS. FOR NOW WE HAVE INDICATED A SLIGHT CHANCE OF
THUNDERSTORMS JUST ABOUT EVERYWHERE FROM LATE TONIGHT THROUGH
THURSDAY AFTERNOON. ELEVATED CONVECTION COULD AT LEAST INITIALLY
CONTAIN MAINLY DRY LIGHTNING BEFORE THE LOWER LEVELS HAVE A CHANCE
TO MOISTEN UP...THEREFORE WILL ADD A HEADLINE TO THE FIRE WEATHER
FORECAST FOR ISOLATED DRY LIGHTNING...ALTHOUGH COVERAGE IS NOT
EXPECTED TO BE SIGNIFICANT ENOUGH TO ISSUE A RFW ATTM.

THE UPPER LEVEL WAVE WILL MOVE NORTH LATE THURSDAY OF OUR REGION
AND LIKELY MERGE OR AT LEAST BECOME ASSOCIATED WITH THE LARGER AND
DEEPER TROUGH MOVING ACROSS NORTHERN CALIFORNIA AND INTO NORTHERN
NEVADA THROUGH FRIDAY. PROGRESSIVE FLOW INTO CALIFORNIA WILL
CONTINUE THROUGH THE WEEKEND AND WILL CONTRIBUTE TO MODERATELY
STRONG ONSHORE FLOW WHICH WILL BRING A COOLING TREND ACROSS OUR
REGION THROUGH THE WEEKEND. MARINE INFLUENCE WILL LIKELY BE NOTED
ACROSS MUCH OF THE VALLEYS AS A RESULT OF THE STRONGER ONSHORE
FLOW.

EARLY TO MID NEXT WEEK INLAND HIGH PRESSURE WILL STRENGTHEN ALOFT
AS THE SUBTROPICAL HIGH BUILDS WEST FROM TEXAS ONCE AGAIN. EXPECT
TO SEE ANOTHER GRADUAL TEMPERATURE INCREASE THROUGH MID NEXT WEEK
FOR INLAND LOCATIONS AS A RESULT AND A WEAKENING OF THE MARINE
INFLUENCE EXCEPT FOR MORE IMMEDIATE COASTAL SECTORS.

&&

.AVIATION...
050935Z... COAST/VALLEYS...VERY FEW LOW CLOUDS PRESENT THIS MORNING.
THERE IS THE POTENTIAL FOR BRIEF CIGS 900-1200 FT AT THE COASTAL
AIRPORTS BETWEEN 11-15Z...BUT CONFIDENCE IS LOW. PATCHY LOW CLOUDS
WITH BASES NEAR 1000-1500 FT MSL DEVELOPING AFTER 06/06Z UP TO 15-20
SM INLAND. OTHERWISE VARIABLE CLOUDS AOA FL150 THROUGH THU MORNING.
THERE IS A SLIGHT CHC OF SHOWERS AND THUNDERSTORMS BEGINNING LATE
TONIGHT AND CONTINUING INTO THU.

MTNS/DESERTS...VARIABLE CLOUDS AOA FL150 AND UNRESTRICTED VIS THROUGH
THU MORNING. THERE IS A SLIGHT CHC OF SHOWERS AND THUNDERSTORMS
BEGINNING LATE TONIGHT AND CONTINUING INTO THU.

&&

.MARINE...
240 AM...WINDS HAVE DECREASED THIS MORNING...BUT WILL STRENGTHEN
AGAIN THIS AFTERNOON AND EVENING. WEST-NORTHWEST WIND GUSTS 20-25 KT
WILL DEVELOP OVER PORTIONS OF THE OUTER COASTAL WATERS DURING THIS
PERIOD. THE SMALL CRAFT ADVISORY OVER THE OUTER WATERS REMAINS IN
EFFECT UNTIL 3 AM THURSDAY. NO OTHER HAZARDOUS MARINE WEATHER IS
EXPECTED THU MORNING THROUGH SUN.

&&

.BEACHES...
245 AM...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS AT
THE BEACHES BEGINNING LATE TONIGHT IN SOUTHERN SAN DIEGO COUNTY AND
SPREADING NORTH INTO ORANGE COUNTY BE THU MORNING. LIGHTNING WILL
POSE A THREAT TO BEACH GOERS SHOULD ANY THUNDERSTORMS DEVELOP. THE
THUNDERSTORM THREAT SHOULD END BY THURSDAY EVENING AS MOISTURE AND
INSTABILITY LIFTS NORTH OUT OF SOUTHERN CA.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR COACHELLA VALLEY-
     SAN DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR BANNING.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 AM PDT THURSDAY FOR
     WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING
     30 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.

&&

$$

PUBLIC...BROTHERTON
AVIATION/MARINE...SS


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