FXUS66 KLOX 142115
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
215 PM PDT THU JUL 14 2005

.SHORT TERM...

ANOTHER HOT DAY ACROSS AREAS AWAY FROM THE COAST. TEMPS AT 2 PM ALREADY BETWEEN 103 AND 108 FROM THE SANTA CLARITA VALLEY THROUGH THE LOWER ELEVATIONS OF THE MOUNTAINS INTO THE DESERT AND ALSO THE INTERIOR VALLEY OF SAN LUIS OBISPO COUNTY. SOME COASTAL STRATUS STILL HUGGING THE COAST NORTH OF POINT CONCEPTION AND RANDOMLY FROM POINT MUGU TO PALOS VERDES. NO THUNDERSTORMS HAVE POPPED ANYWHERE NEAR US SO FAR...BUT WILL LEAVE IN THE VERY SMALL CHANCE INTO THE EVENING HOURS FOR THE SAN GABRIEL MOUNTAINS DUE TO THE SOUTHEAST

FLOW ALOFT...EXTREME...BUT ELEVATED INSTABILITY...AND A SMALL INCREASE IN 850 MB DEWPOINTS THIS AFTERNOON.

THE TRIPLE DIGIT HEAT WILL CONTINUE INLAND THROUGH THE SHORT RANGE...AS ONLY A MINOR DROP IN UPPER LEVEL HEIGHTS AND LOW-LEVEL THICKNESSES ARE FORECAST. IN FACT...THE 950 MB TEMPS ON THE NAM MODEL REMAIN BETWEEN 39 AND 40 DEGREES C ACROSS INTERIOR PORTIONS OF OUR CWA THROUGH SUNDAY. A WEAK EDDY CIRCULATION MAY HELP TO BRING A COUPLE DEGREES OF COOLING TO THE LOWER COASTAL VALLEYS AND INTERIOR COASTAL PLAIN LOCATIONS SATURDAY AND SUNDAY. BUT ALL IN ALL THE SLIGHT CHANGE IN DAY TO DAY MAX TEMPERATURES WILL NOT BE NOTICEABLE.

AFTERNOON HEAT INDEX VALUES GET CLOSE TO 105...BUT NOT QUITE HIGH ENOUGH TO WARRANT EXCESSIVE HEAT WARNING. WILL CONTINUE THE SPECIAL WEATHER STATEMENT TO ADDRESS THE CONTINUED HEAT. OVERNIGHT LOWS IN THE THERMAL BELT OF THE MOUNTAINS WILL NOT GET BELOW 80 DEGREES FOR THE NEXT FEW NIGHTS.

WHERE THE COASTAL STRATUS REACHES INTO THE VALLEYS...THE FOG WILL LIKELY BE LOCALLY DENSE EACH LATE NIGHT AND EARLY MORNING. ANOTHER WEAK VORT MAX ROTATING AROUND THE BASE OF THE UPPER LEVEL RIDGE AND OVER OUR AREA FRIDAY AFTERNOON...COINCIDENT WITH A FURTHER INCREASE IN 850 MB DEWPOINTS WILL BRING US A SLIGHTLY BETTER CHANCE OF SEEING AFTERNOON CONVECTION OVER THE VENTURA/LA COUNTY MOUNTAINS AND DESERT...BUT WILL STILL LIMIT THE PROBABILITY TO 20 PERCENT.



.LONG TERM...

AS A LARGE UPPER LEVEL TROUGH PASSES THROUGH THE NORTHERN TIER OF THE UNITED STATES SUNDAY...IT CAUSES THE UPPER LEVEL RIDGE OVER THE SW U.S. TO SQUIRT WEST AND DIRECTLY OVER US MONDAY AND TUESDAY. THIS WILL ONLY CONTINUE THE TRIPLE DIGIT HEAT INLAND AND EXPAND IT BACK THROUGH THE COASTAL VALLEYS. ONLY SOME SLIGHT RELIEF IS IN SIGHT FOR THE MIDDLE OF NEXT WEEK WHEN THE UPPER LEVEL RIDGE MOVES BACK TO THE EAST AND HEIGHTS DROP SOME OVER SRN CA.



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.AVIATION...

MID LEVEL MOISTURE STARTING TO AFFECT THE MARINE LAYER A BIT AND ESTIMATING THE TIME OF RETURN FOR LIFR CONDITIONS AND A CEILING AT KLAX WILL NOT BE EASY...SO AN INTERMEDIATE TIME OF ABOUT 05Z WAS CHOSEN IN THIS LOW CONFIDENCE SCENARIO. WHEN THE CEILINGS DO COME IN...THEY WILL LIKELY BE LOW AND THE VISIBILITY WILL LIKELY BECOME VERY LOW AT SOME POINT DURING THE OVERNIGHT HOURS. KLGB WILL RECEIVE THE SAME MARINE CLOUD TREATMENT AS KLAX A FEW HOURS LATER. ALL OTHER COASTAL TAF SITES WILL ALSO HAVE THE POTENTIAL TO SEE LOCALLY DENSE FOG AS THE MARINE LAYER CONTINUES AT UNDER 1 KFT.



&&



.LOX WATCHES/WARNINGS/ADVISORIES...

SMALL CRAFT ADVISORY (SEE LAXCWFLOX).

SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).



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PUBLIC...MOYER
AVIATION...SWEET