000
FXUS66 KSGX 080348
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
845 PM PDT SUN SEP 7 2008

.SYNOPSIS...
A LOW PRESSURE TROUGH OVER NORTHERN CALIFORNIA WILL SLOWLY WORK ITS 
WAY SOUTHWARD ALONG THE COAST THIS WEEK. THE MARINE LAYER WILL 
DEEPEN...THE COASTAL CLOUDS WILL BECOME MORE EXTENSIVE...AND IT WILL 
BE NOT QUITE AT HOT THE MIDDLE OF THE WEEK.  

&&

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

HIGH BASED AND LOW TOPPED CUMULUS TODAY WERE NOT TALL ENOUGH TO 
PRODUCE RAIN THIS AFTERNOON. BUT THEY DID PRODUCE GUSTY DOWNDRAFT 
WINDS AS THEY DRIFTED OVER IMPERIAL COUNTY. OUR THUNDERSTORM CHANCES 
IN THE MOUNTAINS REMAIN LOW MONDAY AS THE MID LEVEL MOISTURE 
DECREASES IN CONCERT WITH WEAKER SOUTHEASTERLY 700 MB WINDS. 

THE REST OF THE WEEK WE WILL BE PROGRESSIVELY MORE INFLUENCED BY A 
LONGWAVE TROUGH CURRENTLY OVER NORTHERN CALIFORNIA MOVING DOWN THE 
COAST. LOWER HTS AND STRONG ONSHORE GRADIENTS WILL BRING SLIGHT 
COOLING TUESDAY THROUGH THE END OF THE WEEK.

IN THE LONG TERM...THE MODEL OUTPUT FROM THE GFS...THE ECMWF...AND 
EVEN THE NAM12 DAMPENS OUR CHANCES OF A CLOSED LOW FORMING OFF THE 
COAST NEXT WEEKEND. ALL THREE MODELS FORECAST THE LONG WAVE TROUGH 
TO POWER ITS WAY ACROSS SOUTHERN CAL FRIDAY AND SATURDAY...BRINGING 
DRIER NORTHWESTERLY WINDS ALOFT. THIS SCENARIO WOULD ADVECT ALL THE 
SUBTROPICAL MOISTURE FROM TROPICAL STORM "LOWELL" INTO ARIZONA AND 
NEW MEXICO. BUT SINCE THE LONG RANGE MODEL SOLUTIONS HAVE FLUCTUATED 
DRASTICALLY FROM RUN TO RUN...THIS IS A LONG RANGE FORECAST IN 
LIMBO. 

&&

.AVIATION...080300Z
MARINE LAYER DEPTH BASED ON 00Z NKX SOUNDING WAS AROUND 1600 FEET. 
MARINE LAYER SHOULD DEEPEN ONLY SLIGHTLY TONIGHT WITH FURTHER 
DEEPENING EXPECTED MONDAY NIGHT. LOW CLOUDS ARE FILLING IN OVER THE 
COASTAL WATERS AND ARE ALREADY MOVING INTO SOME COASTAL 
LOCATIONS...WITH BASES AROUND 1000 FEET. COASTAL AIRPORTS SHOULD GET 
CEILINGS BY 05Z AND INLAND VALLEY AREAS BETWEEN 07Z AND 10Z. STRATUS 
IS NOT EXPECTED TO REACH KONT TONIGHT. BREAK UP ON MONDAY SHOULD BE 
BETWEEN 16Z AND 18Z.

ABOVE THE MARINE LAYER...DEBRIS CLOUDS FROM AFTERNOON CONVECTION 
OVER THE MTNS WILL LINGER FOR A FEW HOURS TONIGHT...OTHERWISE A 
MOSTLY CLEAR SKY WITH UNRESTRICTED VISIBILITIES WILL CONTINUE 
THROUGH MONDAY. ISOLATED CONVECTION IS POSSIBLE OVER THE MTNS AGAIN 
ON MONDAY AFTERNOON.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC...MOEDE
AVIATION/MARINE...PG