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
