AREA FORECAST DISCUSSION

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
200 PM PDT SUN AUG 22 2010

.SYNOPSIS...
HIGH PRESSURE ALOFT WILL BUILD THIS WEEK AND CONTINUE TO BRING FAIR
WEATHER WITH SEASONAL TEMPERATURES. MONSOON MOISTURE WILL BRING
CUMULUS CLOUDS OVER THE MOUNTAINS IN THE AFTERNOONS...BUT ANY
THUNDERSTORMS ARE LIKELY TO REMAIN TO THE SOUTH AND EAST. A SHALLOW
MARINE LAYER AND ONSHORE FLOW WILL BRING PATCHY LOW CLOUDS AND FOG
AT THE COAST.

&&

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

THE MARINE LAYER IS STILL ABOUT 1000 FEET DEEP...BUT THE LOW CLOUDS
REMAIN WELL OFF THE COAST TO THE WEST AND ARE NOT LIKELY TO RETURN
TO THE COASTAL AREAS TONIGHT. CUMULUS CLOUDS HAVE FORMED OVER THE
LOCAL MTNS THIS AFTERNOON...BUT ARE UNLIKELY TO DEVELOP INTO TSTMS
DUE TO SUBSIDENCE ALOFT. THE DEEP CONVECTION IS EXPECTED TO REMAIN
TO THE SOUTH AND EAST WHERE THERE IS GREATER INSTABILITY.

AN UPPER LEVEL LOW PRESSURE TROUGH TO THE NORTH WILL WEAKEN AND MOVE
TO THE NE TONIGHT. THIS WILL ALLOW THE HIGH PRESSURE RIDGE TO BUILD
OVER SOCAL INTO FRIDAY...BRINGING WARMER CONDITIONS AND LIMITING THE
MARINE LAYER INFLUENCE TO THE IMMEDIATE COAST. TEMPERATURES AT THE
COAST WILL CONTINUE NEAR SEASONAL AVERAGES WHILE INLAND WILL BE
ABOVE SEASONAL AVERAGES. MID LEVEL MOISTURE IN SE FLOW WILL BRING
CUMULUS CLOUDS OVER THE MTNS DURING THE AFTERNOONS...BUT SUBSIDENCE
ALOFT WILL INHIBIT THE DEVELOPMENT OF DEEP CONVECTION.

BY NEXT WEEKEND...ANOTHER LOW PRESSURE TROUGH MOVES OVER THE WEST
COAST...PUSHING THE HIGH PRESSURE RIDGE OFF TO THE EAST AND BRINGING
COOLER CONDITIONS WITH INCREASING MARINE LAYER.

&&