NWS Forecast Discussion
000 FXUS66 KSGX 051705 AFDSGX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 900 AM PST SUN FEB 5 2012 .SYNOPSIS... HIGH PRESSURE ALOFT ALONG THE WEST COAST AND SURFACE HIGH PRESSURE OVER THE GREAT BASIN WILL BRING FAIR DRY WEATHER THROUGH MONDAY WITH GUSTY NORTHEAST WINDS NEAR THE COASTAL FOOTHILLS AT TIMES. PATCHY NIGHT AND MORNING LOW CLOUDS AND FOG MAY RETURN NEAR THE COAST BEGINNING TONIGHT. A PACIFIC LOW PRESSURE SYSTEM IS EXPECTED TO TRACK JUST OFF THE COAST OF SOUTHERN CALIFORNIA TUESDAY INTO EARLY WEDNESDAY...WITH BEST CHANCES OF PRECIPITATION OVER THE COASTAL WATERS AND COASTAL AREAS. DRY AND WARMER WITH OFFSHORE FLOW AND GUSTY NORTHEAST WINDS FOR THURSDAY INTO NEXT WEEKEND. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... SKIES WERE CLEAR THIS MORNING. THE 12Z KNKX SOUNDING SHOWS WEAK EAST WINDS IN THE LOW LEVELS AND WEAK WEST FLOW ALOFT. SURFACE PRESSURE GRADIENTS REMAIN OFFSHORE WITH ABOUT -4 MB SAN-DAG AND -1 MB SAN-IPL. ISOLATED GUSTY NORTHEAST WINDS CONTINUE THIS MORNING. A COUPLE OF THE WINDIEST SPOTS MAY BRIEFLY APPROACH ADVISORY CRITERIA...BUT OVERALL OFFSHORE WINDS WILL BE LIGHT. EXPECT WINDS TO WEAKEN TODAY AS PRESSURE GRADIENTS DECREASE...WITH LIGHT OFFSHORE WINDS CONTINUING INTO MONDAY MORNING. A WEAK RIDGE OF HIGH PRESSURE ALOFT WILL BRING FAIR AND DRY WEATHER AGAIN TODAY WITH HIGHS IN THE VALLEYS IN THE MID 70S. MINOR COOLING AND A RETURN OF ONSHORE FLOW MONDAY AFTERNOON AS A TROUGH OF LOW PRESSURE BEGINS TO APPROACH THE WEST COAST. PATCHY COASTAL LOW CLOUDS AND FOG MAY RETURN BY LATE TONIGHT INTO EARLY MONDAY MORNING...BECOMING MORE WIDESPREAD AND EXTENDING INTO THE FAR WESTERN VALLEYS FOR MONDAY NIGHT INTO TUESDAY. FOR TUESDAY INTO WEDNESDAY...A SHORT WAVE TROUGH WILL MOVE TOWARDS THE CENTRAL CALIFORNIA COAST. A CLOSED LOW FORMS AND DROPS SOUTH OFF THE COAST OF SOUTHERN CALIFORNIA BY TUESDAY EVENING...EVENTUALLY TRACKING EAST ACROSS BAJA CALIFORNIA ON WEDNESDAY. SUBSTANTIAL DIFFERENCES IN THE MODEL TRACK AND TIMING OF THE LOW PERSISTS. THE TRACK SLIGHTLY FARTHER TO THE WEST AND SOUTH OF THE ECMWF REMAINS PREFERRED. THIS WOULD KEEP THE BULK OF THE PRECIPITATION OVER THE COASTAL WATERS WITH SOME PRECIPITATION EXTENDING LOCALLY INLAND INTO SOUTHERN CALIFORNIA. THIS COULD BRING AMOUNTS OF ONE TENTH TO ONE QUARTER INCH FROM THE COAST INLAND TO THE MOUNTAINS FOR LATE TUESDAY THROUGH EARLY WEDNESDAY WITH AMOUNTS A LITTLE GREATER NEAR THE COAST AND FOR SOUTHERN AREAS. A TRACK A LITTLE FARTHER EAST COULD RESULT IN GREATER PRECIPITATION AMOUNTS. THE SNOW LEVEL WILL GENERALLY BE 5500 TO 6000 FEET. BASED ON THE CURRENT PROFFERED TRACK OF THE LOW ONLY AN INCH OR LESS OF SNOWFALL IS EXPECTED. AS THE LOW TRACKS ACROSS THE BAJA PENINSULA...HIGH PRESSURE ALOFT WILL REBUILD ALONG THE WEST COAST FOR THURSDAY AND FRIDAY. THIS WILL BRING A WARMING TREND FOR SOUTHWEST CALIFORNIA WITH SURFACE HIGH PRESSURE IN THE GREAT BASIN BRINGING GUSTY NORTHEAST WINDS NEAR THE COASTAL FOOTHILLS AT TIMES. TOWARD THE LATTER PART ON NEXT WEEKEND...ANOTHER LOW PRESSURE SYSTEM COULD MOVE THROUGH SOUTHERN CALIFORNIA. && .AVIATION... 051540Z...VFR CONDS WITH FEW CLDS AOA FL200 THROUGH ABOUT 06/0400 UTC. AFTER 06/0400 UTC...FOG/STRATUS WILL BE POSSIBLE ALONG COASTAL AREAS...INCLUDING KSAN KCRQ AND KSNA...WITH BASES 200-400 FT MSL AND AREAS OF VIS 1-3SM BR AND LOCAL VIS AOB 3/4SM BR/FG. CONFIDENCE LOW IN COVERAGE AND TIMING OF FOG/STRATUS. IF FOG/STRATUS DOES FORM...IT SHOULD CLEAR OUT BY 06/1700 UTC. STRATUS APPEARS TO BE MORE LIKELY MONDAY NIGHT. && .MARINE... A STORMY PATTERN WILL BE DEVELOPING OVER THE EASTERN NORTH PACIFIC THIS WEEK SENDING A SERIES OF LARGER WESTERLY SWELLS TOWARD THE CALIFORNIA COAST. SURF AND SWELL WILL BE INCREASING BY TUESDAY NIGHT... AND CONTINUE INTO NEXT WEEKEND. PERIODS OF HIGH SURF AND DANGEROUS RIP CURRENTS ARE LIKELY...ALONG WITH SEAS ABOVE TEN FEET IN THE COASTAL WATERS. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...SS AVIATION/MARINE...HARRISON
NWS SGX Office Area Forecast Discussion