NWS Forecast Discussion
000 FXUS66 KSGX 242027 AFDSGX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 200 PM PDT FRI MAY 24 2013 .SYNOPSIS... DAYTIME TEMPERATURES WILL REMAIN SLIGHTLY BELOW SEASONAL AVERAGES THROUGH MEMORIAL DAY...WITH ONLY MINOR DAY-TO-DAY VARIATIONS. ONSHORE FLOW WITH GUSTY WINDS IN THE MOUNTAINS AND DESERTS WILL ALSO CONTINUE...ALONG WITH AREAS OF LOW CLOUDS EXTENDING INTO THE INLAND VALLEYS DURING THE NIGHTS AND MORNINGS. FOR TUESDAY THROUGH EARLY WEDNESDAY...INCREASING CLOUDS WITH EVEN LOWER TEMPERATURES AND A CHANCE FOR PRECIPITATION. DRY AND WARMER FOR WEDNESDAY AND THURSDAY WITH STRONGER NORTHWEST WINDS IN THE MOUNTAINS AND DESERTS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... SKIES ARE MOSTLY CLEAR THIS AFTERNOON...EXCEPT FOR A FEW PATCHES OF LOW CLOUDS OVER ORANGE COUNTY AS A COASTAL EDDY PERSISTS. SFC PRESSURE GRADIENTS REMAIN ONSHORE WITH +5.1 MB SAN-TPH. THROUGH MEMORIAL DAY...THE LARGE-SCALE LOW/TROUGH OVER THE WEST COAST WILL MAINTAIN THE ONSHORE FLOW FOR GUSTY WEST WINDS IN THE MTNS AND DESERTS. DAYTIME TEMPERATURES WILL CONTINUE TO BE A LITTLE BELOW SEASONAL AVERAGES...AND THE MARINE LAYER WILL REMAIN RELATIVELY DEEP WITH NIGHT AND MORNING LOW CLOUDS EXTENDING INTO THE INLAND VALLEYS. THE COASTAL EDDY WILL LIKELY PERSIST BUT COULD WEAKEN AT TIMES. SMALL DAY-TO-DAY VARIATIONS IN THE MARINE LAYER DEPTH ARE EXPECTED AS MINOR SHORTWAVES MOVE THROUGH THE MEAN CYCLONIC FLOW ALOFT. FOR LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...A STRONGER SHORTWAVE MOVING THROUGH THE NORTHWEST FLOW ALOFT...IS EXPECTED TO DEEPEN THE TROUGH...FORMING A CLOSED UPPER LOW OVER CENTRAL CA BY TUE MORNING. THE DETERMINISTIC MODELS STILL SHOW DIFFERENCES IN THE TIMING AND TRACK OF THE LOW AS IT MOVES EWD THROUGH TUESDAY NIGHT...AND THE INDIVIDUAL MODELS CONTINUE TO MAKE MINOR ADJUSTMENTS TO THEIR VARIOUS SOLUTIONS. HOWEVER...CONFIDENCE IS GROWING THAT THIS SYSTEM COULD PRODUCE RAIN AND SHOWERS LATE MON NIGHT THROUGH TUE NIGHT. PRELIMINARY RAINFALL ESTIMATES ARE FOR ONE TENTH TO ONE QUARTER INCH NEAR THE COAST AND ONE HALF TO ONE INCH IN THE MOUNTAINS. SNOW LEVELS ARE LIKELY TO REMAIN ABOVE 7500 FT...SO ONLY THE HIGHEST ELEVATIONS OF THE SAN BERNARDINO AND RIVERSIDE MTNS COULD SEE MODEST AMOUNTS OF SNOW. ONSHORE FLOW WILL LIKELY STRENGTHEN AND STRONG WEST WINDS COULD DEVELOP IN THE MTNS AND DESERTS...WITH GUSTS OF 45 MPH OR MORE POSSIBLE. DRY AND GRADUALLY WARMER FOR WED THROUGH FRI IN NW FLOW ALOFT AS THE TROUGH MOVES EAST AND HEIGHTS RISE OVER SOCAL. THIS WILL BRING GUSTY NW WINDS IN THE MTNS AND DESERTS AND A SHALLOWER MARINE LAYER. && .AVIATION... 242000Z...COAST/VALLEYS...AREAS OF FEW-SCT STRATUS WILL CONTINUE WEST OF THE MOUNTAINS WITH BASES 2500-3500 FT MSL AND TOPS TO 4000 FT MSL THROUGH LATE AFTERNOON. VIS WILL REMAIN P6SM. STRATUS RETURNING TONIGHT BETWEEN 25/0100-0400Z. A HIGHER PRESSURE ALOFT AND A WEAKER COASTAL EDDIE WILL LEAD TO A SLIGHTLY LOWER CLOUD TONIGHT. BASES BETWEEN 2500-3000 FT MSL AND TOPS NEAR 3500 FT MSL. VIS IS EXPECTED TO REMAIN ABV 5SM. STRATUS WILL ERODE BACK TO THE COAST BETWEEN 25/1500-1700Z. MTNS/DESERTS...WESTERLY WINDS GUSTING TO 35 KT WILL OCCUR OVER THE DESERT MTN SLOPES AND THROUGH/EAST OF SAN GORGONIO PASS LATE THIS AFTERNOON/EVENING. WINDS GUSTS TO 25 KT ELSEWHERE ACROSS THE LOWER DESERTS. OTHERWISE...MOSTLY CLEAR WITH UNRESTRICTED VIS THROUGH SATURDAY AFTERNOON. && .MARINE... ASTRONOMICAL HIGH TIDES TO 7.2 FEET AND BELOW NORMAL LOW TIDES...WITH SWINGS OF 8.9 FEET...WILL COMBINE WITH SLIGHTLY ABOVE NORMAL SURF TO BRING A SMALL CHANCE OF MINOR COASTAL FLOODING TODAY THROUGH MEMORIAL DAY. STRONG RIP CURRENTS WILL CONTINUE THROUGH MEMORIAL DAY...PARTLY DUE TO THE SWINGS IN THE TIDES. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...PG AVIATION/MARINE...JT
NWS SGX Office Area Forecast Discussion