Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 230351
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
855 PM PDT WED OCT 22 2014

.SYNOPSIS...
HIGH PRESSURE BUILDING OVER THE SOUTHWEST WILL BRING WARM DAYS
THROUGH FRIDAY ALONG WITH A SHALLOW MARINE LAYER. ANY NIGHT AND
MORNING FOG WILL BE PATCHY AND LIMITED TO THE COAST. OVER THE
WEEKEND A TROUGH OF LOW PRESSURE MOVING INLAND OVER NORTHERN
CALIFORNIA WILL BRING SIGNIFICANT COOLING AND A MUCH DEEPER MARINE
LAYER. PATCHY DRIZZLE IS POSSIBLE WEST OF THE MOUNTAINS SUNDAY
MORNING. THE TROUGH WILL BE FOLLOWED BY MINOR WARMING AND A
SHALLOWER MARINE LAYER MONDAY AND TUESDAY.

&&

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

THE 5H RIDGE AXIS BUBBLED UP OVER SOUTHERN CALIFORNIA TODAY AND
BROUGHT SEVERAL DEGREES OF WARMING. COASTAL AND VALLEY HIGHS
WERE 4-7 DEGREES HIGHER THAN YESTERDAY...WHILE MTN AND DESERT TEMPS
WERE UNCHANGED. THE MARINE LAYER WAS AROUND 800 FEET DEEP ON THE 00Z
NKX SOUNDING. LOW CLOUDS WERE ABSENT THIS EVENING...BUT
TEMP-DEWPOINT SPREADS WILL BE SMALL AT THE COAST WHERE PATCHY LOW
CLOUDS AND FOG MAY FORM THE NEXT TWO NIGHTS.

THE RIDGE AXIS DRIFTS OVER THE LOWER COLORADO RIVER VALLEY THURSDAY.
BOUNDARY LAYER TEMPS INCREASE A DEGREE OF TWO WHICH WILL TRANSLATE
INTO A WARMER DAY THURSDAY.  THE FORECAST MAX TEMPS WERE RAISED
ACCORDINGLY. ON FRIDAY THE RIDGE MOVES EAST OVER NEW MEXICO BUT THE
BOUNDARY LAYER TEMPERATURES OVER SO-CAL DO NOT CHANGE MUCH. SO
FRIDAY LOOKS LIKE IT WILL BE AS WARM AS THURSDAY AND PERHAPS EVEN A
DEGREE OR TWO WARMER IN THE VALLEYS...MOUNTAINS AND DESERTS.

THIS WEEKEND...THE GFS...ECMWF...AND THEIR RESPECTIVE ENSEMBLES ARE
IN GOOD AGREEMENT. THUS WE CAN EXPECT THE RIDGE OVER THE SOUTHWEST
TO FLATTEN AND SHIFT EASTWARD IN RESPONSE TO A TROUGH PROPAGATING
INTO THE WEST COAST. THIS WILL BRING LOWER HEIGHTS AND A RETURN OF
ONSHORE FLOW BEGINNING ON SATURDAY. HIGH TEMPERATURES WILL FALL BY
5-10 DEGREES ON SATURDAY COMPARED TO FRIDAYS HIGHS...WITH AN
ADDITIONAL DECLINE OF 3-6 DEGREES LIKELY ON SUNDAY. A RAPID
DEEPENING OF THE MARINE LAYER SATURDAY NIGHT INTO SUNDAY HAS THE
POTENTIAL TO PRODUCE DRIZZLE WEST OF THE MOUNTAINS EARLY SUNDAY
MORNING. LIMITED CLEARING OF STRATUS WEST OF THE MOUNTAINS IS ALSO
LIKELY SUNDAY. FOR THE DESERTS...THE LARGEST TEMPERATURE SWING WILL
BE BETWEEN SATURDAY AND SUNDAY...AS HIGHS EAST OF THE MOUNTAINS
SHOULD BE MORE DEPENDENT ON HEIGHT FALLS THAT ARE MORE PRONOUNCED BY
SUNDAY.

NEXT WEEK...MODELS CONTINUE HAVE DIFFICULTY HANDLING THE
INTERACTION BETWEEN THE EXTRA-TROPICAL REMNANTS OF ANA AND A
NORTHERN STREAM SHORTWAVE MOVING INTO THE GULF OF ALASKA. THE
UNCERTAINTY IN THE DEVELOPMENT OF THESE TWO WAVES MAKES NEXT WEEKS
FORECAST TRICKY. HOWEVER...ENOUGH CONSENSUS APPEARS TO EXIST IN THE
DETERMINISTIC AND ENSEMBLE RUNS TO SUGGEST WEAK RIDGING OR ZONAL
FLOW FOR THE FIRST HALF OF NEXT WEEK. THIS WOULD RESULT IN NEAR
AVERAGE TEMPERATURES...AND NIGHT AND MORNING LOW CLOUDS FOR THE
COAST AND VALLEYS FOR MONDAY INTO WEDNESDAY.

&&

.AVIATION...
230400Z...COAST...PATCHY LOW STRATUS/FOG COULD OCCUR LATE
TONIGHT/EARLY THU WITHIN 5 MI OF THE COAST...MAINLY 09Z-15Z.
CONFIDENCE OF TIMING AT ALL COASTAL AIRPORTS IS LOW...BUT BKN
CEILINGS BELOW 600 FT MSL ARE POSSIBLE...INCLUDING AT KSAN. VIS
COULD BE LESS THAN 3 MI NEAR THE COAST...AND LOCALLY LESS THAN 1 MI
MAINLY OVER HIGHER COASTAL TERRAIN 09Z-15Z. THERE IS A SMALL CHANCE
THAT KSAN COULD HAVE VIS BELOW 2 MI THEN. VFR CONDITIONS SHOULD
PREVAIL AFTER 15Z THU...CONTINUING THROUGH AT LEAST THU EVENING.

VALLEYS/MOUNTAINS/DESERTS...SCT CLOUDS ABOVE 20000 FT MSL AND
UNRESTRICTED VIS WILL CONTINUE THROUGH THU NIGHT.

&&

.MARINE...
900 PM...THERE IS A CHANCE OF PATCHY DENSE FOG AND VISIBILITIES OF
ONE MILE OR LESS OVER THE COASTAL WATERS LATE TONIGHT AND EARLY
THURSDAY...AND POSSIBLY AGAIN LATE THURSDAY NIGHT AND FRIDAY
MORNING. OTHERWISE...NO HAZARDOUS MARINE WEATHER CONDITIONS ARE
EXPECTED THROUGH MONDAY.

&&

.BEACHES...
900 PM...SURF FROM THE WEST-NORTHWEST SWELL WILL GRADUALLY DECREASE
THROUGH THURSDAY...WITH MOST SURF BELOW 5 FEET BY THURSDAY AFTERNOON.

&&

.SKYWARN...
SKYWARN ACTIVATION WILL NOT BE NEEDED THURSDAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC SHORT RANGE...MOEDE
PUBLIC LONG RANGE...BA
AVIATION/MARINE/BEACHES...MAXWELL









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