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533
FXUS66 KSGX 251653
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
852 AM PST SUN JAN 25 2015

.SYNOPSIS...
HIGH PRESSURE ALOFT OVER NORTHERN AND CENTRAL CALIFORNIA WILL
CONTINUE WARMER WEATHER TODAY. SURFACE HIGH PRESSURE OVER THE GREAT
BASIN WILL BRING LOCALLY STRONG AND GUSTY NORTHEAST TO EAST WINDS
THIS MORNING...GRADUALLY DIMINISHING THIS EVENING. FOR MONDAY AND
EARLY TUESDAY...A WEAK LOW PRESSURE SYSTEM FROM THE SOUTHWEST WILL
BRING SHOWERS TO THE REGION...WITH BEST SHOWER ACTIVITY OCCURRING
OVER THE MOUNTAINS...LOWER DESERTS AND VALLEYS. A SECOND WEAK LOW
PRESSURE SYSTEM FROM THE SOUTHWEST COULD BRING PERIODS OF SHOWERS
FOR THURSDAY INTO THE WEEKEND.

&&

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

A WESTWARD DRIFTING CUT-OFF UPPER LEVEL LOW IS EVIDENT OFF THE COAST
OF CENTRAL BAJA ON WATER VAPOR SATELLITE IMAGERY THIS MORNING.
MEANWHILE AT THE SURFACE...OFFSHORE FLOW CONTINUES TO BRING STRONG
AND GUSTY NORTHEAST TO EAST TO THE MOUNTAIN
PASSES...CANYONS...COASTAL SLOPES AND FOOTHILLS...ALTHOUGH THE WINDS
ARE OVERALL WEAKER AND LESS WIDESPREAD THAN THEY WERE ON SATURDAY.
CURRENTLY WE ARE SEEING 50 MPH GUSTS AT SILL HILL IN THE SAN DIEGO
COUNTY MOUNTAINS...AND 45 MPH GUSTS AT FREMONT CANYON IN THE SANTA
ANA MOUNTAINS...47 MPH GUSTS AT POTRERO AND 43 MPH AT PLEASANTS
PEAK...AND 42 MPH GUSTS AT ALPINE. THE WINDS ARE WEAKER TODAY PARTLY
DUE TO DIMINISHED OFFSHORE PRESSURE GRADIENTS WHICH ARE NOW AT 15.3
MB FROM SAN DIEGO TO SALT LAKE CITY AND 6.7 MB FROM SAN DIEGO TO LAS
VEGAS...COMPARED TO 17.4 MB AND 8.0 MB RESPECTIVELY 24 HOURS AGO.
ALSO...THE 12Z MIRAMAR SOUNDING SHOWS WEAKER UPPER LEVEL SUPPORT AT
850 MB COMPARED TO THE PREVIOUS MORNING DOWN FROM 35 KT TO 25 KT.
HOWEVER...THE LOCAL WRF DOES SHOW AN INCREASE IN 850 MB WINDS UP TO
40-45 KT FROM THE EAST LATER THIS MORNING INTO THIS
AFTERNOON...WHICH COULD BRING ANOTHER INCREASE IN WINDS TO THE
NORTH-TO-SOUTH ORIENTED MOUNTAINS OF SAN DIEGO AND RIVERSIDE
COUNTIES FOR THAT TIME. THIS IS BACKED UP BY THE CANSAC WRF WHICH
SHOWS A BURST OF WINDS OVER THE SAN DIEGO COUNTY MOUNTAINS/FOOTHILLS
LATE THIS MORNING INTO EARLY THIS EVENING. CONSIDERING THIS...THE
HIGH WIND WARNING FOR THE SAN DIEGO COUNTY MOUNTAINS AND
VALLEYS...AND RIVERSIDE COUNTY MOUNTAINS...MAY NEED TO BE EXTENDED
BEYOND 2 PM TODAY. MEANWHILE...THE WIND ADVISORY FOR INLAND ORANGE
COUNTY...THE SANTA ANA MOUNTAINS/FOOTHILLS...INLAND EMPIRE AND SAN
BERNARDINO COUNTY MOUNTAINS MAY NEED TO BE EXTENDED AS WELL.

THE CONTINUED OFFSHORE FLOW AND AN UPPER LEVEL RIDGE OVER THE REGION
WILL BRING CONTINUED WARMING TODAY...AS DAY-TIME HIGHS REACH 5 TO 15
DEGREES ABOVE NORMAL. SKIES WILL GENERALLY BE CLEAR DUE TO THE
RIDGE...ALTHOUGH SOME WAVE CLOUDS PRODUCED BY THE STRONG EASTERLY
FLOW IN SAN DIEGO COUNTY MAY CONTINUE TO BRING PARTLY TO MOSTLY
CLOUDY SKIES OVER THE SAN DIEGO VALLEYS AND COASTAL AREAS THROUGH
THE AFTERNOON.

MODELS ARE IN GOOD AGREEMENT WITH BRINGING THE AFOREMENTIONED LOW
OFF THE COAST OF BAJA NORTH ON MONDAY AND INTO SOUTHERN AND CENTRAL
CALIFORNIA BY EARLY TUESDAY. MODELS ARE ALSO IN GOOD AGREEMENT WITH
ASSOCIATED DEEP MOISTURE MOVING IN FROM SOUTHEASTERLY FLOW ALOFT
MONDAY INTO EARLY TUESDAY...RESULTING IN WIDESPREAD SHOWERS/RAIN.
SHOWERS MAY START AS EARLY AS MONDAY MORNING...BUT THE LOW LEVELS
LOOK TO REMAIN DRY AT THAT POINT SO MOST OF THE RAIN MAY EVAPORATE
BEFORE REACHING THE GROUND AT LOW ELEVATIONS. THE WHOLE COLUMN
BECOMES MOIST BY LATE MONDAY AFTERNOON AND INTO LATE MONDAY
NIGHT...WHICH IS WHEN THE MODELS SHOW THE MOST ACTIVE TIME OF
PRECIPITATION OCCURRING. GFS AND NAM SHOW NEAR AN INCH OF
PRECIPITABLE WATER BEING ADVECTED INTO THE AREA AT THAT TIME. 850 MB
FLOW WILL BE PRETTY WEAK...SO OROGRAPHIC ENHANCEMENT OF RAINFALL
SHOULD NOT TOO SIGNIFICANT. NEVERTHELESS...HIGH-RES MODELS STILL
SHOW BEST PRECIPITATION OCCURRING IN THE MOUNTAINS...WITH
STORM-TOTAL OF 0.50 TO 1 INCHES FORECAST. HOWEVER...CANSAC WRF AND
NAM4 ACTUALLY SHOW SOME SPOTS IN THE MOUNTAINS GETTING 1.5 TO 2
INCHES TOTAL...SO QPF MAY NEED TO BE ADJUSTED. MODELS BRING DECENT
RAINFALL TO THE LOWER DESERTS COMPARED TO NORMAL DUE TO THE AXIS OF
BEST MOISTURE IN THE SOUTHEASTERLY FLOW ALOFT HITTING THOSE
AREAS...SO 0.25 INCHES TO LOCALLY 0.5 INCHES IN SOME LOCATIONS WILL
BE POSSIBLE. MEANWHILE...THE VALLEYS LOOK TO GET SIMILAR AMOUNTS TO
THE LOWER DESERTS...WHILE THE COAST AND HIGH DESERTS MAY ONLY SEE A
0.10 TO LOCALLY 0.25 INCHES. THE WARM NATURE OF THE SYSTEM WILL KEEP
SNOW LEVELS HIGH...AT AROUND 7500-8500 FEET DURING THE TIME OF
HEAVIEST PRECIPITATION. A FEW INCHES OF SNOW MAY FALL ABOVE THOSE
ELEVATIONS. INSTABILITY DOES NOT LOOK SIGNIFICANT AT THE
MOMENT...BUT WITH THE NAM12 SHOWING A VORT MAX MOVING THROUGH THE
AREA MONDAY NIGHT...WOULD NOT BE SURPRISED TO SEE A FEW LIGHTNING
STRIKES AND LOCALLY HEAVIER DOWNPOURS.

BY TUESDAY MORNING...MOST OF THE MOISTURE WILL HAVE MOVED NORTH OF
THE AREA AS THE TROUGH MOVES INLAND INTO CENTRAL CALIFORNIA. A
TRANSITORY RIDGE AND DRY WEATHER IS EXPECTED FOR WEDNESDAY...AND
THEN ANOTHER TROUGH WILL APPROACH THE COAST ON THURSDAY...MOVE INTO
SOUTHERN CALIFORNIA AND STRENGTHEN INTO A CLOSED LOW ON FRIDAY...AND
THEN MOVE SOUTH INTO CENTRAL BAJA SATURDAY AND SUNDAY. MODELS DIFFER
ON ON THE AMOUNT OF PRECIPITATION...BUT AS OF RIGHT NOW...LOOKS LIKE
WE WILL HAVE CHANCES FOR SHOWERS OVER THE REGION THURSDAY INTO NEXT
WEEKEND.

&&

.AVIATION...
251630Z...VFR WITH SCT-BKN CLOUDS BETWEEN 10000-25000 FT THROUGH
TONIGHT. GUSTY NORTHEAST TO EAST WINDS WILL CONTINUE ALONG THE
WESTERN SLOPES OF THE MOUNTAINS...BELOW THE PASSES AND CANYONS...AND
OVER PORTIONS OF THE INLAND EMPIRE. STRONGEST WINDS WILL OCCUR BELOW
THE BANNING PASS AND OVER THE SAN DIEGO COUNTY MOUNTAINS AND COASTAL
FOOTHILLS. MODERATE TO STRONG UDDFS AND LLWS ARE LIKELY WITH THESE
WINDS OVER AND SW/W OF THE MTNS...INCLUDING VCNTY
KONT...KCNO...KAJO...KRIV...AND KSNA. WINDS WILL WEAKEN SOMEWHAT
THROUGH THIS EVENING...BUT REMAIN OFFSHORE THROUGH MONDAY.

LOW PRESSURE OFF THE COAST OF BAJA WILL BRING LIGHT TO MODERATE
SHOWERS WITH HIGH ELEVATION SNOW FOR MONDAY AND MONDAY NIGHT...WITH
THE HIGHEST PRECIPITATION CHANCES/TOTALS OVER THE MOUNTAINS AND
DESERTS DURING THE PERIOD. MOUNTAIN OBSCURATIONS IN LOW CLOUDS ARE
POSSIBLE AFTER 26/12Z.

&&

.MARINE...
830 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH THURSDAY
EVENING.

&&

.BEACHES...
830 AM...A LONG-PERIOD WEST-NORTHWEST SWELL WILL GENERATE SURF OF
3-6 FEET WITH STRONG RIP CURRENTS THROUGH MONDAY. HIGHEST SURF WILL
BE ALONG WEST-FACING BEACHES NORTH OF NEWPORT BEACH...BETWEEN LAGUNA
BEACH AND SAN CLEMENTE...AND SOUTH OF DEL MAR. SWELL AND SURF WILL
GRADUALLY LOWER ON TUESDAY. A BEACH HAZARD STATEMENT IS IN EFFECT
THROUGH THIS EVENING.

&&

.FIRE WEATHER...
SURFACE HIGH PRESSURE OVER THE GREAT BASIN WILL CONTINUE TO BRING
LOCALLY STRONG AND GUSTY NORTHEAST TO EAST WINDS INTO THIS
MORNING...WITH WINDS STRONGEST IN SAN DIEGO COUNTY. WINDS WILL
DIMINISH LATE THIS AFTERNOON INTO THIS EVENING. DAY-TIME MINIMUM
HUMIDITIES IN THE LOW TEENS WILL CONTINUE FOR THE INLAND AREAS
TODAY. THE LOW HUMIDITIES COMBINED WITH THE GUSTY WINDS WILL BRING
NEAR CRITICAL FIRE WEATHER CONDITIONS THROUGH THIS AFTERNOON.
HUMIDITIES WILL START TO INCREASE TONIGHT INTO MONDAY AS A LOW
PRESSURE SYSTEM FROM THE SOUTH BRINGS MOISTURE AND RAINFALL TO THE
AREA...WITH WETTING RAINS LIKELY IN THE MOUNTAINS...DESERTS AND
VALLEYS INTO EARLY TUESDAY MORNING.

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH WIND WARNING UNTIL 2 PM PST THIS AFTERNOON FOR THE
     RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY MOUNTAINS...
     SAN DIEGO COUNTY VALLEYS.

     WIND ADVISORY UNTIL NOON PST TODAY FOR THE ORANGE COUNTY
     COASTAL AREAS...SAN BERNARDINO COUNTY MOUNTAINS...SAN
     BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND
     EMPIRE...SANTA ANA MOUNTAINS AND FOOTHILLS.

     BEACH HAZARDS STATEMENT UNTIL 6 PM PST THIS EVENING FOR THE
     BEACHES IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO
     COUNTY COASTAL AREAS.

PZ...NONE.

&&

$$

PUBLIC/FIRE WEATHER...HARRISON
AVIATION/MARINE/BEACHES...23






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