Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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000
FXUS66 KMTR 261630
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
930 AM PDT SUN APR 26 2015

.SYNOPSIS...HIGH PRESSURE WILL PRODUCE WARM AND DRY CONDITIONS
TODAY THROUGH MONDAY. SLIGHT COOLING WILL OCCUR BY THE MIDDLE
OF THE WEEK AS A DRY UPPER TROUGH DEVELOPS OVER NORTHERN
CALIFORNIA.

&&

.DISCUSSION...AS OF 9:30 AM PDT SUNDAY...NICE SUNDAY AFTERNOON ON
TAP FOR THE BAY AREA WITH SUNNY SKIES AND TEMPERATURES WARMING
INTO THE 70S AWAY FROM THE COAST WHICH WILL REPRESENT A NICE
WARMING TREND COMPARED TO SATURDAY. HIGH PRESSURE WILL CONTINUE TO
BUILD IN TONIGHT KEEPING SKIES MOSTLY CLEAR AS A DRY NORTHERLY
GRADIENT SETS UP.

EXPECT SOME NORTH TO NORTHEAST WINDS BY MONDAY MORNING ACROSS THE
THE NORTH AND EAST BAY HILLS WHICH WILL SET THE STAGE FOR SOME
DOWNSLOPE WARMING WITH TEMPERATURES WARMING INTO THE 80S BY MONDAY
AFTERNOON FOR MANY INLAND AREAS..WITH COMFORTABLE UPPER 60S AND
70S NEAR THE COAST AND BAYS.

THE RIDGE WILL BREAK DOWN AND BY TUESDAY AFTERNOON WINDS WILL TURN
BACK TO ONSHORE BRINGING A COOLING TREND BACK TO THE COAST.
SEASONABLE BUT DRY WEATHER THEN CONTINUES THE REST OF THE WORK
WEEK WITH NO SIGNIFICANT WEATHER OF INTEREST.

&&

.PREV DISCUSSION...AS OF 3:15 AM PDT SUNDAY...SKIES ARE MOSTLY CLEAR
THIS MORNING EXCEPT FOR AREAS OF STRATOCUMULUS FORMING WHERE NORTHWEST
WINDS ARE IMPINGING ON HIGHER TERRAIN. MOST CLOUDS SHOULD CLEAR BY
LATE MORNING AS WARMING OCCURS IN THE BOUNDARY LAYER AND AS THE
FLOW ALOFT VEERS MORE TO THE NORTH AND BRINGS IN A DRIER AIRMASS.
THESE DEVELOPMENTS...PLUS AIRMASS WARMING UNDER A RIDGE BUILDING
JUST OFFSHORE...WILL RESULT IN WARMER WEATHER ACROSS OUR REGION
TODAY. THE MOST SIGNIFICANT WARMING TODAY WILL OCCUR INLAND WHERE
HIGHS WILL BE 5 TO 10 DEGREES WARMER THAN YESTERDAY. ALTHOUGH
ONSHORE GRADIENTS HAVE EASED SINCE YESTERDAY...THERE IS STILL A
NEARLY 12 MB GRADIENT FROM SFO TO LAS AT THE PRESENT TIME AND THAT
GRADIENT IS FORECAST TO EASE ONLY SLIGHTLY TODAY. THUS...LOCALLY
BRISK NORTHWEST WINDS WILL CONTINUE NEAR THE IMMEDIATE COAST
TODAY...WHICH WILL LIMIT THE AMOUNT OF COASTAL WARMING TO ABOUT 5
DEGREES OR LESS.

THE WARMING TREND WILL CONTINUE INTO MONDAY AS THE UPPER RIDGE
AMPLIFIES AND SHIFTS EASTWARD OVER CA. HIGH TEMPERATURES ON MONDAY
WILL MOSTLY BE IN THE 70S...EXCEPT LOWER TO MID 80S IN THE WARMEST
INLAND VALLEYS. SKIES SHOULD REMAIN MOSTLY CLEAR THROUGH
MONDAY...ALTHOUGH THE MODELS INDICATE AT LEAST PATCHY NIGHT AND
MORNING LOW CLOUDS NEAR THE OCEAN...PARTICULARLY NEAR THE SAN
MATEO COUNTY COAST AND SOUTHERN MONTEREY BAY.

THE UPPER RIDGE IS FORECAST TO BE TRANSITORY AND WILL MOVE OFF TO
OUR EAST BY TUESDAY...ALLOWING A TROUGH OVER THE EASTERN PACIFIC
TO APPROACH THE WEST COAST BY LATE TUESDAY. EXPECT AREAS OF LOW
CLOUDS TO INCREASE ALONG AND NEAR THE COAST BY LATE MONDAY NIGHT
OR TUESDAY MORNING. IN ADDITION...ONSHORE FLOW WILL INCREASE ON
TUESDAY. THE RESULT WILL BE COOLER CONDITIONS IN MOST AREAS ON
TUESDAY...ESPECIALLY COASTAL AREAS AND IN THE COASTAL VALLEYS.
ONLY THE SOUTHERN INLAND VALLEYS ARE EXPECTED TO REMAIN WARM INTO
TUESDAY.

THE UPPER TROUGH THAT WILL SETTLE IN ALONG THE WEST COAST BY
MIDWEEK WILL BE DRY...AND IS NOT FORECAST TO CHANGE THE
TEMPERATURE OF THE AIRMASS OVER OR AREA ALL THAT MUCH.
MOST OF THE MODEST COOLING TREND BY MIDWEEK WILL BE ATTRIBUTED TO
AN INCREASE IN ONSHORE FLOW AND TEMPERATURES WILL ONLY COOL BACK
TO ABOUT NORMAL. TEMPERATURES ARE THEN EXPECTED TO WARM SLIGHTLY
BY THE END OF THE WEEK AS THE TROUGH MOVES OFF TO THE EAST.

THE LONGER RANGE MODELS AGREE IN MAINTAINING DRY CONDITIONS ACROSS
OUR ENTIRE REGION THROUGH THE FIRST FULL WEEK OF MAY. IN
ADDITION...THE CPC 8 TO 14 DAY OUTLOOK INDICATES BELOW NORMAL
PRECIPITATION ALONG THE ENTIRE WEST COAST. IT`S LOOKING
INCREASINGLY LIKELY THAT THE RAIN WE GOT FRI NIGHT/SAT MORNING MAY
BE THE FINAL RAIN EVENT OF THE 2014-15 RAIN YEAR.

&&

.AVIATION...AS OF 4:44 AM PDT SUNDAY...THE CURRENT IR SATELLITE
IMAGE IS SHOWING MOSTLY CLEAR SKIES AROUND THE AREA THIS
MORNING...WITH A STRATUS FIELD WELL OFFSHORE. THE BIGGEST IMPACT
FOR THE TERMINALS TODAY WILL BE CONTINUED MODERATE NORTHWESTERLY
WINDS FILLING IN BEHIND YESTERDAY`S COLD FRONT...WHICH HAS SINCE
MOVED WELL TO THE SOUTHEAST OF THE AREA.

VICINITY OF KSFO...VFR IS ANTICIPATED TO PREVAIL THROUGH THIS
EVENING. GUSTY WEST WINDS WILL REACH 20 TO 25 KT THIS AFTERNOON
WITH GUSTS TO 30 KT.

CONFIDENCE IS HIGH.

SFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...MVFR CIGS BKN-OVC015 WILL BURN OFF
AT KMRY BY 1730Z WITH VFR THEN FORECAST THROUGH AT LEAST THIS
AFTERNOON. VFR IS EXPECTED TO PREVAIL AT KSNS THROUGH AT LEAST
THIS AFTERNOON. GUSTY WESTERLY WINDS WILL REACH 10 TO 15 KT TODAY
WITH GUSTS TO 22 KT POSSIBLE THIS AFTERNOON...STRONGEST IN THE
SALINAS VALLEY.

CONFIDENCE IS MODERATE.

&&

.MARINE...AS OF 9:04 AM PDT SUNDAY...AN STRENGTHENING PRESSURE
GRADIENT WILL LEAD TO STRONGER NORTHWESTERLY WINDS TODAY. THE
STRENGTHENING WINDS WILL RESULT IN DETERIORATING SEA CONDITIONS.
WINDS ARE ANTICIPATED TO FURTHER STRENGTHEN MIDWEEK AS A COLD
FRONT PUSHES TOWARDS THE CALIFORNIA COAST.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...PIGEON PT TO PT PINOS 0-10 NM
             SCA...PT ARENA TO PT REYES 10-60 NM
             SCA...PT REYES TO PIGEON PT 10-60 NM
             SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT REYES TO PIGEON PT 0-10 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PIGEON PT TO PT PINOS 10-60 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM
             SCA...SF BAY SOUTH OF THE BAY BRIDGE FROM 1 PM
             SCA...MONTEREY BAY FROM 1 PM

&&

$$

PUBLIC FORECAST: RWW
AVIATION: LARRY
MARINE: BELL

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