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

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000
FXUS66 KMTR 270540
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1040 PM PDT SUN APR 26 2015

.SYNOPSIS...HIGH PRESSURE WILL BUILD THROUGH MONDAY KEEPING
TEMPERATURES WARM UNDER SUNNY SKIES. A DRY COLD FRONT WILL APPROACH
THE COAST BY TUESDAY ALLOWING WINDS TO TURN BACK ONSHORE WITH A
MODEST COOLING TREND. DRY AND SEASONABLE WEATHER IS THEN FORECAST
WEDNESDAY THROUGH NEXT WEEKEND.

&&

.DISCUSSION...AS OF 9:02 PM PDT SUNDAY...IT`S A FAIRLY QUIET
EVENING WEATHER-WISE AFTER A DAY WITH WARMER TEMPERATURES ACROSS
THE AREA. 8 PM TEMPERATURES CONTINUE TO SETTLE BACK WITH READINGS
NOW IN THE MID TO UPPER 50S IMMEDIATE COAST AND NEAREST THE BAY TO
THE 60S INLAND.

THE SUB-TROPICAL RIDGE WILL CONTINUE TO AMPLIFY OVER NORTHERN
CALIFORNIA THROUGH MONDAY EVENING THEN SHIFT EASTWARD TO NEVADA
LATE MONDAY NIGHT INTO TUESDAY. ABOVE NORMAL DAY-TIME WARMTH WILL
PERSIST ON MONDAY...BUT BY TUESDAY W-NW WINDS WILL STRENGTHEN
HELPING TO START A COOLING TREND THAT`LL LIKELY CARRY THROUGH
LATE WEEK. THE MAJORITY OF COOLING WILL BE FIRST LOCATED AT THE
IMMEDIATE COAST AND NEAR THE BAY WATERS THEN GRADUALLY SPREAD INTO
THE INLAND VALLEYS THROUGH THE REMAINDER OF THE WEEK. THE COOLING
WILL BE RELATIVE HOWEVER SINCE ABOVE TO WELL ABOVE NORMAL DAILY
HIGHS WILL GRADUALLY SETTLE BACK...THROUGH MID-LATE WEEK...TO NEAR
NORMAL HIGHS FOR LATE APRIL AND EARLY MAY. A WEAK OPEN WAVE 500 MB
HEIGHT TROUGH WILL MIGRATE FROM THE HIGHER LATITUDE WESTERLIES
OVER THE EPAC AND BECOME NEARLY STATIONARY OVER NORCAL THROUGH THE
END OF WEEK. A SEPARATE COLDER TROUGH LOCATED FARTHER UPSTREAM
SOUTH OF THE ALEUTIANS WILL GET PROPELLED EASTWARD BY THE JET
STREAM AND REACH THE PACIFIC NW AND NORCAL BY EITHER MONDAY OR
TUESDAY OF NEXT WEEK.

&&

.PREV DISCUSSION...AS OF 2:32 PM PDT SUNDAY...ITS A SUNNY AND PLEASANT
SUNDAY AFTERNOON ACROSS THE BAY AREA WITH TEMPERATURES RUNNING
6-12 DEGREES WARMER THAN SATURDAY AS HIGH PRESSURE BUILDS OVER THE
REGION. NORTHERLY GRADIENT IS BUILDING WITH 4.5 MB DOWN THE COAST
AND NOW 1 MB OFFSHORE FROM THE GREAT BASIN. THIS SHOULD KEEP SKIES
MOSTLY CLEAR OVERNIGHT WITH PERHAPS SOME COASTAL CLOUDS ALONG THE
SAN MATEO AND MONTEREY COASTLINE BY MORNING. OTHERWISE THE
SYNOPTIC PATTERN WILL FAVOR NORTH WINDS IN THE HILLS...TURNING
OFFSHORE OR NORTHEAST BY MORNING. THIS WILL SET THE STAGE FOR A
SUNNY AND WARM MONDAY ACROSS THE DISTRICT WITH THE WARMEST INLAND
SPOTS APPROACHING THE UPPER 80S TO AROUND 90 DEGREES. EXPECT
WIDESPREAD 70S AND LOWER 80S AROUND THE BAY WITH COMFORTABLE 60S
AT THE COAST.

AS EARLY AS MONDAY NIGHT WINDS WILL TURN BACK ONSHORE AS A DRY
COLD FRONT APPROACHES THE NORTHERN CALIFORNIA COAST. EXPECT
STRATUS TO RETURN TO THE COAST BY TUESDAY MORNING AS THIS FEATURE
MOVES THROUGH NORTHERN CALIFORNIA. NOTED COOLING TREND WILL THEN
OCCUR ON TUESDAY...ESPECIALLY NEAR THE COAST BUT EVEN INLAND WITH
AN EARLY AND STRONG SEABREEZE AS THE UPPER TROUGH MOVES OVER
OREGON BY TUESDAY AFTERNOON.

BEHIND THAT FEATURE THE UPPER PATTERN WILL TREND ZONAL WITH
PERHAPS A BAGGY UPPER TROUGH BY THE END OF THE WEEK. THE END
RESULT ON THE SURFACE WEATHER WILL BE MINIMAL WITH DRY AND
SEASONABLE WEATHER FORECAST FROM MIDWEEK THROUGH NEXT WEEKEND.
WERE GETTING DEEP INTO THE SHOULDER SEASONS NOW WHEN STORMS ARE
RARE BUT THE SUMMER MARINE LAYER HASN`T NECESSARILY BECOME
ENTRENCHED.

IN THE LONG RANGE THE 240 HOUR ECMWF AND GFS BOTH DEPICT AN UPPER
LOW APPROACHING THE REGION WITH THE 10-16 DAY GFS RUNS KEEPING THE
PATTERN CYCLONIC WITH NEAR TO BELOW NORMAL TEMPS. NO BIG RIDGES OR
WARM SPELLS IN SIGHT...JUST SEASONABLE AS WE HEAD INTO MAY.

&&

.AVIATION...AS OF 10:40 PM PDT SUNDAY...A STRONG NORTHERLY
GRADIENT WILL MAINTAIN MAINLY CLEAR SKIES ACROSS THE REGION
THROUGH THE FORECAST PERIOD. LIGHT WEST WINDS WILL PERSIST
THROUGH TONIGHT BECOMING LOCALLY OFFSHORE IN THE EARLY MORNING
HOURS. MODERATE WEST WINDS ARE EXPECTED MONDAY AFTERNOON.
HIGH CONFIDENCE.

VICINITY OF KSFO...VFR CONDITIONS EXPECTED THROUGH THE FORECAST
PERIOD. LIGHT WEST WINDS WILL CONTINUE THROUGH MONDAY MORNING.
SUSTAINED WEST WINDS AROUND 15 KT ARE EXPECTED MONDAY AFTERNOON.
HIGH CONFIDENCE.

SFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS EXPECTED THROUGH THE
FORECAST PERIOD. LIGHT AND VARIABLE WINDS WILL CONTINUE THROUGH
TONIGHT. WEST WINDS WILL RETURN MONDAY MORNING. SUSTAINED WEST
WINDS AROUND 12 KT ARE EXPECTED MONDAY AFTERNOON. HIGH CONFIDENCE.

&&

.MARINE...AS OF 9:00 PM PDT SUNDAY...HIGH PRESSURE WILL MAINTAIN
MODERATE NORTHWESTERLY WINDS ACROSS THE COASTAL WATERS THE
OVERNIGHT HOURS. WINDS ARE ANTICIPATED TO FURTHER STRENGTHEN
MIDWEEK AS A COLD FRONT PUSHES TOWARDS THE CALIFORNIA COAST.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 2 AM
             SCA...PT ARENA TO PT REYES 10-60 NM
             SCA...PT REYES TO PIGEON PT 10-60 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PIGEON PT TO PT PINOS 10-60 NM
             SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 5 AM
             SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 5 AM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM

&&

$$

PUBLIC FORECAST: CANEPA/RWW
AVIATION/MARINE: CW

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