000
FXUS66 KMTR 252353
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
453 PM PDT SAT MAY 25 2013

...COOL HOLIDAY WEEKEND WITH SHOWERS POSSIBLE MEMORIAL DAY...

.DISCUSSION...AS OF 02:10 PM PDT SATURDAY...COOL WEATHER WILL
CONTINUE THROUGH THE HOLIDAY WEEKEND WITH A CHANCE FOR RAINFALL
MONDAY AND TUESDAY.

PESKY CLOUDS CONTINUE TO LINGER AROUND THE MONTEREY PENINSULA AND
THE SAN MATEO COAST EARLY THIS AFTERNOON. ELSEWHERE...SUNNY SKIES
PREVAIL THIS AFTERNOON. DESPITE THE MOSTLY CLEAR
SKIES...TEMPERATURES ARE CURRENTLY RUNNING A FEW DEGREES COLDER
THAN YESTERDAY. THIS IS NOT SURPRISING GIVEN THE COLDER AIRMASS OVERHEAD.

NO REAL CHANGE IN THE LONGWAVE SYNOPTIC PATTERN. A BROAD TROUGH
OF LOW PRESSURE REMAINS ALONG THE PACIFIC NORTHWEST COAST. ON THE
WATER VAPOR A FEW EMBEDDED SHORTWAVE TROUGHS CAN BE SEEN ROTATING
THROUGH THE TROUGH.

SHORT TERM(TONIGHT-TUESDAY)...
MUCH OF THE SHORT TERM FORECAST WILL BE FOCUSED AROUND RAIN CHANCES ON
MEMORIAL DAY. UNTIL THEN...UNSEASONABLY COOL WEATHER WILL CONTINUE
ACROSS THE BAY AREA. AN UPPER LEVEL TROUGH WILL SWEEP THROUGH THE
REGION TONIGHT AND EARLY SUNDAY. CURRENT THINKING IS THAT THIS
FEATURE WILL HELP TO ESTABLISH A MORE DEFINED MARINE LAYER. HI-RES
MODELS EVEN GENERATE A LITTLE BIT OF QPF EARLY SUNDAY MORNING.
THEREFORE...CURRENT FORECAST WILL BE FOR MORE CLOUD COVER TONIGHT
AND EARLY SUNDAY WITH PATCHY DRIZZLE ALONG THE COAST. WOULD NOT BE
SURPRISED IF A HUNDREDTH OR TWO IS REPORTED. SIMILAR TEMPERATURES
AGAIN ON SUNDAY WITH HIGHS IN THE 60S ALONG THE COAST AND 70S
INLAND. OVERNIGHT LOWS WILL REMAIN RELATIVELY COOL IN THE 40S TO
LOWER 50S. A FEW SHELTERED LOCATIONS MAY DIP CLOSE TO THE UPPER
30S. FOR MEMORIAL DAY...THE LATEST GUIDANCE HAS NOT CHANGED TOO
MUCH FROM THE PREVIOUS RUN...BUT SOUTHWARD MOVEMENT OF RAIN IS
SLOWER THAN A FEW DAYS AGO. RAIN SHOWERS WILL FIRST BE POSSIBLE
OVER THE FAR NORTH BAY EARLY MONDAY AND THEN SPREADING TOWARD SAN
FRANCISCO BAY BY MID AFTERNOON. LOCATIONS SOUTH OF SAN JOSE MAY
LUCK OUT AND HAVE MUCH OF THEIR MEMORIAL DAY DRY THROUGH 00Z.
THERE AFTER...ALL MODELS PUSH PRECIP SOUTHWARD THROUGH 12Z
TUESDAY. RAINFALL AMOUNTS STILL APPEAR NOT TO BE OVERLY
IMPRESSIVE...0.25-0.5 IN FOR NORTH BAY AND COASTAL SANTA
CRUZ...ELSEWHERE A FEW HUNDREDTHS TO A TENTH OR TWO. MEMORIAL DAY
ALSO APPEARS TO BE THE COOLEST DAY OF THE SHORT TERM. INTERIOR
LOCATIONS WILL STRUGGLE TO EVEN BREAK 70 DEGREES. A FEW LINGERING
SHOWERS WILL BE POSSIBLE ON TUESDAY...BUT THE BULK OF THE RAIN
WILL BE MONDAY THROUGH TUESDAY MORNING.

LONG TERM(WEDNESDAY-SATURDAY)...
ONE CHANGE TO THE LONG TERM FORECAST FROM PREVIOUS FORECAST WAS TO
INCLUDE A SLIGHT CHANCE FOR SHOWERS ACROSS THE NORTH BAY ON
WEDNESDAY. THE LATEST MODEL GUIDANCE DROPS A SHORTWAVE TROUGH
ACROSS NORTHERN CALIFORNIA. BEST RAIN CHANCES WILL BE NORTH OF THE
CWA...BUT A FEW SHOWERS WILL BE POSSIBLE OVER THE NORTH BAY.
THURSDAY THROUGH SATURDAY SHOWS WARMING AND DRYING AS A RIDGE OF HIGH
PRESSURE TRIES TO BECOME RE-ESTABLISHED OVER THE EPAC.

&&

.AVIATION...AS OF 4:47 PM PDT SATURDAY...SATELLITE SHOWS CLOUDS
GATHERING OVER SAN MATEO COUNTY AND PARTS OF NORTHERN MONTEREY
COUNTY. SFO-SAC GRADIENT IS 3.5 MB. ONSHORE WINDS WILL USHER IN
LOW CLOUDS OVERNIGHT.

VICINITY OF KSFO...GUSTY WEST WINDS TO 30 KNOTS TIL 04Z. LOW
CLOUDS WILL INCREASE OVERNIGHT WITH MVFR CIGS FORECAST BY 07Z.

KSFO BRIDGE APPROACH...VFR THROUGH THE EVENING. INCREASING LOW
CLOUDS ARE EXPECTED LATE AT NIGHT.

MONTEREY BAY AREA TERMINALS...LOW CLOUDS WILL GRADUALLY INCREASE
LATER IN THE EVENING AND OVERNIGHT. MVFR CIGS ARE FORECAST TO
DEVELOP BETWEEN 00Z-04Z.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...SF BAY UNTIL 11 PM
             SCA...MRY BAY UNTIL 11 PM
             SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 11 PM
             SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 11 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 2 AM
             SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 2 AM
             SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 2 AM

&&

$$

PUBLIC FORECAST: MM
AVIATION/MARINE: CANEPA

VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO

FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA