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

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KMTR 191206
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
506 AM PDT FRI SEP 19 2014

.SYNOPSIS...DRY CONDITIONS ARE NOW EXPECTED TO PREVAIL ACROSS THE
DISTRICT THROUGH THE WEEKEND AND INTO THE FIRST PART OF NEXT WEEK.
THE DISTURBANCE THAT BROUGHT RAIN TO PORTIONS OF THE DISTRICT ON THURSDAY
HAS NOW WEAKENED AND PROGRESSED SOUTHEASTWARD OF OUR AREA. THE
RESIDUAL MILD AND AND MOIST LOW LEVEL AIR MASS WILL REMAIN HOWEVER.
BOTH OVERNIGHT LOWS AND AFTERNOON HIGHS WILL GENERALLY STAY A BIT
ABOVE SEASONAL NORMS...WITH AREAS OF COASTAL LOW CLOUDS AND FOG
EXTENDING INLAND NIGHT AND MORNING HOURS. THEN BEGINNING AROUND
THE MIDDLE OF NEXT WEEK...ANOTHER PACIFIC WEATHER SYSTEM WILL
APPROACH THE DISTRICT AND RENEW RAIN CHANCES.

&&

.DISCUSSION...AS OF 3:30 AM PDT FRIDAY...DRY AND MILD CONDITIONS
PREVAIL DISTRICTWIDE...ALONG WITH AREAS OF LOW CLOUDS AND PATCHY
FOG. TEMPERATURES ARE GENERALLY RUNNING IN THE UPPER 50S TO MID
60S...WITH DEW POINTS NOT MUCH LOWER...AND THUS ALMOST HINTS OF A BIT
OF TROPICAL FEELING TO THE WEATHER. THIS REFLECTS A COMBINATION OF
THE STILL REMARKABLY HIGH SEA SURFACE TEMPERATURES OF OUR COASTAL
WATERS AND THE RESIDUAL MOIST AND MILD AIR MASS LEFT IN THE WAKE
OF THE WEAK WEATHER SYSTEM THAT MOVED THROUGH YESTERDAY.

LATEST WATER VAPOR SATELLITE IMAGERY SHOWS THE UPPER LEVEL
DISTURBANCE RESPONSIBLE FOR THURSDAY/S PRECIPITATION IS NOW
CENTERED ABOUT 175 MILES WEST OF PT CONCEPTION AND PROGRESSING
GRADUALLY FARTHER SOUTHWARD. MODELS ARE IN GOOD AGREEMENT THAT
OVER THE WEEKEND IT WILL LIFT EAST-NORTHEASTWARDS AND INLAND AS AN
UPPER LEVEL RIDGE OF HIGH PRESSURE TEMPORARILY BUILDS IN OVER THE
COAST.

FOR OUR AREA...THE NET RESULT WILL BE MILD TO WARM AND A BIT MUGGY
DAYS...AND MILD NIGHTS...THROUGH THE WEEKEND AND INTO THE FIRST PART
OF NEXT WEEK...ALONG WITH AREAS OF COASTAL LOW CLOUDS AND FOG
EXTENDING INLAND NIGHT AND MORNING HOURS.

ALTHOUGH NO PRECIPITATION IS EXPECTED...ASIDE FROM THE USUAL
POSSIBILITY OF SOME PATCHY LOCAL LATE NIGHT AND EARLY MORNING
COASTAL DRIZZLE...HAVE NOTED THAT LATEST NAM MODEL OUTPUT DOES
CONTINUE TO SHOW BOTH SOME AREAS OF MID-LEVEL CLOUDINESS ROTATING
THROUGH OUR DISTRICT FROM THE SOUTHEAST AT TIMES...AND ALSO APPRECIABLE
SURFACE BASED CAPE DEVELOPING OVER OUR FAR INLAND MOUNTAINS FRIDAY
AFTERNOON AND AGAIN AND SOMEWHAT MORE ROBUSTLY SATURDAY AFTERNOON.
THE GFS IS SIGNIFICANTLY DRIER...BUT IN JUST NOW LOOKING AT THIS A
BIT MORE CLOSELY...BELIEVE THERE IS ENOUGH OF A CHANCE AT LEAST
SATURDAY AFTERNOON OVER THE ELEVATED TERRAIN OF OUR FAR
SOUTHEASTERN INTERIOR TO WARRANT MENTION OF A SLIGHT CHANCE OF
THUNDERSTORMS IN THE FORECASTS. AND ALTHOUGH THE SIGNAL IS WEAKER
TODAY...AND THEREFORE HAVE FOR NOW ONLY ADDED IN POPS OF 10 AND
PARTLY CLOUDY SKIES FOR THIS AREA...DAY SHIFT WILL NEED TO CLOSELY
MONITOR.

IN THE EXTENDED PORTION OF THE FORECAST...LONGER RANGE MODELS ARE
IN GOOD BASIC AGREEMENT THAT AN UNSEASONABLY STRONG WEATHER SYSTEM
WILL APPROACH THE PACIFIC NORTHWEST LATE TUESDAY...AND THEN SAG SOUTHWARD
INTO OUR DISTRICT WEDNESDAY AND THURSDAY. ALTHOUGH IT WILL THEN BE
WEAKENING...AT PRESENTLY APPEARS IT WILL RETAIN ENOUGH MOISTURE
AND DYNAMICAL FORCING TO RENEW RAIN CHANCES FOR US...ESPECIALLY OVER
THE NORTH BAY.

&&

.AVIATION...AS OF 5:05 AM PDT FRIDAY...A MOIST BOUNDARY LAYER HAS
RESULTED IN AREAS OF LOW CLOUDS ACROSS AREA TERMINALS. PATCHY
DENSE FOG AND LIFR/VLIFR CONDITIONS ARE CURRENTLY BEING REPORTED
OVER THE NORTH BAY WHILE IFR TO MVFR CIGS ARE BEING OBSERVED
ACROSS OTHER AREA TERMINALS. CLEARING ANTICIPATED BETWEEN 16Z-17Z
THIS MORNING. LIGHT WINDS WILL CONTINUE THROUGH MIDDAY WITH A
MODERATE SEABREEZE KICKING IN DURING THE AFTERNOON.

VICINITY OF KSFO...IFR CEILINGS ARE EXPECTED TO CLEAR BETWEEN
16Z-17Z THIS MORNING. LIGHT WINDS INCREASING THIS AFTERNOON WITH
THE ONSET OF THE SEABREEZE.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...MVFR CEILINGS ARE EXPECTED TO CLEAR
BETWEEN 17Z-19Z THIS MORNING. LIGHT WINDS INCREASING THIS
AFTERNOON WITH THE ONSET OF THE SEABREEZE.

&&

.MARINE...AS OF 2:38 AM PDT FRIDAY...LIGHT WINDS WILL TURN ONSHORE
AND STRENGTHEN LATER THIS MORNING AS HIGH PRESSURE BEGINS TO BUILD
OVER THE REGION. A MODERATE LONG PERIOD SOUTHWESTERLY SWELL WILL
CONTINUE TO IMPACT THE WATERS THROUGH THIS AFTERNOON BUT IS
EXPECTED TO SLOWLY SUBSIDE OVER THE NEXT 24 HOURS.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...SF BAY NORTH OF THE BAY BRIDGE FROM 1 PM

&&

$$

PUBLIC FORECAST: BLIER
AVIATION/MARINE: CW

VISIT US AT WEATHER.GOV/SANFRANCISCO

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





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.