FXUS66 KMTR 251119
 AFDMTR
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
 319 AM PST WED NOV 25 2009
 
 .DISCUSSION...AS OF 3:15 AM WEDNESDAY...SLIGHT CHANCE FOR PRECIP
 LATE THURSDAY AND EARLY FRIDAY FOLLOWED BY SEASONABLE WEATHER.
 
 A RIDGE OF HIGH PRESSURE COMBINED WITH LIGHT NORTHERLY OFFSHORE FLOW
 CONTINUES TO PRODUCE GENERALLY DRY CONDITIONS ACROSS THE BAY AREA.
 THE OVERNIGHT FOG PRODUCT SHOWS NO STRATUS IMPACTING THE COASTLINE...
 BUT SOME PATCHY FOG IS NOTED IN THE NORTH BAY. RECENT OBS INDICATE
 PATCHY FOG IN SONOMA AND NAPA VALLEYS WITH VISIBILITIES LESS THAN 1
 MILE AT TIMES. ELSEWHERE...DEW POINT DEPRESSIONS ARE DECENT WITH
 CLEAR SKIES DOMINATING. ONE OTHER ITEM OF NOTE...IS ANOTHER NIGHT
 OF MILD CONDITIONS IN THE HIGHER TERRAIN. CURRENT READINGS ARE A
 LITTLE COOLER THAN LAST NIGHT...BUT TEMPS IN THE UPPER 50S TO LOWER
 60S IS MILD FOR THE HILLS IN NOVEMBER.
 
 CURRENT LONGWAVE PATTERN HAS A RIDGE OF HIGH PRESSURE OVERHEAD AND
 OVER MUCH OF THE WEST COAST. FARTHER UPSTREAM A LOW PRESSURE
 SYSTEM AND ASSOCIATED COLD FRONT CONTINUES TO SWING THROUGH THE
 GULF OF AK AND A SECOND DEEPENING SHORTWAVE TROUGH IS NEAR 150W.
 
 SHORT TERM(TODAY-FRIDAY)...
 LITTLE CHANGE IS FORECAST IN THE OVERALL PATTERN TODAY FROM
 YESTERDAY. AS MENTIONED ABOVE...SOME PATCHY FOG WILL BE POSSIBLE
 THROUGH THE EARLY MORNING HOURS IN THE NORTH BAY. OTHERWISE...
 EXPECT ANOTHER DAY OF WALL TO WALL SUNSHINE. LATER TODAY THE
 RIDGE WILL WEAKEN AND SLIDE TOWARD THE SOUTHEAST. AS THIS HAPPENS...
 THE SECOND UPSTREAM FEATURE WILL DEEPEN AND MOVE TOWARD THE COAST
 THURSDAY. MODELS ARE IN DECENT AGREEMENT WITH THE TIMING OF THIS
 FEATURE. AS MENTIONED IN PREVIOUS DISCUSSIONS...THANKSGIVING DAY
 STILL LOOKS TO START OF MOSTLY SUNNY BUT AS THE SHORTWAVE TROUGH AND
 ASSOCIATED FRONT MOVE CLOSER THROUGH THE DAY CLOUDS WILL STEADILY
 INCREASE. ALL MODEL GUIDANCE KEEPS ANY PRECIP WELL OFFSHORE THROUGH 4
 PM ON THANKSGIVING.  AFTER 4 PM THE LIKELIHOOD FOR DEVELOPING LIGHT
 SHOWERS WILL INCREASE. MODEL GUIDANCE HAS BEEN PRETTY PERSISTENT WITH
 KEEPING THE BULK OF THE PRECIP SAN FRANCISCO BAY NORTHWARD. THE 00Z
 MODELS ARE NO DIFFERENT AND FORECAST WILL REFLECT THIS. EVEN WITH THE
 ADVERTISED RAINFALL THURSDAY NIGHT INTO EARLY FRIDAY AMOUNTS WILL BE
 LIGHT...GENERALLY A FEW HUNDREDTHS TO A TENTH OR TWO. WILL CONTINUE
 TO KEEP MUCH OF THE SOUTHERN CWA DRY WITH ONLY CLOUDS MENTIONED.
 
 THE COLD FRONT WILL EXIT THE CWA ON FRIDAY WITH A CLEARING TO
 FOLLOW. A DROP IN TEMPERATURE IS EXPECTED ON FRIDAY AS 850 MB TEMPS
 DROP A FEW DEGREES AND COOL NORTHWEST FLOW DEVELOPS AT THE SFC.
 
 LONG TERM(SATURDAY-TUESDAY)...
 LITTLE CHANGE WAS MADE TO THE LONG TERM FORECAST.  HIGH PRESSURE IS
 FORECAST TO BUILD BEHIND THE DEPARTING COLD FRONT WITH A SLIGHT
 WARMING TREND.  ANOTHER SYSTEM IS FORECAST TO SWING THROUGH NW PAC
 EARLY NEXT WEEK...BUT WITH LITTLE AFFECT ON THE CWA.
 
 
 
 &&
 
 .AVIATION...AS OF 9:40 PM PST TUESDAY...CLEAR SKIES WILL PERSIST
 THROUGH WEDNESDAY UNDER THE INFLUENCE OF HIGH PRESSURE. PATCHY FOG
 IS POSSIBLE ONCE AGAIN IN THE VALLEYS OVERNIGHT.
 
 ALL TERMINALS(EXCEPT KSTS)...VFR CONDITIONS EXPECTED THROUGH
 WEDNESDAY WITH LIGHT WINDS.
 
 &&
 
 
 .MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...NONE.
 
 
 
 
 PUBLIC FORECAST: MM
 AVIATION/MARINE: CW
 
 NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO