FXUS66 KSTO 251155
 AFDSTO
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SACRAMENTO CA
 330 AM PST WED NOV 25 2009
 
 .DISCUSSION...
 A BROAD RIDGE OF UPPER LEVEL HIGH PRESSURE WILL CONTINUE TO BRING 
 DRY AND MILD WEATHER TO THE REGION TODAY. STRONG SURFACE HIGH 
 PRESSURE CENTERED OVER THE GREAT BASIN CONTINUES TO RESULT IN 
 OFFSHORE FLOW (NORTHEAST TO EAST). THIS IS ONCE AGAIN RESULTING IN 
 LOCALLY GUSTY NORTHEAST WINDS EARLY THIS MORNING ACROSS THE HIGHER 
 ELEVATIONS OF THE NORTHERN SIERRA NEVADA AND DOWN SOME OF THE WEST 
 FACING CANYONS ON THE WEST SLOPES. IT WILL ALSO RESULT IN ANOTHER 
 WARM DAY OVER THE NORTH END OF THE SACRAMENTO VALLEY AND IN THE 
 FOOTHILLS WHERE ADIABATIC COMPRESSION WILL ENHANCE WARMING ALLOWING 
 FOR SOME TEMPERATURES TO REACH INTO THE LOWER 70S. ELSEWHERE... 
 DEWPOINTS ARE RUNNING A COUPLE OF DEGREES HIGHER EARLY THIS MORNING 
 ACROSS THE SOUTHERN SACRAMENTO VALLEY...DELTA AND NORTHERN SAN 
 JOAQUIN VALLEY...SO FOG MAY BE A LITTLE MORE PREVALENT THIS MORNING.
 
 SYSTEM FOR LATE THANKSGIVING AND FRIDAY CONTINUES TO LOOK 
 UNIMPRESSIVE. MODELS SHOW POSITIVE TILT SYSTEM WEAKENING AS IT MOVES 
 INTO THE DOMINANT WEST COAST RIDGE THEN SPLITS. SOME OF THE ENERGY 
 ENDS UP DIGGING SOUTHEAST AND TRIES TO CLOSE OFF OVER THE DESERT 
 SOUTHWEST OVER THE WEEKEND WHILE THE REST STAYS IN THE NORTHERN 
 STREAM AND MOVES OVER THE NORTHERN ROCKIES. THIS PATTERN IS NOT 
 FAVORABLE FOR SIGNIFICANT QPF AND HAVE TRIMMED FORECAST 
 PRECIPITATION AMOUNTS AND SOUTHERN EXTENT OF MEASURABLE 
 PRECIPITATION.
 
 APPEARS THAT PERSISTENT WEST COAST RIDGE WILL REBOUND SATURDAY WITH 
 DRY NORTHERLY FLOW DEVELOPING.
 
 .EXTENDED DISCUSSION (SUNDAY THROUGH WEDNESDAY)...
 HIGH AMPLITUDE RIDGE REBUILDS OFF THE WEST COAST SUNDAY AND SHIFTS 
 INLAND MONDAY. THE ECMWF FLATTENS THE RIDGE SOMEWHAT MONDAY AS A 
 SHORTWAVE MOVES BY TO THE NORTH...HOWEVER THE GEM AND GFS KEEP THIS 
 FEATURE TOO FAR NORTH TO HAVE ANY INFLUENCE ON THE RIDGE. 850MB 
 TEMPERATURES RECOVER TO THE 6C-9C RANGE AND SURFACE HIGH PRESSURE 
 OVER THE GREAT BASIN WILL CONTINUE THE PATTERN OF LOCALLY BREEZY 
 NORTH TO EAST WINDS. FOG SHOULD BE PATCHY AND LIMITED TO THE LATE 
 NIGHT AND EARLY MORNING HOURS IN PRONE AREAS. THIS PATTERN WOULD 
 FAVOR ABOVE NORMAL TEMPERATURES. THE MODELS AMPLIFY THE RIDGE WELL 
 NORTH INTO BRITISH COLUMBIA/YUKON BY TUESDAY...WITH VARYING AMOUNTS 
 OF SHORTWAVE ENERGY DROPPING DOWN THE BACK SIDE OF THE RIDGE. THE 
 18Z DGEX AND 12Z GFS FROM YESTERDAY WERE SUGGESTING THAT AN 
 UNDERCUTTING OF THE WESTERLIES COULD OCCUR TOWARD THE MIDDLE OF NEXT 
 WEEK...AND SEVERAL OF THE GFS ENSEMBLES SUPPORT THIS AS WELL. BUT 
 THE 06Z DGEX AND GFS HAVE BACKED AWAY FROM THIS. SG
 
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 .AVIATION...
 HIGH PRESSURE ALOFT REMAINS IN PLACE OVER CALIFORNIA WITH SURFACE 
 HIGH PRESSURE OVER THE GREAT BASIN. AREAS MVFR CIGS VSBY IN FOG WILL 
 IMPACT KSMF...KSAC AND KMHR UNTIL 17Z THIS MORNING. KSAC WILL HAVE 
 OCCASIONAL LIFR VIS BLO 1/2SM FG VV001 UNTIL 16Z. OTHERWISE VFR 
 CONDITIONS EXPECTED BEYOND 18Z ALL AREAS. LOCAL E SFC WNDS G40KT 
 THIS MORNING ALONG W SLOPE OF THE SIERRA CANYONS. SG 
 
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 .STO WATCHES/WARNINGS/ADVISORIES...NONE. 
 
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