AREA FORECAST DISCUSSION

 
 FXUS66 KMTR 250704
 AFDMTR
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
 1200 AM PDT TUE AUG 25 2009
 
 .DISCUSSION...AS OF 9:00 PM PDT MONDAY...MUCH WARMER WEATHER FOR THE
 REMAINDER OF THE WEEK ESPECIALLY FOR INLAND LOCATIONS.
 
 TYPICAL EVENING SETUP FOR THE SF/MONTEREY BAY FORECAST AREA AS A
 NEARLY 3 MB WESTERLY/ONSHORE FLOW IS COMBINING WITH A MARINE LAYER
 OF AROUND 1800 FEET. THIS IS LEADING TO CLOUDS SPREADING ACROSS
 ALMOST ALL OF THE COASTAL AREAS AND INTO BOTH BAYS. ONE INTERESTING
 FEATURE IS THE NORTHERLY COMPONENT IS EVEN STRONGER AT 3.2 MB.
 THIS WILL HELP TO LIMIT SOME OF THE CLOUDS FOR THE NORTHERN THIRD OF
 THE CWA AND PRODUCE COPIOUS AMOUNTS UP AND DOWN THE ENTIRE SALINAS
 VALLEY. LOWS SHOULD BE MOSTLY IN THE 40S AND 50S.
 
 MAIN STORY FOR THE REST OF THE WEEK WILL BE A SIGNIFICANT WARM-UP
 AS A RIDGE OF HIGH PRESSURE OFF TO THE SOUTHEAST BUILDS WHILE
 TEMPERATURES ALOFT WARM 4-7C AT 850MB. HIGHS ARE EXPECTED TO
 INCREASE 3-5F EACH DAY OVER MANY INLAND SPOTS OVER THE NEXT THREE
 DAYS WITH MANY INTERIOR SPOTS FORECAST TO HIT THE 90S BY FRIDAY AND
 LOWER 100S IN THE WARMEST LOCATIONS. BIGGEST QUESTION MARK APPEARS TO
 BE HOW MUCH IT WILL WARM-UP. THREE PIECES ARE GOING AGAINST THIS
 BEING A WIDE-SPREAD RECORD-SETTING EVENT. ONE...500 MB HEIGHTS ARE
 FORECAST TO "ONLY" BY 594 MB INSTEAD OF THE 598-600 MB RANGE THAT
 WOULD BE NEEDED. TWO...TEMPERATURES AT 850 ARE NOT FORECAST TO WARM
 ABOVE 27C EXPECT IN SPOTS THAT ARE ALWAYS THE WARMEST IN THE CWA SUCH
 AS INTERIOR MONTEREY. THREE...ALL OF THE MODEL GUIDANCE KEEPS AN
 ONSHORE/WESTERLY FLOW GOING WHICH WILL KEEP THE COAST MUCH COOLER AND
 SHOULD ALSO ACT AS A BARRIER TO RECORD HEAT. THIS WILL ALSO HELP TO
 KEEP CLOUDS GOING AT THE COAST AND ELEVATIONS UNDER 1500 FEET AT
 ADJACENT SPOTS. OBVIOUSLY IF THE TREND STARTS TO MOVE MORE TOWARD A
 TROUGH OFF THE COAST AND HIGHER HEIGHTS AND TEMPERATURES...THE
 FORECAST HIGHS AND LOWS WILL BE INCREASED. AT THIS TIME...THAT DOES
 NOT APPEAR LIKELY. MODELS HAVE ALSO BEEN HINTING AT SOME MOISTURE
 BEING BROUGHT IN FROM THE SOUTHEAST AS AN UPPER WAVE OVER THE PACNW
 ON FRIDAY KICKS OFF TO THE NORTHEAST. THIS LOOKS VERY UNLIKELY SO
 POPS WERE KEPT AT 10 PERCENT OR LESS.
 &&
 
 .AVIATION...AS OF 11:00 PM PDT MONDAY...SATELLITE IMAGERY SHOWS ONLY
 A THIN STRIP OF STRATUS CLINGS TO THE NORTH COAST TONIGHT. THIS IS A
 DIRECT RESULT OF THE INCREASING NORTHERLY PRESSURE GRADIENT FROM ACV-
 SFO. MEANWHILE THE FORT ORD PROFILER IS CURRENTLY SHOWING A STEADY
 2000 FOOT MARINE LAYER. STRATUS IS ANTICIPATED TO FILL IN OVER MOST
 TERMINALS OVERNIGHT WILL A SLIGHTLY LATER BURN OFF TUESDAY MORNING
 AS A RESULT OF THE DEEPER MARINE LAYER.
 
 VICINITY OF KSFO...MVFR-VFR CONDITIONS EXPECTED TO DEGRADE TO IFR
 CONDITIONS OVERNIGHT. BKN-OVC 007-009 DECKS WILL SCATTER OUT
 BETWEEN 17Z-18Z TUESDAY MORNING. WINDS WILL REMAIN LIGHT THEN
 INCREASE TO AROUND 15 KT AFTER 20Z TUESDAY.
 
 KSFO BRIDGE APPROACH...VFR CONDITIONS EXPECTED TO DEGRADE TO IFR-
 MVFR (BKN 009-010) AFTER 10Z EARLY TUESDAY MORNING. STRATUS WILL
 SCATTER OUT AROUND 17Z.
 
 MONTEREY BAY TERMINALS...IFR-MVFR (OVC 007-010) CONDITIONS WILL
 PERSIST THROUGH 18-19Z TUESDAY MORNING. WINDS WILL REMAIN LIGHT.
 
 &&
 
 .MTR WATCHES/WARNINGS/ADVISORIES...
      .TNGT...SCA...PT ARENA TO PIGEON PT 10 TO 60 NM
              SCA...PT ARENA TO PT REYES TO 10 NM
 
 
 &&
 
 PUBLIC FORECAST: BELL
 AVIATION/MARINE: CW
 
 $$
 
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