Since July 1, we have had 22.99 " of rain. Average seasonal rainfall for May 21st is 30.82". We are now at 74% of our normal rainfall for this date.

CAZ506-220400- NORTH BAY INTERIOR VALLEYS- 610 AM PDT TUE MAY 21 2013

REST OF TODAY: PARTLY CLOUDY. HIGHS IN THE 70S. WEST WINDS 10 TO 20 MPH.

TONIGHT: MOSTLY CLEAR. LOWS IN THE MID TO UPPER 40S. NORTHWEST WINDS 10 TO 20 MPH.

WEDNESDAY: SUNNY. HIGHS NEAR 70. NORTHWEST WINDS 10 TO 20 MPH.

WEDNESDAY NIGHT: MOSTLY CLEAR. LOWS IN THE MID 40S TO LOWER 50S. NORTHWEST WINDS 15 TO 20 MPH.

THURSDAY: SUNNY. HIGHS NEAR 70. NORTHWEST WINDS 5 TO 15 MPH.

THURSDAY NIGHT: MOSTLY CLEAR IN THE EVENING THEN BECOMING PARTLY CLOUDY. LOWS IN THE UPPER 40S.

FRIDAY THROUGH MEMORIAL DAY: PARTLY CLOUDY. HIGHS IN THE 70S TO LOWER 80S. LOWS AROUND 50. && TEMPERATURE / PRECIPITATION SANTA ROSA 72 46 68 / 0 10 10 SAN RAFAEL 71 49 70 / 0 0 0 NAPA 75 46 71 / 0 10 10

.DISCUSSION...AS OF 2:40 AM PDT TUESDAY...AFTER A STRING OF NICE MILD WEATHER...MUCH COOLER WEATHER IS IN STORE.
AN UPPER LEVEL LOW CURRENTLY NEAR 48N/131W IS EXPECTED TO BRING A BIG CHANGE TO THE SENSIBLE WEATHER ACROSS THE REGION. LATEST SATELLITE IMAGERY REVEALS WIDESPREAD HIGH CLOUDS COVERING MUCH OF THE BAY AREA. SFC OBSERVATIONS INDICATE THAT UNDER THE HIGH CLOUDS...A FEW PATCHY LOW CLOUDS EXIST AROUND 1K FEET. FORT ORD PROFILER AND SODARS PUT THE DIFFUSE MARINE LAYER 1000-1200 FEET.
SHORT TERM(TODAY-THURSDAY)...
A FEW PATCHY LOW CLOUDS WILL BE POSSIBLE EARLY THIS MORNING...BUT AMPLE GRADIENT WILL KEEP WIDESPREAD STRATUS FROM FORMING. MORE IMPORTANTLY TODAY WILL BE THE BIG COOL DOWN AND BREEZY TO OCCASIONALLY GUSTY WINDS. THE AFOREMENTIONED UPPER LOW IS FORECAST TO DROP S AND E INTO THE PACIFIC NORTHWEST TODAY. AS A RESULT...MUCH COLDER AIR WILL FILTER OVER THE REGION.
COMPARING YESTERDAY/S TEMPS FOR TODAY SHOW A BIG DROP. IN FACT...PARTS OF THE NORTH BAY MAY BE AS MUCH AS 20 DEGREES COLDER TODAY. OTHER LOCATIONS WILL LIKELY SEE COLD DOWN OF 10 TO 15 DEGREES COMPARED TO MONDAY. GENERALLY SPEAKING...HIGHS TODAY WILL BE IN THE 60S AT THE COAST AND 70S INLAND...SOUTHERN INTERIOR UP TO THE UPPER 80S. THE COLD ADVECTION ALOFT AND INCREASING ONSHORE FLOW WILL LEAD TO STRONGER WINDS TODAY...BUT JUST BELOW WIND ADVISORY CRITERIA.
HOWEVER...GAPS AND PASSES...LIKE PACHECO...MAY SEE OCCASIONAL GUSTS TO 40-45 MPH. DESPITE THE APPROACHING UPPER LOW...THE BAY AREA IS EXPECTED TO REMAIN DRY. A FEW SHOWERS WILL BE POSSIBLE...BUT WELL NORTH OF THE CWA.
FOR THE REST OF THE SHORT TERM...WINDS WILL EASE UP A BIT WEDNESDAY AND THURSDAY....BUT SEASONABLY COOL TEMPERATURES WILL REMAIN. SOME PATCHY NIGHT AND MORNING LOW CLOUDS WILL BE POSSIBLE...BUT CURRENTLY NOT EXPECTING A WELL ESTABLISHED MARINE LAYER.
LONG TERM(FRIDAY-MONDAY)...
THE LONGWAVE PATTERN INDICATES AN OMEGA BLOCK COVERING MUCH OF THE CONUS WITH AN UPPER LOW LINGERING AROUND THE PACIFIC NORTHWEST. H5 REBOUND SLIGHTLY ON FRIDAY PRODUCING SLIGHTLY WARMER 850MB TEMPS.
A FEW PAC NW UPPER LOW THROUGH NEXT WEEK...BUT WITH LITTLE FAN FARE. ALL THAT BEING SAID...DRY WEATHER AND SEASONABLY COOL CONDITIONS WILL CONTINUE FOR THE HOLIDAY WEEKEND.
&& .AVIATION...AS OF 4:45 AM PDT TUESDAY...A MID LEVEL TROUGH WILL MOVE SE ACROSS THE BAY AREA AND CENTRAL COAST LATER THIS MORNING AND EARLY AFTERNOON. W-NW WINDS WILL INCREASE BEHIND THE TROUGH.
VICINITY OF KSFO...WEST WINDS WILL LIKELY INCREASE BY LATE MORNING.
VFR.
KSFO BRIDGE APPROACH...VFR.
MONTEREY BAY AREA TERMINALS...LOW CLOUDS WILL GRADUALLY MIX OUT AS SURFACE WINDS INCREASE LATER THIS MORNING. VFR AFTER 16Z.
&& .MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PIGEON PT TO PT PINOS 0-10 NM FROM 10 AM SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT ARENA TO PIGEON PT 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 PM SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 PM GLW...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM FROM 3 PM GLW...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM FROM 3 PM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...MRY BAY FROM NOON SCA...SF BAY &&