661  
FXUS66 KMTR 211159 CCA  
AFDMTR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA  
357 AM PST THU FEB 21 2019  
   
SYNOPSIS
 
LINGERING SHOWERS CONTINUE EARLY THURSDAY MORNING  
ESPECIALLY OVER THE CENTRAL COAST AND EAST BAY HILLS WITH SNOW  
SHOWERS ABOVE 3,000 FEET ELEVATION. DRY CONDITIONS RETURN  
THURSDAY INTO FRIDAY WITH NEAR RECORD LOWS POSSIBLE FRIDAY  
MORNING. THE NEXT CHANCE OF RAIN RETURNS TO NORTHERN CALIFORNIA  
OVER THE WEEKEND AND EARLY NEXT WEEK.  
 

 
   
DISCUSSION...AS OF 3:08 AM PM PST THURSDAY
 
METEOROLOGICAL TERM  
FOR THE NIGHT SHIFT - OROGRAPHIC LIFT. IMPRESSIVE TO WATCH THE  
KMUX RADAR IMAGERY FROM LATE WEDNESDAY EVENING THROUGH EARLY  
THURSDAY MORNING AS SHOWERS CONTINUE TO IMPACT THE CENTRAL COAST.  
MOIST AIR OVER THE COASTAL WATERS IS BEING FORCED UPWARD OVER THE  
TERRAIN OF THE CENTRAL COAST LEADING TO A TRAINING EFFECT OF  
PRECIPITATION. THE TRAINING EFFECT IS MOST NOTABLE OVER THE SANTA  
LUCIA RANGE WHERE PEAKS EXCEED 5500 FEET. INTERESTING FACTOID -  
THE HIGHEST COASTAL PEAK IN THE LOWER 48 IS CONE PEAK ALONG THE  
BIG SUR COAST. THERE ARE NO SNOTEL GAUGES IN THE SANTA LUCIA RANGE  
SO IT'S HARD TO SAY HOW MUCH SNOW HAS FALLEN, BUT MRMS DATA  
SUGGESTS POSSIBLY 5-10" WITH A GREATER THAN 10:1 RATIO. IMPACTS  
ARE MINIMAL AS POPULATION BASE IS RATHER SMALL COMPARE TO THE REST  
OF THE BAY AREA, BUT INTERESTING NONETHELESS. THE REST OF THE BAY  
AREA DID SEE SOME PRECIP EARLIER IN THE NIGHT, BUT SHOWER  
ACTIVITY HAS DIMINISHED. GUSTY WINDS STILL REMAIN OVER THE HIGHER  
PEAKS WITH GUSTS IN THE 25-35 MPH RANGE. TEMPERATURES DID COOL OFF  
COMPARE TO 24 HOURS AGO, BUT SOME LINGER WINDS ARE KEEPS  
TEMPERATURES FROM REALLY DROPPING. SHELTERED VALLEYS MAY DIP BELOW  
FREEZING WITH SOME PATCHY FROST.  
 
BASED ON LATEST HI-RES MODELS WILL KEEP OROGRAPHIC SHOWERS GOING  
THROUGH THE MORNING HOURS BEFORE COMPLETE DRYING N TO S BY THIS  
AFTERNOON. IT SHOULD BE NOTED THAT GIVEN THE LOWER SNOW LEVELS ANY  
VERTICALLY DEVELOPED SHOWER COULD DROP SMALL HAIL. INCREASED  
SUNSHINE THIS AFTERNOON, BUT DAYTIME HIGHS WILL BE BELOW SEASONAL  
LEVELS AND IN THE 50S - 30S- 40S HIGHER TERRAIN.  
 
WINDS WILL TAPER OFF UNDER CLEARING SKIES THURSDAY NIGHT LEADING  
TO A COLD NIGHT. OVERNIGHT LOWS WILL DROP INTO THE 30S FOR MOST  
LOCATIONS, INCLUDING SOME URBAN CENTERS, AND LOW 40S FOR  
SF/COASTLINE. THE COLDEST LOCATIONS WILL BE THE INTERIOR VALLEYS  
AND HIGHER PEAKS WITH TEMPS DROPPING INTO THE 20S. WIDESPREAD  
FROST WILL BE POSSIBLE. DRY WEATHER WITH SLIGHTLY WARMER  
TEMPERATURES ARE EXPECTED ON FRIDAY. NEXT CHANCE FOR PRECIPITATION  
RETURNS TO THE BAY AREA SATURDAY AFTERNOON OVER THE NORTH BAY.  
LATEST MODEL GUIDANCE KEEPS SHOWERS CONFINED TO NORTH OF THE  
GOLDEN GATE THROUGH EARLY SUNDAY, BUT SPREADING PRECIPITATION  
SOUTHWARD. AT THIS POINT, MEDIUM RANGE MODELS KEEP THE HEAVIEST  
RAIN NORTH OF THE BAY AREA ON SUNDAY, BUT SOME PRECIP IS POSSIBLE  
AS FAR SOUTH AS SAN JOSE.  
 
MORE WIDESPREAD PRECIP IS EXPECTED ON MONDAY AS A BETTER MOISTURE  
PLUME DRIFTS SOUTHWARD. CONFIDENCE IS MEDIUM AS MEDIUM RANGE  
MODELS HAVE BEEN FLIPPING ON PRECIP AMOUNTS AND POTENTIAL FOR AN  
ATMOSPHERIC RIVER. MOST LIKELY LOCATION FOR MODERATE TO HEAVY RAIN  
EARLY NEXT WEEK WILL BE ACROSS THE NORTH BAY. WILL KEEP RAIN  
CHANCES IN THE FORECAST THROUGH THE MIDDLE OF NEXT WEEK WITH SOME  
GRADUAL DRYING POSSIBLE LATE IN THE WEEK. STAY TUNED AS DETAILS  
WILL LIKELY CHANGE BETWEEN NOW AND THEN.  
 

 
   
AVIATION...AS OF 04:00 AM PST THURSDAY
 
STORM SYSTEM EXITING  
AREA EARLY THIS MORNING WITH COLDER, DRIER AIR FILTERING IN BEHIND.  
LINGERING VICINITY SHOWERS AROUND KMRY/KSNS SHOULD DISSIPATE BY  
SUNRISE. BREEZY TO LOCALLY GUSTY NORTHWEST WINDS TODAY, ALBEIT  
WEAKER THAN YESTERDAYS WINDS. MID LEVEL CLOUDS WILL MIX OUT THROUGH  
EARLY MORNING, OTHERWISE, VFR WITH MOSTLY CLEAR SKIES THROUGH THE  
TAF PERIOD.  
 
VICINITY OF KSFO...VFR. WEST WINDS GUSTING 20 TO 25 KT BY MIDDAY.  
 
SFO BRIDGE APPROACH...SIMILAR TO SFO.  
 
MONTEREY BAY TERMINALS....VFR WITH BRIEF MVFR POSSIBLE INTO  
SUNRISE. LINGERING SHOWERS HAVE NOW MOSTLY MOVED SOUTH INTO BIG  
SUR BUT COULD SEE A FEW MORE PASS IN VICINITY OF KMRY/KSNS.  
OTHERWISE, BREEZY WEST WINDS. SKIES WILL GRADUALLY CLEAR THROUGH  
THE DAY.  
 

 
   
MARINE...AS OF 03:52 AM PST THURSDAY
 
GUSTY NORTHWEST WINDS WILL  
CONTINUE ACROSS THE WATERS TODAY WITH GALE FORCE GUSTS EXPECTED  
ACROSS THE OUTER WATERS. WINDS WILL DECREASE FRIDAY THROUGH  
SUNDAY. GUSTY WINDS WILL GENERATE STEEP FRESH SWELL CAUSING  
HAZARDOUS CONDITIONS ESPECIALLY FOR SMALLER VESSELS. MODERATE  
NORTHWEST SWELL WILL CONTINUE THROUGH THE END OF THE WEEK.  
 

 
   
MTR WATCHES/WARNINGS/ADVISORIES
 
 
.TDAY...SCA...PT ARENA TO PT REYES 0-10 NM  
SCA...PT REYES TO PIGEON PT 0-10 NM  
SCA...PIGEON PT TO PT PINOS 0-10 NM  
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM  
GLW...PT ARENA TO PIGEON PT 10-60 NM  
GLW...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM  
SCA...MRY BAY FROM 1 PM  
 

 
 

 
 
PUBLIC FORECAST: MM  
AVIATION: DRP  
MARINE: DRP  
 
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