Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 160126 AAA
AFDEKA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE EUREKA CA
626 PM PDT TUE APR 15 2014

.SYNOPSIS...DRY CONDITIONS WILL PERSIST FOR THE NEXT SEVERAL DAYS
WITH NIGHTTIME AND MORNING LOW CLOUDS AND FOG. LIGHT RAINS ARE
POSSIBLE THURSDAY PRIMARILY NORTH OF CAPE MENDOCINO AS FRONT MOVES
THROUGH THE AREA.

&&

.UPDATE...DID A QUICK UPDATE ON THE MARINE FORECAST. THE SHORT
PERIOD WAVES OVER THE SOUTHERN WATERS AT BUOY 14 WERE ABOUT 3 FEET
HIGHER THAN CURRENTLY FORECAST. THEY WILL DIMINISH TONIGHT BUT
SLOWED DOWN TREND. MKK

&&

.PREV DISCUSSION......ISSUED AT 310 PM PDT...

SHORT-TERM...(TONIGHT THROUGH THUR NIGHT)...TEMPERATURES WERE
COOLER INLAND WITH COLD ADVECTION FROM MONDAY`S TROUGH.
TEMPERATURES WILL DROP INTO FROST ADVISORY CONDITIONS AROUND
HAYFORK AND WEAVERVILLE AND HAVE GONE AHEAD AND ISSUED FROST
ADVISORY FOR THOSE AREAS. RIDGE BUILDING OVER AREA WED AND
TEMPERATURES WILL REBOUND SLIGHTLY INLAND. THE MARINE LAYER DOES
NOT LOOK AS EXTENSIVE TONIGHT SOUTH OF THE CAPE BUT WILL STILL
HAVE SOME LOW CLOUDS AND FOG IN THE COASTAL VALLEYS. FURTHER NORTH
STRATUS WILL BE SLOWER TO DEVELOP AS INVERSION WEAKENED WITH COOL
ADVECTION. WILL STILL SEE STRATUS DEVELOPING BY SUNRISE NORTH OF
THE CAPE AROUND HUMBOLDT BAY AND EEL RIVER VALLEY. NEXT TROUGH TO
BE PASSING THROUGH THURSDAY INTO EARLY THUR NIGHT MAINLY NORTH OF
THE CAPE. THIS IS ABOUT 6 HOURS FASTER THAN PREVIOUS FORECAST WITH
THE FASTER GFS. AMOUNTS STILL LOOK LIGHT WITH TOTAL VALUES LESS
THAN A QUARTER INCH IN HEAVIEST AREAS. COULD ALSO SEE A FEW
SHOWERS OVER EASTERN MOUNTAINS OF MENDO COUNTY AS SOUTHERN END OF
TROUGH LOOKS LIKE IT IS TRYING TO CUT OFF AND COULD SEE SOME
UPSLOPE SE FLOW. LAPSE RATES DON`T LOOK UNSTABLE ENOUGH FOR TSTMS
BUT WILL HAVE TO WATCH FOR POSSIBILITY. DEAN

LONG TERM...(FRIDAY MORNING THROUGH TUESDAY) THE GLOBAL LONG WAVE
GEO POTENTIAL HEIGHT MODEL INDICATES FLATTENING OF THE UPPER LEVEL
RIDGE FRIDAY TRANSITIONING TO A LONG WAVE TROUGH INTO THE WEEKEND.
THE WEEKEND SHOULD BE MOSTLY DRY WITH UNMENTIONABLE CHANCES FOR
RAIN ASSOCIATED WITH A WEAK SHORTWAVE IN THE UPPER FLOW FOR LATE
SATURDAY INTO EARLY SUNDAY. CHANCES FOR PRECIPITATION INCREASE ON
MONDAY AS MODELS PROG A MORE PROMINENT SHORTWAVE TROUGH TO IMPACT
THE WEST COAST EARLY NEXT WEEK. BOTH THE ECMWF AND THE GFS HAVE
BEEN HINTING AT THIS TROUGH BUT CONTAIN DISAGREEMENT IN THE TIMING
AND PLACEMENT OF THE SHORTWAVE, WITH THE GFS BEING THE MORE
PROGRESSIVE OF THE TWO. MODELS HAVE BEEN DOING A POOR JOB
FORECASTING THE IMPACT OF RAIN IN THE LONG RANGE, HOWEVER, THAT IS
NOT ENOUGH EVIDENCE TO RULE OUT THE POSSIBILITY OF RAIN AT THIS
TIME. THUS, ALL BLEND WAS USED FOR POPS EARLY NEXT WEEK WITH ABOVE
CLIMO POPS FOR THE TAIL END OF THE FORECAST WITH MODELS SHIFTING
THE MAIN BOUT OF RAIN TO LATER MONDAY. KML

AVIATION...ALONG THE COAST...A PRESSURE GRADIENT ALONG THE COAST
IS GENERATING GUSTY NORTHERLY WINDS. THE GRADIENT WILL WEAKEN THIS
EVENING AFTER SUNSET, ALLOWING THE WINDS TO EASE. EXPECT VFR TO
PREVAIL. INLAND...EXPECT VFR TO PREVAIL WITH LIGHT TERRAIN-DRIVEN
WINDS.

MARINE...NEARSHORE BUOY OBSERVATIONS THIS AFTERNOON SHOW STRONG
NORTHERLY WINDS WITH GUSTS NEAR GALE FORCE AND MIXED SEAS AROUND
8-12 FT. THE 19Z ASCAT PASS SHOWED WINDS AROUND 25 KT ACROSS OUR
NORTHERN WATERS AND 25-30 KT ACROSS OUR SOUTHERN WATERS. THIS IS
ON TRACK WITH THE FORECAST AND CONFIRMS THE HEADLINES, ESPECIALLY
THE GALE WARNING, ARE ON TRACK. MODELS REMAIN IN GOOD AGREEMENT
HAVING A STRONG PRESSURE GRADIENT ACROSS OUR WATERS. THIS WILL
ALLOW THE GUSTY NORTHERLY WINDS AND SHORT PERIOD SEAS TO CONTINUE
TONIGHT INTO WEDNESDAY. MODELS SHOW THE WINDS WEAKENING SLIGHTLY
ON WEDNESDAY IN RESPONSE TO THE PRESSURE GRADIENT WEAKENING
SLIGHTLY. THIS MEANS THE WINDS IN ZONE 475 MIGHT DROP BELOW GALE
FORCE, PUTTING THE GALE WARNING IN QUESTION. BUT SEAS SHOULD
REMAIN ELEVATED AND NEAR HAZARDOUS SEAS CRITERIA, SO LEAVING THE
GALE WARNING OUT TO ACCOUNT FOR THIS MIGHT BE EASIER THAN CHANGING
ONE WARNING FOR ANOTHER. THE NIGHT CREW WILL NEED TO TAKE ANOTHER
LOOK AT THIS. WINDS WILL EASE ON THURSDAY AS A WEAK DISTURBANCE
PASSES TO OUR NORTH, CAUSING THE PRESSURE GRADIENT TO WEAKEN. A
LONG PERIOD WESTERLY SWELL GENERATED FROM A DISTANT STORM SHOULD
BEGIN MOVING THROUGH OUR WATERS LATE THURSDAY INTO FRIDAY. EXPECT
LIGHT TO MODERATE WINDS TO PREVAIL FRIDAY INTO THIS WEEKEND.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...FROST ADVISORY FROM 4 AM TO 8 AM PDT WEDNESDAY CAZ004.

NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING PZZ450.

     SMALL CRAFT ADVISORY UNTIL 9 PM PDT WEDNESDAY PZZ455-470.

     GALE WARNING UNTIL 9 PM PDT WEDNESDAY PZZ475.

&&

$$

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