Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 291040
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
340 AM PDT FRI MAY 29 2015

.SYNOPSIS...WARM AND DRY WEATHER WILL CONTINUE ACROSS THE
INTERIOR THROUGH SATURDAY AS A HIGH PRESSURE RIDGE PERSISTS ACROSS
THE AREA. A WEAK COLD FRONT WILL APPROACH THE AREA SUNDAY AND
MONDAY PRODUCING COOLER TEMPERATURES INLAND AND SOME LIGHT
SHOWERS. LATE IN THE WEEK HIGH PRESSURE WILL RETURN.

&&

.DISCUSSION...HIGH PRESSURE REMAINS FIRMLY IN PLACE OVER THE WEST
COAST THIS MORNING. THE MARINE LAYER IS NOT PARTICULARLY
DEEP...AROUND 1500 TO 2000 FT IT APPEARS FROM SURFACE OBSERVATIONS
THE BODEGA BAY PROFILER. ONCE AGAIN IT LOOKS LIKE THE IMMEDIATE
COAST WILL ONLY SEE A FEW BREAKS IN THE CLOUDS. INLAND MOST AREAS
WILL SEE THE HOTTEST TEMPERATURES OF THE WEEK WITH HIGHS IN THE
UPPER 80S TO NEAR 90 TODAY. THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON OVER THE HIGHER ELEVATIONS OF NORTHERN TRINITY COUNTY
AND EASTERN DEL NORTE COUNTY. WITH THE RIDGE OVERHEAD CONVECTIVE
PROFILES ARE NOT OVERLY FAVORABLE...BUT GOOD ENOUGH THAT ITS HARD
TO RULE OUT AN ISOLATED SHOWER OR THUNDERSTORM.

TONIGHT THE MARINE LAYER IS EXPECTED TO START TO DEEPEN AS A WEAK
UPPER LEVEL TROUGH/COLD FRONT APPROACHES THE AREA. SATURDAY THIS
WILL LIKELY KEEP THE NEAR COASTAL AREAS...SUCH AS UKIAH AND
GARBERVILLE...A BIT COOLER EVEN THOUGH THE TEMPERATURES ALOFT
REMAIN STEADY. FARTHER INLAND TEMPERATURES WILL REMAIN NEARLY THE
SAME AS FRIDAY. SATURDAY AFTERNOON EXPECT CLOUDS MAY PERSIST A BIT
FARTHER INLAND THAN ON FRIDAY.

SUNDAY THE UPPER LEVEL TROUGH STARTS TO APPROACH THE AREA. AS
OFTEN HAPPENS WHEN THE MODELS SHOW A SYSTEM BREAKING DOWN A
RIDGE...THE SYSTEM HAS SLOWED DOWN AND WEAKENED A BIT. RAINFALL
AMOUNTS HAVE TRENDED DOWN AND MODEL GUIDANCE NOW SUGGESTS THE
HIGHEST AMOUNTS WILL BE NEAR A HALF INCH AT THE ORCAL BORDER WITH
LOWER AMOUNTS FARTHER SOUTH. WITH THE SYSTEM SLOWING DOWN SKIES
INLAND WILL BE A BIT CLEARER ON SUNDAY AND TEMPERATURES WILL BE
SLIGHTLY WARMER AS WELL. THERE IS STILL THE POTENTIAL FOR
THUNDERSTORMS LATE SUNDAY AFTERNOON AS THE SYSTEM MOVES
INLAND...ALTHOUGH IT IS LOOKING LESS LIKELY THAN ON PREVIOUS RUNS.
WITH THE SLOWER TIMING THE PEAK HEATING IS NOT AS FAVORABLE. THERE
IS STILL THE POTENTIAL FOR SOME THUNDERSTORMS SUNDAY NIGHT AND
MONDAY...HOWEVER CONFIDENCE IS LOW ON THIS. THE GFS SHOWS A COUPLE
HUNDRED J/KG OF CAPE ON MONDAY. MONDAY NIGHT AND TUESDAY IT LOOKS
LIKE THE UPPER LEVEL WILL HANG AROUND AND THERE MAY BE A FEW
LINGERING SHOWERS IN THE NORTH. AGAIN THERE IS THE POTENTIAL FOR
THUNDERSTORMS ON TUESDAY...HOWEVER IT LOOKS LIKE THE BEST DYNAMICS
ARE NORTH OF THE AREA BY THE AFTERNOON.

WEDNESDAY THROUGH FRIDAY HIGH PRESSURE BUILDS BACK IN OVER THE
REGION. THE MODELS ARE IN SOME DISAGREEMENT ON THE HOW FAST THIS
WILL HAPPEN...THE 00Z ECMWF IS FASTER THAN THE 00Z GFS AT BUILDING
THIS BACK. EITHER WAY THERE IS PRETTY GOOD AGREEMENT THAT THE
RIDGE WILL BE IN PLACE OVER THE AREA LATE IN THE WEEK. WITH SOME
WEAK OFFSHORE FLOW THERE IS THE POTENTIAL FOR SOME MORE CLEARING
AT THE COAST DURING THE AFTERNOON. INLAND TEMPERATURES WILL RETURN
TO THE UPPER 80S AND LOW 90S. MKK

&&

.AVIATION...FOG SATELLITE THIS MORNING SHOWS STRATUS ALONG THE COAST
AND MOSTLY CLEAR SKIES INLAND. ALONG THE COAST...EXPECT IFR TO
PREVAIL TODAY DUE TO WEAK ONSHORE WINDS. TEMPO VFR IS POSSIBLE LATE
THIS AFTERNOON. THOUGH, CONFIDENCE IN THIS OCCURRING IS LOW.
INLAND...VFR WILL PREVAIL.

&&

.MARINE...THE BUOYS THIS MORNING ARE REPORTING A NORTHERLY
MODERATE BREEZE AND SEAS RANGING FROM 4-6 FT. THE 0510Z ASCAT PASS
SHOWED WINDS OF ABOUT 15 KT ACROSS ZONE 470 AND 15-25 KT ACROSS
ZONE 475. THIS WAS AS MUCH AS 5 KT HIGHER THAN WHAT WAS
FORECASTED, SO ADJUSTED THE NEAR TERM WIND FORECAST UPWARDS TO
REFLECT THIS. MODELS ARE IN GOOD AGREEMENT SHOWING NORTHERLY WINDS
AND SEAS GRADUALLY TRENDING DOWNWARD TODAY INTO THIS WEEKEND AS
HIGH PRESSURE OFFSHORE WEAKENS, ALLOWING THE PRESSURE GRADIENT
ACROSS OUR WATERS TO WEAKEN. LEFT THE HEADLINE UP, BUT THINK IT
MIGHT NEED TO BE DROPPED EARLY (MAYBE THIS EVENING) BECAUSE THAT`S
WHEN MODELS INDICATE WINDS AND SEAS DROPPING. OTHERWISE, EXPECT A
LIGHT TO MODERATE BREEZE THIS WEEKEND WITH LOW SEAS. WINDS WILL
BECOME SOUTHERLY LATE SUNDAY INTO MONDAY AS A WEAK DISTURBANCE
PASSES TO OUR NORTH. MODELS THEN ARE IN GOOD AGREEMENT SHOWING
NORTHERLY CONDITIONS DEVELOPING AGAIN TOWARDS THE MIDDLE OF NEXT
WEEK AS HIGH PRESSURE OFFSHORE STRENGTHENS, CAUSING THE PRESSURE
GRADIENT ACROSS OUR WATERS TO STRENGTHEN.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PZZ475.

&&

$$

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