Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 282201
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
201 PM PST WED JAN 28 2015

.SYNOPSIS...DRY WEATHER WILL CONTINUE ACROSS NORTHWEST CALIFORNIA
INTO THE WEEKEND. WETTER CONDITIONS ARE EXPECTED TO BEGIN EARLY
NEXT WEEK AS A TROUGH MOVES OVER THE WEST COAST.

&&

.DISCUSSION...THE DRY WEATHER PATTERN WILL CONTINUE INTO THE
WEEKEND AS A RIDGE OF HIGH PRESSURE REMAINS OVER NORTHERN
CALIFORNIA. BY EARLY NEXT WEEK THE MODELS ARE SHOWING THE RIDGE
WEAKENING AND MOVING EASTWARD AS A TROUGH DEVELOPS OFFSHORE AND
MOVES TOWARDS THE WEST COAST. THIS PATTERN CHANGE WOULD BRING US
COOLER TEMPERATURES AND WETTER CONDITIONS. MODELS SHOW A WEAK
FRONT MOVING THROUGH OUR AREA LATE SUNDAY INTO MONDAY. RAISED POPS
A LITTLE BIT TO ACCOUNT FOR THE SLIGHTLY HIGHER CONFIDENCE, WITH
THE HIGHEST POPS ALONG THE NORTH, DECREASING TO THE SOUTH. BUT
RAINFALL AMOUNTS DON`T LOOK TO BE TOO IMPRESSIVE. TUESDAY INTO
WEDNESDAY A RIDGE BEGINS TO REDEVELOP OVER THE WEST COAST,
BRINGING A RETURN TO DRY CONDITIONS. HAVE POPS TRENDING DOWN
THOSE DAYS TO ACCOUNT FOR THIS.

&&

.AVIATION...AN UPPER LEVEL TROUGH WILL MOVE ACROSS NORTHERN
CALIFORNIA TONIGHT GENERATING MID AND HIGH LAYER CLOUD COVER.
PATCHES OF LOW CLOUD AND FOG WILL LIKELY FORM IN THE INTERIOR
VALLEYS LATE TONIGHT AND INTO THU MORNING...THOUGH THE HIGH CLOUDS
SHOULD INHIBIT THE LONG WAVE COOLING SOME. CONFIDENCE IS NOT HIGH
STRATUS OR FOG WILL ENVELOPE COASTAL SITES AS NORTH FLOW DEVELOPS
TONIGHT, SO THE FORECAST HAS BEEN BASED LARGELY ON PERSISTENCE.

&&

.MARINE...WINDS WILL TURN NORTHERLY THIS EVENING AS RIDGING
DEVELOPS OFFSHORE BEHIND A LOW PRESSURE SYSTEM WHICH WILL PASS
ACROSS THE AREA TONIGHT. NORTHERLY FLOW WILL INCREASE ON THURSDAY
AS THE PRESSURE GRADIENT TIGHTENS BRINGING WINDS OF 20-25KT AND
STEEP SEAS ACROSS THE OUTER WATERS INTO FRIDAY. THE INITIAL RAMP
UP OF THE WINDS WILL BE GRADUAL ON THU. SUBJECTIVELY DECIDED TO
HOLD OFF ON HOISTING ADVISORIES FOR SMALL CRAFT...EVEN THOUGH THE
NAM12, ARW, NMM...AND SREF SHOW AREAS OF 20-25 KT BY LATE IN THE
DAY. WINDS OF 20-25KT WILL LIKELY PERSIST INTO FRI WITH SHORT
PERIOD WAVE ENERGY CONTRIBUTING TO THE TOTAL SEA STATE. A LOW
PRESSURE SYSTEM WILL APPROACH OVER THE WEEKEND AND BUST UP THE
NORTHERLY GRADIENT RESULTING IN A REDUCTION OF WINDS.

FORERUNNERS TO A WEST-NORTHWESTERLY SWELL GENERATED FROM A LARGE
PACIFIC STORM ARRIVED TODAY. ACCORDING TO THE 2 CDIP BUOYS THESE
WAVES WERE ABOUT HALF OF A FOOT OR LESS. THE SWELL WILL CONTINUE
TO BUILD TONIGHT INTO THU...UP TO 4 FT AT 17 SECONDS THU
AFTERNOON. SWELL OF THIS MAGNITUDE MAY POSE A SNEAKER WAVE
THREAT...ESPECIALLY WITH THE INCOMING TIDE THU AFTERNOON. NWPS
GUIDANCE HAS A COUPLE OF SHORTER PERIOD WAVE GROUPS IN THE MIX AS
WELL, NW 4 FT AT 6 SECONDS AND W 3 FT AT 11 SECONDS. IF OUR
ASSUMPTIONS ARE CORRECT AND THESE SHORT PERIOD WAVES ACTUALLY
OCCUR...THE RISK FOR SNEAKER WAVES WILL BE REDUCED. IF THEY DO NOT
OCCUR AND THE OBJECTIVE GUIDANCE FROM THE NWPS AND ENP MODELS ARE
TOO HIGH...THEN THE RISK FOR SNEAKER WAVE ACTIVITY WILL BE HIGHER
AND BEACH GOERS WILL NEED TO KEEP A WATCHFUL EYE ON THE SURF. IT
IS NOT KNOWN FOR SURE AT THIS POINT IF THE NUMERICAL MODELS ARE
OVERDONE ON THE SHORTER PERIOD WAVES. IF THEY ARE NOT
OVERDONE...THE SHORT PERIOD WAVES MAY MAKE FOR UNCOMFORTABLE AND
CHOPPY CONDITIONS FOR RECREATIONAL BOATERS THU AFTERNOON.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...

CA...NONE.

NORTHWEST CALIFORNIA COASTAL WATERS...NONE.

&&

$$

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