Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 221413
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
441 AM PDT FRI MAY 22 2015

.SYNOPSIS...DRIER NORTHERLY FLOW WILL DEVELOP OVER NORTHWEST
CALIFORNIA THIS WEEKEND RESULTING IN DECREASING CLOUD COVER
AND SHOWER ACTIVITY ACROSS THE INTERIOR. THE COAST WILL CONTINUE
TO SEE MOSTLY CLOUD COVER.

&&

.DISCUSSION...A BROAD UPPER TROUGH WILL BRING MORE SHOWER
ACTIVITY AND ISOLATED THUNDERSTORMS TO THE INTERIOR AGAIN TODAY.
THE BULK OF THE ACTIVITY WILL SHIFT EASTWARD TODAY AS AN UPPER
RIDGE PUMPS UP NEAR 130W AND THE FLOW ALOFT GOES NORTHERLY. THIS
NORTHERLY FLOW WILL IMPORT DRIER AIR OVER THE AREA. A WEAK TROUGH IN
THE NORTH FLOW WILL DEVELOP INTO A CLOSED LOW JUST TO OUR EAST ON
SAT WITH THE SLIGHTEST POSSIBILITY FOR ISOLATED SHOWERS OVER THE
HIGHER TERRAIN OF EASTERN TRINITY AND EASTERN MENDOCINO COUNTIES IN
THE WRAP AROUND. OTHER THAN THIS SMALL CHANCE OF AFTERNOON SHOWERS
OVER THE MOUNTAINS...THE WEEKEND IS SHAPING UP TO BE FAIRLY TRANQUIL
AND DRY WITH LESS INTERIOR CLOUD COVER.

SATELLITE IMAGERY SHOWED EXTENSIVE LOW CLOUD COVER OFF THE
ENTIRE WEST COAST THIS MORNING. IT IS NOT CLEAR WHAT WILL
CAUSE THIS TO CHANGE SUBSTANTIALLY OVER THE NEXT 24 HOURS. NAM12
AND BUFKIT PROFILES INDICATE SHALLOW MOISTURE AND A STRENGTHENING
INVERSION ALONG THE COAST THROUGH THE WEEKEND AS NORTHERLY FLOW
INCREASES OFFSHORE. THIS DOES NOT BODE WELL FOR CLEARING
ESPECIALLY AROUND EUREKA. GRANTED THERE WILL BE BETTER CHANCES FOR
CLEARING AROUND PT ST GEORGE AND SOUTH OF CAPE MENDO AS NORTH
WINDS INCREASE A TAD.

ANOTHER UPPER TROUGH WILL DEVELOP OVER THE REGION ON MONDAY AND
TUESDAY BRINGING THE POSSIBILITY OF SCATTERED OR ISOLATED SHOWERS
TO MAINLY THE INTERIOR NORTH OF CAPE MENDO. MOISTURE WILL BE
SOMEWHAT LIMITED...SO THE ACTIVITY SHOULD NOT BE AS WIDESPREAD IN
THE INTERIOR AS WE HAVE SEEN THIS WEEK. HIGHEST RAIN CHANCES HAVE
BEEN CONFINED TO TRINITY COUNTY AND HIGHER ELEVATIONS. THERE ARE
INDICATIONS IN THE DATA FOR THUNDERSTORMS AS WELL ON BOTH DAYS. IT
IS STILL 4 TO 5 DAYS OUT AND WILL NOT ADD ANY STORMS TO THE
FORECAST UNTIL THERE IS BETTER CONSISTENCY.

FORECAST CONFIDENCE REALLY TAKES A NOSE DIVE ON WED AND THU.
THE ECMWF HAS A BROAD FLAT RIDGING DEVELOPING OVER THE
AREA...WHILE THE 0Z GFS AND CMC GEM MAINTAIN AN UPPER TROUGH. NO
CHANGES WERE MADE TO THE FORECAST FOR THIS TIME PERIOD. DRY
WEATHER WILL CONTINUE TO PREVAIL FOR MOST AREAS MOST OF THE TIME
THROUGH THE WEEKEND AND ALL OF NEXT WEEK.

&&

.AVIATION...PERSISTENT MARINE LAYER WILL MAINTAIN MVFR CONDITIONS
WITH BRIEF PERIODS OF IFR MAINLY DUE TO LOWER CIGS. NOT EXPECTING
MUCH RELIEF IN TERMS OF MARINE CLOUDS OVER THE NEXT TAF CYCLE EXCEPT
FOR SOME VERY BRIEF BREAKS LATE IN THE AFTERNOON.  THE INTERIOR AIR
TERMINALS WILLE REMAIN MAINLY VFR EXCEPT FOR SOME EARLY MORNING FOG
AND LOW CLOUDS.

&&

.MARINE...A SERIES OF WEAK LOW PRESSURE TROUGHS WILL MOVE THROUGH
THE REGION TODAY MAINTAINING LIGHT TO MODERATE NORTH TO
NORTHWESTERLY WINDS AND LOW SEAS ACROSS THE WATERS. NORTHERLY WINDS
AND STEEP SEAS WILL INCREASE THIS WEEKEND AS AN OFFSHORE HIGH
PRESSURE SYSTEM STRENGTHENS INCREASING THE PRESSURE GRADIENT ACROSS
THE WATERS. WINDS AND SEAS WILL BE HIGHER ACROSS THE OUTER WATERS. A
SMALL CRAFT ADVISORY MAY BE NECESSARY ACROSS PORTIONS OF THE COASTAL
WATERS FOR WINDS AND STEEPENING WAVES ON SATURDAY. MODELS ARE
INDICATING THE PATTERN BECOMING VERY DIFFUSE MONDAY, WHICH WOULD
EASE CONDITIONS FOR THE FIRST HALF OF THE WEEK.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&

$$

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