Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 252244
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
344 PM PDT MON MAY 25 2015

.SYNOPSIS...AN UPPER TROUGH WILL BRING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO TRINITY COUNTY THROUGH THIS EVENING.
OTHERWISE DRY WEATHER WILL CONTINUE TO PREVAIL. LOW CLOUDS WILL
CONTINUE TO IMPACT COASTAL AREAS.


&&

.SHORT TERM...(THROUGH THURSDAY) AN UPPER LOW OVER WASHINGTON
CONTINUES TO PINWHEEL UPPER LEVEL ENERGY OVER NORTHWEST CALIFORNIA.
A SHORTWAVE MOVING OVERHEAD TODAY HAS ALLOWED SHOWERS AND ISOLATED
THUNDERSTORMS TO FORM OVER TRINITY COUNTY WHERE INSTABILITY IS
GREATEST. NORTHWESTERLY FLOW WILL PUSH THE STORMS TOWARD THE
SOUTHEAST OUT OF TRINITY COUNTY BY THE EARLY EVENING HOURS LEAVING
NORTHWEST CALIFORNIA DRY FOR THE OVERNIGHT. THE MARINE LAYER NEAR
THE COAST HAS BEEN QUITE PERSISTENT TODAY AND VERY DEEP. THIS
EVENING THE MARINE LAYER WILL ONCE AGAIN PUSH INLAND IMPACTING MANY
VALLEYS OF DEL NORTE...HUMBOLDT...AND MENDOCINO COUNTIES OVERNIGHT
INTO TUESDAY MORNING.

THE UPPER LEVEL LOW WILL CONTINUE TO SPIN OVER WASHINGTON ON TUESDAY
ALLOWING FOR ANOTHER ROUND OF SHOWERS AND STORMS OVER THE INTERIOR
MOUNTAINS PUSHING OFF TO THE SOUTHEAST. SOME WARMING ALOFT AS AN
UPPER LEVEL RIDGE BEGINS TO BUILD TOWARD THE WEST COAST MAY RESULT
IN MORE CAPPING THAN TODAY LIMITING THE NUMBER OF STORMS THAT
DEVELOP. THE MARINE LAYER WILL ONCE AGAIN PULL BACK TO THE COAST BUT
THEN REMAIN IN PLACE FOR COASTAL LOCATIONS FOR MUCH OF THE DAY.

THE UPPER LOW WILL BE PUSHED TOWARD THE EAST SLIGHTLY TUESDAY NIGHT
INTO WEDNESDAY AND THEN FARTHER EAST ON THURSDAY AS THE RIDGE BUILDS
OVER THE WEST COAST. THE RIDGE WILL END SHOWER DEVELOPMENT OVER THE
INTERIOR AS WARM AIR BUILDS ALOFT. THIS STRENGTHENING INVERSION WILL
COMPACT THE MARINE LAYER LIKELY RESULTING IN LOWERING CEILINGS AND
MORE FOG FOR COASTAL AREAS DURING MOSTLY THE OVERNIGHT AND MORNING
HOURS. /RPA

.LONG TERM...(FRIDAY THROUGH MONDAY) THE MODELS HAVE THE RIDGE
HOLDING INTO FRIDAY FOR CONTINUED WARMING AND DRYING. MODELS
CONTINUE TO SHOW ANOTHER TROUGH OR CLOSED LOW APPROACHING SAT INTO
SUN WITH SOUTHWEST FLOW ALOFT DEVELOPING AS THE RIDGE SHIFTS
SLIGHTLY TO OUR EAST. THIS SW FLOW IS TYPICALLY DRY WITH VERY
LITTLE CHANCES FOR ANYTHING MORE THAN SOME CLOUD BUILDUPS DURING
PEAK HEATING. THE FORECAST REALLY BECOMES MURKY NEXT SUN AND MON.
MODELS PLOW THE TROUGH INTO THE AREA BY 12Z MONDAY. IF THIS
HAPPENS WE WILL SEE MORE TERRAIN DRIVEN SHOWERS AND PERHAPS
STORMS. MODELS HAVE BEEN INCONSISTENT, SO WILL CONTINUE TO NOT
HAVE ANY SHOWERS IN THE FORECAST UNTIL THERE IS BETTER CONTINUITY
AND CONSISTENCY.


&&

.AVIATION...ALONG THE COAST CIGS HAD ACTUALLY LOWERED FROM MVFR TO
IFR...WHICH HAS PREVAILED THROUGH THE EARLY HALF OF THE AFTERNOON.
HOWEVER BY MID AFTERNOON THERE WERE A FEW POCKETS OF CLEARING SKIES
ESPECIALLY NEAR CRESCENT CITY...BUT STILL THE STRATUS CONTINUED TO
ENVELOP MOST OF THE COAST. INLAND...CLOUDS SCOURED OUT OF COASTAL
MOUNTAIN VALLEYS BY 10 AM BRINGING VFR CONDITIONS TO INTERIOR
AREAS. EXPECT TO SEE AT LEAST A FEW MVFR/IFR CLOUDS TO REFORM IN
INTERIOR VALLEYS OVERNIGHT. FOR CONVECTION...WIDELY SCATTERED
SHOWERS DEVELOPED OVER MUCH OF TRINITY COUNTY AND EASTERN MENDOCINO
THIS AFTERNOON AND WILL CONTINUE INTO EARLY EVENING. TA


&&

.MARINE...PRESSURE GRADIENT DRIVEN NORTHERLY WINDS WILL CONTINUE
THIS EVENING CONTRIBUTING TO LOCALLY GENERATED SHORT PERIOD WAVES
GENERALLY 8 TO 10 FT. THE NORTHERLY WINDS AND STEEP SEAS WILL
PERSIST AT LEAST ANOTHER 12-24 HOURS DUE TO AN OFFSHORE HIGH
PRESSURE SYSTEM STRENGTHENING. THE PATTERN BEGINS TO CHANGE TOWARD
WEDNESDAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES OVER THE
REGION...DIMINISHING THE GRADIENT AND RESULTING WINDS.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 11 PM PDT TUESDAY FOR PZZ470-475.

&&

$$

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