698 
FXUS66 KEKA 102245
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
345 PM PDT MON AUG 10 2015

.SYNOPSIS...MOSTLY DRY WEATHER AND SEASONABLE TEMPERATURES ARE 
EXPECTED ONCE AGAIN TODAY. A SLIGHTLY COOLER AIR MASS IS EXPECTED
TO MOVE OVER THE REGION TUESDAY THROUGH THURSDAY AS AN UPPER LOW
SPINS OFF THE COAST. SMOKE ORIGINATING FROM WILDFIRES OVER THE
INTERIOR WILL CONTINUE TO IMPACT MANY AREAS OF NORTHWEST
CALIFORNIA THIS WEEK.

&&

.DISCUSSION...LOW CLOUDS ONCE AGAIN PUSHED INLAND LATE LAST
NIGHT AND EARLY THIS MORNING...BUT THIS CLOUDINESS RAPIDLY PEELED
BACK TO THE COAST AFTER SUNRISE. THICK SMOKE CONTINUES TO BLANKET
THE N HALF OF TRINITY COUNTY WITH THINNER SMOKE OR HAZE ACROSS
MANY OTHER INTERIOR LOCATIONS. CU HAS BEGUN TO DEVELOP JUST N OF
THE TRINITY HORN AND OVER THE YOLLA BOLLYS THIS AFTERNOON...AN
INCREASE OVER WHAT WE SAW SUN AFTERNOON. EXPECT SHOWERS TO DEVELOP
WITH A FEW THUNDERSTORMS POSSIBLE BY LATE THIS AFTERNOON OR THIS
EVENING. MOVEMENT WILL BE TO THE N. BETTER CHANCES OF PRECIP WILL
BE NE OF THE AREA IN SISKIYOU COUNTY.

AS THE UPPER TROF DIGS OFFSHORE AND A NEARLY CUT OFF LOW DEVELOPS
OFFSHORE THE N CA COAST...ISOLATED CONVECTION IS POSSIBLE OVER THE
INTERIOR AS WELL AS THE OUTER WATERS CLOSER TO THE LOW. DUE TO THE
LOW INSTABILITY NUMBERS IN THE MODELS ALONG WITH THE POSSIBLE
FURTHER INFLUENCE OF THICK SMOKE...HAVE LIMITED THUNDERSTORM
CHANCES.

LOW TO MID LEVEL S WINDS ARE INCREASING ACROSS MAINLY THE N ZONES
THIS AFTERNOON. S-SE WINDS MAY ALLOW MORE SMOKE TO SPREAD TOWARD
THE REDWOOD COAST TUE AND WED. IN ADDITION...HAVE CONTINUED
SLIGHTLY WARMER TEMPERATURES IN THIS TIME PERIOD ALONG THE COASTAL
PLAIN TO ACCOUNT FOR DOWNSLOPE FLOW. /SEC

&&

.AVIATION...A SHALLOW MARINE LAYER THIS MORNING HAS CAUSED SOME
ISSUES AT COASTAL TAF SITES...AS CIGS HAVE BOUNCED AROUND FROM VFR
TO LIFR AS LOW STRATUS HAS MOVED IN AND OUT OF TERMINAL SITES.
TOWARDS THE LATE AFTERNOON...THIS WILL BECOME LESS PROMINENT AS
MIXING SCOURS OUT THE STRATUS A BIT MORE. STRATUS WILL LIKELY
RETURN DURING THE EVENING AND OVERNIGHT HOURS...ALTHOUGH THE
PERSISTENCE OF MID/HIGH CLOUDS AND AN APPROACHING TROUGH IS ADDING
UNCERTAINTY TO BOTH THE EXTENT OF THE COVERAGE THE AND HEIGHT OF
THE LOW CIGS. WILL LEAN TOWARDS PERSISTENCE WITH LIFR CIGS AGAIN
TONIGHT...AS MODEL GUIDANCE SUGGESTS THAT THE MARINE LAYER WILL
REMAIN COMPRESSED AND SHALLOW. /BRC

&&

.MARINE...BENIGN CONDITIONS CONTINUE THROUGHOUT THE WATERS...AS
LIGHT WINDS HAVE RESULTED IN MIXED SEAS OF AROUND 3 TO 4 FEET.
THESE LIGHT WINDS CAN BE ATTRIBUTED TO THE SLOW APPROACH OF A LOW
PRESSURE SYSTEM FROM THE NORTH...WHICH HAS ACTED TO WEAKEN THE
PRESSURE GRADIENT BETWEEN THE OFFSHORE WATERS AND THE INLAND
THERMAL TROUGH. LIGHT TO MODERATE WINDS AND LOW SEAS WILL CONTINUE
FOR THE NEXT SEVERAL DAYS AS WELL...AS THIS LOW WILL CONTINUE TO
MOVE THROUGH THE WATERS BEFORE GRADUALLY PULLING AWAY TO THE
NORTHEAST LATE IN THE WEEK. AS IT DOES SO...HIGH PRESSURE WILL
BUILD ACROSS THE WATERS WHILE THE THERMAL TROUGH RE-ASSERTS ITSELF
ACROSS CALIFORNIA...RESULTING IN A RAPIDLY TIGHTENING THE PRESSURE
GRADIENT AND A MORE TYPICAL LATE SUMMER PATTERN. WINDS WILL BEGIN
TO INCREASE EARLY FRIDAY...AND CONTINUE TO INCREASE TO AT LEAST
NEAR GALE STRENGTH IN THE OUTER WATERS OVER THE WEEKEND.
LIKEWISE...SEAS WILL RAPIDLY INCREASE TO HAZARDOUS LEVELS IN AT
LEAST THE OUTER WATERS AS WELL. /BRC

&&

.FIRE WEATHER...AS MENTIONED ABOVE...SOUTHERLY FLOW OFF THE DECK
WILL CONTINUE TO INCREASE INTO TUE. RIDGETOP WIND GUSTS WILL
BECOME A CONCERN BY THIS AFTERNOON WITH GUSTY CONDITIONS POSSIBLY
PERSISTING INTO THU. DUE TO CONCERNS OF FIRE SPREAD AMONGST THE
AREA IMETS...HAVE CONTINUED A RED FLAG WARNING FOR ZONES
203...204 AND 211. SHIFTED THE WATCH FOR ZONES 212 AND 283 TO
BEGIN TUE MORNING. THE WATCH AND WARNING GO THRU TUE EVENING.THESE
WATCHES/WARNINGS MAY NEED TO BE EXPANDED IN BOTH AREAL COVERAGE
AND DURATION WITH LATER PACKAGES. RH RECOVERIES WILL BE FAIR ALONG
RIDGETOPS. DRIEST DAYTIME RH VALUES ARE EXPECTED TUE AFTERNOON.
HIGH CLOUDS MAY ACT TO CUT DOWN ON MIXING THIS AFTERNOON AND
EVENING. HIGH CLOUDS ARE EXPECTED TO THIN LATER TONIGHT WITH
BETTER MIXING ON TUE...ESPECIALLY AWAY FROM THICKER SMOKE. /SEC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...RED FLAG WARNING UNTIL 8 PM TUE ABOVE 3500 FT FOR CAZ003-004.

     FIRE WEATHER WATCH FROM TUE MORNING THRU TUE EVENING 
     ABOVE 3500 FT FOR CAZ003-004.

NORTHWEST CALIFORNIA COASTAL WATERS...NONE.

$$

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