718
FXUS66 KEKA 122157
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
257 PM PDT MON AUG 12 2013
.SYNOPSIS...THE THREAT OF ISOLATED THUNDERSTORMS CONTINUES THROUGH
THIS EVENING. DRIER AND WARMER CONDITIONS WILL PREVAIL THROUGH
MOST OF THE WEEK.
&&
.DISCUSSION...WV IMAGERY SHOWS MINOR SHORTWAVE MOVG ACROSS CWA
ATTM. VIS IMAGERY SHOWS STRATUS DISSIPATING ALONG THE COAST WITH
SOME CU BUILDING OVER THE TRINITY ALPS AND YOLLA BOLLYS. INCREASED
INSTABILITY ASSOCIATED WITH THIS WAVE WILL RESULT IN ISOLD TSTM
DEVELOPMENT THROUGH THIS EVENING. CONTINUED ONSHORE FLOW WILL
RESULT IN STRATUS IMPACTING COASTAL AREAS OVERNIGHT AND IN THE
MORNING WITH BETTER CHCS FOR AFTERNOON CLEARING TO THE COAST TUE
AND WED. ONCE THIS WAVE PASSES...AN UPPER RIDGE WILL BUILD INTO
THE REGION FROM THE SE WHILE UPPER TROUGH LINGERS WELL OFFSHORE.
THIS WILL RESULT IN A GRADUAL WARMING AND SLIGHT DRYING INLAND
WITH HIGHS IN THE MID 90S AND AFTERNOON RHS IN THE MID TEENS TO
LOWERS 20S ALONG WITH POORER HUMIDITY RECOVERIES AT NIGHT ACROSS
THE HIGHER ELEVATIONS WHICH WILL NOT HELP THE WILDFIRES. MODELS IN
GOOD AGREEMENT WITH UPPER TROUGH NUDGING TOWARDS THE COAST
BEGINNING THU. THIS WILL RESULT IN INCREASED COASTAL CLOUDS ALONG
WITH MID/HI CLOUDS CROSSING CWA. THIS TROUGH IS FCST TO
WEAKEN/FILL AS IT MOVES INLAND LATE THIS WEEK. -DZ IS POSSIBLE
ALONG THE COAST FRI AS THE APPROACHING TROUGH DEEPENS THE MARINE
LAYER. INSTABILITY WILL ALSO INCREASE AS THE TROUGH CROSSES THE
REGION. FCST SOUNDINGS SHOW TOTAL TOTALS 30-40...BUT MOISTURE
ISN/T VERY IMPRESSIVE. GIVEN THE LIMITED MOISTURE...ELECTED TO
KEEP TSTMS OUT OF FCST ATTM. MODELS SHOW SOME ENERGY SHEARING OFF
THE MAIN TROUGH AND LINGERING OFFSHORE/ACROSS NRN CA. THIS WOULD
MAINTAIN MARGINAL INSTABILITY FOR CONVECTION THROUGH THE WEEKEND.
GIVEN THE DISPARITIES IN THE LOCATION AND STRENGTH OF THIS
FEATURE...FCSTR CONFIDENCE REMAINS LOW AND ELECTED NOT TO INCLUDE
MENTION ATTM.
&&
.AVIATION...COASTAL MARINE CLOUDS CONTINUED ALONG THE NORTH COAST
THROUGH EARLY AFTERNOON...ALTHOUGH NOT AS EXTENSIVE AS YESTERDAY.
PARTIAL CLEARING OCCURRED A LITTLE EARLIER TODAY. VISIBILITIES
WERE GENERALLY VFR EXCEPT AROUND HUMBOLDT BAY TO ACV WHERE THEY
DROPPED TO LIFR CONDITIONS THROUGH MID-MORNING. 2030Z SATELLITE
VIS PICTURE SHOWED CLEARING OVER CEC EVEN AS SOME LOW CLOUDS
WERE HANGING AROUND CEC'S SOUTHERN FRINGE. ACV REMAINED CLOUDED
OVER EVEN AS THE VICINITY SHOWED WIDESPREAD CLEARING. THEREFORE
SOME COASTAL CLEARING THROUGH EARLY EVENING...THEN BACK TO ANOTHER
OVERNIGHT OF RESTRICTED CIGS AND VISIBILITIES FOR COASTAL AIRFIELDS.
INLAND AIRPORTS AGAIN WILL REMAIN VFR WITH NO EXPECTED HAZARD
THREATS EXCEPT FOR A WEAK CHANCE OF AFTERNOON/EVENING CONVECTION
OVER THE INTERIOR RANGES.
&&
.MARINE...LIGHT NORTHERLY WINDS AND LOW SEAS WILL CONTINUE THROUGH
MOST OF THE WEEK. WINDS HAVE BEEN STRONGER SOUTH OF THE CAPE IN THE
OUTER WATERS...10-60NM...WHERE SPEEDS HAVE REACHED 20 KTS AND
SEA HEIGHTS 6 FT. A WEAK TROUGH ALOFT WILL APPROACH THE WEST COAST
AROUND MID WEEK. THIS WILL FORCE A SURFACE RIDGE AXIS OVER OR NEARBY
THE NORTHERN WATERS AND RESULT IN LESS NORTH WINDS SOUTH OF THE CAPE.
WINDS MAY EVEN GO LIGHT SLY NORTH OF THE CAPE...BUT VARIABLE SEEMS
MORE LIKELY. SEAS SHOULD REMAIN FAIRLY LOW THROUGH MOST OF THE
WEEK...WITH MOSTLY SHORT PERIOD COMPONENTS DOMINATING THE SPECTRUM.
DETERIORATING CONDITIONS ARE EXPECTED THIS WEEKEND. NORTHERLY WINDS
AND SHORT PERIOD SEAS WILL BE ON THE INCREASE THIS FRIDAY AND SHOULD
RAMP UP OVER WEEKEND AS THE TROUGH ALOFT PROGRESSES TO THE EAST. THE
GFS ENSEMBLE AND OTHER MODELS LOOK TO BE IN GOOD AGREEMENT WITH HIGH
PRES BUILDING TOWARD THE PAC NW AND THERMAL LOW PRES DEVELOPING OVER
INTERIOR CA. THE MAGNITUDE OF THE WINDS ARE A BIT SKETCHY AT THIS
TIME. HOWEVER...A LOW END GALE IS NOT COMPLETELY OUT OF THE QUESTION
IN THE OUTER WATERS. IT LOOKS LIKE THE LONG STRETCH OF FAIRLY LIGHT
WINDS AND LOW SEAS WILL BE COMING TO AN END THIS WEEKEND.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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