Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 020431
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
931 PM PDT SAT AUG 1 2015

.SYNOPSIS...SUB-TROPICAL MOISTURE STREAMING IN FROM THE SOUTH AND
A VIGOROUS LOW OFF THE COAST WILL COMBINE TO GENERATE SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS NORTHWEST CALIFORNIA THROUGH
SUNDAY. CONDITIONS WILL GRADUALLY IMPROVE MONDAY WITH MORE
SEASONAL TEMPERATURES EXPECTED.

&&

.UPDATE...UPDATED THE RFW...FWF...AND HWO TO REMOVE RED FLAG
WARNING HEADLINE. NO OTHER CHANGES MADE AT THIS TIME. /SEC

&&

.PREV DISCUSSION......ISSUED AT 402 PM...

SHORT TERM...(TODAY THROUGH TUESDAY) AN UPPER LOW WELL WEST OF
THE NW CAL COAST WILL STALL OVER THE NEXT COUPLE OF DAYS WHILE
BEING ABSORBED INTO A BROAD SCALE UPPER TROUGH APPROACHING FROM
THE SOUTHERN GULF OF ALASKA. THIS LOW WILL BRING INSTABILITY TO
OUR AREA WHILE ALSO HELPING PULL MONSOONAL MOISTURE INTO OUR AREA
FROM THE SOUTH. AS A RESULT THUNDERSTORMS ARE EXPECTED ACROSS OUR
AREA TODAY, CONTINUING INTO TONIGHT, THEN AGAIN ON SUNDAY. IF
ANYTHING, MODELS INDICATE SUNDAY MIGHT BE BETTER THAN TODAY FOR
CONVECTION. ADD TERRAIN INTO THIS EQUATIONS AND WE WILL NOT BE
LACKING FOR LIFT. FOR MORE INFORMATION ON THE THUNDERSTORM CHANCES
FOR NW CAL, SEE THE FIRE WEATHER DISCUSSION BELOW.

EARLY NEXT WEEK, THE LOW OFFSHORE WILL HAVE FILLED SIGNIFICANTLY
AND BECOME ABSORBED INTO A BROAD EAST PACIFIC TROUGH. THIS PATTERN
WILL HELP TO COOL NW CAL AND BRING HIGHER HUMIDITY LEVELS WITH
A DEEPENING MARINE LAYER.

LONG TERM...(WEDNESDAY THROUGH SATURDAY)...A WEAK COLD FRONT
WILL APPROACH THE REGION THE MIDDLE OF THIS NEXT WEEK. AN OFFSHORE
HIGH PRESSURE SYSTEM WILL STRENGTHEN BEHIND THE FRONT PRODUCING
PARTLY CLOUDY SKIES WITH THE EXCEPTION OF EARLY MORNING PATCHY FOG
ALONG SOME COASTAL AREAS. SEASONAL TEMPERATURES AND DRIER
CONDITIONS WILL PREVAIL ACROSS THE REGION THE MIDDLE OF THIS NEXT
WEEK THROUGH NEXT WEEKEND. CLEAR TO PARTLY CLOUDY SKIES WILL OCCUR
ACROSS INLAND AREAS WEDNESDAY THROUGH NEXT WEEKEND.

AVIATION...MVFR CONDITIONS AND LIGHT TO MODERATE WINDS WILL
CONTINUE AT KCEC AND KACV THROUGH THIS AFTERNOON DUE TO REDUCED
CEILINGS. MVFR CONDITIONS AND TEMPORARY IFR CONDITIONS WILL OCCUR
AT KCEC AND KACV OVERNIGHT AND EARLY SUNDAY MORNING WITH LIGHT
WINDS TO CALM CONDITIONS OCCURRING. THE LOWER CONDITIONS WILL BE
DUE PATCHY FOG REDUCING VISIBILITIES AND CEILINGS. VFR CONDITIONS
AND LIGHT WINDS TO CALM CONDITIONS WILL CONTINUE AT KUKI THROUGH
SUNDAY.

MARINE...A WEAK OFFSHORE LOW PRESSURE SYSTEM WILL MAINTAIN LIGHT
TO MODERATE WINDS AND LOW SEAS THROUGH MONDAY. A WEAK COLD FRONT
WILL APPROACH THE AREA TUESDAY AND WEDNESDAY. AN OFFSHORE HIGH
PRESSURE SYSTEM WILL STRENGTHEN BEHIND THE FRONT INCREASING
NORTHERLY WINDS AND SHORT PERIOD SEAS ACROSS THE WATERS TUESDAY
AND WEDNESDAY.

FIRE WEATHER...LEFT THE RED FLAG WARNING UP THROUGH THIS
EVENING. 2245Z RADAR DOESN`T SHOW MUCH CONVECTION ACROSS NORTHWEST
CALIFORNIA. HOWEVER, THERE ARE THUNDERSTORMS OUTSIDE OF OUR
DISTRICTS. PLUS, THE ATMOSPHERE REMAINS RIPE FOR THUNDERSTORM
DEVELOPMENT INTO THIS EVENING AND POSSIBLY OVERNIGHT ACROSS
PORTIONS OF THE INTERIOR. THIS IS DUE TO MONSOONAL MOISTURE
STREAMING IN FROM THE SOUTH COMBINED WITH LOW PRESSURE DRIFTING IN
FROM THE SW, BOTH PROVIDING THE NEEDED INGREDIENTS TO GENERATE
ISOLATED TO SCATTERED THUNDERSTORMS. PEAK ACTIVITY IS EXPECTED TO
OCCUR DURING THE HOTTEST PORTION OF THE DAY, MID AFTERNOON TODAY
THROUGH EARLY EVENING, AND AGAIN ON SUNDAY. THE MODELS ARE
ACTUALLY INDICATING SUNDAY MIGHT BE BETTER FOR THUNDERSTORMS, SO
ISSUED A FIRE WEATHER WATCH FOR THE SAME LOCATIONS AS THE CURRENT
WARNING (ZONES 203, 204, AND THE NORTHERN PORTION OF 283) FOR
SUNDAY AFTERNOON AND EVENING. EVEN THOUGH PWATS ARE AROUND 1 INCH,
STORMS ARE NOT EXPECTED TO PRODUCE SIGNIFICANT WETTING RAINS,
ESPECIALLY SINCE THEY WILL BE MOVING IN A GENERAL NORTHWARD
DIRECTION. PLUS, WITH ABUNDANT LIGHTNING EXPECTED, STRIKES AWAY
FROM A RAIN SHAFT ARE HIGHLY LIKELY. WINDS SHOULD REMAIN TERRAIN
DRIVEN, WITH THE EXCEPTION OF LOCALLY GUSTY AND ERRATIC WINDS
AROUND THUNDERSTORMS. RH VALUES SHOULD GRADUALLY INCREASE THE
NEXT FEW DAYS.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...FIRE WEATHER WATCH FROM SUN AFTERNOON THRU SUN EVENING
     FOR CAZ003-004.

NORTHWEST CALIFORNIA COASTAL WATERS...NONE.

$$

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