Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 040416
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
916 PM PDT FRI JUL 3 2015

.SYNOPSIS...MONSOONAL MOISTURE WILL BRING CHANCES FOR ISOLATED TO
SCATTERED THUNDERSTORMS THROUGH SATURDAY NIGHT...WITH THE BEST
CHANCES OVER INTERIOR NORTHWEST CALIFORNIA SATURDAY AFTERNOON.
MORE SEASONAL TEMPERATURES WILL RETURN TO THE INTERIOR IN THE
COMING WEEK.


&&

.UPDATE...ISOLATED SHOWERS AND THUNDERSTORMS HAVE FORMED OVER THE
COASTAL WATERS WHILE MOST INLAND AREAS HAVE CLEARED OUT THIS
EVENING. THE TREND OF SHOWERS MOVING NORTH AND WEST OF THE AREA
WILL ONLY CONTINUE THROUGH THE NIGHT AS A SHORTWAVE TROUGH MOVES
NORTH OVER NORTHWEST CALIFORNIA. THE ONLY AREAS THAT MAY SEE A
FEW SHOWERS OR POSSIBLY A THUNDERSTORM TONIGHT WILL BE FAR
NORTHERN HUMBOLDT COUNTY AND DEL NORTE COUNTY...AS WELL AS THE
COASTAL WATERS NORTH OF CAPE MENDOCINO. THE FORECAST HAS BEEN
UPDATED TO REFLECT THESE TRENDS.

&&

.PREV DISCUSSION......ISSUED AT 317 PM PDT...

SYNOPSIS...MONSOONAL MOISTURE WILL BRING ISOLATED TO SCATTERED
THUNDERSTORMS TO THE MOUNTAINS CONTINUING THIS AFTERNOON AND
PERSISTING THROUGH THE WEEKEND. ISOLATED SHOWERS AND A FEW STORMS
ARE POSSIBLE ELSEWHERE. MORE SEASONAL TEMPERATURES WILL RETURN TO
THE INTERIOR IN THE COMING WEEK.

DISCUSSION...AN UPPER LEVEL RIDGE CONTINUES FROM SW UT TO N CA
AND S OR. THIS RIDGE HAS WEAKENED ABOUT 3 DAM OVER THE LAST DAY OR
SO AND WILL GRADUALLY WEAKEN THROUGH THE WEEKEND. AS A RESULT...
HIGH TEMPERATURES WILL CONTINUE TO SLIDE BACK BELOW 100 OVER THE
INTERIOR. HOWEVER...READINGS WILL AVERAGE ABOUT 5 DEGREES ABOVE
NORMAL DURING THE DAY UNTIL MON OR TUE OF NEXT WEEK. MONSOONAL
MOISTURE WILL SPREAD INTO THE AREA FROM THE SE WITH INCREASES IN
CLOUD COVER AS WELL AS AFTERNOON AND EVENING THUNDERSTORM CHANCES
OVER THE INTERIOR. A LIMITING FACTOR TO MORE AREAL COVERAGE WILL
BE MID AND HIGH CLOUDINESS...BUT THIS IS EXPECTED TO THIN SOMEWHAT
DURING THE MID TO LATE AFTERNOON HOURS. BOTH THE NAM AND GFS ARE
FORECASTING HIGHEST MUCAPES OVER N TRINITY COUNTY LATE THIS
AFTERNOON AND THIS EVENING WITH FAIRLY LOW CIN VALUES. STORMS THAT
DO FIRE WILL MOVE NW AT ABOUT 15 MPH WITH MOTION GRADUALLY
INCREASING AND BECOMING MORE NORTHERLY INTO THE EVENING HOURS. SEE
MORE INFO IN THE FIRE WX SECTION BELOW. LOW CLOUDS AND PATCHY
NIGHTTIME AND MORNING FOG WILL CONTINUE AFFECT COASTAL AREAS...WITH
IMPROVING CONDITIONS MOST AFTERNOONS. A BIT OF DRIZZLE IS POSSIBLE
EARLY THIS MORNING ALONG THE REDWOOD COAST PER LOW LEVEL OMEGA AND
SURFACE MOISTURE FLUX CONVERGENCE PROGS. THE UPPER RIDGE WILL
CONTINUE TO GRADUALLY BREAK DOWN INTO THE WEEKEND...TO BE REPLACED
BY A COL REGION. AN UPPER LOW IS PROGGED TO SLOWLY DEEPEN WELL SW
OF N CA LATE IN THE WEEK...THEN GRADUALLY SHIFT NE. THE MODELS
CONTINUE TO HAVE TROUBLE WITH THE EXACT MOTION OF THIS LOW...NOW
TRENDING BACK CLOSER TO THE COAST OF CENTRAL CA BY MID-WEEK. AS A
RESULT...LONG TERM MOS HAS TRENDED MAX TEMPERATURES A BIT COOLER
AGAIN FOR LATE IN THE WEEK. MOIST S FLOW BETWEEN THIS LOW AND THE
SW U.S. RIDGE WILL BRING ISOLATED TO LOW END SCATTERED POPS OVER
THE INTERIOR MOUNTAINS FOR MUCH OF THE COMING WEEK. HOWEVER...THIS
IS HIGHLY DEPENDENT ON THE FUTURE TRACK OF THE UPPER LOW. /SEC/JT

AVIATION...MVFR CONDITIONS AND LIGHT WINDS WILL CONTINUE AT KCEC
AND KACV THROUGH THE EARLY EVENING WITH THE LOWER CONDITIONS DUE TO
LOWER CEILINGS. TEMPORARY IFR CONDITIONS WILL OCCUR AT TIMES AT KACV
DUE TO REDUCED CEILINGS AND/OR VISIBILITIES. CEILINGS AND
VISIBILITIES WILL DIMINISH THIS EVENING AND OVERNIGHT TO IFR
CONDITIONS AT KCEC AND KACV. LIGHT WINDS TO CALM CONDITIONS WILL
PREVAIL AT KCEC AND KACV OVERNIGHT. VFR CONDITIONS AND LIGHT WINDS
TO CALM CONDITIONS WILL CONTINUE AT KUKI THROUGH SATURDAY.

MARINE...AN OFFSHORE HIGH PRESSURE RIDGE WILL GRADUALLY WEAKEN THE
NEXT FEW DAYS RELAXING THE PRESSURE GRADIENT ACROSS THE WATERS.
WINDS AND SEAS WILL SLOWLY DIMINISH THIS WEEKEND AND EARLY NEXT
WEEK. HOWEVER A SMALL CRAFT ADVISORY REMAINS IN EFFECT ACROSS THE
NORTHERN OUTER WATERS THROUGH TONIGHT DUE TO SHORT PERIOD SEAS.
LIGHT WINDS AND LOW SEAS WILL PERSIST ACROSS THE WATERS SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK.

FIRE WEATHER...A MOIST UNSTABLE AIRMASS CONTINUES TO ENVELOPE THE
REGION WHILE AN UPPER LEVEL LOW PROMOTES INSTABILITY. THE LOW WILL
MIGRATE OFF THE COAST AND WITH THE SUBTLE MOVEMENT THE STEERING
WINDS WILL ALSO FLUCTUATE. FOR THE REMAINDER OF THIS AFTERNOON
SHOWER AND THUNDERSTORM CELLS WILL GENERALLY MOVE FROM SOUTHEAST TO
NORTHWEST INCREASING THE CHANCES OF NEW FIRE STARTS ACROSS NW
CA...HOWEVER AS WE MOVE INTO TONIGHT AND TOMORROW THE FLOW SHIFTS TO
A MORE SOUTHERLY DIRECTION ALLOWING DEVELOPING STORMS TO MOVE INTO
SOUTHERN OREGON. EITHER WAY MOST OF THE CELLS ARE ASSOCIATED WITH
RAINFALL AND ARE NOT EXPECTED TO PROMOTE A TON OF STRIKES THUS NOT
WARRANTING A RED FLAG WARNING. THIS PATTERN WILL CONTINUE INTO NEXT
WEEK BUT ONE CHANGE WILL BE AN INCREASE IN SURFACE MOISTURE AND
CORRESPONDING RH VALUES. TEMPS WILL COOL A BIT TOO WHILE SHOWER
ACTIVITY IS EXPECTED TO CONTINUE MAINLY OVER THE NORTHERN ZONES.
THUS ANY NEW STARTS WILL LIKELY BE IN A FAVORABLE ENVIRONMENT THAT
WILL NOT PROMOTE LARGE OR RAPID FIRE GROWTH DUE TO THE FINE FUELS
RESPONDING TO THE COOLER AND MORE MOIST CONDITIONS.

TONKIN

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 5 AM PDT SATURDAY FOR PZZ470.

&&

$$

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