Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 031216
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
516 AM PDT FRI JUL 3 2015

.SYNOPSIS...MONSOONAL MOISTURE WILL BRING ISOLATED TO SCATTERED
THUNDERSTORMS TO THE MOUNTAINS BEGINNING 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...ISOLATED LIGHT SHOWERS CONTINUE TO PIVOT ACROSS THE
S 1/3 OF THE AREA EARLY THIS MORNING IN RESPONSE TO A MID-LEVEL
VORTICITY SPOKE WRAPPING AROUND A DEEPENING UPPER LOW WELL SW OF
THE AREA. ENUF MID-LEVEL INSTABILITY AND DYNAMICS OVER THE S
OFFSHORE WATERS ARE ALLOWING A FEW THUNDERSTORMS TO FORM. THE NAM
INDICATES DIFFERENTIAL VORTICITY ADVECTION WILL INCREASE FARTHER
TO THE N DURING THE MORNING HOURS. IF SHOWERS START FORMING IN
THAT AREA...WE MAY NEED TO DO A QUICK UPDATE TO THROW ISOLATED
THUNDER IN OVER LAND THIS MORNING.

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

&&

.AVIATION...MONSOONAL MOISTURE STREAMING IN FROM THE SOUTH IS
BRINGING SHOWERS TO PORTIONS OF NORTHWEST CALIFORNIA THIS MORNING.
ALONG THE COAST...STRATUS/FOG WILL BRING IFR/LIFR CONDITIONS TO THE
COAST THIS MORNING. CONDITIONS WILL IMPROVE TO BORDERLINE IFR/MVFR
DURING THE LATE MORNING AND INTO THE AFTERNOON AS SHOWERS MOVE OVER
THE COAST. TEMPO REDUCTIONS ARE POSSIBLE IN SOME OF THE STRONGER
SHOWERS. INLAND...EXPECT SHOWERS AND THUNDERSTORMS TODAY. TEMPO
REDUCTIONS ARE POSSIBLE IN SOME OF THE STRONGER SHOWERS/STORMS.

&&

.MARINE...THE NEAR SHORE BUOYS THIS MORNING ARE REPORTING A
SOUTHERLY GENTLE TO MODERATE BREEZE AND MIXED SEAS RANGING FROM
5-7 FT. THE 0550Z ASCAT PASS FURTHER OFFSHORE SHOWED NORTHERLY
WINDS OF ABOUT 20- 25 KT ACROSS THE NORTHERN PART OF ZONE 470,
DECREASING TO ABOUT 10- 15 KT ACROSS THE SOUTHERN PORTION OF THE
ZONE. IT ALSO SHOWED WINDS RANGING FROM 5-15 KT ACROSS ZONE 475.
THESE WINDS WERE WITHING ABOUT 5 KT OF THE FORECAST AND INDICATED
THE HEADLINE IN ZONE 470 WAS ON TRACK. NORTHERLY WINDS WILL
CONTINUE ACROSS THE OUTER WATERS INTO SATURDAY MORNING. THE
STRONGEST WINDS WILL BE ACROSS THE NORTHWESTERN PORTION OF THE
COASTAL WATERS, EASING AS ONE HEADS TO THE SOUTH AND CLOSER TO THE
COAST. WINDS AND SEAS WILL SLOWLY TREND DOWNWARD ON INDEPENDENCE
DAY, THEN BECOME SOUTHERLY ON SUNDAY AS AN UPPER LEVEL LOW
APPROACHES FROM THE SOUTHWEST. LIGHT WINDS AND LOW SEAS WILL
PERSIST INTO THE MIDDLE OF NEXT WEEK AS THE UPPER LEVEL LOW MOVES
OVER OUR AREA.

&&

.FIRE WEATHER...MODELS CONTINUE TO INDICATE BEST CHANCES FOR
THUNDERSTORMS TODAY OVER N TRINITY COUNTY MOVING INTO W SISKIYOU
COUNTY WITH A SMALL AREA OF 30-35% POPS. AFTER COORDINATION WITH
MFR AND STO...HAVE DECIDED TO CONTINUE TO HEADLINE THIS IN THE
FWF PRODUCT. WILL CONTINUE TO COURSE OF ACTION FOR SAT AS WELL.
AS MENTIONED ABOVE...A FEW LIGHTNING STRIKES ARE NOT OUT OF THE
QUESTION ELSEWHERE...PARTICULARLY THIS MORNING. /SEC

&&

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

$$

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