Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 311124
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
424 AM PDT MON AUG 31 2015

.SYNOPSIS...TEMPERATURES WILL REMAIN NEAR OR BELOW NORMAL FOR THE
NEXT SEVERAL DAYS AS A TROUGH SITS OVER THE WEST COAST. LITTLE TO
NO RAIN IS EXPECTED...ALTHOUGH A FEW LIGHT SHOWERS WILL BE
POSSIBLE NORTH OF CAPE MENDOCINO EARLY WEDNESDAY.

&&

.DISCUSSION...MILD...BENIGN WEATHER CAN BE EXPECTED MONDAY AND
TUESDAY AS A TRANSIENT SHORTWAVE RIDGE WILL USHER IN DRIER AIR AND
SLIGHTLY WARMER TEMPERATURES. WHILE TEMPERATURES WILL BE WARMER
ACROSS THE INTERIOR THAN THE PAST COUPLE OF DAYS...HIGHS WILL
LIKELY REMAIN SLIGHTLY BELOW NORMAL WITH TEMPERATURES REACHING
THE LOW TO MID 80S IN VALLEY LOCATIONS. ALONG THE
COAST...INCREASING NORTHERLY WINDS WILL SEE TEMPERATURES DROP A
FEW DEGREES INTO THE MID TO UPPER 60S...WITH A RETURN OF STRATUS
AND FOG LIKELY OVERNIGHT MONDAY AND TUESDAY MORNING. DRIER AIR
ALOFT IS EXPECTED TO FILTER INTO THE REGION THIS EVENING AND
DESCEND IN ALTITUDE OVERNIGHT...WITH IMPLICATIONS FOR FIRE
WEATHER TONIGHT THROUGH TOMORROW AFTERNOON. FOR MORE DETAILS IN
THAT REGARD...PLEASE SEE THE FIRE WEATHER DISCUSSION BELOW.

DURING THE DAY TUESDAY...HEIGHTS WILL GRADUALLY BEGIN TO FALL
ACROSS THE NORTHEAST PACIFIC AS A POTENT SHORTWAVE SLIDES DOWN THE
BRITISH COLUMBIA COAST. TEMPERATURES TUESDAY AFTERNOON ARE NOT
LIKELY TO BE AFFECTED MUCH...BUT A COOLDOWN IS EXPECTED WEDNESDAY
THROUGH FRIDAY AS THE AXIS OF THE PRIMARY TROUGH SLIDES EASTWARD
ONTO THE WEST COAST AND SEVERAL SHORTWAVES MOVE THROUGH THE AREA.
ASIDE FROM A FEW LIGHT SHOWERS IN OUR NORTHERN AREAS ASSOCIATED
WITH A WASHED OUT FRONT OVERNIGHT TUESDAY AND EARLY
WEDNESDAY...NORTHWEST CA SHOULD REMAIN DRY THROUGHOUT THIS PERIOD.
ANOTHER LONGSHOT FOR RAIN EXISTS ACROSS THE INTERIOR TOWARDS THE
END OF THE WEEK AS A FINAL VORT MAX DROPS SOUTH INTO THE PACIFIC
NORTHWEST...BUT GUIDANCE HAS THUS FAR ALMOST UNANIMOUSLY KEPT
PRECIPITATION NORTH AND EAST OF OUR AREA.

AT SOME POINT OVER THE WEEKEND...THE TROUGH AXIS WILL FINALLY
BEGIN TO SLIDE EASTWARD...RESULTING IN A WARMING AND DRYING TREND.
MODEL GUIDANCE IS A BIT INCONSISTENT REGARDING WHEN EXACTLY THIS
WILL OCCUR...SO FOR NOW WILL KEEP TEMPERATURES ON THE COOL SIDE
UNTIL SUNDAY WHERE CONFIDENCE IS HIGHEST IN WARMER TEMPERATURES.
/BRC

&&

.AVIATION...VISIBILITIES DROPPED OFF SIGNIFICANTLY LATE IN THE
EVENING AT KCEC...A RESULT OF RADIATIONAL COOLING AND RECENT
RAINFALL. THERE DOESN`T SEEM TO BE MUCH IN THE WAY OF MARINE LOW
CLOUDS AND/OR FOG UNTIL YOU GET S OF PATRICKS POINT WHERE N FLOW
IS BEGINNING TO PILE UP LOW-LEVEL MOISTURE JUST OFFSHORE. THIS
CLOUDINESS WILL LIKELY CONTINUE THRU THE AFTERNOON HOURS WHEN
MODELS INDICATE CLOUDS WILL GRADUALLY EXPAND...SPREADING INLAND
LATE IN THE AFTERNOON. NAM IS FORECASTING STRONGER WINDS THAN THE
GFS AT THE COASTAL TAF SITES THIS AFTERNOON AND EVENING. WILL LEAN
TOWARD THE NAM...ESPECIALLY WITH RESPECT TO GUSTS. VFR CONDITIONS
AND LIGHT WINDS ARE ANTICIPATED AT KUKI. /SEC

&&

.MARINE...N-NW WINDS WILL CONTINUE TO SLOWLY INCREASE ACROSS THE
COASTAL WATERS TODAY...PARTICULARLY S OF CAPE MENDOCINO. WIND
GUSTS WILL OCCASIONALLY REACH GALE FORCE OVER THE S OFFSHORE
WATERS. SEAS ARE ALREADY AT SMALL CRAFT ADVISORY LEVELS S OF THE
CAPE...AND HAVE EXPANDED THE EXISTING ADVISORY INTO THE S NEAR
SHORE WATERS. THERE WILL BE A TIGHT GRADIENT IN SEAS ACROSS THE S
NEAR SHORE ZONE... ESPECIALLY TUCKED IN JUST S OF THE CAPE.
COMBINED SEAS OF 10 TO 12 FT WILL REMAIN POSSIBLE IN THE S
OFFSHORE WATERS INTO TONIGHT...WITH SEAS GRADUALLY SUBSIDING
THEREAFTER. /SEC


&&

.FIRE WEATHER...AS EXPECTED...RECOVERIES WERE GENERALLY GOOD
THROUGHOUT THE REGION OVERNIGHT...WITH THE EXCEPTION OF SOME
PEAKS ABOVE 5000 FT WHERE DRIER AIR EXISTS ALOFT. THIS IS LIKELY A
BIT OF FORESHADOWING FOR WHATS TO COME LATER TODAY...AS MORE MID
LEVEL DRY AIR IS EXPECTED TO FILTER INTO THE REGION THIS AFTERNOON
AND EVENING AND DESCEND IN ALTITUDE OVERNIGHT. BEFORE THIS
OCCURS...TEMPERATURES TODAY WILL LIKELY BE 5 TO 10 DEGREES WARMER
THAN YESTERDAY...RESULTING IN LOWER MINIMUM RH VALUES AS WELL.
THE HUMIDITY FORECAST FOR THE OVERNIGHT WILL BE A BIT
TRICKIER...AS THE TIMING OF THE DESCENDING DRY AIR IS A BIT
UNCERTAIN. WHAT WILL LIKELY HAPPEN IS THAT AS THE SUN
SETS...COOLING TEMPERATURES WILL ALLOW HUMIDITY VALUES TO RECOVER
FOR A BRIEF PERIOD DURING THE EVENING AND EARLY OVERNIGHT
HOURS...BUT LATE INTO THE NIGHT RH VALUES WILL LIKELY DROP
QUICKLY ON THE PEAKS AND MID SLOPES AS THE DRY AIR DESCENDS. THIS
DRY AIR WILL LIKELY LINGER INTO TUESDAY AFTERNOON AS WELL BEFORE
MOISTURE INCREASE AHEAD OF A WEAK FRONT OVERNIGHT. TEMPERATURES
SHOULD REMAIN COOLER THAN NORMAL THROUGH THE END OF THE WORK
WEEK...WITH MORE DRY AIR ALOFT EXPECTED TO MOVE INTO THE REGION
FOLLOWING WEDNESDAYS WEAK FRONT. OVER THE WEEKEND...A WARMING AND
DRYING TREND CONTINUES TO APPEAR LIKELY.

WINDS ARE EXPECTED TO RESUME THEIR TYPICAL NW ONSHORE/NE OFFSHORE
DIURNAL FLUCTUATIONS THIS AFTERNOON WITH SPEEDS GENERALLY AROUND 5
TO 10 MPH...WITH A FEW HIGHER GUSTS POSSIBLE ALONG RIDGES. THIS
PATTERN IS EXPECTED TO CONTINUE THROUGH THE WEEK...WITH A SLIGHT
INCREASING TREND IN WIND SPEEDS TOWARDS THURSDAY AND FRIDAY. /BRC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 9 AM PDT TUESDAY FOR PZZ455.

     SMALL CRAFT ADVISORY UNTIL 3 PM PDT TUESDAY FOR PZZ475.

&&

$$

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