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Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 281030
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
330 AM PDT MON JUL 28 2014

.SYNOPSIS...A STRONG UPPER RIDGE OVER NW CALIFORNIA WILL BRING
ANOTHER HOT DAY TO THE INTERIOR...WHILE THE COAST SITS UNDER LOW
CLOUDS AND FOG. COASTAL AREAS WILL SEE PARTIAL AFTERNOON CLEARING
FOLLOWED BY A RETURN OF LOW CLOUDS AND FOG THIS EVENING.

.SHORT TERM (TODAY THROUGH THURSDAY)...UPPER LEVEL HIGH PRESSURE
RIDGING IN FROM THE DESERT SW WILL CONTINUE TO BRING WARM TEMPS TO
THE NW CAL INTERIOR THROUGH MIDWEEK. 850MB TEMPS ARE EXPECTED TO
VERY SIMILAR TO THOSE OF YESTERDAY AND TODAY WILL START WITH LESS
CLOUD COVER. THIS WILL ALLOW FOR EFFECTIVE HEATING AT THE SURFACE
TODAY, BRINGING DAYTIME HIGHS TO AROUND THE CENTURY MARK FOR MANY
AREAS. SOME LOCATIONS WILL REACH TO AROUND 105F OR SO. EARLY THIS
MORNING TEMPS AT THE 4000FT LEVEL ARE HOVERING AROUND THE MID 70S,
INDICATING VERY WARM AIR ALOFT. WITH A VERY SHALLOW MARINE LAYER AND
HIGH TEMPS EXPECTED THIS AFTERNOON, CRITICALLY LOW HUMIDITIES WILL
LIKELY DEVELOP WITH RH VALUES IN THE SINGLE TO LOW TEEN DIGITS
EXPECTED THIS AFTERNOON. RECOVERIES WILL BE MODEST OVERNIGHT IN THE
VALLEYS DUE TO RADIATIONAL COOLING AND WEAK ALONG THE RIDGES WITH
CONTINUED WARM AIR ALOFT. THUNDERSTORMS ARE NOT EXPECTED TODAY UNDER
THIS STOUT RIDGE, SO HAVE REMOVED THEM FROM THE FORECAST FOR TODAY.

THIS UPPER RIDGE IS PROVIDING A STRONG LOW LEVEL INVERSION ALONG THE
COAST THIS MORNING TRAPPING LOW LEVEL MOISTURE AND CAUSING FOG
ACROSS COASTAL REGIONS. THIS INVERSION WILL TAKE SOME TIME TO BREAK
THIS MORNING, KEEPING LOW CLOUDS AND FOG ALONG THE IMMEDIATE COAST
INTO THE EARLY AFTERNOON. SOME AFTERNOON SUNSHINE WILL FOLLOW, THEN
THE INVERSION WILL SET UP AGAIN EARLY IN THE EVENING BRINGING A
RETURN OF THE FOG.

AN ENTRENCHED UPPER TROUGH OVER THE NE PACIFIC WILL SWING MORE WEAK
SHORTWAVES THROUGH NW CAL TUE THROUGH THU. THIS WILL HELP TO SCOUR
OUT SOME OF THE FOG WED AND THU MORNING WHILE DEEPENING THE MARINE
LAYER ALLOWING FOR HIGHER OVERNIGHT RH VALUES INLAND. THESE
SHORTWAVES WILL ALSO BRING BETTER DYNAMICS DURING THE DAYTIME FOR
THUNDERSTORM DEVELOPMENT OVER THE NW CAL INTERIOR MOUNTAINS. AS
SUCH, HAVE KEPT THUNDERSTORMS IN THE FORECAST EACH LATE AFTERNOON
AND EARLY EVENING FOR TUE THROUGH THU IN CONJUNCTION WITH PEAK
HEATING. MODELS CONTINUE TO SHOW THE BEST THREAT OF THUNDERSTORMS ON
WED AND THU AFTERNOON OVER THE TRINITY AND DEL NORTE MOUNTAINS. BFG

.LONG TERM (THURSDAY THROUGH MONDAY)...MODELS REMAIN CONSISTENT IN
THE LONG TERM WITH BROAD TROUGHING OVER THE NORTHEASTERN PACIFIC AND
WEAK DISTURBANCES ALOFT MOVING OVER THE AREA MOST DAYS. MODELS HAVE
CONTINUED THE TREND OF FAVORABLE CONVECTIVE PARAMETERS OVER THE
NORTHERN PART OF THE AREA EACH AFTERNOON AND EVENING. AS HAS BEEN
THE CASE...THE BEST INSTABILITY LOOKS TO BE JUST NORTH OF THE AREA.
THE TIMING AND STRENGTH OF THE WAVES OF ENERGY COINCIDING WITH PEAK
HEATING AND A MID-LEVEL STABLE LAYER IS STILL UNCERTAIN. HAVE
CONTINUED THE SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE NORTHERN
FRINGE OF THE CWA TO PORTRAY THE UNCERTAINTY. HIGH TEMPERATURES
ACROSS THE INTERIOR VALLEYS WILL RANGE FROM THE UPPER 80S TO NEAR
100F WITH 60S TO NEAR 70F ALONG THE COAST. COASTAL CLOUDS WILL BE
PRESENT MOST NIGHTS AND MORNINGS. STP/BFG

.AVIATION...VFR CONDITIONS AND CALM WINDS ARE OCCURRING AT KCEC
AND KUKI. IFR CONDITIONS AND LIGHT WINDS ARE OCCURRING AT KACV DUE
TO REDUCED CEILINGS AND VISIBILITIES. CEILINGS AND/OR VISIBILITIES
WILL DECREASE AT KCEC TO MVFR TO IFR CONDITIONS EARLY THIS
MORNING. VFR CONDITIONS WILL CONTINUE AT KUKI THE NEXT FEW DAYS.
VFR CONDITIONS AND LIGHT TO MODERATE WINDS WILL OCCUR AT KCEC AND
KACV DURING THE AFTERNOON.

.MARINE...THE PERSISTENT INTERACTION BETWEEN THE THERMAL LOW
PRESSURE TROUGH ACROSS CALIFORNIA AND THE OFFSHORE HIGH PRESSURE
RIDGE WILL MAINTAIN A TIGHT PRESSURE GRADIENT OVER THE OUTER
WATERS THROUGH THE END OF THIS WEEK. THEREFORE ELEVATED WINDS AND
SEAS WILL PERSIST ACROSS THE OUTER WATERS THIS WEEK. SMALL CRAFT
ADVISORIES WILL CONTINUE ACROSS THE OUTER WATERS THROUGH FRIDAY
EVENING AND WILL LIKELY BE EXTENDED INTO THE WEEKEND.

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT FRIDAY PZZ470-475.

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