Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 131256
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
556 AM PDT SUN JUL 13 2014

.SYNOPSIS...HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION TODAY
THROUGH MONDAY PRODUCING HOT WEATHER CONDITIONS ACROSS THE INTERIOR.
SURFACE HIGH PRESSURE WILL BUILD TOWARD THE COAST TODAY THROUGH
MONDAY AND BRING BETTER CHANCES OF AFTERNOON CLEARING.

&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWED A DRY MID LEVEL SHORTWAVE
DISTURBANCE HEADING NORTHEAST TOWARD THE PACIFIC NW COAST EARLY
THIS MORNING. SATELLITE ALSO SHOWED A STREAM OF HIGH CIRRUS CLOUDS
ASSOCIATED WITH A SOUTHWESTERLY SPEED MAX. THE GFS MODEL CONTINUES
TO SHOW SOME INSTABILITY OVER NE DEL NORTE COUNTY PEAKING THIS
MORNING. SO FAR THERE HAS BEEN NOTHING ON RADAR OR SATELLITE TO
INDICATE CONVECTION FIRING UP THIS MORNING. THE HIGH RESOLUTION
MODELS HAVE CONVECTION DEVELOPING THIS AFTERNOON WELL TO OUR NE
OVER THE OREGON CASCADES AND EASTERN OREGON...SO HAVE REDUCED THE
TSTM CHANCES FOR TODAY.

THE MAIN FOCUS FOR THE NEXT DAY OR SO WILL BE WARMER TEMPERATURES
ACROSS THE INTERIOR. 850MB TEMPERATURES WARM UP TODAY AND THEN A
LITTLE MORE ON MONDAY AS A STRONG RIDGE ALOFT BUILDS OVER NRN CAL.
SO FAR THE MOST IMPRESSIVE 24 HOUR TEMP CHANGES HAVE BEEN ACROSS
SOUTHERN MENDO COUNTY WHERE HOPLAND UC SHOWED +15F. THE WARMING
WAS NOT AS GREAT ACROSS THE REST OF THE AREA...BUT THAT SHOULD
CHANGE TODAY AND TONIGHT AS THE RIDGE BUILDS. SURFACE HIGH PRESSURE
WILL ALSO BUILD TOWARD THE COAST TODAY AND BRING STRONGER NORTH
FLOW TO THE COASTAL TERRAIN. OFFSHORE FLOW ON MONDAY DOES NOT LOOK
STRONG ENOUGH TO COMPLETELY ERADICATE THE STRATUS AND FOG...BUT
THE MARINE LAYER SHOULD DECREASE SOME WITH LESS INLAND INTRUSION.

CONCERN HEADING INTO TUE AND WED WILL BE SHWR AND TSTM CHANCES.
THE GFS CONTINUES TO INDICATE A SOUTHEASTERLY WAVE FEATURE MOVING
TOWARD THE AREA MONDAY NIGHT AND TUE. 700-500MB LEVEL HUMIIDITIES
INCREASE ON TUE. ALL THIS RH WILL RESULT IN MOSTLY CLOUDY SKIES
WHICH WILL HAMPER SOLAR INSOLATION AND CONVECTIVE DEVELOPMENT.
THUS WE SHOULD SEE SEVERAL DEGREES OF COOLING ACROSS THE INTERIOR
ON TUE DUE TO CLOUD COVER. PWATS INCREASE TO AROUND 1 INCH ON
TUE...BUT MOST OF THIS LOOKS TO BE ABOVE 600MB. CONFIDENCE WE WILL
SEE A LOT OF LIGHTNING IS NOT HIGH. THERE WILL BE SOME CINH TO
OVERCOME EACH DAY AS WELL. ALSO THE GFS HAS BEEN SHOWING CONVECTIVE
PRECIP SPREADING INTO THE AREA AS EARLY AS MONDAY NIGHT. ISOLATED
SHOWERS OR SPRINKLES MAY NEED TO ADDED TO THE FORECAST FOR MON NGT
IF THIS TREND CONTINUES.

THE GFS CONTINUES TO INDICATE INSTABILITY LINGERING ON WED AND THU
FOR THE POSSIBILITY OF TSTMS IN MAINLY TRINITY COUNTY. ONCE AGAIN
NOT SURE IF THE STORMS WILL BE WET OR DRY AND IF COVERAGE WILL BE
ISOLATED OR SCATTERED. DRIER AIR AND MORE STABLE CONDITIONS SHOULD
SPREAD INTO THE AREA ON FRI AND SAT. THE MODELS WERE NOT IN REAL
GOOD AGREEMENT WITH A TROUGH LATE NEXT WEEK. THE OVERALL PATTERN
ADJUSTMENT TO A MORE ZONAL FLOW INTO THE PAC NW SEEMS SIMILAR AS
THE RIDGE ALOFT RETROGRADES. FOR NOW WILL MAINTAIN NEAR NORMAL
CONDITIONS FOR MID JULY FRI THROUGH SUN.

&&

.AVIATION...SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATED IFR
TO LIFR CONDITIONS ACROSS MUCH OF COASTAL CALIFORNIA EARLY THIS
MORNING. EXPECT A DAY MUCH LIKE YESTERDAY WITH MVFR TO IFR CEILINGS
AND FEW COASTAL AREAS SCATTERING OUT WHILE INTERIOR AREAS SHOULD
REMAIN MOSTLY VFR. IFR TO LIFR CEILINGS ARE EXPECTED TO RETURN
TONIGHT AS COASTAL STRATUS FILLS BACK IN. INTERIOR AREAS MAY SEE
SOME PATCHY VALLEY FOG BUT WILL OTHERWISE REMAIN MOSTLY CLEAR
OVERNIGHT. KML

&&

.MARINE...NORTHERLY CONDITIONS WILL BUILD TODAY AS A PACIFIC RIDGE OF
HIGH PRESSURE INTERACTS WITH THE THERMAL TROUGH CENTERED OVER
CALIFORNIA. THIS WILL CAUSE THE PRESSURE GRADIENT TO STRENGTHEN
ACROSS THE COASTAL WATERS TODAY FROM SOUTH TO NORTH. A SMALL CRAFT
ADVISORY HAS BEEN ISSUED, IN ADDITION TO THE EXISTING ADVISORY, FOR
MARINE ZONE 470 STARTING LATER THIS EVENING. NEAR GALES ARE
POSSIBLE ACROSS THE OUTER WATERS ON MONDAY BUT WITHHELD FROM ISSUING
ANY WATCHES DUE TO MINIMAL AREAL COVERAGE OF GALE FORCE GUSTS.
STEEPER SEAS AND GUSTY WINDS ARE EXPECTED FOR PARTS OF THE COASTAL
WATERS WITHIN 10 NAUTICAL MILES, ESPECIALLY NEAR CAPE MENDOCINO AND
POINT ARENA. SMALL CRAFT ADVISORIES WILL NEED TO BE CONSIDERED WITH
THE NEXT FORECAST PACKAGE FOR THESE AREAS ON MONDAY.

WINDS WILL EASE FROM SOUTH TO NORTH ON TUESDAY AS A SURFACE LOW
DEVELOPS OFF OF THE CALIFORNIA COAST AND PUSHES THE PRESSURE
GRADIENT FARTHER OFFSHORE. DESPITE THE WINDS EASING, SEAS SHALL
REMAIN STEEP AND ELEVATED. CONDITIONS WILL FURTHER DETERIORATE LATER
IN THE WEEK AS BUILDING HIGH PRESSURE PUSHES THAT STRONGER PRESSURE
GRADIENT BACK ONSHORE. KML

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 PM PDT TUE PZZ470.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 3 AM PDT TUE PZZ475.

&&

$$

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