Heavy Rain in California, June 9 to 18, 2005

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE EUREKA CA
440 AM PDT THU JUN 9 2005

UPDATED AVIATION SECTION

.SYNOPSIS...THE INFLUENCE OF A BROAD UPPER TROUGH OVER THE WEST COAST
WILL SLOWLY BE REPLACED BY THE INFLUENCE OF A BROAD UPPER RIDGE
CENTERED OVER THE EASTERN PACIFIC THE NEXT SEVERAL DAYS. HIGHER
TEMPERATURES AND WEATHER CONDITIONS MORE TYPICAL FOR MID JUNE WILL
RETURN THIS WEEKEND.

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.SHORT-TERM...AN UPPER CIRCULATION WAS OVER SWRN IDAHO...MOVING EAST
THIS MORNING. AS THE UPPER LOW DRIFTS EAST...LIGHT RAINFALL AND
DRIZZLE SHOULD GRADUALLY END BY THIS AFTERNOON. WITH LINGERING COOL
AIR ALOFT AND LOW LEVEL MOISTURE...THERE MIGHT STILL BE A FEW LIGHT
SHOWERS THROUGH THE AFTERNOON...MAINLY OVER THE MTNS. THE OFFSHORE
RIDGE AMPLIFIES SOMEWHAT ON FRI...BUT THE GFS AND ETA SOLNS BRING A
SHORT WAVE TROUGH IN NWRLY FLOW OVER THE AREA FRI AFTERNOON AND
EVENING. THE ETA IS STRONGER THAN THE GFS WITH THIS WEAK FEATURE. SO
THE FORECAST WILL REFLECT A SLIGHT CHANCE OF SHOWERS. WITH HIGHER
BOUNDARY LYR TEMPS...LIS NEAR -3C AND BL CAPE OF 300-400J/KG...THE
POSSIBILITY EXISTS FOR A FEW TSTMS OVER THE MTNS IN ZONE 4. GOING
HOOK-LINE-AND-SINKER WITH THE GFS SOLUTION...THE UPPER TROUGH/LOW
SHOULD BE FAR ENOUGH AWAY SAT AFTERNOON TO GENERATE SHOWERS. ANY
RESIDUAL SHOWERS BY THEN SHOULD BE OVER THE FAR EASTERN AND
NORTHEAST FRINGES OF NRN CA. FOR NOW...WILL LEAVE SHOWERS OUT ON
SAT. A SHORT-WAVE RIDGE WILL BUILD ON SUNDAY...INCREASING THE
NORTHERLY FLOW DOWN THE COAST...WHICH WILL HELP TO SCOUR OUT THE LOW
LEVEL MOISTURE IN THE VALLEYS. AT SAME TIME...THE INCREASING NORTH
FLOW WILL PUSH LOW CLOUDS ONTO THE COAST NORTH OF THE CAPE. DJB

.LONG-TERM...SUNDAY THROUGH WEDNESDAY....BROAD AND FLAT UPPER RIDGE
SHOULD HOLD THROUGH MON. SOLUTIONS DIFFER AS TO THE STRENGTH AND
SPEED OF ANOTHER TROUGH DURING THE LATER PORTION OF THE EXTDD.
MARINE LAYER SHOULD DEEPEN TUE AND WED AS 500MB HGTS DECREASE. FOR
NOW...WILL MAINTAIN A DRY AND NEAR NORMAL TEMP FORECAST.  DJB

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.AVIATION...CERTAINLY NO LACK OF LOW LEVEL MOISTURE THIS
MORNING...WITH MOIST SUBTROPICAL FEEL TO THE AIR CURRENTLY TRAPPED
IN THE LOW LAYERS OF THE ATMOSPHERE. MODEL FORECAST SOUNDINGS DO NOT
INDICATE AN INVERSION...QUITE SIMILAR TO THE 00Z KOAK SOUNDING. WITH
SURFACE LOW DYING A SLOW DEATH RIGHT ALONG THE NORTH COAST...A
LOCALLY INDUCED MESOSCALE LOW PRESSURE CIRCULATION IS NOW EVIDENT ON
THE 11-3.9 MICROMETER SATELLITE CHANNEL. THIS USUALLY MEANS BAD
THINGS FOR THOSE LOOKING TO SEE THE SUN AND IMPROVING CONDITIONS AT
THE COAST. EXPECT MOST OF THE MORNING TO STAY AS IS...WITH
IMPROVEMENT EXPECTED...ESPECIALLY IN VISIBILITIES...LATE MORNING TO
EARLY AFTERNOON AS SURFACE HEATING PENETRATES THE THINNING CLOUD
DECK. THIS AFTERNOON LOW LEVEL MOISTURE SHOULD START LIFTING UP AND
PUSHING INLAND...WITH REAL QUESTION BEING WHAT WILL KEEP THINGS
FROM MIXING RIGHT OUT? POSSIBLE ANSWERS WOULD BE US NOT GETTING UP
TO 60F...AND THE OTHER BEING NO WIND TO MOVE THE MESS OUT. DO EXPECT
TEMPS TO GET WARM ENOUGH AND WIND TO GET GOING ENOUGH TO MOVE THE
LOW DECK UP AND OUT AS DIURNAL MOTIONS GET GOING OVER THE CWA...BUT
LIKELY 3 TO 6 HOURS BEHIND MESOETA GUIDANCE BASED ON CURRENT
GUESSTIMATES OF THE NORTHERN EXTENT OF THE LOW (LESS THAN VFR) DECK.
TONIGHT COOLER AIR MOVES IN ALOFT...BUT GROUND IS WET AND SKY WILL
BE TRYING TO CLEAR. THIS WILL MEAN SOME PATCHY FOG FORMATION PRIOR
TO CLOUD COVER COMING IN ALOFT AHEAD OF FRIDAYS WEAK
SHORTWAVE. LUTZ

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.EKA WATCHES/WARNINGS/ADVISORIES...NONE.

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