Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 262227
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
227 PM PST THU FEB 26 2015

.SYNOPSIS...A STORM SYSTEM APPROACHING FROM THE NORTH WILL BRING
RAIN SHOWERS...COOLER TEMPERATURES AND SOME MOUNTAIN SNOW THIS
EVENING THROUGH SATURDAY. DRY CONDITIONS ARE EXPECTED SUNDAY
FOLLOWED BY ANOTHER STORM SYSTEM WITH RAIN SHOWERS MONDAY AND
TUESDAY.

&&

.DISCUSSION...AFTERNOON RADAR IMAGERY SHOWS SHOWERS OVER THE
NORTHERN PART OF OUR CWA, MOVING SOUTHEASTWARD. THESE SHOWERS ARE
ASSOCIATED WITH A STORM SYSTEM AND ACCOMPANYING TROUGH, WHICH IS
COMING FROM THE PACIFIC NORTHWEST. THE TROUGH WILL CONTINUE TO
APPROACH OUR AREA TONIGHT AND FRIDAY, MOVING OVERHEAD LATE FRIDAY
INTO EARLY SATURDAY, THEN SHIFTING TO OUR SOUTHEAST ON SUNDAY. THE
STORM SYSTEM IS COLDER THAN MOST THIS WINTER BECAUSE IT ORIGINATED
IN THE NORTH PACIFIC. IT WILL BRING PRECIPITATION IN THE FORM OF
SHOWERS TO OUR AREA TONIGHT. THE SHOWERS WILL CONTINUE ON FRIDAY
WITH THE HEAVIEST PRECIPITATION EXPECTED DURING THE MORNING HOURS.
THE SHOWERS WILL DISSIPATE ON SATURDAY AS THE STORM MOVES AWAY
FROM US. QPF STILL DOESN`T LOOK TO BE TOO SIGNIFICANT. PARTS OF
DEL NORTE COUNTY MAY SEE AROUND 0.5 INCHES OF PRECIPITATION, WITH
THE EASTERN MOUNTAINS SEEING HIGHER AMOUNTS. NORTHERN HUMBOLDT
COUNTY CAN EXPECT AROUND 0.5 INCHES WHILE SOUTHERN PORTIONS CAN
EXPECT AROUND 0.1 INCHES. TRINITY COUNTY CAN EXPECT 0.1-0.25
INCHES WHILE MENDOCINO COUNTY SHOULD SEE AROUND 0.1 INCHES. SNOW
LEVELS CONTINUE TO BE WATCHED GIVEN THE COLD SOURCE REGION OF THIS
STORM. THEY ARE CURRENTLY IN THE 6,000-7,000 FT AND WILL DROP TO
ABOUT 4,000-5,000 FT ON FRIDAY, BEFORE FINISHING AROUND
3,500-4,000 FT SATURDAY MORNING. GIVEN THE SHOWERY NATURE OF THE
PRECIPITATION, IT`S STILL HARD TO SAY WHAT THE SNOW AMOUNTS WILL
BE. THE LATEST FORECAST NOW HAS AMOUNTS OF 1-3 INCHES AT THE
HIGHEST ELEVATIONS (ABOVE 5,000 FT AND MAINLY FOR THE TRINITY
ALPS). AGAIN, THIS SHOWS THE VARIABILITY IN THE MODELS AND THIS
SYSTEM. STILL, VERY LOCALIZED LOCATIONS AT HIGH MOUNTAIN
ELEVATIONS COULD HAVE HIGHER SNOW AMOUNTS. SNOW LEVELS ON AVERAGE
STILL APPEAR TO STAY A FEW HUNDRED TO SEVERAL THOUSAND FEET ABOVE
THE PASSES (DEPENDING ON THE LOCATION). EVEN AS THE SNOW LEVELS
ARE AT THEIR LOWEST THE PRECIPITATION WILL BE ENDING. MORE THAN
LIKELY THE PASSES WON`T SEE ANY ACCUMULATING SNOW, BUT A FEW
FLURRIES AT THE HIGHEST PASSES ARE NOT OUT OF THE QUESTION. KEPT
THE THUNDERSTORMS OVER THE WATERS SATURDAY MORNING INTO THE
AFTERNOON, WHEN THE BEST INSTABILITY IS. HOWEVER, EXTENDED IT INTO
PARTS OF MENDOCINO COUNTY LATE SATURDAY TO MATCH UP WITH THE BEST
INSTABILITY PARAMETERS AND THE NEWEST SPC OUTLOOKS. THIS THREAT
REMAINS LOW. THE SAME CAN BE SAID FOR SMALL HAIL, AS ONLY ABOUT
HALF OF THE PARAMETERS ARE BEING MET. PLUS, THE CONCERN IS WARMER
AIR NEAR THE SURFACE MAY STUNT DEVELOPMENT. THE BEST CHANCE OF IT
WILL BE FRIDAY NIGHT INTO SATURDAY ALONG THE DEL NORTE COUNTY
COAST. REGARDLESS, PRECIPITATION DIMINISHES ON SATURDAY AND DRYING
CONDITIONS CAN BE EXPECTED FOR THE REST OF THE WEEKEND AS A WEAK
RIDGE MOVES OVER OUR AREA. MORE PRECIPITATION IS EXPECTED MONDAY
AND TUESDAY, BUT CONFIDENCE IS STILL LOW GIVEN THE VARIABILITY IN
THE MODELS. RIGHT NOW IT APPEARS PRECIPITATION WILL BE LIGHT. WENT
NEAR CLIMO POPS FOR THIS TIME PERIOD. BEYOND THAT, DRY AIR RETURNS
IN THE FORM OF A RIDGE.

&&

.AVIATION...A SHORT-WAVE TROUGH AND MOIST NW FLOW WILL BRING
WORSENING CONDITIONS TO THE REGION TONIGHT. SHOWERS AND WIDESPREAD
MVFR CONDITIONS ALONG THE NORTH COAST WILL SPREAD INLAND AND
SOUTHWARD THROUGH THE NIGHT. PERIODS OF IFR WILL ALSO BE POSSIBLE
IN LIGHT TO MODERATE PRECIP. A STRONG SPEED MAX WILL MOVE OVER THE
AREA LATE TONIGHT INTO FRIDAY MORNING AND PRODUCE TURBULENT AND
GUSTY WIND CONDITIONS. THE SHOWER ACTIVITY AS WELL AS OCCASIONAL
MVFR CONDITIONS AND LOWERING SNOW LEVELS WILL PERSIST ON FRIDAY.
THE AIR MASS WILL COOL DOWN AND DRY OUT OVER THE WEEKEND AS THE
UPPER LOW MOVES SOUTH OF THE AREA AND BRISK NE FLOW DEVELOPS. THE
NE AND E FLOW WILL PRODUCE CLEARING SKIES AS WELL AS STRONG RIDGE
LEVEL WINDS AND LOW LEVEL TURBULENT FLYING CONDITIONS.

&&

.MARINE...THE HIGH PRESSURE RIDGE WILL SHIFT WESTWARD TODAY
DECREASING THE PRESSURE GRADIENT ACROSS THE WATERS AND ALLOWING
THE WINDS AND SEAS TO DIMINISH. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT ACROSS THE SOUTHERN OUTER WATERS THROUGH FRIDAY NIGHT DUE
TO THE WINDS AND/OR SHORT PERIOD SEAS. SMALL CRAFT ADVISORIES WILL
REMAIN IN EFFECT ACROSS THE SOUTHERN NEAR SHORE WATERS THROUGH
THIS EVENING.

A LOW PRESSURE SYSTEM WILL STRENGTHEN ACROSS THE WESTERN UNITED
STATES FRIDAY AND SATURDAY. THE COMBINED EFFECTS OF THE LOW
PRESSURE AREA AND A STRENGTHENING OFFSHORE HIGH PRESSURE RIDGE
WILL TIGHTEN THE PRESSURE GRADIENT ACROSS THE WATERS INCREASING
THE WINDS AND SEAS. SMALL CRAFT ADVISORIES ARE LIKELY ACROSS THE
OUTER WATERS THIS WEEKEND AND MAY BE NECESSARY ACROSS THE NEAR
SHORE WATERS DUE TO WINDS AND/OR SEAS.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...

CA...NONE.

NORTHWEST CALIFORNIA COASTAL WATERS...

SMALL CRAFT ADVISORY FOR PZZ455-475.

&&

$$

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