AFDEKA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EUREKA CA 237 PM PDT SAT APR 14 2018 .SYNOPSIS...A FRONT MOVING EAST ACROSS THE REGION DURING SUNDAY WILL RESULT IN WIDESPREAD RAINFALL. COLDER AIR AND SHOWERS WILL OCCUR BEHIND THE FRONT, WITH A FEW THUNDERSTORMS POSSIBLE ALONG THE COAST, AND LIGHT SNOW LIKELY ACROSS THE MOUNTAINS. A BRIEF PERIOD OF DRY WEATHER IS EXPECTED ON TUESDAY, FOLLOWED BY ADDITIONAL SHOWERS WEDNESDAY AND THURSDAY. && .DISCUSSION...AN UPPER TROUGH LOCATED OVER THE NORTHEAST PACIFIC AND SOUTHERN GULF OF ALASKA IS FORECAST TO DIG SOUTHWARD ACROSS NORTHWEST CALIFORNIA DURING SUNDAY AND MONDAY. AN ASSOCIATED FRONTAL BOUNDARY WILL MOVE EAST ACROSS THE REGION BY EARLY SUNDAY AFTERNOON, AND WILL YIELD A PERIOD OF LIGHT TO MODERATE RAINFALL ACROSS THE ENTIRE CWA. AFTER FRONTAL PASSAGE, COLD MIDLEVEL TEMPERATURES (AT OR BELOW -32C AT 500 MB) WILL SPREAD ACROSS THE AREA AND LEAD TO THE DEVELOPMENT OF STEEP LAPSE RATES, RESULTING IN A CONDITIONALLY UNSTABLE ENVIRONMENT. WIDESPREAD SHOWERS WILL OCCUR IN RESPONSE, AS WELL AS A FEW THUNDERSTORMS NEAR THE COAST SUNDAY NIGHT INTO MONDAY (AS WELL AS INTERIOR MENDOCINO COUNTY DURING MONDAY AFTERNOON), A FEW OF WHICH COULD YIELD ACCUMULATING SMALL HAIL ACROSS AREA ROADWAYS. IN ADDITION, SNOW LEVELS ARE FORECAST TO LOWER TO AROUND 2500-3000 FEET, WHICH WILL FAVOR LIGHT SNOW ACCUMULATIONS ACROSS THE MOUNTAINS AND INTERIOR HIGHWAY PASSES. THE UPPER TROUGH IS FORECAST TO EXIT EAST OF THE REGION DURING MONDAY NIGHT AND TUESDAY. AS THAT TAKES PLACE, SKIES WILL BEGIN TO CLEAR, WHICH WILL ENHANCE THE POTENTIAL FOR FROST/FREEZE CONDITIONS ACROSS MUCH OF TRINITY AND NORTHEASTERN MENDOCINO COUNTIES TUESDAY MORNING. PLEASANT WEATHER WILL THEN BECOME PROBABLE TUESDAY AFTERNOON. THE NEXT DISTURBANCE TO IMPACT THE REGION WILL ENTER DURING WEDNESDAY. SHOWERS WILL BE LIKELY AS A RESULT, THOUGH THEY MAY CLEAR THE REGION QUICKLY GOING INTO THURSDAY AS THE TROUGH DIGS SOUTH OF NORTHWEST CA. CURRENT MODEL GUIDANCE SHOWS ANOTHER TROUGH PASSING NORTH OF THE AREA DURING LATE WEEK, WHICH WILL GENERALLY FAVOR DRY AND MILD CONDITIONS OVER NORTHERN CA. && .AVIATION...A SUNNY DAY ACROSS NW CALIFORNIA, WITH ALL TERMINALS ENJOYING SOME VFR CONDITIONS. DO EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE EVENING. HOWEVER, DO EXPECT DETEORIATING THE CONDITIONS TO MOVE IN FROM THE NORTHWEST. THIS WILL BRING LOWERING CEILING AND VISIBILITIES FROM CRESCENT CITY, THEN TO ARCATA, THEN TO UKIAH. DO EXPECT MVFR CONDITIONS TO DEVELOP TO DEVELOP IN CRESCENT CITY LATE TONIGHT, THEN SPREADING INTO ARCATA IN THE EARLY MORNING HOURS, AND THEN TO UKIAH IN THE MORNING. DO EXPECT GUSTY SOUTH WINDS AND MODERATE RAIN. && .MARINE...STILL FAIRLY ACTIVE MARINE WEATHER FOR THE NEXT FEW DAYS. THE SMALL CRAFT ADVISORY FOR THE SIGNIFICANT SWELL HAS JUST ENDED EARLY THIS AFTERNOON FOR THE WATERS OTHER THAN NORTHERN OUTSIDE WATERS. WITH THE NEXT WEATHER FRONT MOVING TOWARDS THE OR/CA BORDER COAST LATE TONIGHT, DO EXPECT A BRIEF PERIOD OF STRONG SOUTH WINDS EARLY SUNDAY MORNING. THUS, SMALL CRAFT ADVISORY IS IN EFFECT FOR THE NORTHERN OUTSIDE WATERS. AFTER THE FRONT PUSHES THROUGH THE AREA, THE WINDS WILL DIMINISH SUNDAY MORNING. HOWEVER, WE WILL BE DEALING WITH ANOTHER SIGNIFICANT WESTERLY SWELL GROUP, WITH WNW WAVES AT AROUND 11 TO 12 FEET AT AROUND 16 SECONDS. THUS, WILL HAVE ANOTHER SMALL CRAFT ADVISORY FOR ALL WATERS FROM SUNDAY MORNING THROUGH MONDAY MORNING. AFTER THAT, WE SHOULD HAVE A FEW DAYS OF ADVISORY-FREE MARINE WEATHER. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NONE. NORTHWEST CALIFORNIA COASTAL WATERS...SMALL CRAFT ADVISORY FROM 9 AM SUNDAY TO 9 AM PDT MONDAY FOR PZZ450-455-475. SMALL CRAFT ADVISORY UNTIL 9 AM PDT MONDAY FOR PZZ470. &&