AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
500 AM PDT SUN APR 22 2018

.SYNOPSIS...HIGH PRESSURE WILL BRING MAINLY CLEAR SKIES AND DRY
CONDITIONS INTO EARLY NEXT WEEK. HIGH TEMPERATURES WILL BE ABOVE
NORMAL IN THE INLAND AREAS. MID TO LATE WEEK AN UPPER LEVEL LOW
APPROACHING THE AREA WILL BRING COOLER TEMPERATURES AND THE CHANCE
FOR SHOWERS.

&&

.DISCUSSION...A SHORTWAVE APPROACHING THE REGION IS THE MAIN
WEATHER FEATURE THIS MORNING. IT WILL PASS THROUGH THE AREA EARLY
THIS MORNING. HIGH PRESSURE BUILDS IN QUICKLY BEHIND IT WHICH WILL
BRING BREEZY NORTH WINDS AND SLIGHT COOLER TEMPERATURES IN THE
INLAND AREAS. TONIGHT FROST IS POSSIBLE IN THE COLDEST INTERIOR
VALLEYS OF TRINITY, BUT IS NOT LOOKING VERY LIKELY. WILL HOLD OFF
ON ISSUING ANY ADVISORIES. SOME STRATUS IS POSSIBLE ALONG THE
COAST, BUT IT IS EXPECTED TO BE FAIRLY MINIMAL.

MONDAY HIGH PRESSURE IS IN PLACE THE AREA. THIS WILL BRING HIGHS
TO THE INLAND AREAS IN THE 80S. ANY LINGERING STRATUS SHOULD CLEAR
QUICKLY IN THE MORNING AND DRY CONDITIONS ARE EXPECTED ACROSS THE
AREA. FROST IS NOT EXPECTED MONDAY NIGHT INTO TUESDAY AS
TEMPERATURES CONTINUE TO WARM. TUESDAY THE HIGH PRESSURE STARTS TO
MOVE OFF TO THE EAST AS AN UPPER LEVEL LOW STARTS TO APPROACH THE
AREA. DRY WEATHER IS EXPECTED TO CONTINUE, BUT STRATUS MAY RETURN
ALONG THE COAST. THIS WILL KEEP TEMPERATURES ALONG THE COAST A
FEW DEGREES COOLER. INLAND TEMPERATURES ARE EXPECTED TO BE SIMILAR
TO MONDAY.

WEDNESDAY THE UPPER LEVEL CONTINUES TO MOVE TOWARDS THE COAST. THE
ECMWF IS SLOWER WITH THE PROGRESSION OF THIS THAN THE GFS. THE
ECMWF SOLUTION WOULD KEEP TEMPERATURES ON WEDNESDAY NEARLY AS WARM
AS TUESDAY AND THE AREA WOULD STAY DRY, WHILE THE GFS STARTS THE
COOLING TREND AND BRINGS SOME SHOWERS TO THE AREA. GENERALLY TOOK
A BLEND OF THE SOLUTIONS, BUT WOULD FAVOR THE SLOWER ECMWF
SOLUTION AS MODELS OFTEN TRY TO MOVE A CLOSED LOW LIKE THIS
THROUGH TOO QUICKLY.

THURSDAY AND FRIDAY THERE IS GENERAL MODEL AGREEMENT THAT THE LOW
WILL STALL JUST OFFSHORE. THIS WOULD BRING TEMPERATURES BACK TO
NEAR OR BELOW SEASONAL NORMALS AND SOME LIGHT RAIN SHOWERS ARE
POSSIBLE. COASTAL STRATUS IS LIKELY AS WELL. SATURDAY THERE IS
SOME GENERAL AGREEMENT THAT AN UPSTREAM SYSTEM WILL START TO PUSH
IT OUT OF THE AREA, BUT THE EXACT DIRECTION REMAINS IN QUESTION.
CURRENT MODEL RUNS HAVE SOME SHOWERS OVER THE AREA ON SATURDAY.
THUNDERSTORMS ARE POSSIBLE AS THIS UPPER LEVEL LOW MOVES OVERHEAD,
BUT DUE TO THE UNCERTAINTY IN THE TIMING AND TRACK OF THIS LOW
HAVE NOT ADDED THEM TO THE FORECAST YET. OVERALL THERE IS LOWER
THAN NORMAL CONFIDENCE IN THIS PATTERN. MKK

&&

.AVIATION...PATCHES OF LOW CLOUDS AND EVEN SOME FOG HAVE FORMED
ALONG PORTIONS OF THE REDWOOD COAST EARLY THIS MORNING. THE EXTENT
OF THIS CLOUDINESS IS HARD TO ASCERTAIN DUE TO HIGH CLOUDS WHICH
CONTINUE TO OBSCURE THE LOWER CLOUDS ON SATELLITE IMAGERY. CLOUDS
ARE EXPECTED THIN LATER THIS MORNING, AND DAYTIME HEATING SHOULD
ERODE THIS CLOUDINESS FROM THE MAINLAND EDGE AS N LOW-LEVEL FLOW
CHIPS AWAY AT THE MARINE SIDE. GUSTY NW TO N WINDS ARE EXPECTED ONCE
AGAIN LATE THIS MORNING AND THIS AFTERNOON ALONG THE REDWOOD COAST.
LIGHTER WINDS ARE EXPECTED AT KUKI WITH VFR CONDITIONS. INCREASING
OFFSHORE FLOW SHOULD KEEP CLOUDS AND/OR FOG AWAY FROM KCEC TONIGHT,
PARTICULARLY AFTER MIDNIGHT. /SEC

&&

.MARINE...N WINDS HAVE NEARLY REACHED THEIR EXPECTED MAXIMUM OVER
THE OUTER WATERS EARLY THIS MORNING. HAVE CONTINUED THE GALE WARNING
FOR THE OUTER WATERS. HAVE HOISTED A HAZARDOUS SEAS WARNING FOR THE
INNER WATERS AS SEAS AT THE BUOYS THERE HAVE RAMPED UP TO 12 FEET OR
A BIT MORE.

WINDS ARE EXPECTED TO REMAIN QUITE STRONG THROUGH THE EVENING HOURS
BEFORE GRADUALLY DROPPING BELOW GALE WARNING CRITERIA. CONDITIONS
WILL CONTINUE A GRADUAL IMPROVING TREND THROUGH MID-WEEK WITH WINDS
SHIFTING TO LIGHT SOUTHERLY BY WEEK`S END. NW SWELL TRAINS WILL
CONTINUE TO TRAVERSE THE AREA THROUGH THE PERIOD. /SEC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
  SMALL CRAFT ADVISORY UNTIL MIDNIGHT PDT TONIGHT FOR PZZ450-455.

     HAZARDOUS SEAS WARNING UNTIL MIDNIGHT PDT TONIGHT FOR PZZ450-455.

     GALE WARNING UNTIL MIDNIGHT PDT TONIGHT FOR PZZ470-475.

&&