367
FXUS66 KEKA 202314
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
314 PM PST MON JAN 20 2025
SYNOPSIS
ANOTHER FRIGID NIGHT IS EXPECTED UNDER A DRY AIRMASS
WITH LIGHT OR CALM WINDS IN THE VALLEYS. DRY WEATHER AND CHILLY
MORNINGS WILL CONTINUE WEDNESDAY AND THURSDAY. SOME RAIN OR SNOW
SHOWERS ARE POSSIBLE WITH A COLD UPPER LEVEL TROUGH FRIDAY INTO
SATURDAY. BLUSTERY NORTHERLY WINDS WILL DEVELOP ON FRIDAY AND
CONTINUE INTO THE WEEKEND. COLDER WEATHER FOR THE WEEKEND.
DISCUSSION
TEMPERATURES BOTTOMED OUT IN THE LOWER TO MID 30'S
IN COASTAL AREAS AND ADJACENT RIVER VALLEY EARLY THIS MORNING.
LOW DEWPOINTS TONIGHT UNDER AN UNSEASONABLY DRY AIR MASS WILL
ALLOW TEMPERATURES TO PLUMMET THIS EVENING AND OVERNIGHT WHERE
WINDS REMAIN LIGHT OR CALM. TRENDED LOW TEMPERATURES UP SOME PER
THE NBM AND MOS GUIDANCE, HOWEVER THERE MAY BE MIXED RESULTS.
SOME SITES MAY DECREASE A FEW DEGREES WITH LESS VALLEY FOG WHILE
OTHERS INCREASE DUE TO WARMER AIR ALOFT MIXING DOWN. MOSTLY
THIN HIGH CIRRUS CLOUDS MAY ALSO FACTOR IN LATE TONIGHT. A COLD
WEATHER ADVISORY HAS BEEN ISSUED WITH APPARENT TEMPERATURES
EXPECTED IN THE UPPER 20'S. IT WILL NOT TAKE VERY MUCH WIND FOR
IT TO FEEL COLDER THAN 30F.
OTHERWISE, A WIND ADVISORY REMAINS IN EFFECT FOR LAKE COUNTY
WHERE RIDGE LEVEL GUSTS UP TO 50 MPH ARE EXPECTED. NOT CONFIDENT
ABOUT IMPACTS FOR THESE REMOTE RIDGE TOPS. MOST POPULATION
CENTERS AND TRAVEL CORRIDORS HAVE BEEN SUFFICIENTLY WINDY WITH
GUSTS FROM 20 TO 35 MPH TO WARRANT CONTINUATION OF THE ADVISORY.
THERE WAS ONE REPORT FROM A CWOP AT LAKE LEVEL WITH A MAX GUST
REPORT OF 54 MPH EARLY IN THIS MORNING.
UPPER LEVEL RIDGE OVER THE EASTERN PACIFIC EJECTS A COUPLE OF
SHORTWAVE RIDGES ON ITS EASTERN PERIPHERY FOR EARLY TO MID WEEK TO
ENSURE DRY WEATHER THROUGH THURSDAY. THE FIRST SHORTWAVE RIDGE
AXIS ARRIVES TONIGHT, AND THE SECOND ARRIVES WEDNESDAY NIGHT. A
CONSISTENTLY FORECAST TROUGH IS STILL FORECAST FROM ENSEMBLES TO
SLIDE INTO THE EASTERN PERIPHERY OF THE EASTERN PACIFIC RIDGE AND
WILL HAVE AT LEAST SOME INFLUENCE ON OUR WEATHER FROM FRIDAY
THROUGH SUNDAY NIGHT, ALTHOUGH THE MEAN TROUGH AXIS WILL REMAIN
SOUTHEAST OF THE CWA. THEREFORE ANY PRECIPITATION AMOUNTS FOR
FRIDAY MORNING THROUGH SUNDAY NIGHT WILL BE LIGHT. WE WILL BE ON
THE LOOKOUT FOR GUSTY WINDS FRIDAY AND SATURDAY, FOCUSED ON THE
COAST FOR FRIDAY, AND FARTHER INTO THE INTERIOR FOR SATURDAY.
ECMWF EFI IS ALREADY SIGNALING THE POTENTIAL FOR STRONG NORTH
WINDS ON FRIDAY BEHIND COLD FRONTAL PASSAGES, FOLLOWED BY ROBUST
NE OR N WINDS OVER THE WEEKEND. ENSEMBLE MEANS ARE ON THE ORDER
OF 25-30 MPH GUSTS FOR THE COASTAL LAND AREAS, WITH PERHAPS HIGHER
GUSTS FOR THE HEADLANDS. NOW THE RIDGES AND VENTURI EFFECT SITES
WILL HAVE STRONGER GUSTS TO 50 MPH OR MORE BASED ON THE NBM
75-90TH PERCENTILES, ESPECIALLY IN THE KING RANGE AND EVENTUALLY
OVER THE RIDGES AND CHANNELED TERRAIN OF LAKE COUNTY.
SYNOPTIC PATTERN CONFIDENCE IS HIGH AS ENSEMBLES CONTINUE TO HAVE
GOOD AGREEMENT AND CONSISTENCY WITH THE OMEGA BLOCK HIGH DOMINATING
OUR WEATHER THROUGH THURSDAY BEFORE THE EASTERN PERIPHERY GIVES WAY
TO A COLD CORE TROUGH SLIDING IN FROM THE EASTERN SIDE WITH
INCREASING MAGNITUDE. THEREFORE CONFIDENCE IS HIGH FOR A DRY
FORECAST HEADING INTO THURSDAY. WITH THE AFOREMENTIONED TROUGH
COMES A BIT OF PRECIPITATION POTENTIAL. LATEST WPC GUIDANCE HAS
VERY LITTLE TO ONLY A FEW HUNDREDTHS OVER THE HIGHER TERRAIN.
EVEN THE DETERMINISTIC AND ENSEMBLE MEANS ARE DRIER. IT IS TOO
EARLY TO REMOVE ALL PRECIP CHANCES AS A FEW CLUSTER MEANS INDICATE
A LOW END CHANCE THE COLD CORE POSSIBLY DIGGING OFFSHORE BEFORE
SWINGING INLAND. THIS OVER-WATER TRAJECTORY COULD DEFINITELY BE
BETTER FOR PRECIP PRODUCTION VS WHAT MOST CLUSTER MEANS INDICATE
WHICH IS A DRY OVERLAND TRAJECTORY. RIGHT NOW THE MAIN IMPACTS
FROM THE COLD SURGE WILL BE STRONG AND BLUSTERY NORTHERLY AND
NORTHEASTERLY WINDS AND COLD TEMPERATUERES. NAEFS INDICATE A 1 DAY
EVERY 2-5 YEARS FOR 850MB TEMPERATURES OF -2C TO -4C, WHILE THE
ECMMWF EFI IS SHOWING POCKTS OF -0.5 TO -0.7 WITH NO SHIFT OF
TAILS, THERE IS POTENTIAL FOR AN UNSEASONABLY COLD AIR OUTBREAK
FILTERING INTO NW CAL, HOWEVER RIGHT NOW THE SIGNAL IS NOT
DECISIVE FROM ANY OF THESE TOOLS. KEY MESSAGE RIGHT NOW IS COLD
AND BLUSTERY. DB
AVIATION
VFR AND LIGHT WINDS CONTINUE INTO TUESDAY. SOME PATCHY
VALLEY FOG IS POSSIBLE EARLY TUESDAY MORNING, ALTHOUGH IT IS UNCLEAR
IF THIS WILL AFFECT ANY TERMINALS, AND SHOULD ANY FORM IT WILL MIX
OUT BY LATE MORNING.
MARINE
WINDS WILL CONTINUE TO DIMINISH THIS AFTERNOON AND
EVENING. TONIGHT THE WIND TURN SOUTHERLY AROUND 5 TO 10 KT AND THIS
CONTINUES THROUGH TUESDAY. SEAS REMAIN CALM, WITH BUOYS PRIMARILY
PICKING UP A SWELL OF 7 FT AT 16 SECONDS MOVING THROUGH THE WATERS.
THE BUOYS ARE SHOWING SOME SET BEHAVIOR IN THESE WAVES. THIS WILL
CREATE A RISK FOR INTERMITTENT LARGER WAVES BREAKING IN THE SHALLOW
AREAS OR SHOALS.
WEDNESDAY THERE IS DECENT MODEL AGREEMENT THAT THE NORTHERLY WINDS
WILL START TO INCREASE AGAIN, REACHING AROUND 15 TO 20 KT BY THE
AFTERNOON IN THE OUTER WATERS. LATE WEDNESDAY NIGHT AND THURSDAY
THESE WINDS DIMINISH SOME, ALTHOUGH EXACTLY HOW MUCH IS UNCERTAIN.
ANOTHER LONG PERIOD WAVE IS EXPECTED TO MOVE THROUGH ON THURSDAY,
ALTHOUGH THE CURRENT MODELS ONLY SHOW IT AROUND 3 TO 6 FEET THURSDAY
NIGHT.
A MORE SIGNIFICANT WIND EVENT IS FORECAST FRIDAY AND SATURDAY. THE
GLOBAL ENSEMBLE MEANS SHOW A 40 TO 60 PERCENT PROBABILITY OF
SUSTAINED GALE FORCE WINDS. IF THIS TREND CONTINUES, THE FORECAST
WILL LIKELY NEED TO BE INCREASED. MKK
EKA WATCHES/WARNINGS/ADVISORIES
CA...
BEACH HAZARDS STATEMENT UNTIL 4 PM PST THIS AFTERNOON FOR
CAZ101-103-104-109.
COLD WEATHER ADVISORY FROM 1 AM TO 9 AM PST TUESDAY FOR
CAZ103-104-109-112-113-115.
WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR CAZ114-115.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR
PZZ470-475.
VISIT US AT HTTPS://WWW.WEATHER.GOV/EUREKA
FOLLOW US ON FACEBOOK AND TWITTER AT:
HTTPS://WWW.FACEBOOK.COM/NWSEUREKA
HTTPS://WWW.TWITTER.COM/NWSEUREKA
FOR FORECAST ZONE INFORMATION
SEE THE FORECAST ZONE MAP ONLINE:
HTTPS://WWW.WEATHER.GOV/IMAGES/EKA/ZONEMAP.PNG
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page