123
FXUS66 KEKA 170727
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1227 AM PDT FRI APR 17 2026
SYNOPSIS
NEAR-FREEZING TO FREEZING OVERNIGHT LOW TEMPERATURES
EXPECTED THROUGH THE END OF THE WEEK. BREEZY WINDS FORECASTED FOR
LAKE COUNTY THROUGH FRIDAY AFTERNOON. RAIN EXPECTED LATE WEEKEND
INTO NEXT WEEK BEFORE A POTENTIAL DRYING TREND TO END NEXT WEEK.
DISCUSSION
SURFACE HIGH PRESSURE OFF THE PACNW COASTLINE IS INTERACTING
WITH SURFACE LOW PRESSURE NEAR LAS VEGAS. THIS PRESSURE GRADIENT IS
THE DRIVING FORCE FOR THE BREEZY WINDS THAT WERE PRESENT THURSDAY.
THESE WINDS ARE FORECASTED TO CONTINUE THROUGH FRIDAY MORNING, THE
STRONGEST OF WHICH ARE EXPECTED TO FORM IN LAKE COUNTY. OVERALL, WINDS
WILL BE BELOW WIND ADVISORY LEVEL. HOWEVER, DUE TO THE COMPLEX TERRAIN
OF LAKE COUNTY, SPORADIC GUSTS COULD 30MPH WITH EXPOSED RIDGES POSSIBLY
REACHING UP TO 40MPH.
THE AFOREMENTIONED SURFACE HIGH PRESSURE SYSTEM IS FORMED BY COLDER
AIR ALOFT. THIS DRY, COLD AIR IS ALLOWING OVERNIGHT AND EARLY MORNING
TEMPERATURES TO GET VERY COLD. INTERIOR TEMPERATURES ARE FORECASTED
TO DROP AS LOW AS DECAF BELOW FREEZING AGAIN THIS MORNING. COASTAL
TEMPERATURES COULD GET AS LOW AS FREEZING FOR THE ENTIRE NW CA COASTLINE.
FREEZE WARNINGS HAVE BEEN ISSUED FOR SOME OF THE COLDEST INTERIOR VALLEYS,
ALONG WITH FROST ADVISORIES FOR MOST COASTAL AREAS. IT IS RECOMMENDED
TO COVER SENSITIVE PLANTS AND TAKE OTHER PRECAUTIONS TO PROTECT AGRICULTURAL
PROPERTY. ICY ROADS ALSO POSE A POSSIBLE THREAT THROUGH THE MORNING.
THIS COMING WEEKEND'S STORM TRACK AS VARIED SLIGHTLY. GLOBAL MODELS
NOW SHOW AN UPPER LEVEL TROF DEVELOPING FARTHER OUT IN THE PACIFIC
THAN PREVIOUS MODELS INDICATED. BY THE TIME THIS STORM BEGINS TO IMPACT
NW CA, THE STORM LOOKS TO BE MORE OF A CUTOFF LOW THAN A SUSTAINED
DEEP TROUGH. 250MB WINDS SHOWS THE POLAR JET STREAM BREAKING OFF FROM
THIS STORM. RAINFALL IS STILL FORECASTED FOR THE ENTIRE CWA. CW3E SHOWS
AROUND AN 80% PROBABILITY OF IVT VALUES OVER 250KG/M/S AND A MAJORITY
OF ENSEMBLES MEMBERS SHOW IVT VALUES BETWEEN 200-400 IVT. THIS VERY
WEAK AR WILL MOVE SLOWLY, STALLING OFF THE COAST FUNNELING MOISTURE
OVER THE AREA FROM SUNDAY THROUGH MONDAY. SUNDAY'S RAIN IS FORECASTED
TO ARRIVE ANYTIME FROM THE MORNING TO THE EARLY AFTERNOON AS OF NOW.
SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON LOOKS TO BE RAINIEST PERIOD.
NBM DATA SHOWS THE HEAVIEST RAINFALL RATES AND TOTALS FOR THE KING
RANGE AND NORTHERN MENDOCINO COUNTY OF 2.00-3.00". ELSEWHERE, RAIN
LOOKS TO BE BETWEEN 0.50-1.00" FOR VALLEYS AND BETWEEN 1.00-1.50" FOR
INTERIOR MOUNTAINS OF DEL NORTE, HUMBOLDT, SOUTHERN TRINITY, AND MENDOCINO
COUNTIES. SNOW LEVELS ARE GENERALLY EXPECTED TO BE AROUND 5,000 FEET
AHEAD OF THE UPPER LEVEL LOW.
WIDESPREAD RAIN COULD SHIFT INTO SHOWERS AS SOON AS MONDAY EVENING WITH
LESS WIDESPREAD COVERAGE. SHOWERS MAY LINGER INTO WEDNESDAY AS THE UPPER
LEVEL LOW SLOWLY TAKES ITS TIME MOVING OUT OF THE AREA. THE GFS AND
ECMWF BOTH SHOW HIGH PRESSURE AND DRY WEATHER IS FORECASTED FOR THE
END OF NEXT WEEK AFTER THESE SHOWERS PASS. DS
AVIATION...(06Z TAFS)
VFR CONDITIONS ARE LIKELY AT ALL TERMINALS
FOR THE NEXT 24 HOURS. SURFACE WINDS ARE FORECAST TO EASE EARLY THIS
MORNING , AND GENERALLY TURN EASTERLY. THERE WILL BE A SLIGHT LOW
LEVEL WIND SHEAR (LLWS) THREAT EARLY THIS MORNING ACROSS THE AREA,
ESPECIALLY OVER THE INTERIOR, AS NORTH WINDS REMAIN STRONG ALOFT.
THIS LLWS THREAT DIMINISHES BY SUNRISE. JB
MARINE
NORTHERLY WINDS CONTINUE TO EASE THROUGH THIS
MORNING AS THE PRESSURE GRADIENT WEAKENS. STEEP SEAS AROUND 10 TO 12
FT AT 10 SECONDS WILL SLOWLY SUBSIDE DOWN TO 5 TO 7 FT BY FRIDAY
AFTERNOON. THE STRONGEST WINDS IN THE LEE OF CAPE MENDOCINO AND IN
THE NORTHERN OUTER WATERS IN THE LEE OF CAPE BLANCO WILL STAY ABOVE
GALE FORCE INTO EARLY/MID MORNING. A FRONTAL SYSTEM MOVES THROUGH
THE AREA SATURDAY NIGHT INTO SUNDAY. WINDS WILL INCREASE AND TURN
SOUTHERLY. WIND GUSTS ARE FORECAST TO PEAK AT AROUND 20 TO 25 KTS,
BUT THERE IS A LOW-END CHANCE (15%) FOR GALE FORCE GUSTS SUNDAY AND
MONDAY IN THE OUTER WATERS. A MID-PERIOD WEST SWELL WILL ALSO ARRIVE
MONDAY, PEAKING AT AROUND 8 TO 10 FT AT 13 SECONDS. WINDS AND SEAS
GRADUALLY SUBSIDE TUESDAY. STRONGER NORTHERLY WINDS RETURN MID TO
LATE NEXT WEEK. JB&JLW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
FROST ADVISORY UNTIL 9 AM PDT THIS MORNING FOR CAZ101-103-
104-109-112-113.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ102-105-
106-108-110-111-114-116>118.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 3 AM PDT EARLY THIS MORNING FOR
PZZ450.
GALE WARNING UNTIL 3 AM PDT EARLY THIS MORNING FOR PZZ455-
470-475.
NOTE: THE FULL FORECAST DISCUSSION IS NOW REGULARLY ISSUED BETWEEN
10 AM/PM AND 1 PM/AM. ADDITIONAL UPDATES WILL BE ISSUED AS NEEDED.
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