767
FXUS66 KEKA 152043
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
143 PM PDT MON SEP 15 2025
SYNOPSIS
HOT AND DRY WEATHER WILL BRIEFLY BUILD THROUGH TUESDAY
WITH GUSTY NORTH WIND NEAR SHORE. COOLER WEATHER WILL THEN RETURN
LATER IN THE WEEK WITH SCATTERED SHOWERS FOR THE SOUTHERN HALF OF
THE AREA POSSIBLE BY THURSDAY INTO FRIDAY.
DISCUSSION
TRANSIENT HIGH PRESSURE IS BUILDING OVER
THE AREA TODAY ALLOWING FOR UNSEASONABLY WARM AND DRY CONDITIONS
ACROSS THE INTERIOR WITH VALLEYS REACHING INTO THE MID 90S.
STRENGTHENING NORTH WIND ALONG SHORE HAS HELPED SCATTER OUT THE
MARINE LAYER WITH SOME LOW CLOUDS PERSISTING JUST AROUND THE
PROTECTED AREAS OF HUMBOLDT BAY THIS AFTERNOON.
HIGH PRESSURE WILL PEAK TUESDAY WITH A SLIGHT POTENTIAL (30%) OF THE
HOTTEST VALLEYS JUST REACHING NEAR 100 ALONG THE TRINITY RIVER.
GUSTY NORTH WINDS WILL GENERALLY KEEP THE MARINE LAYER WEAK ALONG
SHORE. A TROUGH WILL BEGIN TO APPROACH THE AREA ON WEDNESDAY WITH
TEMPERATURES QUICKLY DROPPING BACK DOWN INTO THE 80S AND AN ELEVATED
MARINE LAYER RETURNING NEAR SHORE.
AS A DEEP TROUGH GRADUALLY APPROACHES SHORE LATER IN THE WEEK, THERE
IS HIGH CONFIDENCE THAT SOUTHERLY WIND ALONG THE TROUGH WILL PULL
MOISTURE UP FROM THE TROPICAL PACIFIC. BY FRIDAY, PRECIPITABLE WATER
VALUES WILL MOST LIKELY SOAR TO BETWEEN 1 AND 1.6 INCHES ALL ACROSS
THE AREA, BRINGING A THE POTENTIAL FOR PRECIPITATION. THE EXACT
CHARACTER AND LOCATION OF THIS PRECIPITATION IS HIGHLY UNCERTAIN,
PARTIALLY DUE TO POSSIBLE INTERACTIONS WITH A TROPICAL SYSTEM OFF
THE COAST OF SOUTHERN CALIFORNIA. UNLIKE MOST SYSTEMS OVER THE PAST
SEVERAL MONTHS, THE CORE OF RAIN SHOWERS WOULD MOST LIKELY BE
FOCUSED IN THE SOUTHERN HALF OF THE AREA. MOST MODELS CURRENTLY
RESOLVE LITTLE INSTABILITY, BUT SHOWERS COULD MANIFEST AS ELEVATED
THUNDERSTORMS AS THE TROUGH MOVES ONSHORE FRIDAY AND INTO THE
WEEKEND. MOST LIKELY RAINFALL IS CURRENTLY ONLY 0.1 TO 0.4 INCHES
WITH THE GREATEST RAINFALL OVER THE YOLLA BOLLYS AND ONLY A TRACE
CLOSER TO THE COAST. AGAIN, THERE REMAIN HIGH UNCERTAINTY WITH A 65%
CHANCE OF NO REAL PRECIPITATION AT ALL. AN UNSETTLED AND TROUGHY
WEATHER PATTEN WILL MOST LIKELY PERSIST INTO EARLY NEXT WEEK WITH
COOLER AND MORE MOIST WEATHER ALONGSIDE RAIN SHOWER CHANCES. /JHW
AVIATION
A SMALL PATCH OF SHALLOW COASTAL STRATUS WILL
DISSOLVE NORTH TO SOUTH THIS AFTERNOON. CEC HAS CLEARED OUT AND IS
FIRMLY IN VFR CONDITION. THE MARINE LAYER AROUND ACV TO AROUND CAPE
MENDOCINO IS SHALLOW AT 200-400 FT AGL AND IS PRODUCING TEMPO FOG.
THIS WILL REMAIN A THREAT AT THIS TERMINAL THROUGH 21Z. SURFACE
WINDS ARE RELATIVELY LIGHT TODAY AT 5-11 KTS FROM THE NORTHWEST TO
WEST.
OFFSHORE FLOW WILL DRY OUT THE COLUMN TONIGHT, AND THIS WILL THWART
STRATUS REFORMATION. A LOW CHANCE (20%) FOR PATCHY LIFR CEILINGS AND
FOG WILL DEVELOP EARLY TUESDAY MORNING ALONG THE NORTH COAST, BUT
COVERAGE LOOKS TO BE VERY LIMITED. FLOW WILL TURN MORE SOUTHERLY
TUESDAY, TAPPING INTO BETTER MOISTURE. WITH THE RETURN OF LOW LEVEL
MOISTURE, THE MARINE LAYER WILL QUICKLY REDEVELOP, BUT CURRENT HIGH
RESOLUTION GUIDANCE STRUGGLES TO FILL LOW CLOUDS OVER THE THE COAST
UNTIL AT LEAST 18Z. MODELS WILL CONTINUE TO STRUGGLE WITH THE TIMING
OF THE STRATUS RESURGENCE FOR TUESDAY IN THE NEAR TERM.
MARINE
THE NORTHERLY WINDS AND SHORT PERIOD SEAS WILL BE
TRENDING DOWNWARD TODAY. SEAS WILL DROP BELOW 10 FT IN THE OUTER
ZONES (BEYOND 10 NM) TONIGHT. LIGHT WESTERLY WINDS 5-10 KTS AND 4-6
FT SEAS WILL REMAIN TUESDAY, WHILE NEARSHORE WATERS SEE LIGHT
WESTERLY TO SOUTHERLY WINDS.
STARTING LATE TUESDAY, THE NORTHERLY WINDS WILL BEGIN AN INCREASING
TREND. THE STRENGTHENING WILL START IN THE SOUTHERN WATERS LATE
TUESDAY THROUGH WEDNESDAY MORNING, BUT NORTHERLY WINDS WILL QUICKLY
RAMP UP WEDNESDAY AFTERNOON IN THE NORTHERN ZONES AS WELL. A REMNANT
TROPICAL SYSTEM IS FORECAST TO THEN PUSH NORTHWARD THROUGH THURSDAY.
THE PRESSURE GRADIENT WILL BECOME LOCALLY STRENGTHENED FROM THE
TROPICAL LOW SOUTH AND A DOMINANT RIDGE OF HIGH PRESSURE OVER THE
NORTH PACIFIC. SUBSEQUENT GALE CONDITIONS, POTENTIALLY WITH
SUSTAINED GALE WINDS ARE FORECAST LATE WEDNESDAY THROUGH THURSDAY.
LARGE AND STEEP SHORT PERIOD HAZARDOUS SEAS WILL BUILD IN EXCESS OF
16 FEET IN RESPONSE. WINDS AND SEAS ARE CURRENTLY FORECAST TO EASE
GOING INTO THE WEEKEND.
FIRE WEATHER
BRIEFLY HOT AND VERY DRY CONDITIONS THROUGH TUESDAY
WILL ALLOW FOR FUELS TO RAPIDLY DRY. INTERIOR VALLEY HIGHS WILL BE
INT HE 90S WITH RH SOLIDLY BELOW 20 PERCENT. STRONG THERMAL BELTS
WILL PROMOTE POOR OVERNIGHT RECOVERIES. WIND WILL GENERALLY BE
GENTLE AND TERRAIN DRIVEN. CONDITIONS WILL BEGIN TO EASE AGAIN
WEDNESDAY THROUGH THE END OF THE WEEK AS A DEEPER TROUGH APPROACHES
SHORE. THERE IS POTENTIAL BY THURSDAY (10% CHANCE) AND ESPECIALLY
FRIDAY (20%) OF SCATTERED SHOWERS AND THUNDERSTORMS OVER HIGH
TERRAIN. CHANCES WILL BE GREATEST OVER THE SOUTHERN HALF OF THE AREA
(35% CHANCE OF WETTING RAIN) WITH LESSER CHANCES FURTHER NORTH (15%
CHANCE WETTING RAIN). STORMS WOULD HAVE MODERATE STORM MOVEMENT AND
WOULD BE RELATIVELY WET. NOT THERE IS CURRENTLY HIGH UNCERTAINTY IN
THE EXACT DETAILS FOR SHOWERS WITH A 65% CHANCE OF THERE BEING NO
SHOWERS AT ALL.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 3 AM PDT TUESDAY FOR PZZ470-475.
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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