857
FXUS66 KEKA 160726
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1226 AM PDT TUE SEP 16 2025
SYNOPSIS
HOT AND DRY WEATHER WILL BRIEFLY BUILD THROUGH TUESDAY
WITH GUSTY NORTH WINDS 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
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...(06ZTAFS)
LIGHT OFFSHORE FLOW WILL AID IN DRYING OUT
THE AIR COLUMN WHICH WILL THWART WIDESPREAD 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; HOWEVER, SOUTHERLY FLOW COULD BRING IN LOW LEVEL MOISTURE
EARLY TUESDAY. IN GENERAL, FLOW WILL TURN MORE SOUTHERLY TUESDAY,
TAPPING INTO BETTER MOISTURE. WITH THE RETURN OF LOW LEVEL MOISTURE,
THE MARINE LAYER WILL QUICKLY REDEVELOP. 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 CONTINUE TO
TREND DOWN INTO TUESDAY MORNING. SEAS HAVE DROPPED BELOW 10 FT IN
THE OUTER ZONES (BEYOND 10 NM). 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 EARLY THIS MORNING 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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