535
FXUS66 KEKA 121933
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1233 PM PDT SAT JUL 12 2025
SYNOPSIS
EXCESSIVE HEAT IS FORECAST TO PERSIST IN THE INTERIOR
SUNDAY THROUGH MONDAY. HEAT RISK IS FORECAST TO DIMINISH BY MID
NEXT WEEK. UNHEALTHY AIR QUALITY DUE TO NEARBY WILDFIRES IS POSSIBLE.
THERE IS A SLIGHT CHANCE FOR ISOLATED DRY THUNDERSTORMS SUNDAY
AFTERNOON AND EVENING OVER THE MOUNTAINS OF NORTHERN TRINITY
COUNTY.
DISCUSSION
HIGH PRESSURE HAS BUILT INTO THE AREA, BRINGING A SHALLOW MARINE
LAYER WITH DENSE FOG AT TIMES ALONG THE COAST AND HOT WEATHER TO
THE INTERIOR. SMOKE FROM THE BUTLER AND GREEN FIRES REMAINING IN
THE VALLEYS WILL LIKELY POOL BACK IN OVERNIGHT. SMOKE MODELS ARE
SHOWING THE TRINITY AND KLAMATH RIVER VALLEYS WITH HIGH SMOKE
CONCENTRATIONS OVERNIGHT WITH GENERAL HAZINESS IS POSSIBLE ACROSS
THE AREA.
AS FOR THE HEAT, HIGH TEMPERATURES BETWEEN 100-110 ARE POSSIBLE,
WITH THE HIGHEST TEMPERATURES LIKELY IN TRINITY COUNTY ALONG THE
TRINITY RIVER VALLEY. WIDESPREAD HAZE MAY BRING HIGHS SLIGHTLY BELOW
WHAT IS FORECAST, BUT NO MAJOR IMPACT TO TEMPERATURES ARE LIKELY.
THE OVERNIGHT LOWS MAY ACTUALLY BE A FEW DEGREES WARMER THAN
FORECAST (FORECAST BEING LOW TO MID 60S) IN THE VALLEYS AS DENSER
SMOKE COULD TRAP SOME HEAT THE VALLEYS. REGARDLESS, THIS HEAT DOES
BRING MODERATE TO MAJOR HEATRISK AND IS DANGEROUS TO THOSE WITHOUT
PROPER COOLING AND THOSE SENSITIVE TO HEAT RELATED ILLNESS.
SUNDAY, THE UPPER LEVEL RIDGE BEGINS TO MOVE EAST SLIGHTLY. THIS
COULD SUPPORT A SLIGHTLY DEEPER MARINE LAYER AND TEMPERATURES A
DEGREE OR TWO LOWER IN INTERIOR DEL NORTE AND SOUTHERN HUMBOLDT.
STILL, TEMPERATURES WILL REMAIN HOT. MODELS ARE PICKING UP A
MOISTURE INTRUSION FROM THE EAST BY SUNDAY AFTERNOON. CAMS WITHIN
RANGE ARE SHOWING A LOW CHANCE (15%) FOR SOME ACTIVITY IN NORTHERN
TRINITY COUNTY. MODEL SOUNDINGS DO SHOW A WEAK CAPPING INVERSION
AND MOISTURE REMAINS LIMITED, SO CONFIDENCE REMAINS LOW.
MONDAY, THE RIDGE CONTINUES TO PUSH FURTHER EAST, WHICH WILL
ALLOW THE MARINE LAYER TO GRADUALLY DEEPEN EARLY NEXT WEEK.
TRIPLE DIGIT TEMPERATURES ARE LIKELY TO CONTINUE INTO AT LEAST
MONDAY, WITH "COOLING" FINALLY ARRIVING BY TUESDAY AND WEDNESDAY.
TEMPERATURES ARE LIKELY TO REMAIN WARM, WITH 90S EXPECTED FOR MUCH
OF THE INTERIOR THROUGH THE END OF NEXT WEEK.
AVIATION
COASTAL STRATUS LAYER WAS QUICKLY SCOURED OUT THIS AFTERNOON BY
INCREASING NORTHERLY WINDS OFFSHORE. VFR CONDITIONS EXPECTED
THROUGH 00Z AS DAYTIME TEMPERATURES INCREASE. GUSTY WINDS EXPECTED
AGAIN AT CEC WITH GUSTS 20 TO 30 KNOTS POSSIBLE THIS AFTERNOON.
SIMILARLY, UKI WILL REMAIN CLEAR WITH BREEZY WNW WINDS 10 TO 15
KNOTS. HREF PROBABILITIES ARE 50-70% FOR IFR CEILINGS RETURNING TO
ACV BY 06Z AS A STRONG MARINE INVERSION DEVELOPS BENEATH STRONG
HIGH PRESSURE. A SOUTHERLY WIND REVERSAL IS LIKELY ADJACENT TO THE
COAST AS THE STRONGEST WINDS MOVE OFFSHORE OVERNIGHT. SOUTHERLY
WINDS 5 TO 10 KNOTS WILL ADVECT IFR CEILINGS INTO CEC AFTER 06Z.
BOTH COASTAL TERMINALS EXPECTED TO SEE REDUCED VIZ WITH MIST/FOG
THROUGH SUNRISE (HREF 50-60% FOR VIZ <4SM). MODEL SOUNDINGS SHOW
THE MARINE LAYER RELUCTANT TO SCATTER OUT ON SUNDAY.
MARINE
A TIGHT COASTAL PRESSURE GRADIENT CONTINUES TO PRODUCE STRONG
NORTHERLY WINDS. GALE GUSTS WILL RETREAT INTO NW PZZ470 THIS
AFTERNOON THROUGH SUNDAY, BUT STEEP AND HAZARDOUS WIND DRIVEN SEAS
9 TO 14 FEET WILL CONTINUE. WINDS AND SEAS WILL STILL REMAIN
ELEVATED IN THE SOUTHERN OUTER WATERS WITH MODERATE TO FRESH
BREEZES AND WAVES 7 TO 9 FEET. CONDITIONS WILL DIMINISH IN THE
INNER WATERS ON SUNDAY AS THE STRONGEST WINDS IDLE FURTHER
OFFSHORE. GALES EXPECTED TO RAMP UP AGAIN ON MONDAY, EXPANDING
INTO THE SOUTHERN OUTER WATERS AND PUSHING CLOSER TO SHORE. SEAS
EXPECTED TO RESPOND ACCORDINGLY WITH ANOTHER ROUND OF 12 TO 16
FOOT WAVES. INCREASING CONFIDENCE IN HIGH PRESSURE BEGINNING TO
BREAK DOWN TUESDAY, DIMINISHING HAZARDOUS CONDITIONS BY MIDWEEK.
FIRE WEATHER
BUILDING HIGH PRESSURE ALONG WITH OFFSHORE FLOW HAS BROUGHT WARMING
AND DRYING TO THE INTERIOR AND NEAR-COASTAL AREAS. AFTERNOON RHS
REMAIN VERY DRY, INTO THE TEENS AND 20S ACROSS MOST THE INTERIOR.
HIGH ELEVATION AREAS (ABOVE 2000-2500 FT OR SO) CONTINUE TO SEE
MODERATE TO POOR OVERNIGHT RH RECOVERIES. LOWER ELEVATIONS ARE
LARGELY SEEING MODERATE TO GOOD OVERNIGHT RECOVERIES. OFFSHORE
WINDS IN THE HIGHER TERRAIN ARE FORECAST TO REMAIN BREEZY OVERNIGHT,
ESPECIALLY IN DEL NORTE COUNTY, THOUGH AT LEAST SUNDAY MORNING.
SOME MARGINAL IMPROVEMENT IS POSSIBLE SUNDAY AND MONDAY NIGHTS,
BEFORE FINALLY EASING BY TUESDAY NIGHT.
UPPER-LEVEL MOISTURE ARRIVES FROM THE EAST SUNDAY AND MONDAY AFTERNOONS.
ELEVATED INSTABILITY ALONG WITH SOME MOISTURE BRINGS A SLIGHT CHANCE
(10-15%) FOR ISOLATED DRY THUNDERSTORMS TO NORTHERN TRINITY COUNTY.
AS OF NOW, MOISTURE LOOKS MORE LIMITED ON MONDAY, BUT THERE IS
STILL A 5-10% CHANCE FOR ISOLATED DRY THUNDERSTORMS.
THE RIDGE BEGINS TO WEAKEN MONDAY INTO EARLY NEXT WEEK, WHICH WILL
SLOWLY DEEPEN THE MARINE LAYER INTO THE MIDDLE OF NEXT WEEK. RHS
WILL IMPROVE IN THE NEAR-COASTAL AREAS WITH MODERATE TO GOOD OVERNIGHT
RECOVERIES POSSIBLE IN THE HIGHEST TERRAIN BY THE TUESDAY OR
WEDNESDAY. JB
EKA WATCHES/WARNINGS/ADVISORIES
CA...
HEAT ADVISORY UNTIL 11 PM PDT SUNDAY FOR CAZ102-105-110-111-
113>115.
EXTREME HEAT WARNING UNTIL 11 PM PDT MONDAY FOR CAZ102-105-
107-108.
HEAT ADVISORY UNTIL 11 PM PDT MONDAY FOR CAZ106.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 5 AM PDT SUNDAY FOR PZZ450.
GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ470.
HAZARDOUS SEAS WARNING FROM 11 PM THIS EVENING TO 5 PM PDT
SUNDAY FOR PZZ470.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT MONDAY FOR PZZ475.
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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