086
FXUS66 KMFR 041345
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
645 AM PDT SAT JUL 4 2026
KEY POINTS
* LOW IMPACT WEATHER CONTINUES TODAY, THOUGH WITH COASTAL LOW
CLOUDS PERSISTING FOR MOST OF THE MORNING. ALSO, TYPICALLY
BREEZY CONDITIONS FOR THE AFTERNOON AND EVENING.
* THE INLAND WARMING TREND CONTINUES TODAY, WITH HIGHS A FEW
DEGREES HIGHER THAN YESTERDAY. HIGHS WILL THEN FLUCTUATE LITTLE
FROM DAY-TO-DAY DURING THE NEXT WEEK, REMAINING AROUND 5 TO 10
DEGREES ABOVE NORMAL THROUGH TUESDAY, THEN A FEW DEGREES LESS
HOT INTO NEXT WEEKEND.
* SUNDAY/MONDAY - ISOLATED LATE DAY THUNDERSTORMS ACROSS NORTHERN
CALIFORNIA AND FROM THE CASCADES EASTWARD. MOST LIKELY ACROSS
LAKE, NORTHERN KLAMATH, AND EASTERN MODOC COUNTIES. FIRE STARTS
WILL BE A CONCERN AS THESE THUNDERSTORMS WILL ARISE FROM HIGH
BASED CLOUDS WITH A FAIRLY DRY LOW-LEVEL AIR MASS.
* SUNDAY NIGHT/MONDAY MORNING - FOR THE SAME BROAD AREA, THOUGH
THUNDERSTORM ACTIVITY WILL DECREASE OVERNIGHT, EMBEDDED
SHORTWAVES COULD PRODUCE SHOWERS AND A FEW THUNDERSTORMS.
* TUESDAY THROUGH SATURDAY - STILL HOT AND BREEZY WITH LOW
HUMIDITY, BUT A RETURN OF A STABLE AIR MASS. CONDITIONS WILL BE
SIMILAR TO THOSE OF TODAY.
DISCUSSION
COASTAL STRATUS THIS MORNING FROM FLORENCE TO
BROOKINGS WILL BE STUBBORN TO CLEAR WITH BREAKS BECOMING
NOTICEABLE AFTER 10 AM PDT AND CLEARING LIKELY BY NOON. LOW
CLOUDS WILL BE RETURNING TO THE COAST THIS EVENING, PARTICULARLY
AFTER 8 PM PDT. OTHERWISE, SCATTERED CUMULUS BUILDUPS OVER
NORTHERN CALIFORNIA LATE TODAY WILL BE A FIRST SIGN OF THE COMING
CHANGE IN THE PATTERN. A WEAK, BUT BROAD TROUGH FAR OFFSHORE FROM
NORTHERN CALIFORNIA WILL TRACK TOWARD THE COAST.
WHILE THERE ARE STILL SOME MODEL DIFFERENCES, THE LAST FEW MODEL
RUNS HAVE REMAINED FOCUSED OVER SOUTH CENTRAL OREGON AND NORTHERN
CALIFORNIA FOR A RISK OF HIGH-BASED CONVECTION LATE IN THE DAY ON
SUNDAY AND MONDAY, INCLUDING BOTH BROADER COVERAGE AND A SLIGHTLY
HIGHER PROBABILITY ON MONDAY. ACTIVITY DOES LOOK TO REMAIN
ISOLATED ON SUNDAY WITH THE HIGHEST PROBABILITY OF THUNDERSTORMS
IN LAKE COUNTY. WE TEND TO GET WHAT I CHARACTERIZE AS HYBRID
STORMS IN OUR AREA, NOT CLASSICALLY DRY THUNDERSTORMS BUT NOT BIG
RAIN PRODUCERS EITHER. THESE CELLS LOOK TO LEAN TOWARD DRIER THAN
NORMAL WITH CLOUD BASES (AROUND 11-13K FT) A LITTLE HIGHER THAN
NORMAL, AND A DRY LOWER LEVEL OF THE AIR MASS. THE SAME FACTORS
THAT FAVOR DRIER CELLS ON SUNDAY WILL ALSO SOMEWHAT HINDER THE
DEVELOPMENT OF STORMS. EMBEDDED SHORTWAVES AHEAD OF THE TROUGH
COULD PRODUCE VIRGA, LIGHT SHOWERS, AND EVEN A FEW OVERNIGHT
THUNDERSTORMS. AVAILABLE MID-LEVEL MOISTURE LOOKS TO REACH A PEAK
DURING THE LATE MORNING/EARLY AFTERNOON ON MONDAY, AHEAD OF PEAK
HEATING. IT WILL BE A BIT OF A RACE TO SEE HOW MUCH ACTIVITY
DEVELOPS IN NORTHERN CALIFORNIA ON MONDAY BEFORE DRIER AIR ALOFT
FILTERS IN. COMPARED TO THE DATA FROM 24 HOURS AGO, CONFIDENCE IS
HIGHER FOR LATE DAY STORMS FROM THE CASCADES EASTWARD, WITH THE
WESTERN EDGE OF SUFFICIENT MID-LEVEL MOISTURE FOR THUNDERSTORM
DEVELOPMENT SHOWING A HIGHER PROBABILITY OF INCLUDING SOUTHERN
AND EASTERN JACKSON COUNTY. THOUGH LIKELY TO BE TAPERING OFF,
THUNDERSTORMS COULD LINGER JUST A BIT LONGER THAN USUAL ON MONDAY
EVENING, PAST SUNSET FOR DIAMOND LAKE EASTWARD ACROSS NORTHERN
PORTIONS OF KLAMATH AND LAKE COUNTIES.
BEHIND THE UPPER LEVEL TROUGH, A RETURN OF A MORE WESTERLY FLOW
ALOFT IS EXPECTED ON TUESDAY, WITH A STABLE MARITIME INFLUENCED
AIR MASS. THE 00Z AND 06Z MODELS HAVE CONTINUED TO TREND WEAKER
WITH WHAT WAS ORIGINALLY SHAPING UP TO BE AN IMPACTFUL DRY FRONTAL
PASSAGE. THE HIGHEST PROBABILITY NOW IS TO MERELY SEE DRY MINIUM
HUMIDITY LEVELS ON THE EAST SIDE NUDGE A COUPLE OR FEW PERCENT
LOWER THAN PREVIOUS DAYS AND BREEZY AFTERNOON WEST WINDS TO BE
AROUND 5 MPH STRONGER THAN TYPICAL. BOTH OF THOSE FEATURES COULD
STILL BE JUST ENOUGH TO TIP THE BALANCE PAST CRITICAL THRESHOLDS
OF FIRE DANGER. OVERALL, MOST OF NEXT WEEK, TUESDAY ONWARD WILL
SEE CONDITIONS EACH DAY QUITE SIMILAR TO THOSE OF TODAY.
AVIATION...04/12Z TAFS
MARINE LAYER LOW CLOUDS EXTEND INTO THE
COASTAL VALLEYS EARLY THIS MORNING, INCLUDING THE COQUILLE, CAMAS,
AND LOWER UMPQUA VALLEYS (TO AROUND SUTHERLIN). THESE CONDITIONS ARE
LIFR FROM GOLD BEACH TO BROOKINGS, AND IFR FOR THE REMAINDER OF THAT
AREA. CONDITIONS WILL BEGIN TO IMPROVE AFTER SUNRISE, WITH BREAKS IN
THE OVERCAST FORMING AROUND 17Z-18Z, AND WIDESPREAD VFR FROM 20Z-
02Z. A SIMILAR SCENARIO IS EXPECTED LATER THIS EVENING INTO SUNDAY
MORNING. OTHERWISE, VFR CONTINUES ACROSS THE REMAINDER OF THE AREA
WITH A FEW AFTERNOON CUMULUS BUILDUPS EXPECTED OVER NORTHERN
CALIFORNIA.
MARINE...UPDATED 200 AM PDT SATURDAY, JULY 4, 2026
GUSTY NORTH
WINDS WILL PERSIST INTO EARLY NEXT WEEK, MAINTAINING STEEP TO VERY
STEEP SEAS. ADVISORY LEVEL WINDS WILL PERSIST SOUTH OF CAPE BLANCO
AND MAINTAIN STEEP SEAS SOUTH OF PORT ORFORD THIS MORNING.
CONDITIONS WORSEN THIS AFTERNOON INTO SUNDAY AS NORTH WINDS
INCREASE. STEEP SEAS WILL RETURN TO AREAS NORTH OF CAPE BLANCO WITH
VERY STEEP SEAS DEVELOPING SOUTH OF CAPE BLANCO AND BEYOND 5 NM FROM
SHORE. THERE COULD BE A BRIEF PERIOD OF GALE FORCE GUSTS THIS
AFTERNOON SOUTH OF GOLD BEACH BETWEEN 10 AND 30 NM FROM SHORE. THESE
CONDITIONS ARE LIKELY TO PERSIST THROUGH SUNDAY EVENING, THEN
IMPROVE MONDAY INTO WEDNESDAY AS NORTH WINDS WEAKEN.
FIRE WEATHER...UPDATED 400 AM PDT SATURDAY, JULY 4, 2026
THERE
IS A SLIGHT CHANCE OF LATE DAY THUNDERSTORMS ON SUNDAY AND MONDAY
FOR NORTHERN CALIFORNIA AND FROM THE CASCADES EASTWARD, WITH THE
HIGHEST PROBABILITY FOR LAKE COUNTY, AND ON MONDAY. A FEW
THUNDERSTORMS MAY ALSO DEVELOP IN LAKE AND MODOC COUNTIES LATER
SUNDAY NIGHT INTO MONDAY MORNING. FIRST, A MODEST INCREASE IN MID-
LEVEL SHOULD ALLOW SCATTERED CUMULUS BUILDUPS OVER SISKIYOU AND
MODOC COUNTIES THIS AFTERNOON INTO THE EARLY EVENING.
OTHERWISE, HIGH TEMPERATURES REMAIN AROUND 5 TO 10 DEGREES ABOVE
NORMAL, AND AFTERNOON BREEZES REMAIN TYPICAL TO SLIGHTLY ENHANCED
DURING THE NEXT WEEK. THIS WILL RESULT IN VERY DRY CONDITIONS,
GENERALLY JUST SHY OF CRITICAL WIND AND HUMIDITY THRESHOLDS. ALSO,
GUSTY NORTHEAST WINDS WILL CONTINUE AT COASTAL RIDGES DURING THE
OVERNIGHT HOURS THROUGH SUNDAY, STRONGEST EARLY ON SUNDAY.
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 2 AM PDT MONDAY
FOR PZZ356.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM PDT MONDAY
FOR PZZ350-370.
HAZARDOUS SEAS WARNING FROM 2 PM THIS AFTERNOON TO 2 AM PDT
MONDAY FOR PZZ356-376.
SMALL CRAFT ADVISORY UNTIL 2 PM PDT THIS AFTERNOON FOR PZZ376.
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