536
FXUS66 KMFR 041127
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
427 AM PDT TUE AUG 4 2026
KEY MESSAGES
* TEMPERATURES WEST OF THE CASCADES LOOK TO BE 5 TO 15 DEGREES
ABOVE NORMAL, WITH TEMPERATURES TO THE EAST UP TO 5 DEGREES
ABOVE SEASONAL AVERAGES. ADDITIONAL EAST SIDE WARMING IS
EXPECTED ON WEDNESDAY.
* WEDNESDAY AND THURSDAY HAVE THE WARMEST TEMPERATURES OF THE
FORECAST PERIOD ACROSS THE AREA.
* MORNING WILDFIRE SMOKE ACCUMULATION LOOKS TO CONTINUE, WITH
AFTERNOON BREEZES BRINGING SOME CLEARING BEFORE THE PATTERN
CONTINUES.
* TEMPERATURES COOL ON FRIDAY AND THROUGH THE WEEKEND, POSSIBLY
CONTINUING INTO EARLY NEXT WEEK.
DISCUSSION
THE AXIS OF AN UPPER LEVEL RIDGE APPROACHES THE AREA
TODAY, BRINGING A 5 TO 10 DEGREE INCREASE IN DAYTIME HIGHS ACROSS
THE AREA. COASTAL AREAS LOOK TO BE IN THE HIGH 70S TO LOW 80S, WHILE
MOST WEST SIDE VALLEYS ARE FORECAST TO BE IN THE 100 TO 105 RANGE
AND PARTS OF THE KLAMATH RIVER VALLEY COULD EXCEED 110 DEGREES. FOR
THOSE INLAND VALLEYS, A HEAT ADVISORY IS IN PLACE STARTING THIS
AFTERNOON TO HIGHLIGHT THE THREAT THAT THESE TEMPERATURES POSE TO
ANYONE WITHOUT ADEQUATE COOLING OR HYDRATION. EAST OF THE CASCADES,
DAYTIME HIGHS IN THE LOW TO MID 90S ARE EXPECTED TODAY. WHILE EAST
SIDE TEMPERATURES FALL SHORT OF ADVISORY LEVEL, THEY ARE STILL ABOUT
5 DEGREES ABOVE NORMAL SUMMER WARMTH.
WITH THE RIDGE AXIS SLOWLY MOVING FROM WEST TO EAST, TEMPERATURES
WEST OF THE CASCADES MAY GAIN ANOTHER DEGREE OR TWO ON WEDNESDAY
WHILE EAST SIDE DAYTIME HIGHS LOOK TO INCREASE BY UP TO 5 DEGREES.
THESE TEMPERATURES CONTINUE INTO THURSDAY, MAKING THESE TWO DAYS THE
WARMEST OF THE FORECAST PERIOD FOR MOST AREAS. TUESDAY'S HEAT
ADVISORY EXPANDS TO COVER MOST OF THE CWA ON WEDNESDAY AFTERNOON
(WESTERN COOS AND CURRY COUNTIES, EASTERN DOUGLAS COUNTY AND
NORTHERN KLAMATH COUNTIES, AND THE MOUNT SHASTA REGION SOUTH OF WEED
FELL JUST SHORT OF ADVISORY CONDITIONS). EVEN FOR THESE "LESS HOT"
AREAS, EXTRA CAUTION IS WORTHWHILE FOR ANYONE PARTICIPATING IN
RECREATIONAL ACTIVITIES.
WILDFIRE SMOKE LOOKS TO CONTINUE ACCUMULATING OVERNIGHT THROUGH THE
MIDDLE OF THE WEEK, WITH AFTERNOON BREEZES BRINGING SOME RELIEF.
LAKE AND KLAMATH COUNTIES ARE EXPECTED TO SEE THE HIGHEST
CONCENTRATIONS OF SMOKE. WITH ATMOSPHERIC CONDITIONS BEING FAIRLY
STABLE, THIS PATTERN OF OVERNIGHT ACCUMULATION AND AFTERNOON
CLEARING SHOULD BE SOMEWHAT RELIABLE THROUGH THURSDAY. WHILE PEAK
SMOKE AND SPEAK HEATING DO NOT OVERLAP, THIS ALSO MEANS THAT AIR
QUALITY MAY BE POOREST WHILE PEOPLE DO THINGS IN THE MORNING TO
AVOID AFTERNOON HEAT. FOR ANYONE SENSITIVE TO UNSEASONABLE WARMTH
AND POOR AIR QUALITY, THIS MIDWEEK PERIOD MAY BE DIFFICULT TO
NAVIGATE.
THE RIDGE AXIS LOOKS TO BE JUST EAST OF THE AREA ON FRIDAY, WHICH
WILL ALLOW FOR THE FIRST DEGREES OF COOLING. A SLOW AND STEADY
COOLING TREND MAY CONTINUE OVER THE WEEKEND AND INTO EARLY NEXT
WEEK, AS THERE'S SOME AGREEMENT OF A ZONAL/SLIGHTLY SOUTHWEST FLOW
PATTERN TAKING CONTROL BEHIND THE RIDGE. WHILE THIS LOOKS TO BRING
COOLER TEMPERATURES, DRY AIR ALOFT IS KEEPING ABUNDANT
PRECIPITATION OUT OF THE LONG-TERM FORECAST. THESE FLOW PATTERNS
ALSO OFFER LITTLE SUPPORT FOR THUNDERSTORM DEVELOPMENT AFTER THE
HEAT WAVE. -TAD
AVIATION...04/12Z TAFS
VFR LEVELS CONTINUE ACROSS NORTHERN OREGON
AND FAR NORTHERN CALIFORNIA THROUGH THE NEXT 24 HOURS. BREEZY
AFTERNOON AND EVENING WINDS WILL REMAIN STRONGEST AT THE COAST.
WILDFIRE SMOKE MAY BRING PERIODS OF VFR VISIBILITIES TO AREA
TERMINALS, ESPECIALLY IN MORNING HOURS BEFORE AFTERNOON BREEZES CAN
BRING SOME CLEARING.
MARINE...UPDATED 200 AM PDT TUESDAY, AUGUST 4, 2026
NORTHERLY
WINDS HAVE SOMEWHAT EASED, TAKING GALE GUSTS OUT OF THE FORECAST.
VERY STEEP AND HAZARDOUS SEAS ARE PRESENT IN WATERS SOUTH OF CAPE
BLANCO, WITH STEEP SEAS IN WATERS TO THE NORTH. NORTH WINDS AND SEAS
SHOULD EASE FURTHER WEDNESDAY INTO THURSDAY, ALTHOUGH STEEP SEAS ARE
LIKELY TO REMAIN HAZARDOUS TO SMALL CRAFT.
FIRE WEATHER...UPDATED 200 AM PDT TUESDAY, AUGUST 4, 2026
RIDGING ALOFT AND A THERMAL TROUGH AT THE SURFACE WILL PRODUCE
PERSISTENT NEAR-CRITICAL TO CRITICAL FIRE WEATHER CONCERNS THROUGH
THE WEEK. TEMPERATURES WILL REMAIN HOT THROUGH THE WEEK, PEAKING AT
ABOUT 10 TO 15 DEGREES ABOVE NORMAL WEDNESDAY/THURSDAY, BEFORE
DIMINISHING CLOSER TO NORMAL VALUES INTO THE WEEKEND.
POOR RH RECOVERIES ARE BEING OBSERVED ACROSS ALL OF SW OREGON AND
NORTHERN CALIFORNIA UPPER SLOPES/RIDGES EARLY THIS MORNING. SOME
GUIDANCE IS SHOWING RH ONLY RECOVERING INTO THE LOW 20S (UPPER
TEENS?!) TODAY THROUGH THURSDAY, WHILE DAYTIME MINIMUM HUMIDITIES
COULD EASILY DROP INTO THE SINGLE DIGIT PERCENTAGES. FORTUNATELY,
WINDS WILL DIMINISH SOME FROM THE PREVIOUS DAY. WITH THESE HOT, DRY,
AND WINDY CONDITIONS IN THE VALLEYS DURING THE DAY MONDAY AND
TUESDAY,AND WITH THE POOR RECOVERIES AND EAST WINDS OVERNIGHT OVER
THE MOUNTAINS, A RED FLAG HAS BEEN ISSUED FOR THE ILLINOIS AND ROGUE
VALLEYS, AS WELL AS THE SISKIYOUS AND SOUTHERN OREGON CASCADES,
BEGINNING THIS AFTERNOON AND CONTINUING INTO TUESDAY EVENING.
ALTHOUGH POOR OVERNIGHT RECOVERIES AND BREEZY EAST WINDS RETURN
AGAIN FOR THE MOUNTAINS TUESDAY NIGHT, CONDITIONS SHOULD IMPROVE
JUST ENOUGH (MAINLY SLIGHTLY WEAKER WINDS) TO PRECLUDE CONTINUING
THE RED FLAG THROUGH THE OVERNIGHT HOURS. GUIDANCE SHOWS ONLY
MINIMAL IMPROVEMENT, IF ANY, IN WIND AND HUMIDITY DURING THE DAY
WEDNESDAY, IN ADDITION TO MUCH MORE INSTABILITY AS THE THERMAL
TROUGH PUSHES INLAND. WITH WEDNESDAY BEING THE HOTTEST DAY, AND WITH
CONTINUED DRY, WINDY, AND UNSTABLE CONDITIONS, CRITICAL FIRE WEATHER
WILL EXPAND INTO WESTERN SISKIYOU COUNTY AND INTO DOUGLAS COUNTY.
ANOTHER RED FLAG WARNING HAS BEEN ISSUED FOR ALL OF THESE AREAS FOR
WEDENSDAY AFTERNOON/EVENING.
WE MAY SEE SOME SLIGHT COOLING AND SLIGHT IMPROVEMENT TO OVERALL
WINDS AND HUMIDITIES THURSDAY AND/OR FRIDAY, BUT IT MAY NOT BE ENOUGH
TO BRING SECTIONS OF THE AREA OUT OF RED FLAG CONCERNS. THIS WILL BE
FURTHER ASSESSED IN THE COMING DAYS.
OUTSIDE OF THE RED FLAG WARNING AREAS, CONDITIONS WILL STILL BE HOT,
DRY, WINDY, AND UNSTABLE, WITH POOR RIDGETOP AND EAST SIDE
RECOVERIES, AND PERIODS OF NEAR-CRITICAL CONDITIONS.
MFR WATCHES/WARNINGS/ADVISORIES
OR...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR ORZ616-617-
620>623.
HEAT ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT THURSDAY FOR
ORZ023-024-026-028>031.
CA...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR CAZ280-282.
HEAT ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT THURSDAY FOR
CAZ080-081-083>085.
PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING UNTIL 9 PM PDT THIS
EVENING FOR PZZ356-376.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 5 PM PDT
WEDNESDAY FOR PZZ356-376.
SMALL CRAFT ADVISORY UNTIL 5 PM PDT WEDNESDAY FOR PZZ350-370.
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