337
FXUS66 KMFR 121043
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
343 AM PDT TUE MAY 12 2026
DISCUSSION
A MARINE STRATUS LAYER COVERS SECTIONS OF THE COAST WITH SOME MID
AND HIGH CLOUDS MOVING OVER THE FORECAST AREA THIS MORNING. TODAY
WILL BE AN INTERESTING DAY WITH REGARDS TO SYNOPTIC WEATHER ACROSS
SOUTHERN OREGON AND NORTHERN CALIFORNIA.
A LOW OFF THE OREGON COAST WILL TAKE ON A NEGATIVE TILT LATER
THIS EVENING, PROVIDING SOME EXTRA DYNAMICS FOR CONVECTION AND
STRONG WINDS ACROSS THE FORECAST REGION. IT WILL BE A BREEZY DAY WITH
SUSTAINED WINDS 10 TO 20 MPH WITH GUSTS UP TO 35 MPH EAST OF THE
CASCADES THIS AFTERNOON AND EVENING. IT LOOKS LIKE THE STRONGER
WINDS ALOFT AROUND 9000 FEET SHOW UP LATE IN THE EVENING AND
OVERNIGHT HOURS WHEN WE'RE NOT MIXING, SO WE'LL AVOID THE REALLY
STRONG WINDS.
IN ANY CASE, THERE IS AN ELEVATED FIRE WEATHER RISK EAST OF THE
CASCADES IN LAKE AND MODOC COUNTIES AS WINDS AND HUMIDITIES IN
THE LOWER TEENS COMBINE FOR A FEW HOURS. THE HOT DRY WIND INDEX IS
ABOVE THE 95TH PERCENTILE FOR THIS TIME OF YEAR WITH VALUES
AROUND 200 TO 300, WHICH ISN'T BAD DURING FIRE SEASON, YET
UNUSUALLY HIGH FOR THIS TIME OF YEAR.
THUNDERSTORMS ARE ANOTHER CONCERN, SPECIFICALLY ALONG THE CASCADE
CREST. THE GFS FORECAST SOUNDINGS SHOW UNCAPPED CAPE AROUND 800
J/KG LATER THIS EVENING WITH 0-6KM SHEAR AROUND 50 KNOTS ALONG THE
CASCADE CREST, WHICH IS RATHER HEALTHY. IT LOOKS LIKE THE HIGH
RESOLUTION MODELS ARE MOST AMBITIOUS WITH CONVECTION TO OUR
NORTH, ALTHOUGH WE WOULDN'T BE SURPRISED WITH A FEW THUNDERSTORMS
FIRING NEAR CRATER LAKE THIS AFTERNOON. THE SPC HREF LIGHTNING
PROBABILITY IS AROUND 10% FOR THAT AREA, SO ODDS AREN'T THAT
GOOD.
EVENTUALLY, THIS LOW AND A COLD FRONT WILL PUSH ONSHORE DURING THE
OVERNIGHT HOURS. THE PRECIPITATION MODE ALONG THIS FRONT WILL JUST
BE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED ALONG THE COAST
OVERNIGHT. MANY WOULD CONSIDER THIS BENEFICIAL RAIN WITH A FEW
TENTHS FALLING ALONG THE COAST WITH A FEW HUNDRETHS FARTHER INLAND
UP TO THE CASCADES.
ONCE THE COLD FRONT MOVES THROUGH, TEMPERATURES WILL TREND NOTABLY
LOWER BY 10 TO 15 DEGREES COMPARED TO TUESDAY. THIS WILL PUSH US
TO MORE NORMAL SPRING WEATHER WITH A BRIEF WARM UP INTO THE 80'S
ON THURSDAY BEFORE WE COOL AGAIN ON FRIDAY. BY SATURDAY, MODELS
ARE BRINGING ANOTHER LOW AND COLD FRONT, ALTHOUGH PRECIPITATION
WILL BE VERY LIGHT OVER OUR AREA. THE BEST CHANCES FOR RAIN WILL
BE TO THE NORTH IN NORTHERN OREGON. THERE IS PRETTY GOOD CONSENSUS
THAT WE DRY OUT AFTER SATURDAY WITH TEMPERATURES WARMING INTO THE
80'S HERE IN MEDFORD NEXT WEEK.
-SMITH
AVIATION...12/06Z TAFS
VFR PREVAILS OVER INLAND AREAS LATE THIS
EVENING, BUT AS EXPECTED, IFR STRATUS AND/OR FOG HAS ALREADY
REDEVELOPED ALONG THE COAST. THE LOWER CLOUDS/FOG WILL CONTINUE TO
FILL IN TO MOST LOCATIONS ABOUT 5-10 MILES INLAND OVERNIGHT INTO
TUESDAY MORNING, BUT A BIT FARTHER INLAND (10-20 MILES) INTO THE
COQUILLE VALLEY NEAR COQUILLE AND MYRTLE POINT. VFR PREVAILS
ELSEWHERE INLAND OVERNIGHT INTO TUESDAY MORNING (INCLUDING
ROSEBURG).
STRATUS/FOG SHOULD LIFT/BREAK UP A BIT AT THE COAST TUESDAY
AFTERNOON, BUT SINCE THE FLOW WILL BE MORE ONSHORE, COULD SEE SOME
PERSISTENT CLOUDY AREAS. SOUTHERLY FLOW OVER INLAND AREAS AND SOME
INSTABILITY LATE TUESDAY AFTERNOON/EVENING COULD LEAD TO ISO/SCT
SHOWERS (EVEN A THUNDERSTORM?) IN SOME SPOTS FROM WESTERN SISKIYOU
COUNTY UP ACROSS THE SISKIYOUS TO THE CASCADES (THUNDER PROBABILITY
IS ABOUT 10-20% IN THESE AREAS). WITH DECENT MID-LEVEL FLOW ANYTHING
THAT GETS GOING COULD DRIFT OVER THE VALLEYS (MOSTLY JACKSON/EASTERN
DOUGLAS), BUT AS FAR WEST AS ILLINOIS VALLEY, GRANTS PASS AND EVEN
PERHAPS ROSEBURG DURING THE EVENING. EXPECT GUSTY SOUTHERLY
AFTERNOON BREEZES IN NORCAL (ESP. THE SHASTA VALLEY), BUT ALSO IN
OREGON EAST OF THE CASCADES AS WELL AS NEAR ANY SHOWER/TSTM THAT
DEVELOPS.
TUESDAY NIGHT, AN UPPER TROUGH WILL MOVE ONSHORE WITH MORE
WIDESPREAD MVFR CLOUDS AND COASTAL SHOWERS SPREADING INLAND BY
WEDNESDAY MORNING. THE SHOWERS COULD REACH NORTHERN KLAMATH AND LAKE
COUNTIES WEDNESDAY MORNING, BUT AREAS SOUTH AND EAST OF THE
MOUNTAINS WILL LARGELY REMAIN DRY WITH VFR. THINGS MOSTLY DRY OUT
WITH A MUCH COOLER AIR MASS WEDNESDAY AFTERNOON. -SPILDE
MARINE...UPDATED 815 PM PDT MONDAY, MAY 11, 2026
GUSTY NORTHERLY
WINDS AND STEEP SEAS ARE EASING, AND SEAS FALL BELOW ADVISORY LEVELS
BEFORE MIDNIGHT.
AN APPROACHING COMPACT LOW WILL BRING SHOWERS TUESDAY NIGHT INTO
EARLY WEDNESDAY. THERE WILL BE AN INCREASE IN WESTERLY WINDS AND
SWELL WEDNESDAY. THUNDERSTORMS ARE NOT EXPECTED AND SEAS ARE
FORECAST TO REMAIN BELOW ADVISORY LEVELS. NORTHERLY WINDS SOUTH OF
CAPE BLANCO INCREASE ON THURSDAY AND MAY BUILD STEEP SEAS ON FRIDAY.
-TAD/HERMANSEN
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
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