465
FXUS66 KMFR 061143
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
443 AM PDT MON APR 6 2026
UPDATED AVIATION DISCUSSION
AVIATION...06/12Z TAFS
VFR CONDITIONS WILL PERSIST THROUGH MONDAY
NIGHT FOR MOST THE AREA. AN EXCEPTION WILL BE AREAS OF LIFR/IFR
CEILINGS AND VISIBILITIES OVER THE MARINE WATERS AND ALONG THE COAST
NORTH OF GOLD BEACH, INCLUDING NORTH BEND (KOTH), THROUGH AROUND 18Z
THIS MORNING. ALSO, THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS
AFTERNOON INTO EARLY EVENING FOR BOTH THE WINTER RIM (ALONG THE
BORDER OF KLAMATH AND LAKE COUNTIES), AND IN SOUTHERN SISKIYOU
COUNTY NEAR MT. SHASTA.
PREV DISCUSSION
/ISSUED 324 AM PDT MON APR 6 2026/
DISCUSSION...IN GENERAL, UPPER LEVEL TROUGHING WILL DOMINATE THE
WEATHER THIS WEEK, THOUGH WE'LL BE BETWEEN SYSTEMS UNDER A SPLIT
FLOW REGIME. WAVES OF LOW PRESSURE WILL SKATE BY TO THE NORTH
THROUGH BRITISH COLUMBIA THIS WEEK WHILE ANOTHER LOW PRESSURE
SYSTEM MEANDERS OFFSHORE OF CALIFORNIA THROUGH MID-WEEK BEFORE
MOVING SOUTHWARD OVER THE WEEKEND. TEMPERATURES WILL TREND COOLER
WITH PERIODS OF SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH WEEK,
ESPECIALLY THE LATTER HALF OF THE WEEK. HEADING INTO THE WEEKEND,
THE NORTHERN BRANCH OF SYSTEMS SAGS FARTHER SOUTH, BRINGING MORE
STABLE CONDITIONS WITH INCREASING CHANCES FOR MORE WIDESPREAD
SHOWERS AND COOLER TEMPERATURES.
A QUIET MORNING IS UNDERWAY WITH SATELLITE SHOWING SOME SCATTERED
MID AND HIGH LEVEL CLOUDS ACROSS THE REGION, AND NO RETURNS ON THE
RADAR. OVERALL, TODAY WILL BE MUCH LIKE YESTERDAY WITH MOSTLY CLEAR
SKIES AND AFTERNOON TEMPERATURES MORE TYPICAL OF JUNE THAN APRIL.
ONE DIFFERENCE, HOWEVER, WILL BE THE CHANCE FOR SOME ISOLATED
SHOWER/THUNDERSTORMS THIS AFTERNOON ACROSS THE CASCADES AND INTO
NORTHERN KLAMATH/LAKE COUNTIES. MODELS INDICATE SUFFICIENT
INSTABILITY AND MOISTURE IN THESE AREAS, BUT THE WEAKER SIGNAL IS
A SUFFICIENT TRIGGER TO INITIATE ANY CONVECTION. HIGH RESOLUTION
CONVECTION ALLOWING MODELS (CAMS) ARE PINPOINTING THE NORTHERN
PORTIONS OF KLAMATH AND LAKE COUNTIES TODAY, BUT STILL WITH FAIRLY
LOW CHANCES (10-20%) FOR LIGHTNING. SOME SHOWER ACTIVITY IS ALSO
POSSIBLE ALONG THE SISKIYOUS AND FARTHER SOUTH AROUND THE TRINITY
HORN, BUT INSTABILITY PARAMETERS ARE LESS FAVORABLE FOR LIGHTNING
ACTIVITY THERE. INSTABILITY AND MID-LEVEL MOISTURE DECREASE ON
TUESDAY, SO WE AREN'T EXPECTING ANY SHOWERS/THUNDERSTORMS. IT DOES
GET BREEZY IN THE AFTERNOON, HOWEVER, AS ANOTHER WAVE PASSES TO
THE NORTH AND LOW PRESSURE OFFSHORE MOVES CLOSER TO THE COAST.
WINDS WILL BE STRONGEST EAST OF THE CASCADES WITH GUSTS OF 15 TO
25 MPH COMMON. AFTERNOON TEMPERATURES TREND LOWER BY ABOUT 5 TO 10
DEGREES, MOST NOTABLE ACROSS NORTHERN AREAS.
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST BY WEDNESDAY AND
LINGER THROUGH THE REMAINDER OF THE WEEK. LOW PRESSURE MOVES CLOSER
TO THE CALIFORNIA COAST ON WEDNESDAY AND HOVERS THERE THROUGH
FRIDAY. THIS WILL PUT THE REGION UNDER FAVORABLE DYNAMICS FOR
SHOWERS AND THUNDERSTORMS, ESPECIALLY THURSDAY AND FRIDAY. OVERALL,
THE GREATEST ACTIVITY IS EXPECTED SOUTH OF THE OR/CA BORDER, BUT
THERE ARE SOME POSITION DIFFERENCES ON THE LOCATION OF THE UPPER
LEVEL LOW AND THIS WILL INFLUENCE HOW FAR NORTH OF THE OR/CA BORDER
THAT SHOWERS/THUNDERSTORMS MAKE IT. FOR WEDNESDAY, MOST ACTIVITY IS
EXPECTED ACROSS NORTHERN CALIFORNIA WITH THE NORTHERN MOST EXTENT
EXPECTED THURSDAY AND FRIDAY. DESPITE THE POSITION DIFFERENCES, THE
BETTER CHANCES FOR SHOWER/THUNDERSTORM ACTIVITY WILL BE ACROSS
NORTHERN CALIFORNIA, SISKIYOUS/CASCADES AND THE EAST SIDE. WITH
SOUTHERLY FLOW, HOWEVER, SHOWERS/THUNDERSTORMS OVER THE SISKIYOUS
COULD MOVE INTO PORTIONS OF JACKSON/JOSEPHINE COUNTIES THURSDAY AND
FRIDAY AFTERNOONS.
LOW PRESSURE SHIFTS SOUTHWARD ON SATURDAY AS LOW PRESSURE FROM THE
NORTH DIGS SOUTHWARD. THIS WILL BRING STABILIZING CONDITIONS FOR
AREAS WEST OF THE CASCADES UNDER A MORE WESTERLY FLOW PATTERN. THERE
LOOKS TO BE SOME LINGERING INSTABILITY ACROSS LAKE/MODOC COUNTIES
FOR SATURDAY, BUT IT LOOKS MORE LIKE IT'LL JUST BE SHOWERS WITH NO
LIGHTNING. THERE ARE SOME DIFFERENCES IN JUST HOW FAR SOUTH THIS
NORTHERN LOW WILL MAKE IT, SO CONFIDENCE IS LOW FOR WIDESPREAD
PRECIPITATION AT THIS TIME FOR SUNDAY INTO MONDAY. BEST CHANCES WILL
BE ALONG THE COAST AND INTO THE UMPQUA BASIN AS WELL AS THE
CASCADES, WITH THE CURRENT NATIONAL BLEND OF MODELS GIVING ABOUT A
40-60% CHANCE OF PRECIPITATION FOR THOSE AREAS AND 20-30% CHANCE FOR
EVERYWHERE ELSE. SNOW LEVELS ARE FORECAST TO LOWER TO AROUND 5000 FT
(COULD BE LOWER IF THIS SYSTEM ENDS UP FARTHER SOUTH), BUT WITH THE
MAIN DYNAMICS TO THE NORTH, SNOW AMOUNTS ARE CURRENTLY EXPECTED TO
BE LIGHT. HIGH TEMPERATURES WILL FEEL PRETTY COOL DUE TO HOW WARM IT
CURRENTLY IS, BUT IN REALITY, HIGH TEMPERATURES WILL RETURN TO MORE
SEASONAL VALUES OVER THE WEEKEND (MID 50S EAST, MID 60S WEST).
WHILE DETAILS ARE HIGHLY VARIABLE AT THIS POINT IN TIME, BOTH GFS
AND EC ENSEMBLES MAINTAIN PERIODS OF WET WEATHER WITH TEMPERATURES
CLOSER TO SEASONABLE VALUES BEYOND THE WEEKEND AND THROUGH NEXT
WEEK. THIS LINES UP WELL WITH THE CLIMATE PREDICTION CENTER'S 8-14
DAY OUTLOOK WHICH PREDICTS TEMPERATURES AND PRECIPITATION BOTH
LEANING TOWARD ABOVE NORMAL VALUES (30-50% CHANCE).
MARINE...UPDATED 115 AM PDT MONDAY, APRIL 6, 2026...RELATIVELY
CALM CONDITIONS ARE EXPECTED THROUGH TONIGHT. A WEAK THERMAL TROUGH
DEVELOPS ON TUESDAY, RESULTING SOME GUSTY NORTH WINDS THAT WILL
CREATE BORDERLINE ADVISORY LEVEL SEAS TUESDAY THROUGH WEDNESDAY. THE
THERMAL TROUGH WEAKENS ON WEDNESDAY AS THE UPPER LEVEL PATTERN
TRANSITIONS. A TROUGH APPROACHES THE CALIFORNIA COAST ON THURSDAY,
THEN SHIFTS SOUTHWARD OVER THE WEEKEND. THIS WILL CONTINUE THE
PATTERN OF LOW PRESSURE INLAND AND HIGH PRESSURE OFFSHORE, RESULTING
IN PERIODS OF INCREASED NORTH WINDS AND STEEP SEAS WITH BORDERLINE
ADVISORY CONDITIONS THROUGH THE END OF THE WEEK.
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 5
PM PDT WEDNESDAY FOR PZZ350-356-370-376.
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