827
FXUS66 KMFR 282123
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
223 PM PDT FRI MAR 28 2025
DISCUSSION
AN UPPER LOW IS CENTERED OFF VANCOUVER ISLAND WITH
A TROUGH EXTENDING INTO THE REGION. THIS COMBINED WITH MOIST
ONSHORE FLOW IS PROVIDING PLENTY OF SUPPORT FOR CONTINUED SHOWERS
TODAY. SNOW LEVELS ARE AROUND 4000 TO 5000 FEET, BUT AS
PRECIPITATION AMOUNTS ARE LIGHT WITH THESE SHOWERS, SNOWFALL
AMOUNTS IN THE CASCADES AND SISKIYOUS HAVE DROPPED BELOW WHAT
WOULD BE NEEDED FOR WINTER WEATHER ADVISORIES. SHOWERS WILL
DECREASE LATE TONIGHT INTO SATURDAY AS ONSHORE FLOW WEAKENS AND
THE UPPER LOW RETREATS TO THE NORTH.
AS THE OFFSHORE LOW PUSHES NORTH, IT WILL MERGE WITH THE NEXT LOW
IN THE SEQUENCE THAT WILL ARRIVE OFFSHORE THIS WEEKEND. MEANWHILE,
A WEAK SHORTWAVE TROUGH WILL MOVE OVER THE REGION TONIGHT INTO
EARLY TOMORROW, BRIEFLY AND ONLY SLIGHTLY INTENSIFYING SHOWER
ACTIVITY. SNOW LEVELS WILL LOWER TO 3000 TO 4000 FEET TONIGHT AND
SATURDAY MORNING, BUT EXPECT ONLY LIGHT SNOWFALL ACCUMULATIONS.
PRECIPITATION CLEARS THE AREA BY SATURDAY AFTERNOON, AND
TEMPERATURES WILL TREND SLIGHTLY WARMER BUT REMAIN CLOSE TO NORMAL
VALUES FOR THIS TIME OF YEAR.
AFTER THIS BRIEF BREAK IN THE ACTION SATURDAY AFTERNOON AND
EVENING, THE SECOND OFFSHORE LOW WILL APPROACH THE COAST WITH MORE
WIND AND RAIN SATURDAY NIGHT INTO SUNDAY. MODELS HAVE BACKED OFF
QUITE A BIT ON THE STRENGTH OF THIS SYSTEM, SLOWING IT DOWN A BIT,
AND AIMING THE BULK OF MOISTURE TO OUR SOUTH. SNOW LEVELS ARE
EXPECTED TO REMAIN ABOVE ROUGHLY 4500 FEET AGAIN, SO WINTER
WEATHER CONCERNS WILL BE LIMITED. HOWEVER, THE SOUTH TO NORTH
PRESSURE GRADIENT AND SW TO NE ORIENTATION OF THE LOW AND
MIDLEVEL FLOW WILL RESULT IN WINDY CONDITIONS IN THE SHASTA VALLEY
AND ACROSS THE EAST SIDE, BUT EVEN THEN THE MIDLEVEL WINDS ARE
EXPECTED TO BE 50KT OR LESS. AT THIS TIME WE ARE ANTICIPATING THAT
NO MORE THAN ADVISORY HEADLINES WILL BE NEEDED FOR WIND AND SNOW
SUNDAY AFTERNOON THROUGH MONDAY. THE EXCEPTION WILL BE THE SHASTA
HIGHLANDS AND THE MOUNTAINS OF WESTERN SISKIYOU COUNTY, WHERE THE
SOUTHERLY TRAJECTORY OF MOISTURE HAS THE POTENTIAL TO PRODUCE
HEAVIER SNOW, BUT THEN AGAIN, ONLY ABOVE 4500 TO 5000 FEET. WE'LL
KEEP AN EYE ON THIS.
BEYOND SUNDAY/MONDAY THROUGH MUCH OF NEXT WEEK, THE MODEL
SOLUTIONS VARY QUITE A BIT ON THE DETAILS OF ANY APPROACHING
SYSTEMS. HOWEVER, THERE DOES APPEAR TO BE A STRONG TREND OF
CONTINUED CYCLONIC FLOW, OR "TROUGHINESS," WITH ONSHORE FLOW,
WHICH SUGGESTS THAT SHOWERS WILL BE CONTINUING THROUGH MUCH OF THE
WEEK. TEMPERATURES WILL ALSO TREND JUST SLIGHTLY BELOW NORMAL DUE
TO ONGOING CLOUDINESS AND THE COOLER AIR MASS ALOFT. WE WILL
CONTINUE TO MONITOR THE MODELS, HOWEVER, AS THERE ARE SOME
INDICATION OF A STRONGER SYSTEM POSSIBLE ROUGHLY MIDWEEK, ALTHOUGH
CURRENT TRENDS SUGGEST IT IS LIKELY TO BE AIMED TO OUR SOUTH IN
CENTRAL CALIFORNIA. THERE ARE ALSO TRENDS TOWARDS HIGH PRESSURE
TOWARDS THE END OF THE WEEK, SO PERHAPS A DRY, WARM PERIOD IS
IN STORE FOR THE FIRST WEEKEND OF APRIL. WE SHALL SEE. -BPN
AVIATION...28/18Z TAFS
AN UNSTABLE ENVIRONMENT WILL REMAIN IN
PLACE THROUGH THIS EVENING. THIS WILL RESULT IN ISOLATED CONVECTIVE
SHOWERS ALONG WITH GUSTY BREEZES THIS AFTERNOON INTO EARLY THIS
EVENING GOT ALL OF THE TERMINALS. THE INSTABILITY WILL ALSO RESULT
IN VFR CEILINGS REMAINING THE PREDOMINATE CONDITION THROUGH THE TAF
PERIOD. HOWEVER, THE HIGHER TERRAIN COULD END UP PARTLY OBSCURED FOR
BRIEF PERIODS OF TIME IN SHOWERS UNTIL AT LEAST 0Z. -PETRUCELLI
MARINE...UPDATED 200 PM FRIDAY, MARCH 28, 2025
SOUTH WEST WINDS
WILL DIMINISH THIS EVENING WITH LIGHT TO OCCASIONALLY MODERATE WINDS
TONIGHT INTO SATURDAY MORNING. HOWEVER, SEAS WILL REMAIN VERY STEEP
AND HAZARDOUS INTO TONIGHT. WEAK HIGH PRESSURE BUILDS INTO THE AREA
SATURDAY INTO SATURDAY NIGHT WITH LIGHT TO OCCASIONALLY MODERATE
WINDS. BUT, SEAS WILL REMAIN ELEVATED ENOUGH FOR SMALL CRAFT
CONDITIONS TO CONTINUE INTO SATURDAY AFTERNOON.
THERE COULD BE BRIEF BREAK IN THE WEATHER SATURDAY NIGHT INTO SUNDAY
MORNING WITH LIGHT TO MODERATE WINDS AND CALMER SEAS, THEN ANOTHER
FRONT WILL MOVE INTO THE AREA BRINGING INCREASING SOUTH WINDS AND
STEEP SEAS SUNDAY AFTERNOON INTO SUNDAY NIGHT.
THE PATTERN WILL REMAIN ACTIVE FOR MOST OF NEXT WEEK WITH LOW
PRESSURE MOVING INTO THE WATERS TUESDAY THAT COULD BRING MODERATE
WINDS AND STEEP SEAS, WITH A RELATIVE BREAK IN THE ACTION TUESDAY
NIGHT THROUGH WEDNESDAY. -PETRUCELLI
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING UNTIL 11 PM PDT THIS
EVENING FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM PDT
SATURDAY FOR PZZ350-356-370-376.
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