807
FXUS66 KMFR 201756
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
956 AM PST MON JAN 20 2025
.UPDATED AVIATION DISCUSSION.
DISCUSSION
NOT MUCH CHANGE IN THE OVERALL PATTERN IS EXPECTED
THROUGH MOST OF NEXT WEEK. UPPER LEVEL RIDGING OVER THE EASTERN
PACIFIC AND JUST OFFSHORE OF THE WEST COAST AND VERY STRONG AND
BROAD TROUGHING OVER ALMOST THE ENTIRE CONTINENT WILL KEEP THE
AREA GENERALLY UNDER HIGH PRESSURE WITH NORTH FLOW ALOFT. IN THE
LOW TO MID LEVELS, DRY EAST FLOW WILL PREVAIL, WITH DOWNSLOPE
EFFECTS KEEPING RIDGES AND MIDSLOPES WARM AND VERY DRY, WITH
STRONG INVERSIONS TRAPPING COLDER, MOIST AIR IN THE VALLEYS,
ESPECIALLY WEST OF THE CASCADES. IN OTHER WORDS, THE DAY-TO-DAY
FORECAST WILL CHANGE VERY LITTLE FOR MUCH OF THE WEEK.
WITH THE STRONG INVERSIONS IN PLACE, AND WITH NO ACTIVE WEATHER TO
BREAK THEM, STAGNATE AIR CONDITIONS AND FOG/LOW STRATUS CLOUDS ARE
EXPECTED TO CONTINUE IN AREA VALLEYS. AN AIR STAGNATION ADVISORY
REMAINS IN EFFECT. A WEAK SHORTWAVE WILL MOVE OVER THE RIDGE
TUESDAY, BUT IT LIKELY WON'T BE ENOUGH BREAK THINGS UP, SO IT'S
POSSIBLE THE STAGNANT AIR COULD LAST THROUGH MOST OF NEXT WEEK.
THE DRY EAST FLOW WILL ALSO CONTINUE TO PRODUCE A CHETCO EFFECT,
KEEPING TEMPERATURES IN AND AROUND BROOKINGS MUCH WARMER THAN THE
REST OF THE AREA THROUGH AT LEAST MONDAY AFTERNOON.
THERE'S SOME EVIDENCE POINTING TOWARDS A SLIGHT DISRUPTION IN THE
PATTERN TOWARDS THE END OF THE WEEK WITH A SHORTWAVE TROUGH
DROPPING IN FROM THE NORTH. THE OPERATIONAL MODELS ARE IN PRETTY
GOOD AGREEMENT WITH THE TRAJECTORY OF THE UPPER TROUGH, WHICH IS
ONE THAT TYPICALLY DOES NOT RESULT IN ANY PRECIPITATION FOR MOST
OF THE AREA, ASIDE FROM THE COAST AND MAYBE THE NORTH-FACING
SLOPES. MORE LIKELY IT WILL BE A DRY COLD FRONT THAT WILL DROP
INTO THE AREA FRIDAY WITH GUSTY NORTH TO NORTHEAST BREEZES EAST OF
THE CASCADES AND MID SLOPES AND RIDGES ALONG THE CASCADES AND
COASTAL MOUNTAINS IN SOUTHWEST OREGON AND WESTERN SISKIYOU COUNTY.
DESPITE AN OVERLY WET NBM SOLUTION, THE DETERMINISTIC MODELS AND
THE MAJORITY OF THE ENSEMBLE MEMBERS SHOW VERY LITTLE
PRECIPITATION, AND HAVE IT COMING IN 12 OR MORE HOURS AFTER THE
NBM. HAVE TRENDED THE FORECAST DRIER, AND ALSO DELAYED THE ONSET
OF PRECIPITATION TO BRING THE FORECAST IN LINE WITH THE MAJORITY
OF FORECAST SOLUTIONS AND THE KNOWN CHARACTERISTICS OF SYSTEMS
LIKE THIS ONE. MOST LIKELY, THE SYSTEM WILL PASS THROUGH THE AREA
WITH LITTLE TO SHOW FOR IT OTHER THAN INCREASED CLOUDS, A
HUNDREDTH OR TWO OF PRECIPITATION SCATTERED AROUND THE AREA, AND
A TEMPORARY PERIOD OF GOOD MIXING AND BROKEN INVERSIONS.
THIS DISRUPTION WILL BE BRIEF, WITH HIGH PRESSURE, STAGNATE
CONDITIONS, AND STRONG INVERSIONS RETURNING FOR LATTER PART OF
NEXT WEEKEND INTO MOST OF THE FOLLOWING WEEK. THE MODEL SUITES DO
SUGGEST A PATTERN CHANGE COULD BE IN THE WORKS TOWARDS THE END OF
THE MONTH WITH THE UPPER RIDGE FLATTENING OUT ENOUGH TO ALLOW
SYSTEMS TO MOVE INTO THE AREA, AND THE LONG TERM ENSEMBLES
TRENDING WETTER, BUT MUCH REMAINS TO BE SEEN. STAY TUNED. -BPN
AVIATION...20/18Z TAFS
FREEZING FOG IS BRINGING LIFR LEVELS TO
MEDFORD. THE MORNING SOUNDING SHOWS A VERY DRY AIR MASS
APPROXIMATELY 1200 FEET AGL. GUIDANCE SHOWS THE FOG AND LOW CLOUDS
BURNING OFF TOWARDS 21Z. GIVEN THE SHALLOW MOIST LAYER, IT'S
POSSIBLE MEDFORD COULD BREAK OUT EARLY THIS AFTERNOON AND HAVE
INTRODUCED THIS IN THE TAF. HOWEVER, WE'LL KEEP A WATCH ON THE TREND
OF THE SATELLITE IMAGE AND ADJUSTMENTS WILLBE MADE AS NEEDED. IT'S
ALSO WORTH NOTING IMPROVING CONDITIONS COULD BE DELAYED BY AN HOUR
OR TWO.
SATELLITE IMAGE SHOWS LOW CLOUDS AND FOG BURNING OFF IN THE UMPQUA
BASIN AND ROSEBURG COULD CLEAR OUT TOWARDS 18Z AND HAVE THIS AS THE
PREVAILING CONDITION IN THE TAF.
LOW CLOUDS AND FOG WILL RETURN IN THE SAME AREAS AS THIS MORNING
EARLY THIS EVENING AND LASTING UNTIL THE END OF THE TAF PERIOD.
ELSEWHERE, VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD.
-PETRUCELLI
MARINE...UPDATED 200 AM MONDAY, JANUARY 20, 2025
GUSTY NORTH TO
NORTHEAST WINDS UNDER A THERMAL TROUGH PATTERN WILL MAINTAIN
CONDITIONS HAZARDOUS TO SMALL CRAFT FOR THE OUTER WATERS SOUTH OF
NESIKA BEACH THIS MORNING. THE THERMAL TROUGH ALONG THE COAST WILL
WEAKEN THIS AFTERNOON INTO TUESDAY NIGHT ALLOWING CONDITIONS TO FALL
BELOW ADVISORY LEVELS AND GRADUALLY IMPROVE WITH WEST-NORTHWEST
SWELL DOMINATED SEAS REACHING A MINIMUM AT AROUND 5 TO 6 FT AT 14
SECONDS.
THE THERMAL TROUGH IS EXPECTED TO STRENGTHEN AGAIN WEDNESDAY WITH
SEAS LIKELY BECOMING STEEP, AT LEAST FOR THE OUTER WATERS SOUTH OF
CAPE BLANCO. GUSTY NORTH WINDS ARE EXPECTED TO CONTINUE TO INCREASE
LATE IN THE WEEK WITH GALES POSSIBLE AND STEEP TO VERY STEEP SEAS
LIKELY. -DW
BEACH HAZARDS...UPDATED 200 AM PST MONDAY, JANUARY 20, 2025
THE SNEAKER WAVE RISK IS PAST ITS PEAK, BUT WILL RISE WITH AN
INCREASED RISK ON THE INCOMING TIDE EARLY THIS MORNING. A MODERATE
RISK WILL CONTINUE AT SOUTHERN OREGON BEACHES THROUGH THIS AFTERNOON.
SNEAKER WAVES ARE A TYPE OF WAVE THAT CAN RUN HIGHER UP THE BEACH
THAN A NORMAL WAVE. SNEAKER WAVES CAN WASH OVER PATHWAYS OR ROCK
OUTCROPPINGS. THEY CAN LIFT AND CARRY LOGS, WHICH CAN THEN STRIKE OR
PIN BEACHGOERS. SNEAKER WAVES CAN KNOCK A PERSON OFF THEIR FEET AND
CARRY THEM OUT TO DEEPER WATERS, WHERE HYPOTHERMIA BECOMES POSSIBLE.
SNEAKER WAVES CAN POSE A LETHAL THREAT. AS THESE CONDITIONS MAY
OCCUR WHILE THE SUN IS DOWN, VISIBILITY WILL BE LIMITED. ALWAYS KEEP
YOUR EYES ON THE SEA AND USE EXTRA CAUTION.
MFR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST TUESDAY FOR ORZ021-
023>026-029>031.
BEACH HAZARDS STATEMENT THROUGH THIS AFTERNOON FOR ORZ021-022.
FREEZE WARNING UNTIL 8 AM PST THIS MORNING FOR ORZ021.
FREEZING FOG ADVISORY UNTIL 9 AM PST THIS MORNING FOR ORZ024-
026.
CA...NONE.
PACIFIC COASTAL WATERS...BEACH HAZARDS STATEMENT THROUGH THIS
AFTERNOON FOR PZZ350-356.
SMALL CRAFT ADVISORY UNTIL 10 AM PST THIS MORNING FOR PZZ376.
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