169
FXUS66 KMFR 200545
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
945 PM PST SUN JAN 19 2025
..UPDATED AVIATION DISCUSSION FOR 06Z TAFS
UPDATE
FREEZING FOG HAS DEVELOPED THIS EVENING IN THE ROGUE
VALLEY FROM MEDFORD TO NEAR GRANTS PASS AND IN NEARBY VALLEYS.
FOG IS EXPECTED TO EXPAND INTO OTHER VALLEY AREAS IN JOSEPHINE
AND JACKSON COUNTIES OVERNIGHT. OBSERVATIONS NEAR GRANTS PASS AND
MEDFORD INDICATE VISIBILITIES HAVE BEEN DOWN TO OR LESS THAN LESS
THAN A QUARTER MILES AT TIMES. VERY LOW VISIBILITIES MAY BRING
HAZARDOUS DRIVING CONDITIONS. ALSO WITH FREEZING FOG, ICY SPOTS
MAY DEVELOP TONIGHT AND EARLY MONDAY MORNING ON ROADWAYS. A
FREEZING FOG ADVISORY (NPWMFR) HAS BEEN ISSUED THROUGH EARLY
MONDAY MORNING. FURTHER EAST, FOG IS EXPECTED INTO THE LOWER ROGUE
VALLEY NEAR AGNESS TONIGHT AND EARLY MONDAY MORNING. MEANWHILE,
TO THE NORTH, IN THE UMPQUA BASIN, SATELLITE IMAGERY AND
OBSERVATIONS INDICATE A MIX OF FOG AND LOW CLOUDS. WE WILL
CONTINUE TO MONITOR CONDITIONS IN THE UMPQUA OVERNIGHT, AS LOCALLY
DENSE FOG IS POSSIBLE, WITH A 20-30% CHANCE BASED ON HIGH
RESOLUTION MODELS (HREF).
AVIATION...20/06Z TAFS
FREEZING FOG IS BRINGING LIFR LEVELS TO
MEDFORD, WHILE IFR CEILINGS REMAIN OVER ROSEBURG. THE ROSEBURG
CEILINGS MAY LIMIT FOG DEVELOPMENT IN THE UMPQUA VALLEY, WITH
GUIDANCE SPLIT ON IF FOG WILL DEVELOP OR NOT. BOTH UMPQUA AND ROGUE
VALLEYS ARE EXPECTED TO STAY UNDER AT LEAST IFR LEVELS THROUGH THE
TAF PERIOD, ALTHOUGH BRIEF PERIODS OF IMPROVEMENT ARE POSSIBLE
MONDAY AFTERNOON.
OTHER AREAS ARE EXPECTED TO STAY AT VFR THROUGH THE TAF PERIOD. -TAD
PREV DISCUSSION
/ISSUED 342 PM PST SUN JAN 19 2025/
DISCUSSION...NOT MUCH CHANGE IN THE OVERALL PATTERN IS EXPECTED
THROUGH MOST OF NEXT WEEK. SATELLITE IMAGE SHOWS LOW CLOUDS SLOW TO
BURN OFF IN THE UMPQUA BASIN, NORTHERN END OF THE ROGUE VALLEY, AND
GRANTS PASS AREA. BASED ON HOW THINGS ARE SLOW TO BURN OFF, IT MAY
NOT CLEAR OUT AT ALL IN THE UMPQUA BASIN. THE ROGUE AND PORTIONS
OF THE ILLINOIS VALLEY SHOULD CLEAR OUT WITHING THE NEXT HOUR OR
SO.
AS IN IN PREVIOUS EVENINGS AND NIGHTS WITH LOW CLOUDS AND FOG LIKELY
TO RETURN IN THE EVENING AND LASTING THROUGH THE MORNING HOURS
MONDAY. SOUNDING PROFILES SUGGEST THE LOW LEVEL MOISTURE ASSOCIATED
WITH THE FOG AND LOW CLOUDS WILL BE SHALLOW WITH MUCH DRIER AIR
ALOFT AT THE MID AND UPPER LEVELS.
WITH THE STRONG INVERSIONS IN PLACE, AND WITH NO ACTIVE WEATHER TO
BREAK THEM, STAGNATE AIR CONDITIONS ARE ONCE AGAIN EXPECTED 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.
A THERMAL TROUGH ALONG THE SOUTH OREGON COAST WILL RESULT IN A DRY
EAST FLOW WITH WARMER TEMPERATURES OVER THE MID SLOPES AND RIDGES,
AND NEAR BROOKINGS. THIS IS EXPECTED TO LAST THROUGH AT LEAST MONDAY
AFTERNOON. THUS, WE CAN EXPECT BREEZY CONDITIONS NEAR AND AT THE
RIDGES IN SOUTHWEST OREGON. ALSO THE PRESSURE GRADIENT TIGHTENS UP
ALONG THE CASCADES SUNDAY NIGHT INTO MONDAY WHICH WILL BRING BREEZY
EAST WINDS NEAR AND AT THE RIDGES.
THE RIDGE WILL REMAIN JUST TO OUR WEST, AND WITH THE VERY BROAD,
DEEP TROUGH COVERING ALMOST THE ENTIRE CONTINENT, WE WILL REMAIN
UNDER NORTH FLOW ALOFT. A FEW SHORTWAVES MAY PASS OVERHEAD OVER THE
NEXT SEVERAL DAYS AS THEY TRAVERSE THIS FLOW, BUT THERE WILL BE
LITTLE TO NO DISCERNIBLE EFFECTS AT THE SURFACE. IN OTHER WORDS, THE
DAY-TO-DAY FORECAST WILL CHANGE VERY LITTLE FOR MUCH OF THE WEEK.
THERE'S SOME EVIDENCE POINTING TOWARDS A SLIGHT DISRUPTION IN THE
PATTERN TOWARDS THE END OF NEXT WITH A SHORTWAVE TROUGH DROPPING IN
FROM THE NORTH. THE OPERATIONAL MODELS ARE IN PRETTY GOOD AGREEMENT
WITH THE TRAJECTORY OF THE UPPER TROUGH. THE TRAJECTORY IS ONE THAT
TYPICALLY DOES NOT RESULT IN ANY PRECIPITATION, 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. THUS IT COMES AT NO SURPRISE THE
OPERATIONAL MODELS SHOW A DRY SOLUTION. EVEN THE MAJORITY OF THE
INDIVIDUAL ECMWF ENSEMBLES SUGGEST LITTLE IF ANYTHING WILL HAPPEN
FRIDAY AND FRIDAY NIGHT WITH MOST MEMBERS SHOWING NO PRECIPITATION.
TAKING THE NBM AT FACE VALUE SUGGEST PRECIPITATION CHANCES AND
COVERAGE AREA IS WAY OVERDONE AND COVERS TOO MUCH OF THE FORECAST
AREA. HAVE SEEN THIS TREND ENOUGH THIS SEASON TO KNOW THAT THE
DETERMINISTIC ARE ON TO SOMETHING, AND THE NBM WILL BE VERY SLOW TO
RESPOND. HAVE PUSHED THE CHANCE OF PRECIPITATION LOW END FRIDAY INTO
FRIDAY EVENING, WITH THE DISTINCT POSSIBILITY THAT THE TROUGH WILL
PASS THROUGH THE AREA WITHOUT ANY MEASURABLE PRECIPITATION AT ALL,
AND THE ONLY NOTABLE EFFECT BEING INCREASED CLOUDS AND A TEMPORARY
PERIOD OF GOOD MIXING AND BROKEN INVERSIONS.
IT'S ALSO WORTH NOTING THAT THE ENSEMBLES SUGGEST THE DISRUPTION IN
THE PATTERN LATE NEXT WEEK WILL BE BRIEF WITH RIDGING BUILDING BACK
OVER THE PAC NW THE LATTER PART OF NEXT WEEKEND INTO MOST OF THE
FOLLOWING WEEK. THEY DO SHOW 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. STAY
TUNED. -PETRUCELLI
MARINE...UPDATED 100 PM SUNDAY, JANUARY 19, 2025...GUSTY NORTH
WINDS UNDER A THERMAL TROUGH PATTERN WILL MAINTAIN CONDITIONS
HAZARDOUS TO SMALL CRAFT FOR AREAS SOUTH OF CAPE BLANCO THROUGH
MONDAY MORNING. CONDITIONS IMPROVE TONIGHT FOR AREAS WITHIN 15 NM OF
SHORE, BUT ADVISORY LEVEL CONDITIONS WILL CONTINUE THROUGH MONDAY
MORNING IN THE OUTER WATERS (FROM AROUND NESIKA BEACH SOUTHWARD).
THE THERMAL TROUGH ALONG THE COAST WILL WEAKEN LATER MONDAY INTO
TUESDAY ALLOWING CONDITIONS TO FALL BELOW ADVISORY LEVELS AND REMAIN
THAT WAY THROUGH THURSDAY. ANOTHER PERIOD OF MODERATE TO STRONG
NORTH WINDS (POSSIBLY REACHING GALE FORCE) AND STEEP SEAS IS
POSSIBLE FRIDAY INTO NEXT WEEKEND. -SPILDE/BR-Y
BEACH HAZARDS...UPDATED 100 PM PST SUNDAY, JANUARY 19, 2025...
LONG PERIOD (17-19 SECONDS) WEST-NORTHWEST SWELL OVER THE COASTAL
WATERS WILL BRING A HIGH RISK OF SNEAKER WAVES TO SOUTHERN OREGON
BEACHES TODAY. THESE LONG PERIOD WAVES CAN CAUSE WAVES TO RUN UP
MUCH HIGHER ON THE BEACH THAN USUAL WITH THE HIGHEST RISK ON
INCOMING TIDES. THE THREAT IS EXPECTED TO DIMINISH, BUT REMAIN
MODERATE TONIGHT INTO MONDAY WITH A LOWERING SWELL PERIOD (TO 14-15
SECONDS) AND LESS CHAOTIC SEA STATE.
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 MONDAY AFTERNOON FOR ORZ021-022.
FREEZE WARNING FROM 1 AM TO 8 AM PST MONDAY FOR ORZ021.
FREEZING FOG ADVISORY UNTIL 9 AM PST MONDAY FOR ORZ024-026.
CA...NONE.
PACIFIC COASTAL WATERS...BEACH HAZARDS STATEMENT THROUGH MONDAY
AFTERNOON FOR PZZ350-356.
SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR PZZ356.
SMALL CRAFT ADVISORY UNTIL 10 AM PST MONDAY FOR PZZ376.
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