477
FXUS66 KMFR 182144
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
244 PM PDT FRI OCT 18 2024
DISCUSSION
WITH AN UPPER TROUGH EXITING THE AREA, UPPER RIDGING
WILL BRING A RELATIVELY WARM AND DRY PERIOD TODAY AND SATURDAY.
TODAY'S HIGHS WILL BE 5 TO 10 DEGREES WARMER THAN YESTERDAY'S, AND
TEMPERATURES WILL RISE ANOTHER 5 TO 10 DEGREES ON SATURDAY AND
SUNDAY AS WELL. OVERNIGHT LOWS WILL RISE SOME TONIGHT, WHICH WILL
GENERALLY HELP TO BRING TEMPERATURES OUT OF FREEZING LEVELS FOR MOST
WEST SIDE VALLEYS. THE SCOTT AND SHASTA VALLEYS AS WELL AS THE MOUNT
SHASTA REGION WILL REMAIN IN THE LOW TO MID 30S, AND THOSE LOWS WILL
ONLY BE PRESENT BRIEFLY. ADDITIONAL FROST OR FREEZING PRODUCTS WILL
NOT BE NEEDED FOR WEST SIDE AREAS TONIGHT. LOW TEMPERATURES WILL
INCREASE FURTHER ON SATURDAY NIGHT INTO SUNDAY MORNING AS WELL.
ANOTHER COLD FRONT WILL APPROACH THE AREA DURING THE DAY ON SUNDAY
AND MOVE OVER THE AREA THROUGH MONDAY. THE RAINFALL FROM THIS FRONT
IS EXPECTED TO FALL MAINLY ALONG THE OREGON COAST, WITH AN INCH OF
RAINFALL EXPECTED FOR COASTAL CITIES AND NEARING 1.5 INCHES OVER
COASTAL RANGES. JOSEPHINE AND INLAND DOUGLAS COUNTIES COULD GET
BETWEEN 0.3 AND 0.5 INCHES OF RAINFALL. OTHER AREAS ARE FORECAST TO
GET 0.3 INCHES OR LESS. HOWEVER, NBM PROBABILISTIC GUIDANCE DOES
COMMUNICATE SOME UNCERTAINTY WITH THIS FRONT. WHILE THERE'S A 90%
CHANCE OF SOME AMOUNT OF RAINFALL, THE EXPECTED AMOUNTS VARY WILDLY.
FOR A 6-HOUR PERIOD ON MONDAY MORNING, THE NBM'S INTERQUARTILE RANGE
FOR BROOKINGS IS BETWEEN 0.19 AND 0.84 INCHES OF RAINFALL. LITTLE
DIFFERENCES IN HOW THE FRONT APPROACHES COULD CAUSE MEANINGFUL
CHANGES IN HOW MUCH RAIN FALLS AND WHERE IT FALLS, SO THERE'S ONLY
MODERATE CONFIDENCE IN ANY FORECAST AMOUNTS RIGHT NOW. OTHERWISE,
THIS FRONT LOOKS TO BE UNIMPACTFUL. SNOW LEVELS WILL FALL BEHIND THE
FRONT ITSELF, SO SNOW IS NOT A CONCERN. TEMPERATURES ACROSS THE AREA
WILL COOL TO SEASONAL LEVELS ON MONDAY AND TUESDAY, WITH NO
HAZARDOUS COLD TEMPERATURES EXPECTED.
ANOTHER DRY PERIOD IS EXPECTED THROUGH THE MIDDLE OF THE WEEK. AN
UPPER RIDGE LOOKS TO DEVELOP OVER THE WESTERN UNITED STAKES, KEEPING
A LOW PRESSURE SYSTEM OUT OVER THE PACIFIC. UPPER LEVEL FLOW FOR
THIS AREA COULD BE IN A MORE ZONAL PATTERN ALONG THE TOP OF THAT
RIDGE, WHICH WOULD KEEP TEMPERATURES FROM WARMING TOO MUCH. RIGHT
NOW, AREAS WEST OF THE CASCADES WILL SEE TEMPERATURES IN THE HIGH
60S TO LOW 70S FOR TUESDAY THROUGH THURSDAY, WITH TEMPERATURES IN
THE LOW TO MID 60S TO THE EAST.
ACTIVE WEATHER LOOKS TO RETURN BY THE END OF THIS WEEK OR INTO THE
WEEKEND, ALTHOUGH THERE IS ABUNDANT UNCERTAINTY IN MODEL GUIDANCE.
AT SOME POINT, THE RIDGE WILL MOVE EASTWARD AND ALLOW THAT UPPER LOW
TO MOVE OVER THE AREA, BRINGING WIDESPREAD PRECIPITATION. THERE'S
GOOD DETERMINISTIC AND ENSEMBLE GUIDANCE AGREEMENT THAT THIS WILL
HAPPEN, BUT HOW AND WHEN VARIES. THERE ARE SLIGHT VARIATIONS IN THE
GRAPHICAL PATTERNS WITHIN AND AROUND THIS LOW THAT COULD CAUSE
DIFFERENT OUTCOMES. AT THE VERY END OF THE CURRENT FORECAST PERIOD
(FRIDAY, OCTOBER 25TH), FORE FORECAST INCLUDES COOLING TEMPERATURES
AND SLIGHT TO MODERATE (30-60%) PRECIPITATION CHANCES.
WHEN CONSIDERING LONG TERM CONDITIONS, THREE MAIN SOURCES OF
GUIDANCE (NBM, GFS, ECMWF) ALL EXPECT COOLER TEMPERATURES TO
CONTINUE PAST NEXT WEEKEND AND INTO NOVEMBER. PRECIPITATION IS
HARDER TO PIN DOWN OF COURSE. POSSIBILITIES FOR CONTINUING
PRECIPITATION DO ALSO REMAIN IN THESE LONG-TERM GUIDANCE SOURCES
INTO NOVEMBER, RATHER THAN ANY WELL-DEFINED DRY PERIODS. -TAD
AVIATION...18/18Z TAFS
VFR WITH LIGHT, VARIABLE WINDS WILL
PREVAIL OVER THE AREA FOR THE NEXT 24 HOURS. MID AND HIGH CLOUDS
WILL DRIFT OVER MAINLY NORTHERN AND WESTERN SECTIONS AT TIMES. THESE
CLOUDS WILL LOWER SOME TONIGHT ALONG THE COAST, PERHAPS TO MVFR AT
NORTH BEND. ALSO, PATCHY FOG COULD REDEVELOP IN SOME TYPICAL WEST
A SIDE VALLEY LOCATIONS, BUT PROBABLY NOT AT THE TERMINALS. -SPILDE
MARINE...UPDATED 230 PM PDT FRIDAY, OCTOBER 18, 2024
RELATIVELY LIGHT WINDS AND LOW SEAS WILL CONTINUE TONIGHT.
INCREASING WEST TO NORTHWEST SWELL SATURDAY WILL BRING ELEVATED SEAS
AREA WIDE WITH STEEPENING WIND WAVES SOUTH OF CAPE BLANCO. EVEN SO,
CONDITIONS SHOULD REMAIN BELOW ADVISORY LEVELS. SOUTH WINDS INCREASE
AHEAD OF A COLD FRONT ON SUNDAY AND THIS COULD BRIEFLY BRING
HAZARDOUS CONDITIONS DUE TO A COMBINATION OF STEEP WIND WAVES AND
WESTERLY SWELL, ESPECIALLY NORTH OF CAPE BLANCO. RAIN WILL ACCOMPANY
THE FRONT THROUGH SUNDAY NIGHT, THEN MOVE ONSHORE WITH IMPROVING
CONDITIONS MONDAY.
NORTH WINDS AND RETURN TUESDAY AND WEDNESDAY, PERHAPS PEAKING NEAR
ADVISORY LEVELS. THEN, LOW PRESSURE OFFSHORE WILL TURN WINDS AROUND
TO THE SOUTH THURSDAY. THIS LOW WILL BRING AN ELEVATED RISK OF
HAZARDOUS CONDITIONS, INCLUDING POSSIBLE GALES THURSDAY NIGHT INTO
FRIDAY. -SPILDE
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
TAD/BMS/MAS
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