270
FXUS66 KMFR 180305
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
805 PM PDT SAT AUG 17 2019
DISCUSSION
NO UPDATES PLANNED THIS EVENING. AS EXPECTED, THE
WEATHER THIS EVENING IS PRACTICALLY INDISTINGUISHABLE FROM LAST
EVENING. THERE IS VERY LITTLE DIFFERENCE IN SENSIBLE WEATHER: IT'S
MAINLY CLEAR AND WINDS AND TEMPERATURES ARE VIRTUALLY IDENTICAL.
THERE ARE, HOWEVER, LESS PERCEPTIBLE CHANGES AFOOT. NAMELY,
PRESSURES ARE LOWER THAN YESTERDAY, AND THIS IS A SIGN THAT THE
THERMAL TROUGH THAT HAS BEEN PARKED ALONG THE COAST IS BEGINNING
TO SHIFT INLAND. GUIDANCE DOES SHOW THE THERMAL TROUGH CONTINUING
TO MOVE INLAND OVER THE NEXT 24 HOURS, AND THIS WILL RESULT IN THE
MOST NOTICEABLE CHANGES ALONG THE COAST. GONE TOMORROW WILL BE
THE WARM TEMPERATURES THAT HAVE BEEN EXPERIENCED OVER THE LAST
COUPLE OF DAYS, ESPECIALLY AT THE SOUTH COAST AS THE CHETCO EFFECT
ENDS. STRATUS WILL MOVE ONTO AT LEAST THE NORTH COAST TONIGHT,
AND WHILE IT MAY STAY OFFSHORE OF THE CURRY COAST TONIGHT, IT WILL
TRY TO PUSH IN LATER TOMORROW. INLAND AREAS, BY CONTRAST, WILL
LIKELY SEE A SIMILAR TO SLIGHTLY WARMER DAY TOMORROW AS THE
THERMAL TROUGH MOVES THROUGH. THIS IS ALL RELATIVELY WELL COVERED
BY THE GOING FORECAST. -WRIGHT
AVIATION...FOR THE 18/00Z TAFS...AT THE COAST
VFR WILL CONTINUE
THROUGH EARLY THIS EVENING THEN AREAS OF MVFR CIGS WILL DEVELOP
LOWERING TO IFR CIGS LATE TONIGHT AND EARLY SUNDAY MORNING MAINLY
NORTH OF CAPE BLANCO. THE TIMING OF WHEN LOWER CONDITIONS DEVELOP IN
THE NORTH BEND TAF IS LOW TO MODERATE. ONSHORE FLOW WILL BE STRONGER
THAN LAST NIGHT ALLOWING MARINE STRATUS TO DEVELOP IN THE COQUILLE
VALLEY LATE TONIGHT. THE MARINE STRATUS MAY DEVELOP IN PORTIONS
OFTHE UMPQUA DIVIDE TOWARDS DAYBREAK SUNDAY, BUT WERE NOT EXPECTING
THE LOWER CONDITIONS TO MOVE INTO ROSEBURG.
ELSEWHERE, VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD.
-PETRUCELLI
MARINE...UPDATED 200 PM PDT SATURDAY 17 AUGUST 2019
A STRONG
THERMAL TROUGH PATTERN WILL CONTINUE THROUGH THIS EVENING, THEN
SLOWLY WEAKEN SUNDAY. THIS WILL PRODUCE STRONG NORTH WINDS AND
CHOPPY WIND DRIVEN SEAS ACROSS THE AREA, PEAKING LATE THIS AFTERNOON
AND EVENING. GALES AND VERY STEEP SEAS ARE EXPECTED SOUTH OF GOLD
BEACH. WINDS AND SEAS WILL EXCEED SMALL CRAFT CRITERIA OVER MOST OF
THE REMAINDER OF THE AREA. WINDS WILL DIMINISH INTO SUNDAY, BUT
THERE WILL STILL BE SIGNIFICANT FRESH NORTHWEST SWELL OVER THE
WATERS AND MOST OF THE AREA WILL REMAIN HAZARDOUS TO SMALL CRAFT.
SEAS WILL SUBSIDE FURTHER INTO MONDAY. WINDS AND SEAS SHOULD BE
BELOW SMALL CRAFT ADVISORY LEVELS MONDAY MORNING THROUGH TUESDAY.
FROM WEDNESDAY INTO THURSDAY A MIXTURE OF TWO SWELLS MAY BRING THE
RETURN OF CONDITIONS HAZARDOUS TO SMALL CRAFT. KEENE/BR-Y
PREV DISCUSSION
/ISSUED 430 PM PDT SAT AUG 17 2019/
UPDATED AVIATION DISCUSSION.
SHORT TERM...AN UPPER LEVEL RIDGE IS CENTERED OFFSHORE AND IS
LOCATED SURFACE THERMAL TROUGH ALONG THE COAST. THIS PATTERN IS
BRINGING CLEAR SKIES AND WARM AND DRY CONDITIONS TO THE AREA TODAY.
A MILD CHETCO EFFECT CONTINUES TODAY IN THE BROOKINGS AREA WITH
DAYTIME TEMPERATURES IN THE 80S. THE UPPER RIDGE WILL WEAKEN
SLIGHTLY ON SUNDAY AS AN UPPER TROUGH MOVES DOWN OVER BRITISH
COLUMBIA BUT WARM AND DRY CONDITIONS WILL REMAIN IN PLACE ACROSS
INLAND AREAS. AT THE COAST, THE SURFACE THERMAL TROUGH WILL WEAKEN
TONIGHT INTO SUNDAY. THE UPPER RIDGE WILL SHIFT INLAND OVER
REGION ON MONDAY THEN REMAIN IN PLACE ON TUESDAY AS A FRONTAL
SYSTEM APPROACHES FROM THE WEST.
WITH THE THERMAL TROUGH WEAKENING ALONG THE COAST TONIGHT AND
SUNDAY, EXPECT LIGHTER WINDS AT THE COAST AND OVER THE COASTAL
MOUNTAINS. MARINE LOW STRATUS AND PATCHY FOG IS EXPECTED TO
DEVELOP TONIGHT AND PERSIST INTO SUNDAY MORNING, ESPECIALLY FOR
AREAS NORTH OF CAPE BLANCO AND FROM BROOKINGS SOUTH. LOW CLOUDS
ARE ALSO EXPECTED TO SPREAD INTO THE UMPQUA BASIN LATE TONIGHT AND
SUNDAY MORNING. THESE LOW CLOUDS WILL GRADUALLY CLEAR IN THE LATE
MORNING. AREAS NEAR BROOKINGS ARE NOT EXPECTED TO SEE A CHETCO
EFFECT TOMORROW AND WILL SEE A RETURN TO NEAR NORMAL TEMPERATURES
ON SUNDAY DUE TO WEAKENING OF THE OFFSHORE FLOW/ THERMAL TROUGH
PATTERN.
INLAND, EXPECT CONTINUED WARM AND DRY WEATHER ON SUNDAY WITH HIGH
TEMPERATURES SIMILAR TO TODAY FOR MOST AREAS. BREEZY TO GUSTY
SOUTHWEST TO WEST WINDS ARE EXPECTED EAST OF THE CASCADES ALONG
WITH GUSTY SOUTH WINDS IN THE SHASTA VALLEY ON SUNDAY.
MONDAY AND TUESDAY, THE WARM AND DRY WEATHER PATTERN CONTINUES.
HIGH TEMPERATURES MAY TREND SLIGHTLY WARMER FOR INLAND AREAS AS
THE UPPER RIDGE STRENGTHENS OVER THE AREA ON TUESDAY. THEN MODELS
CONTINUE TO SHOW A FRONTAL SYSTEM APPROACHING THE COAST LATE
TUESDAY.
LONG TERM...WEDNESDAY THROUGH SATURDAY...TWO FRONTS WILL MOVE
TOWARDS THE AREA BUT WEAKEN AND DISSIPATE AS THEY MOVE INLAND
INTO THE RIDGE. SO EXPECT INLAND AREAS TO CONTINUE TO SEE WARM AND
DRY CONDITIONS. COASTAL AREAS WILL SEE INCREASED CLOUDS WITH
THESE FRONTS.
MODELS ARE SHOWING FAIRLY GOOD AGREEMENT THAT THE FIRST OF THESE
FRONTS WILL ARRIVE LATE WEDNESDAY. THIS FRONT IS EXPECTED TO
WEAKEN AS IT MOVES ONSHORE AND INTO THE RIDGE. SOME LIGHT DRIZZLE
OR SHOWERS ARE POSSIBLE NEAR THE COAST, MAINLY NORTH OF CAPE
BLANCO, WEDNESDAY EVENING AND NIGHT. OTHERWISE, EXPECT WARM AND
DRY WEATHER TO CONTINUE OVER THE AREA ON WEDNESDAY AND THURSDAY.
ANOTHER FRONT MAY APPROACH THE COAST LATE FRIDAY INTO SATURDAY.
MODELS INDICATE THIS FRONT MAY BE WEAKER THAN THE FIRST FRONT. SO
HAVE KEPT DRY WEATHER IN THE FORECAST FOR THIS PERIOD, INCLUDING
AT THE COAST.
FIRE WEATHER...UPDATED 200 PM PDT SATURDAY 7 AUGUST 2019...WARM
AND DRY CONDITIONS ARE EXPECTED ACROSS THE AREA FOR THE NEXT
SEVERAL DAYS. TEMPERATURES WILL REMAIN STABLE THROUGH MONDAY
BEFORE BECOMING A BIT HOTTER BY TUESDAY INTO FRIDAY. GUSTY WINDS
WITH LOW HUMIDITIES WILL BE SEEN FOR A SHORT PERIOD SUNDAY
AFTERNOON IN THE SHASTA VALLEY AND EAST OF THE CASCADES, BUT ARE
EXPECTED TO REMAIN BELOW RED FLAG CRITERIA.
CONFIDENCE IN THE LONG TERM FORECAST REMAINS LOW, BUT MODELS ARE
SHOWING A DISTINCT TREND TOWARDS CONTINUING DRY AND WARM CONDITIONS
FOR NEXT WEEK, WITH ABOVE NORMAL TEMPERATURES RESULTING FROM A
BUILDING RIDGE ALOFT. THERE ARE A FEW INDICATIONS THAT A WEAK
IMPULSE COULD PASS THROUGH THE REGION WITH INSTABILITY PRODUCING AN
INCREASED RISK FOR THUNDER THURSDAY, BUT MID LEVEL MOISTURE IS TOO
LOW FOR ANY DECENT VERTICAL DEVELOPMENT AT THIS TIME. -SVEN
MFR WATCHES/WARNINGS/ADVISORIES
OR...SMALL CRAFT ADVISORY UNTIL 5 AM PDT SUNDAY FOR ORZ021.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 5 PM PDT SUNDAY FOR
PZZ350-356-370-376.
GALE WARNING UNTIL 5 AM PDT SUNDAY FOR PZZ356-376.
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