Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 230400
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
900 PM PDT WED OCT 22 2014

.SHORT TERM...A STRONG FRONT IS MOVING INLAND TONIGHT AND IS
EXPECTED TO GRADUALLY PUSH INTO THE CASCADES AND JUST EAST DURING
THE MORNING HOURS TOMORROW. GUSTY WINDS WILL CONTINUE FOR INLAND
AREAS DURING THIS PERIOD AND LIGHT TO MODERATE RAIN SPREAD ACROSS
THE AREA TONIGHT AND THURSDAY MORNING. BEHIND THE FRONT, WINDS
HAVE DECREASED SHARPLY ALONG THE COOS COAST AND NORTHERN CURRY
COAST AS WELL AS OVER THE MARINE WATERS. ALSO RAIN WILL TAPER OFF
TO SHOWERS ALONG THE COASTAL AREAS. OF NOTE IS THAT THE NAM AND
GFS ARE TOO SLOW WITH MOVEMENT OF THE FRONT INLAND AND HAVE LEANED
TOWARDS THE 12Z HIGH RESOLUTION ARW MODEL WHICH IS DEPICTING THE
INLAND MOVEMENT OF THE FRONT THE BEST. HAVE UPDATED THE FORECAST WEATHER
AND CHANCE OF PRECIPITATION TO SHOW THE QUICKER MOVEMENT OF THE
FRONT INLAND TONIGHT AND THRUSDAY MORNING WITH SHOWERS BEHIND IT.
ALO BASED ON THE ARW MODEL AND THE EXPECTED MOVEMENT OF A COLD
POOL WITH SHOWERS OFFSHORE, HAVE ADDED A SLIGHT CHANCE FOR
THUNDERSTORMS INTO THE COASTAL WATERS, MAINLY NORTH OF GOLD BEACH,
FOR THE LATE NIGHT AND MORNING HOURS TOMORROW.

THEN DURING THE DAY THURSDAY, EXPECT THIS FRONT TO SHIFT SOUTHEAST
AND LINGER OVER THE EXTREME SOUTHEAST PORTIONS OF THE CWA. EXPECT
A COOL AND SHOWERY AIRMASS TO MOVE OVERHEAD BEHIND THE FRONT. THEN
MODELS CONTINUE TO SHOW THIS LINGERING FRONTAL BOUNDARY LIFTING NORTH
LATE THURSDAY NIGHT INTO FRIDAY MORNING AS A STRONG SURFACE LOW AND
FRONTAL SYSTEM APPROACH FROM THE SOUTHWEST. THIS SURFACE LOW WILL
APPROACH THE SOUTHERN OREGON AND CENTRAL OREGON COAST FRIDAY NIGHT
INTO SATURDAY MORNING BEFORE SHIFTING NORTH ALONG THE COAST.
SOUTHERLY WINDS ARE EXPECTED TO INCREASE AHEAD OF THIS LOW ACROSS
THE AREA AS THE PRESSURE GRADIENT INCREASES AND A MID LEVEL JET OF
60 TO 75 KNOTS AT 700 MB MOVES OVER THE AREA LATE FRIDAY NIGHT
AND SATURDAY.MODELS VARY ON THE EXACT TRACK OF THE LOW BUT GIVEN
CURRENT MODEL SOLUTIONS, HIGH WIND WARNING LEVELS ARE POSSIBLE IN THE
SHASTA VALLEY AND INTO THE SUMMER LAKE AREAS WITH STRONG AND GUSTY
WINDS OVER THE MOUNTAINS. WILL NEED TO MONITOR THESE AREAS WITH
FUTURE MODELS RUNS AND FORECASTS FOR HIGH WIND POTENTIAL.
OTHERWISE, EXPECT RAIN TO MOVE INLAND SATURDAY WITH THIS FRONTAL
SYSTEM WITH MODERATE TO HEAVY RAIN POSSIBLE FOR SOUTHWESTERN
PORTIONS OF THE CWA SATURDAY AFTERNOON INTO SATURDAY NIGHT.


.AVIATION...BASED ON THE 23/00Z TAF CYCLE...
A FRONTAL SYSTEM HAS ALREADY PUSHED ONSHORE ENDING THE WINDS AT KOTH
THIS EVENING...AND THE THREAT FOR LOW-LEVEL WIND SHEAR...BUT MVFR TO
OCCASIONALLY IFR CIGS/VIS WILL PERSIST IN AREAS OF MODERATE
RAINFALL. RAIN WILL GRADUALLY TAPER OFF TO SHOWERS OVERNIGHT AND
THURSDAY WITH A MIX OF VFR/MVFR. GUSTY WINDS WILL CONTINUE THIS
EVENING FROM CAPE BLANCO SOUTHWARD ALONG THE COAST AS THE FRONT
MOVES ONSHORE, BUT WILL DIMINISH SHARPLY BEHIND IT. LOW LEVEL
TURBULENCE IS ALSO LIKELY TO PERSIST INLAND DUE STRONG WINDS ALOFT.
RAIN WILL OVERSPREAD THE WEST SIDE THIS EVENING...THEN PUSH TO THE
EAST SIDE OVERNIGHT INTO THURSDAY. EXPECT MOSTLY VFR CIGS AT THE TAF
SITES...BUT MAY OCCASIONALLY LOWER TO MVFR IN HEAVIER RAINFALL.
TERRAIN OBSCURATIONS WILL BE TOTAL WEST OF THE CASCADES TONIGHT THEN
ALL AREAS THURSDAY. SPILDE

&&

.MARINE...UPDATED 545 PM PDT WED 22 OCT 2014...
WINDS HAVE ALREADY PEAKED AND COME DOWN AT BUOY 15 OFF CAPE BLANCO
THIS EVENING AS A FRONTAL SYSTEM IS ABOUT 3-6 HOURS AHEAD OF
SCHEDULE TO MOVE THROUGH. AS A RESULT...HAVE CANCELLED THE GALE
WARNING FOR PZZ370. GALES AND WARNING LEVEL SEAS WILL END SHARPLY
FROM NORTHWEST TO SOUTHEAST ACROSS THE REMAINDER OF THE WATERS BY
LATE THIS EVENING. HOWEVER, SEAS WILL REMAIN ELEVATED AND HAZARDOUS
TO SMALL CRAFT OVERNIGHT THROUGH THURSDAY NIGHT DUE TO WESTERLY
SWELL. THERE WILL BE A LULL IN BOTH WINDS AND SEAS FRIDAY. MODELS
ARE COMING INTO BETTER AGREEMENT WITH THE FRIDAY NIGHT/SATURDAY
SYSTEM. ALL SHOW A DEEPENING SURFACE LOW MOVING NORTHWARD ALONG THE
130 W BENCHMARK FRIDAY NIGHT THEN NORTHEASTWARD INSIDE 130 W
SATURDAY. VERY STRONG SOUTH WINDS WILL DEVELOP AHEAD OF THIS SYSTEM
FRIDAY NIGHT WITH HIGH END GALE CONDITIONS AND POSSIBLE STORM FORCE
GUSTS SATURDAY. STAY TUNED FOR FURTHER UPDATES REGARDING THIS
POTENTIAL BIG WIND-MAKER. CONDITIONS WILL IMPROVE THROUGH THE
REMAINDER OF THE WEEKEND, AND AFTER ANOTHER BRIEF ROUND OF CALMER
WINDS AND SEAS, ANOTHER FRONT IS EXPECTED EARLY NEXT WEEK. SPILDE

&&

.PREV DISCUSSION... /ISSUED 613 PM PDT WED OCT 22 2014/

DISCUSSION...THE COLD FRONT IS MOVING THROUGH THE COASTAL WATERS
THIS AFTERNOON. SOUTH WINDS ARE INCREASING ACROSS THE SHASTA
VALLEY AND AT THE HIGHER ELEVATIONS. WE ARE GETTING A LOT OF
DOWNSLOPING ACROSS THE ROGUE VALLEY AND THIS HAS KEPT RAIN OUR OF
THE AREA. A WAVE IS EXPECTED TO FORM ON THE FRONT OFFSHORE AND
THIS COULD DELAY THE EASTWARD MOVEMENT FURTHER. AS A RESULT, GUSTY
WINDS WILL CONTINUE LONGER THAN EXPECTED AND I HAVE EXTENDED THE
WIND ADVISORY OVERNIGHT THROUGH THURSDAY MORNING. UNFORTUNATELY
THIS COULD ALSO MEAN THAT RAIN MAY NOT MOVE INTO THE ROGUE VALLEY
UNTIL MIDNIGHT OR SO. THE KLAMATH BASIN WILL SEE PASSING LIGHT
SHOWERS.

ON FRIDAY NIGHT..A STRONG LOW PRESSURE WILL APPROACH THE COASTAL
WATERS FROM THE SOUTHWEST. THIS LOW PRESSURE IS FORECAST TO MOVE
NORTHEAST INTO THE COASTAL WATERS ON SATURDAY. PRESSURE GRADIENTS
INCREASE SIGNIFICANTLY ACROSS THE FORECAST AREA. HAVE INCREASED
WINDS TO HIGH END GALE IN THE COASTAL WATERS AND IN THE SHASTA
VALLEY. WE MAY NEED TO ISSUE A HIGH WIND WATCH IF NEXT MODEL RUN
CONTINUES WITH THIS TREND. /FB

PRECIPITATION PROBABILITIES AND AMOUNTS...
AMOUNTS IN THE COASTAL ZONES, THUS FAR, THIS AFTERNOON HAVE MOSTLY
BEEN IN THE 0.25" TO 0.75". RADAR AND SATELLITE IMAGERY INDICATE
THAT THE MODERATE TO HEAVY RAIN WITH THE FRONTAL BOUNDARY TO BE
MOVING ONSHORE NOW, SO EXPECT PRECIPITATION AMOUNTS TO BE ON THE
INCREASE OVER THE NEXT FEW HOURS. RAINFALL AMOUNTS FOR THIS CURRENT
STORM SYSTEM HAVE BEEN ADJUSTED DOWN SOME TODAY THROUGH THURSDAY
EVENING FOR AREAS INLAND FROM THE COAST, BUT HAVE LEFT 3 TO 5 INCH
AMOUNTS INTACT FOR THE COAST AND COASTAL MOUNTAIN AREAS, WITH MOST
OF THE RAIN THERE EXPECTED FROM NOW THROUGH 5AM PDT THURSDAY. WE
EXPECT 1.3 TO 2.3 INCHES ACROSS DOUGLAS COUNTY, 1-3 INCHES ACROSS
JOSEPHINE COUNTY, AND 0.50" TO 1.5" ACROSS JACKSON COUNTY. ON THE
LOW END, IN THE EAST SIDE VALLEYS, WE EXPECT 0.10" TO 0.50", LOWEST
FAR EASTERN AREAS.

THE FRONT WILL PUSH INLAND TONIGHT THROUGH THURSDAY, WITH MOST OF
THE RAIN ACROSS THE INTERIOR WEST SIDE TONIGHT THROUGH THURSDAY
MORNING, AND MOST OF THE RAIN EAST OF THE CASCADES EXPECTED ON
THURSDAY. THE FRONT WILL DIP TO SOUTHEASTERN SECTIONS AND WEAKEN
LATER ON THURSDAY, AND THEN THE FRONT WAVES BACK NORTH AS A WARM
FRONT THURSDAY NIGHT THROUGH FRIDAY. FRIDAY AFTERNOON THROUGH
SATURDAY MORNING LOOKS TO BE A RELATIVE LULL IN THE PRECIPITATION
FOR AREAS AWAY FROM THE COAST AND NOT IN SOUTH FLOW FAVORED
LOCATIONS AS A STRONG LOW FORM BETWEEN 130 WEST AND THE OREGON
COAST. THIS FRONT WILL MOVE ONSHORE SATURDAY WITH SHOWERS BEHIND IT
EVEN INTO SUNDAY, SO THE WEEKEND LOOKS GENERALLY WET. IT SHOULD BE
NOTED, HOWEVER, THAT THE TIMING OF PRECIPITATION IS A LOWER
CONFIDENCE FORECAST PARAMETER THAN THE PRESENCE OF IT IN THE
FORECAST, SO IT WILL NOT BE A WASHOUT OF A WEEKEND FOR ALL
LOCATIONS. PRECIPITATION ON SUNDAY MAY WANE OVER CENTRAL AND
SOUTHEASTERN SECTIONS.

NUMERICAL MODELS INDICATE ABOUT TWO FRONTAL SYSTEMS NEXT WEEK WITH
MONDAY BEING DRY FOR MOST LOCATIONS AWAY FROM THE COAST. TIMING OF
THE FRONTS NEXT WEEK IS A BIT IN QUESTION, BUT SUFFICE IT TO SAY
THAT THE WEATHER PATTERN DOES LOOK TO REMAIN ACTIVE WITH A FRONTAL
SYSTEM EVERY 2-3 DAYS. ALSO, THE OVERALL PARENT TROUGH OVER THE AREA
SINKS SOUTHWARD NEXT WEEK, SO EXPECT SNOW LEVELS WILL LIKELY COME
DOWN SOME, INTO THE 5000 TO 7000FT RANGE. BTL

AVIATION...BASED ON THE 23/00Z TAF CYCLE...
A FRONTAL SYSTEM HAS ALREADY PUSHED ONSHORE ENDING THE WINDS AT KOTH
THIS EVENING...AND THE THREAT FOR LOW-LEVEL WIND SHEAR...BUT MVFR TO
OCCASIONALLY IFR CIGS/VIS WILL PERSIST IN AREAS OF MODERATE
RAINFALL. RAIN WILL GRADUALLY TAPER OFF TO SHOWERS OVERNIGHT AND
THURSDAY WITH A MIX OF VFR/MVFR. GUSTY WINDS WILL CONTINUE THIS
EVENING FROM CAPE BLANCO SOUTHWARD ALONG THE COAST AS THE FRONT
MOVES ONSHORE, BUT WILL DIMINISH SHARPLY BEHIND IT. LOW LEVEL
TURBULENCE IS ALSO LIKELY TO PERSIST INLAND DUE STRONG WINDS ALOFT.
RAIN WILL OVERSPREAD THE WEST SIDE THIS EVENING...THEN PUSH TO THE
EAST SIDE OVERNIGHT INTO THURSDAY. EXPECT MOSTLY VFR CIGS AT THE TAF
SITES...BUT MAY OCCASIONALLY LOWER TO MVFR IN HEAVIER RAINFALL.
TERRAIN OBSCURATIONS WILL BE TOTAL WEST OF THE CASCADES TONIGHT THEN
ALL AREAS THURSDAY. SPILDE

MARINE...UPDATED 545 PM PDT WED 22 OCT 2014...
WINDS HAVE ALREADY PEAKED AND COME DOWN AT BUOY 15 OFF CAPE BLANCO
THIS EVENING AS A FRONTAL SYSTEM IS ABOUT 3-6 HOURS AHEAD OF
SCHEDULE TO MOVE THROUGH. AS A RESULT...HAVE CANCELLED THE GALE
WARNING FOR PZZ370. GALES AND WARNING LEVEL SEAS WILL END SHARPLY
FROM NORTHWEST TO SOUTHEAST ACROSS THE REMAINDER OF THE WATERS BY
LATE THIS EVENING. HOWEVER, SEAS WILL REMAIN ELEVATED AND HAZARDOUS
TO SMALL CRAFT OVERNIGHT THROUGH THURSDAY NIGHT DUE TO WESTERLY
SWELL. THERE WILL BE A LULL IN BOTH WINDS AND SEAS FRIDAY. MODELS
ARE COMING INTO BETTER AGREEMENT WITH THE FRIDAY NIGHT/SATURDAY
SYSTEM. ALL SHOW A DEEPENING SURFACE LOW MOVING NORTHWARD ALONG THE
130 W BENCHMARK FRIDAY NIGHT THEN NORTHEASTWARD INSIDE 130 W
SATURDAY. VERY STRONG SOUTH WINDS WILL DEVELOP AHEAD OF THIS SYSTEM
FRIDAY NIGHT WITH HIGH END GALE CONDITIONS AND POSSIBLE STORM FORCE
GUSTS SATURDAY. STAY TUNED FOR FURTHER UPDATES REGARDING THIS
POTENTIAL BIG WIND-MAKER. CONDITIONS WILL IMPROVE THROUGH THE
REMAINDER OF THE WEEKEND, AND AFTER ANOTHER BRIEF ROUND OF CALMER
WINDS AND SEAS, ANOTHER FRONT IS EXPECTED EARLY NEXT WEEK. SPILDE

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 11 AM PDT THURSDAY FOR ORZ031.

CA...WIND ADVISORY UNTIL 11 AM PDT THURSDAY FOR CAZ081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM PDT FRIDAY
     FOR PZZ350-356-370-376.
     GALE WARNING UNTIL 2 AM PDT THURSDAY FOR PZZ356-376.
     HAZARDOUS SEAS WARNING UNTIL 2 AM PDT THURSDAY FOR PZZ356-376.
     GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ350.
     HAZARDOUS SEAS WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ350.

$$

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