Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 200439 AAA
AFDMFR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MEDFORD OR
938 PM PDT SUN OCT 19 2014

.DISCUSSION...EVENING UPDATE. THE LATEST SATELLITE IMAGES ARE
CONFIRMING THE LATEST MODELS SOLUTION OF A SLIGHTLY FASTER
PROGRESSION OF THE FRONT INLAND OVERNIGHT INTO THE MORNING. HAVE
ADJUSTED THE FORECAST TO BRING PRECIPITATION ON MORE QUICKLY
TONIGHT.

PREVIOUS DISCUSSION...THE LEADING EDGE OF THE FRONT IS STARTING TO
MOVE INTO OUR OUTER WATERS AND IS SLOWLY MOVING EAST AND SKIES
REMAIN CLEAR OVER MOST OF THE CWA. THE CLOUD FORMATION ALONG THE
COAST SUGGEST THERE ARE STRONG WINDS ALOFT. THE MODELS REMAIN IN
PRETTY GOOD AGREEMENT WITH THE LEADING EDGE OF THE FRONT EXPECTED TO
REACH THE COAST LATE THIS EVENING. MOST OF THE PRECIPITATION TONIGHT
WILL BE ALONG THE SOUTH COAST AND COASTAL MOUNTAINS WITH MOST AREAS
PICKING UP BETWEEN 0.25-0.50 OF AN INCH. FURTHER INLAND
PRECIPITATION AMOUNTS WILL BE LIGHTER AND THE ROGUE VALLEY IS NOT
LIKELY TO GET ANYTHING MEASURABLE. THE FRONT WILL MOVE INLAND MONDAY
MORNING WITH MODERATE TO HEAVY PRECIPITATION LIKELY SOUTH OF CAPE
BLANCO AND SOUTH COASTAL MOUNTAINS WITH RAINFALL AMOUNTS RANGING
BETWEEN 1-2 INCHES. PRECIPITATION WILL ALSO SPREAD OVER MUCH OF THE
WESTSIDE WITH 0.10-0.20 OF AN INCH EXPECTED IN THE ROGUE VALLEY.
WHILE ISOLATED THUNDERSTORMS ARE POSSIBLE IN THE MORNING OVER THE
MARINE WATERS, THERE`S A BETTER CHANCE IN THE AFTERNOON AS THE COOL
POOL ALOFT (500 MB TEMPS BETWEEN -22 AND -24C) MOVES OVERHEAD LATE
MONDAY AFTERNOON.

MEANWHILE, WINDS EAST OF THE CASCADES ARE ALREADY STARTING TO
PICK UP AND THEY ARE EXPECTED TO INCREASE TONIGHT. PARTICULARLY OVER
THE HIGHER TERRAIN EAST OF THE CASCADES AND SHASTA VALLEY.
ADDITIONALLY, THE WINDS ARE FAIRLY ALIGNED IN THE SHASTA VALLEY AND
SOME OF THESE STRONGER WINDS COULD MIX DOWN. WOULD NOT BE SURPRISED
IF WE SEE PEAK WIND GUST NEAR 45 MPH IN THE SOUTH END OF THE
SHASTA VALLEY. THUS, THE WIND ADVISORY REMAINS IN EFFECT. WINDS ARE
EXPECTED TO GRADUALLY DECREASE MONDAY EVENING AS THE UPPER TOUGH
AXIS AND SURFACE FRONT MOVES EAST OF THE CASCADES.

CONDITIONS WILL SETTLE DOWN MONDAY NIGHT INTO TUESDAY AS THE TROUGH
AXIS SHIFTS EAST AND WEAK RIDGING BUILDS OVER THE REGION.
PRECIPITATION WILL DECREASE FROM WEST TO EAST AND WINDS WILL ALSO
DECREASE. A FEW SHOWERS COULD LINGER TUESDAY MORNING WITH MOSTLY DRY
CONDITIONS TUESDAY AFTERNOON.

NEXT WE TURN OUR ATTENTION TO THE NEXT FRONT WHICH COULD IMPACT OUR
AREA WITH MODERATE TO HEAVY PRECIPITATION AND GUSTY WINDS. RIGHT NOW
TIMING IS SOMEWHAT UNCLEAR. THE EC AND GEM SHOW THE FRONT KNOCKING
ON OUR DOORSTEP TUESDAY EVENING (THE GEM IS THE FASTEST OF THE
MODELS). IN CONTRAST, THE NAM AND GFS ARE SLOWER AND DO NOT BRING
THE FRONT INTO OUR AREA UNTIL EARLY WEDNESDAY MORNING. HOWEVER THEY
ARE ALL TRENDING FURTHER SOUTH AND THEY ARE SUGGESTING THE CORE OF
THE HEAVIEST PRECIPITATION IS HEADING RIGHT INTO SOUTHWEST OREGON.
THIS IS LINING UP WELL WITH THE IVT TRANSPORT WITH BOTH THE GEFS AND
OPERATIONAL GFS SHOWING THE CORE OF THIS TAKING AIM AT SOUTHWEST
OREGON. THUS HAVE INCREASED POPS SIGNIFICANTLY, ESPECIALLY ALONG THE
COAST AND NORTHWEST PART OF THE CWA WEDNESDAY AND WEDNESDAY NIGHT.
-PETRUCELLI

THURSDAY THROUGH SUNDAY...THERE IS FAIRLY GOOD MODEL
AGREEMENT THAT THURSDAY WILL BE A WET DAY ACROSS MUCH OF OUR AREA AS
AN ATMOSPHERIC RIVER REMAINS AIMED AT US AND A FRONT SLOWLY MOVES
THROUGH. THE FETCH OF THE MOISTURE AND THE FACT THAT THE FRONT MOVES
SLOWLY MEANS THAT THERE MAY BE SUBSTANTIAL RAIN ALONG THE CURRY
COAST AND MOUNTAINS AS WELL AS INTO THE SISKIYOUS. THERE ARE ONLY
SLIGHT TIMING DIFFERENCES WITH THE ECMWF BEING SLIGHTLY SLOWER THAN
THE GFS/GEM ON THURSDAY, BUT THE RAIN SHOULD TAPER TO SHOWERS FROM
WEST TO EAST THROUGH THE DAY. I RAISED POPS SUBSTANTIALLY ON
THURSDAY.

MODEL DIFFERENCES START TO CREEP BACK IN FOR FRIDAY INTO THE
WEEKEND. THE GFS/GEM CONTINUE TO SHOW ANOTHER VERY WET FRONT FRIDAY
FOLLOWED BY THE UPPER TROUGH OVER THE WEEKEND. THE ECMWF IS SHOWING
MORE DIGGING AND A SLOWER PROGRESSION OF THE FRONT INTO THE COAST.
IT ALSO TAKES THE BULK OF THE RAINFALL IN NORTH OF US. THIS IS THE
SAME THING IT DID LAST WEEK WITH OUR WED/THU FRONT. GIVEN THAT THE
GFS/GEM HAVE BEEN DOING BETTER THAN THE ECMWS WITH THIS WEEK`S
SYSTEMS, I`M INCLINED TO LEAN IN THEIR DIRECTION FOR THE ACTION
LATER THIS WEEK AND NEXT WEEKEND. THUS I`VE ALSO RAISED POPS FOR THE
REMAINDER OF THE EXTENDED AS WELL. -WRIGHT

&&

.AVIATION...20/00Z TAF CYCLE...VFR CEILINGS HAVE REACHED THE COAST
THIS AFTERNOON WITH SUNNY SKIES BUT ALSO BREEZY SOUTHERLY LOW LEVEL
WINDS INLAND. A SLOW MOVING COLD FRONT WILL SEND LIGHT TO MODERATE
RAIN AND MVFR CEILINGS TO THE COAST BEGINNING AROUND 03Z THIS
EVENING. SKY CONDITION WILL DETERIORATE FROM WEST TO EAST OVERNIGHT
WITH RAIN AND MVFR CIGS EXPECTED TO REACH ROSEBURG/KRBG AROUND 06Z
THEN MOVE TO THE ROGUE VALLEY AND SHASTA VALLEY BY 12Z MONDAY
MORNING. BEHIND THE FRONT, CIGS WILL IMPROVE TO VFR WITH SOME BREAKS
IN THE CLOUDS BUT ALSO SCATTERED SHOWERS. THIS CONDITION WILL BEGIN
AT THE COAST AND IN THE UMPQUA VALLEY BY MONDAY AFTERNOON THEN IN
THE ROGUE VALLEY AND SHASTA VALLEY BY MONDAY EVENING WHILE THE
REMNANTS OF THE FRONT ARE EXPECTED TO FINALLY PRODUCE AREAS OF RAIN
AND MVFR CIGS EAST OF THE CASCADES INCLUDING KLAMATH FALLS/KLMT
MONDAY EVENING. /DW

&&

.MARINE...UPDATED 930 PM PDT SUN 19 OCT 2014...A SERIES OF
DISTURBANCES WILL IMPACT THE MARINE WATERS OVER THE NEXT WEEK.
A COLD FRONT IS MOVING ACROSS THE WATERS THIS EVENING WITH RAIN
AND MODERATE WIND WAVES THAT ARE LOCALLY HIGH WITH THE STRONGEST
WINDS IN THE OUTER WATERS NORTH OF CAPE BLANCO. DESPITE THESE LARGE
WIND WAVES, THE LARGEST COMPONENT OF THE SEAS IS A BUILDING LONG
PERIOD WEST SWELL AT 16 SECONDS. WINDS WILL DIMINISH BEHIND THE
FRONT LATE TONIGHT THEN A WEAKER FRONT WILL CAUSE WINDS TO BECOME
MODERATE AGAIN FROM AROUND 9 AM MONDAY MORNING THROUGH MONDAY
EVENING. MEANTIME, THE WEST SWELL WILL BE CONTINUING TO BUILD WITH
PEAK COMBINED SEAS OF AROUND 16 FEET EXPECTED MONDAY AFTERNOON AND
EVENING.

EVEN THOUGH BOTH SWELL HEIGHT AND SOUTHERLY WIND WAVES WILL DECREASE
LATE MONDAY NIGHT INTO TUESDAY, THE LONG PERIOD WEST SWELL WILL
REMAIN HIGH AND STEEP. THE STRONGEST FRONT OF THE WEEK IS LIKELY TO
APPROACH THEREAFTER WITH SMALL CRAFT ADVISORY LEVEL WINDS LIKELY
DEVELOPING TUESDAY AFTERNOON INTO THE EVENING THEN POSSIBLY GALES
AND HEAVY SEAS WITH MODERATE TO HEAVY RAIN LATE TUESDAY NIGHT INTO
WEDNESDAY EVENING. THERE IS STILL MODERATE UNCERTAINTY ON THE TIMING
AND STRENGTH OF THIS SYSTEM BUT CONDITIONS ARE LIKELY TO BE WORSE
FROM THE SOUTHERN OREGON WATERS NORTHWARD THAN TO THE SOUTH. SVEN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

CA...WIND ADVISORY UNTIL 8 PM PDT MONDAY FOR CAZ081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM
PDT
     THIS EVENING FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 9 AM MONDAY TO 2 AM PDT
     TUESDAY FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT TUESDAY
     FOR PZZ356-376.
     HAZARDOUS SEAS WARNING UNTIL 11 PM PDT THIS EVENING FOR
     PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 PM THIS EVENING
     TO 5 PM PDT TUESDAY FOR PZZ350-370.
     GALE WARNING UNTIL 8 PM PDT THIS EVENING FOR PZZ370.

$$











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