Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 211150
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
350 AM PST SUN DEC 21 2014

.DISCUSSION...A MAJOR PRECIPITATION EVENT CONTINUES IN SOUTHERN
OREGON AND IS CAUSING FLOODING IMPACTS AT THE COAST...COAST
RANGE...CASCADE FOOTHILLS...AND CASCADES. RIVERS CONTINUE TO
RISE...AND WILL GENERALLY CONTINUE THROUGH THIS MORNING AT
LEAST...AND INTO THE AFTERNOON IN SOME PLACES.

RAIN RATES CONTINUE TO BE HIGH THIS MORNING...WITH 1 HOUR RATES OF A
THIRD TO HALF AN INCH ACROSS PORTIONS OF COOS...CURRY...AND DOUGLAS
COUNTIES.  A WHOPPING 24 HOUR RAINFALL TOTAL NEAR 9 INCHES HAS
OCCURRED AT RED MOUND NEAR THE CURRY COUNTY COAST. IN ADDITION...THE
AFTERNOON BALLOON SOUNDING REGISTERED 1.07 INCHES OF PRECIPITABLE
WATER WHICH RANKS 7TH FOR DECEMBER SOUNDINGS AND IS 3 STANDARD
DEVIATIONS HIGHER THAN NORMAL. IN OTHER WORDS...THIS IS A VERY JUICY
AIR MASS.

THE DURATION OF THE HEAVY RAIN IS THE MOST SIGNIFICANT ASPECT OF
THIS SYSTEM...AND WHEN ALL IS SAID AND DONE THERE WILL HAVE BEEN
ESSENTIALLY 48 HOURS OF 500 KG/MS INTEGRATED VAPOR TRANSPORT ACROSS
THE AREA. THESE IVT VALUES SUGGEST THIS TYPE OF RAIN EVENT OCCURS
ONLY ONCE IN 5-10 YEARS FOR THE COAST AND CASCADES. IMPACTS THUS FAR
HAVE BEEN AT LEAST ONE RIVER...THE EAST FORK OF THE COQUILLE NEAR
SITKUM...OVERFLOWING ITS BANKS LATE LAST NIGHT WHICH PROMPTED THE
ISSUANCE OF AN AREAL FLOOD WARNING FOR EASTERN COOS COUNTY THAT WILL
CONTINUE THROUGH THIS MORNING. AREAL FLOOD WATCHES COVER MUCH OF THE
REST OF THE AREA FROM THE CASCADES WEST. A FLOOD WARNING CONTINUES
FOR THE COQUILLE AT COQUILLE AT FLSMFR...WITH MINOR FLOODING
FORECAST TO BEGIN THIS AFTERNOON. ADDITIONALLY...HIGH WATER HAS BEEN
REPORTED ON HIGHWAY 101 AT THE COAST AND HIGHWAY 138 IN THE CASCADE
FOOTHILLS...WITH ROCKS THE SIZE OF BASKETBALLS FALLING ON HIGHWAY
138 AND BEING REPORTED BY ODOT. NEEDLESS TO SAY...TRAVEL ON THESE
ROADS THIS MORNING WILL BE HAZARDOUS...AND DRIVERS NEED TO USE
EXTRA CAUTION IF VENTURING OUT IN THESE AREAS.

SNOW LEVELS ARE HIGH AT THIS MOMENT...ABOVE 7000 FEET...AND WILL
REMAIN HIGH THROUGH TODAY. WINDS WILL CONTINUE TO BE GUSTY EAST OF
THE CASCADES AND A HIGH WIND WARNING AND WIND ADVISORY CONTINUE AT
NPWMFR.

VALLEYS LIKE THE ROGUE HAVE BEEN SHELTERED FROM THE MOST SIGNIFICANT
RAIN WITH ONLY 0.22 INCHES IN THE PAST 24 HOURS...WITH DOWNSLOPING
DRYING THE VALLEY OUT COMPARED TO HIGHER TERRAIN. MEDFORD STILL WILL
LIKELY SEE AT LEAST A HALF INCH OF RAIN FROM THIS SYSTEM THOUGH.

ATTENTION THEN TURNS TO A CHRISTMAS EVE COLD UPPER TROUGH WHICH
ARRIVES THE AFTERNOON OR EVENING OF THE 24TH...AND BRINGS WITH IT A
GOOD CHANCE FOR A WHITE CHRISTMAS AT ELEVATIONS ABOVE 3000 FEET.
MODEL CONSENSUS AT THIS TIME BETWEEN THE EC AND GFS SUGGESTS FOLKS
COULD GO TO SLEEP CHRISTMAS EVE WITH RAIN OR RAIN/SNOW MIX...OR DRY
CONDITIONS EAST OF THE CASCADES...AND WAKE UP TO A FEW INCHES OR
MORE OF THE WHITE STUFF. WE WILL BE WORKING HARD TO FINE-TUNE THIS
FORECAST IN THE NEXT FEW SHIFTS...AND CONVEY ANY WEATHER MESSAGES
ABOUT THIS POTENTIALLY SIGNIFICANT WINTRY EVENT.


&&

.AVIATION...A MOIST PACIFIC JET STREAM REMAINS AIMED AT OUR AREA THROUGH
THIS MORNING. WIDESPREAD RAIN AND IFR AND MVFR CIGS/VIS WILL
CONTINUE THROUGH THE MORNING AT LEAST...WITH A BETTER CHANCE FOR
MVFR CONDITIONS DURING THE AFTERNOON. THERE HAVE BEEN AND WILL
CONTINUE TO BE PERIODS OF HEAVIER RAIN WHICH LOWERS CIGS/VIS TO
IFR, ESPECIALLY AT THE COAST AND OVER WEST SIDE VALLEYS. ALL
MOUNTAINS WILL REMAIN OBSCURED THROUGH THE DAY. THE HEAVIEST RAIN
WILL BEGIN LIFTING NORTH LATER TODAY. LOW LEVEL WIND SHEAR OVER
SHELTERED VALLEYS...BOTH WEST AND EAST SIDE...WITH STRONG WINDS IN
MORE EXPOSED EAST SIDE LOCATIONS. -WRIGHT


&&

.MARINE...UPDATED 1000 PM PST SAT DEC 20 2014...WINDS WILL
CONTINUE TO DIMINISH THROUGH THE DAY THEN REMAIN RELATIVELY LIGHT
THROUGH TUESDAY. SEAS WILL ALSO FALL THROUGH THE DAY AS BOTH
SWELL AND WIND WAVE GRADUALLY DIMINISH. THE WIND WAVE COMPONENT
WILL BE MUCH LESS TONIGHT THROUGH TUESDAY, BUT MODERATE WEST
SWELL WILL CONTINUE AND THUS A SMALL CRAFT FOR HAZARDOUS SEAS HAS
BEEN ISSUED THROUGH WEDNESDAY. A STRONG COLD MAY BRING MODERATE
NORTH WINDS AND WIND WAVES TO THE AREA WEDNESDAY THROUGH THURSDAY.
-WRIGHT


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING UNTIL 10 PM PST THIS EVENING FOR
     ORZ030-031-624-625.
     FLOOD WATCH THROUGH THIS EVENING FOR ORZ025-027-616-617-623-624.
     FLOOD WATCH THROUGH THIS EVENING FOR ORZ024-618>621.
     FLOOD WATCH THROUGH THIS EVENING FOR ORZ021-022-615.
     FLOOD WATCH THROUGH THIS EVENING FOR ORZ023.

CA...HIGH WIND WARNING UNTIL 10 PM PST THIS EVENING FOR CAZ085-285.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST THURSDAY
     FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST EARLY THIS MORNING
     FOR PZZ350-370.

$$

NSK/NSK/BTL


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