Area Forecast Discussion
Issued by NWS Medford, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KMFR 251653
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
853 AM PST THU DEC 25 2014

.DISCUSSION...AN UPDATE TO THE FORECAST IS NOT NECESSARY THIS
MORNING. THE 4 POINTS OF FOCUS FOR THE NEXT 7 DAYS ARE: A DUSTING
OF SNOW IS POSSIBLE FROM SNOW FLURRIES AT ELEVATIONS ABOVE 2500
FEET TODAY AND TONIGHT...MAINLY IN THE SOUTHERN OREGON CASCADES, A
FLOOD WARNING REMAINS IN EFFECT FOR THE COQUILLE RIVER AT COQUILLE
WITH THE LEVEL LIKELY TO FALL BELOW FLOOD STAGE THIS EVENING, A
TROUGH MOVING SOUTHEAST ACROSS EASTERN OREGON IS LIKELY TO PROVIDE
UP TO A FEW INCHES OF SNOW TO THE SOUTHERN OREGON CASCADES AND
AROUND AN INCH OF ACCUMULATION EAST OF THE CASCADES SATURDAY
NIGHT INTO SUNDAY MORNING, AND LASTLY A COLD CONTINENTAL AIR MASS
WILL LIKELY FILTER IN WITH NORTHEAST FLOW BEGINNING SUNDAY NIGHT
AND BELOW NORMAL TEMPERATURES CONTINUING INTO MID-WEEK.

&&

.AVIATION...FOR THE 25/12Z TAF CYCLE...AREAS OF MVFR CEILINGS AND
MOUNTAIN OBSCURATION...ESPECIALLY IN THE VICINITY OF SCATTERED RAIN
AND SNOW SHOWERS...WILL CONTINUE THROUGH 18-21Z TODAY. THE FREEZING
LEVEL WILL BE ABOUT 2-3KFT MSL EARLY THIS MORNING.

EXPECT CONDITIONS TO MOSTLY IMPROVE TO VFR THIS AFTERNOON...EXCEPT
OVER THE HIGHER TERRAIN OF SOUTHWEST OREGON WHERE ISOLATED SHOWERS
MAY BRING LOCAL MVFR.

TONIGHT...MODEL MOS GUIDANCE BRINGS IFR/LIFR CIGS/FOG INTO THE
VALLEYS WEST OF THE CASCADES...BUT AIR MASS IS STILL MARGINALLY
UNSTABLE WITH ISOLATED SHOWERS. AS A RESULT...HAVE GONE WITH AN MVFR
DECK AT KRBG AND KMFR. REST OF THE AREA WILL BE VFR WITH AREAS OF
MVFR ALONG THE COAST. SPILDE


&&

.MARINE...UPDATED 330 AM PST THU DEC 25 2014...NORTHERLY WINDS WILL
GRADUALLY DIMINISH TODAY. MODERATE WIND WAVES WILL COMBINE WITH A
WESTERLY SWELL TO PRODUCE HIGH AND STEEP SEAS INTO THIS EVENING.
OFFSHORE HIGH PRESSURE IS REBUILDING AND WILL PERSIST INTO THE
WEEKEND. WINDS AND SEAS REACH A MINIMUM ON FRIDAY THEN NORTHERLY
WINDS WILL INCREASE AGAIN DURING THE WEEKEND. SEAS MAY BECOME STEEP
EARLY NEXT WEEK. SPILDE

&&

.PREV DISCUSSION... /ISSUED 313 AM PST THU DEC 25 2014/

DISCUSSION...MULTIPLE SHOWERS ARE MOVING OVER THE AREA THIS
MORNING, BUT MUCH COLDER AIR HAS MOVED INTO THE REGION, DROPPING
SNOW LEVELS TO BETWEEN 2000 AND 3000 FEET. AREA TRAFFIC CAMS HAVE
SHOWN SNOW FALLING ACROSS THE CASCADES, WITH AMOUNTS OF SEVERAL
INCHES FALLING SINCE YESTERDAY. WITH SNOW SHOWERS CONTINUING
THROUGH THE MORNING, TRAVELERS THIS CHRISTMAS DAY SHOULD KEEP
INFORMED OF PASS CONDITIONS VIA CALTRANS OR ODOT, AND BE PREPARED
FOR WINTRY TRAVEL. A WINTER WEATHER ADVISORY WILL CONTINUE THROUGH
8 AM THIS MORNING FOR THE CASCADES AND SISKIYOUS DUE TO THE
ONGOING SNOWFALL. ALSO, FLOODING ALONG THE COQUILLE RIVER
CONTINUES, WITH WATERS NOT EXPECTED TO DROP BELOW FLOOD STAGE
UNTIL TOMORROW AT THE EARLIEST.

RIDGING WILL BUILD INTO THE REGION BEGINNING TODAY, BUT WITH
NORTHWEST FLOW ALOFT AND MOIST ONSHORE FLOW IN THE LOWER LEVELS,
AREAS ALONG THE COAST NORTH OF CAPE BLANCO AND PORTIONS OF THE
UMPQUA BASIN COULD SEE LIGHT SHOWERS THROUGH FRIDAY MORNING.
AGAIN, PRECIPITATION AMOUNTS WILL BE LIGHT, AND NO MAJOR TRAVEL
IMPACTS ARE EXPECTED.

THE NEXT SYSTEM WILL ARRIVE SATURDAY IN THE FORM OF A TROUGH
DROPPING SOUTH ALONG THE WEST COAST. THIS WILL BE A COLD SYSTEM,
BUT IT WILL HAVE LIMITED ACCESS TO MOISTURE. SNOW LEVELS WILL
REMAIN IN THE 2000 TO 3000 FEET RANGE, BUT AGAIN, WITH LIGHT
PRECIPITATION AMOUNTS, THERE WILL NOT BE A SIGNIFICANT AMOUNT OF
RAIN OR SNOW TO SPEAK OF. THE REAL STORY WITH THIS SYSTEM WILL BE
THE COLD AIR THAT FOLLOWS THE TROUGH ON SUNDAY AND MONDAY. LOW
TEMPERATURES SHOULD DROP BELOW FREEZING FOR VIRTUALLY THE ENTIRE
FORECAST AREA BOTH MONDAY AND TUESDAY. WITH HIGH PRESSURE THEN
BUILDING IN OVERHEAD, AND INVERSIONS EXPECTED IN THE VALLEYS, FOG
WILL BE A LIKELY RESULT. THIS COULD KEEP DAYTIME TEMPERATURES LOW
IN THE VALLEYS AS WELL.

BEYOND THIS POINT, FORECAST UNCERTAINTY INCREASES, AS MODEL
SOLUTIONS DEPICT THE TROUGH CLOSING OFF OVER SOUTHERN CALIFORNIA.
CLOSED LOWS ARE BY NO MEANS HANDLED VERY WELL BY MODELS IN THE
EXTENDED TERM, AND WITH THE GFS KEEPING THE LOW IN THE REGION FOR
SEVERAL DAYS, AND THE EC QUICKLY SHIFTING IT EAST, HAVE LITTLE
CONFIDENCE IN EITHER SOLUTION AT THIS TIME. HAVE TRENDED THE
FORECAST TOWARDS CLIMO, WITH A LEAN TOWARDS A COOLER SCENARIO,
CONSIDERING THE LIKELIHOOD OF TROUGHS AND THE CLOSED LOW IN THE
VICINITY, BUT HAVE ALSO KEPT THE FORECAST DRY UNTIL CONFIDENCE
IMPROVES IN ANY GIVEN SCENARIO.

&&

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

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM
     PST THIS MORNING FOR PZZ350-356-370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM PST THIS
     EVENING FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THIS AFTERNOON
     FOR PZZ376.

$$

DW/SBN


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.