Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 012318
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
318 PM PST SUN FEB 1 2015

.DISCUSSION... A WEAK FRONT HAS MOVED THROUGH THE AREA WITH SOME
SHOWERS STILL LINGERING ALONG THE UMPQUA DIVIDE, CASCADES AND ALSO
IN KLAMATH AND LAKE COUNTIES. AMOUNTS HAVE GENERALLY BEEN LIGHT
RANGING FROM A FEW HUNDRETHS EAST OF THE CASCADES TO ALMOST A
QUARTER OF AN INCH IN THE HIGHER TERRAIN OF THE COASTAL MOUNTAINS,
UMPQUA DIVIDE, AND CASCADES. SNOW LEVELS ARE HIGH...ABOVE
7500...SO ALL THIS PRECIPITATION HAS FALLEN AS RAIN. THERE WILL BE
A VERY BRIEF BREAK IN COVERAGE OF SHOWERS THIS EVENING BEFORE
ANOTHER MORE POTENT FRONT MOVES IN TONIGHT. THIS FRONT WILL STALL
OVER THE AREA THROUGH TUESDAY BEFORE BEING NUDGED TO THE NORTH BY
A BRIEF PERIOD OF RIDGING WEDNESDAY. THIS RIDGING WILL BE SHORT
LIVED AS A VERY POTENT WET STORM APPROACHES THE COAST EARLY
THURSDAY.

MONDAY`S FRONT WILL HAVE A DECENT AMOUNT OF MOISTURE TO WORK WITH.
MODELS HAVE TRENDED WETTER WITH THIS SYSTEM SO BUMPED UP QPF AMOUNTS
SOME FOR THIS FRONT BUT NOT DRASTICALLY. SOUTH CURRY COAST CAN
EXPECT AROUND 1.25 INCHES, INLAND VALLEYS BETWEEN A QUARTER AND A
HALF AN INCH AND GENERALLY LESS THAN A QUARTER OF AN INCH EAST OF
THE CASCADES. WINDS WITH THIS FIRST FRONT WILL BE GUSTY EAST OF THE
CASCADES AROUND THE SUMMER LAKE AREA BUT NOT QUITE ADVISORY CRITERIA
LEVEL.

ANOTHER SHOT OF MOISTURE ARRIVES TUESDAY MORNING BRINGING MORE RAIN
TO THE AREA. RAINFALL AMOUNTS WILL BE HIGHER FOR THE CURRY COAST
WITH TOTALS IN THE 1.5 TO 2 INCH RANGE. THE HIGHER AMOUNTS ARE
EXPECTED AT THE USUAL HIGHER TERRAIN LOCATIONS SUCH AS RED MOUND.
AMOUNTS FOR THE REMAINDER OF THE AREA WILL BE AROUND THE SAME AS
THE MONDAY FRONT. HOWEVER, WINDS WITH TUESDAY`S SYSTEM WILL BE A
BIT STRONGER AT THE 700MB LEVEL. BOTH THE GFS AND THE NAM ARE
SHOWING WINDS IN THE 50 TO 55KT RANGE AND THE WIND DIRECTION IS
MORE FAVORABLE FOR WINDS TO GUST DOWN INTO THE SUMMER LAKE AREA.
BECAUSE OF THIS, A WIND ADVISORY HAS BEEN ISSUED FOR PARTS OF THE
EAST SIDE AND IS COVERED AT NPWMFR.

SHORT LIVED RIDGING BEGINS BUILDING INTO THE AREA WEDNESDAY MORNING,
ESSENTIALLY PUSHING THE BULK OF THE MOISTURE TO THE VERY NORTHERN
PORTIONS OF THE CWA. SHOWERS WILL DIMINISH IN COVERAGE WEDNESDAY
MAKING THIS THE DRIEST DAY OF THE WEEK, RELATIVELY SPEAKING. THE
ACTIVE WEATHER RESUMES THURSDAY. -MND

.LONG TERM...THURSDAY THROUGH SUNDAY NIGHT...THE WET PATTERN WILL
CONTINUE INTO THE EXTENDED PERIOD. MODEL SOLUTIONS SUGGEST THAT THE
LARGE SCALE PATTERN WILL SHIFT EVEN MORE SO TO THE EAST, PUSHING THE
RIDGE AXIS OVER THE ROCKY MOUNTAINS AND ALLOWING THE TROUGH TO INCH
CLOSER TO THE WEST COAST. THIS WILL PLACE OUR FORECAST AREA UNDER
THE GUN, OR RATHER, UNDER THE FIRE HOSE. NUMEROUS WAVES, EACH WITH A
RATHER STRONG CONNECTION TO SUBTROPICAL MOISTURE, WILL PUSH IN TO
THE AREA, RESULTING IN A ROUGHLY 3 DAY PERIOD OF RAIN AND WIND.

THE MOST SIGNIFICANT OF THESE WILL BE FRIDAY INTO SATURDAY, AND
JUDGING BY MOISTURE TRANSPORT GUIDANCE AND FORECAST PRECIPITATION,
RAINFALL WILL BE MEASURED NOT SO MUCH IN TENTHS OF AN INCH, BUT
WHOLE INCHES. THIS SCENARIO COULD RESULT IN FLOODING CONCERNS FOR
THE COAST OVER THE WEEKEND. CONFIDENCE IS MODERATE BUT INCREASING
REGARDING THIS WET SCENARIO, BUT GIVEN THE DRY PERIOD LEADING UP TO
THIS EVENT AND THE OVERALL UNCERTAINTY OF RAINFALL AMOUNTS, THERE
DOES REMAIN SO QUESTION AS TO THE DETAILS. ALSO BEARING WATCH WILL
BE WINDS, AS THE GFS AND EC SUGGEST WIND SPEEDS AT 700 MB, A GOOD
INDICATOR OF WIND GUST STRENGTH OVER PORTIONS OF THE AREA, MAY
APPROACH 80 KNOTS. THIS STORM WILL BE SOMETHING TO WATCH OVER THE
NEXT SEVERAL FORECAST CYCLES.

THE NEXT SYSTEM IS EXPECTED SUNDAY. WHILE SIMILAR TO THE PREVIOUS
TROUGH, LATEST MODEL RUNS SHOW LESS MOISTURE AND WIND. HOWEVER,
THERE IS STILL ENOUGH OF BOTH TO WARRANT A CLOSE EYE, ESPECIALLY
SINCE IT WILL FOLLOW SO CLOSELY ON THE HEELS OF THE PREVIOUS ONE.

FOR BOTH OF THESE SYSTEMS, HAVE SPENT THE LARGE PART OF EFFORTS
TODAY REFINING THE TIMING OF PRECIPITATION CHANCES AND THE STRENGTH
OF THE WINDS TO COME CLOSER IN LINE WITH THE LATEST MODEL RUNS.
UNFORTUNATELY FOR THOSE WISHING FOR SNOW IN THE MOUNTAINS, THESE
SYSTEMS WILL BE ACCOMPANIED BY WARM AIR, AND SNOW LEVELS WILL LIKELY
NOT DROP MUCH BELOW 7000 FEET, WELL ABOVE THE PASSES AND MOST
RECREATIONAL AREAS.

FURTHER ADJUSTMENTS WILL BE NEEDED AS THE STORM SYSTEMS APPROACH THE
SHORT TERM, BUT THOSE MAKING PLANS FOR THE WEEKEND SHOULD BEGIN TO
PREPARE NOW FOR WHAT COULD AMOUNT TO A SIGNIFICANT WIND AND RAIN
EVENT. -BPN

&&

.AVIATION...BASED ON THE 01/18Z TAF CYCLE...MAINLY VFR CONDITIONS
ARE EXPECTED THROUGH MUCH OF THE NEXT 24 HOURS. AN INCOMING WEAK
FRONTAL SYSTEM WILL BRING SHOWERS AND SOME WEST SIDE MVFR CIGS
THROUGH THE DAY, AS WELL AS SIGNIFICANT AREAS OF TERRAIN
OBSCURATION. AFTER A BRIEF PERIOD OF SLIGHTLY IMPROVED CONDITIONS
THIS EVENING, MVFR CIGS ARE EXPECTED TO BECOME MORE WIDESPREAD LATE
TONIGHT INTO TOMORROW MORNING AS A WARM FRONT PUSHES MORE MOISTURE
AND PRECIPITATION INTO THE REGION. -BPN

&&

.MARINE...UPDATED 815 AM PST SUNDAY, FEBRUARY 1, 2015...LIGHT SOUTH
WINDS AND PERIODS OF RAIN ARE EXPECTED TODAY AS A WEAK FRONT PUSHES
IN FROM THE WEST. MODERATE WEST SWELL WILL BUILD AS A SOMEWHAT
STRONGER FRONT APPROACHES THE COASTAL WATERS TONIGHT, THEN GUSTY
SOUTH WINDS AND STEEP SEAS ARE LIKELY AS THIS FRONT PASSES ON
MONDAY. UNSETTLED CONDITIONS WILL THEN CONTINUE THROUGH MIDWEEK,
WITH A STRONG STORM SYSTEM POSSIBLY RESULTING IN AND EXTENDED PERIOD
OF GALES THURSDAY AND FRIDAY. MODEL GUIDANCE CONTINUES TO SHOW THE
POTENTIAL FOR SEAS OF 15 TO 20 FT DEVELOPING LATE THURSDAY INTO
FRIDAY DUE TO WIND SEAS AND FRESH SOUTH TO SOUTHWEST SWELL.
-CC/BPN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY FROM 10 AM TO 7 PM PST TUESDAY FOR
     ORZ030-031-624-625.

CA...WIND ADVISORY FROM 10 AM TO 7 PM PST TUESDAY FOR CAZ085-285.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 10 AM PST MONDAY FOR
     PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM TO 4 PM PST
     MONDAY FOR PZZ350-356-370-376.

$$

MND/BPN


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