Weather Service Report


313 
FXUS66 KMFR 011631
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
904 AM PDT WED APR 1 2015

.DISCUSSION...MORNING UPDATE. WITH THE VERY COLD AIR MASS ALOFT OVER 
THE REGION THE NEWEST MODEL RUNS ARE INDICATING INSTABILITY ON THE 
EAST SIDE THIS AFTERNOON AS WELL.

PREVIOUS DISCUSSION...A COOL, SHOWERY AIRMASS REMAINS OVER OUR 
FORECAST AREA THIS MORNING. THE SHOWERS DECREASED LAST EVENING AS 
EXPECTED, BUT ANOTHER BATCH OF SHOWERS IS MOVING ONSHORE RIGHT NOW. 
THIS WILL BRING PRECIPITATION MAINLY TO THE COAST, UMPQUA, AND 
CASCADES THROUGH THE MORNING. HOWEVER, THE BACK EDGE OF THE UPPER 
TROUGH WILL SWING THROUGH THIS AFTERNOON. THE COLD POOL AND 
ASSOCIATED INSTABILITY SHOULD BE BOTH MORE IMPRESSIVE AND WIDESPREAD 
THAN YESTERDAY, SO WE DO EXPECT AN UPTICK IN SHOWERS FOR ALL AREAS 
THIS AFTERNOON. ONCE AGAIN, LIGHTNING, HEAVY DOWNPOURS, AND EVEN 
SMALL HAIL WILL BE POSSIBLE WITH THE HEAVIER CELLS.

SHOWERS WILL DIMINISH TONIGHT, AND THEN MAINLY DRY WEATHER IS
EXPECTED THROUGH FRIDAY. THE AIRMASS WILL GRADUALLY MODERATE, BUT
NIGHTS WILL BE CHILLY, EVEN OVER WEST SIDE OREGON AND THE SHASTA
VALLEY WHERE THE SPRING GROWING SEASON HAS ALREADY BEGUN. THE
FREEZE WARNING CONTINUES FOR THE SHASTA VALLEY THIS MORNING AND A
FREEZE WARNING WAS ISSUED FOR TONIGHT AND THURSDAY MORNING AS
WELL. FREEZING IS NOT AS CERTAIN FOR FRIDAY MORNING, BUT IT IS
CERTAINLY POSSIBLE, SO A WATCH WAS ISSUED. WEST SIDE OREGON
VALLEYS WILL ALSO BE CLOSE TO FROST/FREEZE CONDITIONS OVER THE
NEXT FEW NIGHTS. CLOUDS WILL BE THE LIMITING FACTOR, AND THUS THE
GREATEST POTENTIAL WILL BE FRIDAY MORNING WHEN SKIES ARE MOST
LIKELY TO BE CLEAR. THIS IS ESPECIALLY TRUE IN THE ROGUE VALLEY
WHERE CLEAR SKIES ARE MOST LIKELY. HOWEVER, WE ARE CURRENTLY ONLY
ISSUING FREEZE WARNINGS (NOT FROST) FOR THE ROGUE VALLEY, AND THE
AIRMASS WILL MODERATE BY THE TIME SKIES CLEAR. NEEDLESS TO SAY,
THERE IS MUCH UNCERTAINTY REGARDING TEMPERATURES FOR THESE AREAS,
SO THOSE CONCERNED WITH FREEZING TEMPERATURES SHOULD PAY CLOSE
ATTENTION TO FORECASTS OVER THE NEXT FEW DAYS.

ANOTHER COLD FRONT WILL APPROACH THE COAST LATE FRIDAY AND
MOVE INLAND SATURDAY. MODEL CONSISTENCY IS GOOD THAT A LARGE
UPPER LOW WILL THEN MOVE IN OVER THE WEEKEND AND REMAIN INTO EARLY
NEXT WEEK. THIS LOOKS LIKE A WET PERIOD FOR OUR ENTIRE AREA, AND
FOR ONCE, SNOW LEVELS ACTUALLY LOOK FAIRLY LOW - PERHAPS AS LOW AS
3000 FEET AT TIMES. THUS, WE COULD ACTUALLY GET SOME DECENT SNOW
IN THE MOUNTAINS! -WRIGHT

&&

.AVIATION...FOR THE 01/12Z TAF CYCLE...MOSTLY VFR CONDITIONS WILL 
PREVAIL THROUGH THIS EVENING...EXCEPT ROUNDS OF SHOWERS AND ISOLATED 
THUNDERSTORMS MAY BRING LOCAL TO AREAS OF MVFR CIGS WITH TERRAIN 
OBSCURATION ALONG THE COAST AND EASTWARD TO THE CASCADES THIS 
AFTERNOON. SHOWERS WILL DIMINISH DURING THE EVENING THEN LATE NIGHT 
WEST SIDE VALLEY STRATUS IS LIKELY TO PRODUCE MVFR CIGS INTO 
THURSDAY MORNING. /DW
 
&&

.MARINE...UPDATED 830 AM PDT WEDNESDAY 01 APR 2015...CURRENT BUOY 
OBSERVATIONS HAVE SHOWN THAT SEAS ARE BUILDING A BIT QUICKER THAN 
PREVIOUSLY THOUGHT, SO HAVE ADJUSTED THEFORECAST ACCORDINGLY, AND 
HAVE BUMPED FORWARD THE START OF THE SMALL CRAFT ADVISORY TO THE 
CURRENT TIME, RATHER THAN WAITING UNTIL 18Z.  NUMEROUS SHOWERS WILL 
CONTINUE TODAY, WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS. 
NORTHERLY WINDS INCREASE THROUGH THIS EVENING, DIMINISH SLIGHTLY 
LATE TONIGHT, THEN INCREASE AGAIN THURSDAY AFTERNOON AND EVENING. 
THE NEXT COLD FRONT WILL ARRIVE ON FRIDAY, WITH CONDITIONS REMAINING 
UNSETTLED THROUGH EARLY NEXT WEEK. THE STRONGEST OF MULTIPLE SYSTEMS 
EXPECTED THIS WEEK IS CURRENTLY INDICATED TO ARRIVE SUNDAY NIGHT 
INTO MONDAY. 
-BPN/DW

&&

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

CA...FREEZE WATCH FROM 1 AM TO 9 AM PDT FRIDAY MORNING FOR CAZ081.
     FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ081.
     FREEZE WARNING FROM 1 AM TO 9 AM PDT THURSDAY MORNING FOR
     CAZ081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM THIS AFTERNOON TO 11 PM 
     PDT THIS EVENING FOR PZZ356-376. 
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS 
     EVENING FOR PZZ350-356-370-376. 

$$

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