Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 202233
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
333 PM PDT SUN APR 20 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT. A HIGH PRESSURE
RIDGE WILL LINGER OVER THE WESTERN STATES INTO MONDAY MORNING. THE
RIDGE, AN INCREASE OF HIGH CLOUDS SHOULD RESULT IN LOW
TEMPERATURES ON MONDAY THAT ARE SEVERAL DEGREES HIGHER THAN THEY
WERE THIS MORNING. THE WEATHER PATTERN STILL LOOKS TO BE VERY
ACTIVE FROM MONDAY THROUGH NEXT WEEKEND.

THE 00Z GFS AND ECMWF ARE IN VERY GOOD AGREEMENT IN THE SHORT
TERM. A COLD FRONT IS EXPECTED TO REACH THE COAST AROUND NOON ON
MONDAY AND APPROACH ROSEBURG AND CAVE JUNCTION BY THE END OF THE
AFTERNOON. GUSTY SOUTHWEST WINDS WILL DEVELOP AHEAD OF THE FRONT
WITH THE HIGHEST SPEEDS...GUSTS TO 35 MPH EAST OF THE CASCADES.
THE FRONT WILL SPREAD EAST IN THE EVENING WITH ADDITIONAL SHORTWAVES
FOLLOWING CLOSE BEHIND THAT WILL ENHANCE PRECIPITATION AMOUNTS. AS
A RESULT, THE PROBABILITY OF PRECIPITATION AND QPF HAVE BEEN
INCREASED. PRECIPITATION LOOKS TO BE VERY LIGHT IN LAKE AND MODOC
COUNTIES BUT LIGHT TO MODERATE ELSEWHERE. THE SNOW LEVEL NEAR 7000
FEET IS FORECAST TO FALL TO 3500 TO 4000 FEET ON THE WEST SIDE AND
IN THE CASCADES AND AROUND 5000 FEET ON THE EAST SIDE. THUS, THOSE
DRIVING OVER THE CASCADE, SISKIYOU, AND EAST SIDE PASSES LATE
MONDAY NIGHT SHOULD BE PREPARED FOR A LIGHT ACCUMULATION OF SNOW,
UP TO A COUPLE OF INCHES.

THE COLD UPPER TROUGH WILL SWING INLAND ON TUESDAY WITH ISOLATED
TO SCATTERED COVERAGE OF LIGHT SHOWERS ACROSS OUR AREA BUT ALSO A
SLIGHT CHANCE OF THUNDERSTORMS...NEAR THE COOS COAST IN THE
MORNING THEN SHIFTING ACROSS THE CRATER LAKE AREA TO NEARLY ALL OF
THE EAST SIDE IN THE AFTERNOON.

A SECOND, COLDER LOBE OF THE UPPER LOW WILL BE OFFSHORE FROM
WASHINGTON ON TUESDAY THEN MOVE INTO WASHINGTON WITH A SURFACE
TROUGH TUESDAY NIGHT. THIS TROUGH WILL EXTEND SOUTH AND REACH THE
SOUTHERN OREGON COAST LATE TUESDAY EVENING. THE RESULT FOR TUESDAY
NIGHT WILL BE A MOIST ONSHORE FLOW WITH SHOWERS FOCUSED IN
WESTERN OREGON...ESPECIALLY WEST AND NORTH OF JACKSON COUNTY.

A WARM FRONT WILL FOLLOW ON WEDNESDAY. SNOW LEVELS WERE RAISED
SLIGHTLY AND COULD BE RAISED FURTHER DEPENDING UPON HOW QUICKLY
THE FRONT WILL MOVE INLAND. THIS FRONT WILL ENHANCE RAINFALL RATES
IN SOUTHWEST OREGON...STILL MAINLY WEST AND NORTH OF JACKSON
COUNTY. BUT, THERE WILL BE A SLIGHT CHANCE TO CHANCE OF LIGHT
SHOWERS OVER THE REMAINDER OF THE AREA. THE ASSOCIATED COLD FRONT
WILL FOLLOW AND REACH THE COAST LATE WEDNESDAY NIGHT. CONTINUING
THE SAME THEME, THIS FRONT WILL BE SLOW-MOVING WITH MOST OF THE
RAIN WEST AND NORTH OF JACKSON COUNTY.


.LONG TERM...THURSDAY THROUGH SUNDAY.
IT LOOKS LIKE THE ACTIVE SPRING WEATHER PATTERN WILL BECOME
ANOTHER NOTCH MORE ACTIVE. THIS IS GOOD NEWS BECAUSE SOME AREAS
COULD DELAY USING IRRIGATION. HOWEVER...THESE WEATHER SYSTEMS WILL
DO LITTLE TO ALLEVIATE THE LONG TERM DROUGHT CONDITIONS OVER THE
REGION. TIMING THESE WEATHER SYSTEMS IN THE LONG TERM WILL BE
DIFFICULT AS THE COMPUTER MODELS OFTEN HAVE THEIR LARGEST ERRORS
IN THE SPRING SEASON DURING AN ACTIVE PATTERN.

THERE MAY BE A SIGNIFICANT COLD FRONT ON THURSDAY. THIS COULD BE
A WET AND BREEZY SYSTEM WITH A DEEP LOW DEVELOPING OFF THE
WASHINGTON COAST. THIS COLD FRONT WILL USHER IN COOLER AIR WITH
LOWER SNOW LEVELS BY FRIDAY MORNING. EXPECT AN UNSTABLE AIR MASS
ON FRIDAY AFTERNOON WITH SHOWERS REDEVELOPING. THERE COULD BE A
BRIEF BREAK IN THE WEATHER FRIDAY NIGHT INTO SATURDAY BEFORE
ANOTHER WARM FRONT FOLLOWED BY A COLD FRONT REACHES THE AREA
SATURDAY NIGHT AND SUNDAY. BUT THIS IS WHEN THE MODELS REALLY BEGIN
TO DEPART IN THEIR SOLUTIONS. AT THIS POINT THE BEST CHANCE FOR
FROSTY CONDITIONS IN THE INLAND VALLEYS COULD BE SATURDAY MORNING.
SANDLER


&&

.AVIATION...BASED ON 20/18Z TAF CYCLE...
HIGH CLOUDS WILL SPREAD ACROSS THE REGION THIS AFTERNOON AND
TONIGHT. THE HIGHER CLOUD COVER WILL KEEP LOW CLOUD AND FOG
DEVELOPMENT TO A MINIMUM ON MONDAY MORNING. MAINLY VFR CONDITIONS
EXPECTED INTO MONDAY MORNING.
-SANDLER


&&

.MARINE...WEST SWELLS WILL CONTINUE TO GRADUALLY SUBSIDE THROUGH
TONIGHT AND EVENTUALLY STABLIZE AT AROUND 10 FEET ON MONDAY. VARIOUS
SWELL TRAINS WILL MOVE THROUGH KEEPING SEAS AT AROUND 10 FEET
THROUGH WEDNESDAY. A WEAK FRONT WILL MOVE THROUGH MONDAY WITH A
PERIOD OF LIGHT NORTH WINDS (15-20 KT) BEHIND IT INTO MONDAY
EVENING. A STRONGER FRONT IS EXPECTED WEDNESDAY AND THIS WILL BRING
SOLID SMALL CRAFT ADVISORY WINDS TO ALL WATERS WITH GALES POSSIBLE
OVER THE WATERS NORTH OF CAPE BLANCO. THE MODELS ARE STARTING TO
SHOW SOME CONSISTENCY WITH THIS SOLUTION, SO WILL PROBABLY NEED TO
HOIST A GALE WATCH OVER THE NEXT COUPLE OF MODEL CYCLES IF THIS
TREND HOLDS. THURSDAY AND FRIDAY LOOK QUIET, BUT ANOTHER MODERATELY
STRONG FRONT IS POSSIBLE NEXT WEEKEND AND PERHAPS ANOTHER EARLY NEXT
WEEK. -WRIGHT


&&

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

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
     5 PM PDT WEDNESDAY FOR PZZ350-356-370-376.

$$

DW/RES/TRW





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