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 210351
AFDMFR

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

.DISCUSSION...TRANQUIL WEATHER WILL CONTINUE OVERNIGHT. MOST AREAS
WILL REMAIN DRY MONDAY, BUT THE NEXT COLD FRONT IS SET TO MOVE
ONSHORE MONDAY EVENING. SOME SHOWERS MAY PRECEDE THE FRONT INLAND
DURING THE AFTERNOON, MAINLY OVER THE MOUNTAINS, BUT THESE SHOULD
BE MORE THE EXCEPTION THAN THE RULE. SOUTH TO SOUTHWEST WINDS WILL
PICK UP OVER THE EAST SIDE MONDAY AHEAD OF THE FRONT AND WILL BE
QUITE GUSTY DURING THE AFTERNOON.

RAIN ARRIVES AT THE COAST LATE MONDAY AFTERNOON THEN SPREADS
INLAND MONDAY NIGHT. A POTENT SHORT WAVE WILL ROUND THE BASE OF
THE TROUGH AND AN AREA OF STRONG LIFT WILL DEVELOP OVER THE WEST
SIDE OVERNIGHT. THIS SHOULD ENHANCE PRECIPITATION FOR SEVERAL
HOURS OVER THE UMPQUA/ROGUE/LOWER KLAMATH VALLEYS EASTWARD TO THE
CASCADES OVERNIGHT. THIS IS THE KIND OF SITUATION THAT CAN
ACTUALLY PRODUCE MORE RAIN HERE IN MEDFORD THAN AT PORTIONS OF THE
COAST (NORTH OF CAPE BLANCO). FOR THIS REASON, HAVE INCREASED POPS
AND QPF AMOUNTS IN THE VALLEYS WEST OF THE CASCADES FOR THIS TIME
FRAME. LOOKS LIKE MUCH OF THE AREA WILL HAVE 0.25-0.50 OF AN INCH
OF RAIN WITH 0.50-1.00 INCH IN SOME OF THE FAVORED TERRAIN AREAS
IN CURRY, JOSEPHINE, WESTERN SISKIYOU COUNTIES AND ALSO THE
CASCADES/FOOTHILLS. THE FRONT MOVES EAST OF THE CASCADES BY
TUESDAY MORNING WITH SOME LEFTOVER SHOWERS. PRECIPITATION AMOUNTS
OVER THE EAST SIDE WILL BE LOWER...FROM 0.10-0.25 OF AN INCH IN
GENERAL, BUT LESS THAN 0.10 OF AN INCH IN THE DESERTS EAST OF
LAKEVIEW. SNOW LEVELS LOWER DOWN TO NEAR OR JUST BELOW THE MAJOR
PASSES TUESDAY MORNING. EVEN THOUGH WE`RE NOT ANTICIPATING MUCH
SNOW ACCUMULATION, THOSE PLANNING TO TRAVEL OVER THE HIGHER PASSES
TUESDAY MORNING SHOULD BE PREPARED FOR SLIPPERY ROADS. SPILDE

&&

.AVIATION...BASED ON 21/00Z TAF CYCLE...VFR CONDITIONS EXPECTED
OVERNIGHT EXCEPT IN THE UMPQUA AND COOS COAST (INCLUDING KRBG AND
KOTH) WHERE ANOTHER ROUND OF RADIATIONAL STRATUS/FOG WITH
IFR/LIFR CIGS AND VIS IS EXPECTED LATE TONIGHT INTO MONDAY MORNING.
STRATUS WILL LIFT LATE MORNING, THEN A FRONT WILL BRING SOME RAIN TO
THE COAST MID AFTERNOON MONDAY WHICH WILL SPREAD INLAND THROUGH THE
EVENING. THIS WILL PRODUCE MVFR CIGS AT MOST WEST SIDE LOCATIONS
LATE TOMORROW. EAST SIDE AND NORCAL LOCATIONS WILL LIKELY REMAIN VFR
THROUGH MONDAY. -WRIGHT

&&

.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

&&

.PREV DISCUSSION... /ISSUED 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.

$$

MAS/DW/RES/TRW






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