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 260551
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1051 PM PDT SAT APR 25 2015

.UPDATE...
UPDATES TO THE FORECAST THIS EVENING WERE TO REMOVE THE THREAT OF
THUNDERSTORMS OVER PORTIONS OF THE EAST SIDE, TO ADD THE
POSSIBILITY OF RAIN TO THE FORECAST FOR THE COASTAL WATERS AS WELL
AS PORTIONS OF THE COAST NORTH OF CAPE BLANCO FOR LATE TONIGHT
THROUGH SUNDAY, AND TO FINE TUNE THE WIND FORECAST IN THE COASTAL
WATERS THROUGH MIDDAY SUNDAY. BTL

&&

.DISCUSSION...
THE UPPER LEVEL COLD CORE THAT HELPED FORM SUBSTANTIAL SHOWERS
ACROSS PORTIONS OF THE FORECAST AREA TODAY HAS MOVED EAST OF LAKE
COUNTY THIS EVENING, ALONG WITH ITS ASSOCIATED 140 KNOT
NORTHWESTERLY JET MAXIMUM. THUS, THE THREAT FOR THUNDER ACROSS
PORTIONS OF THE EAST SIDE IS OVER.

A 700MB TROUGH LAGGING BEHIND THE UPPER LEVEL FEATURES IS BRINGING
ONE LAST ROUND OF SHOWERS TO THE WEST SIDE THIS EVENING. OVERNIGHT
THROUGH SUNDAY A WARM FRONT MOVING THROUGH THE AREA WILL BRING A
MIX OF CLOUDS AND SUN TO THE AREA, WITH CLOUDS MOST NUMEROUS FROM
THE COASTAL MOUNTAINS WESTWARD. MODELS HAVE TRENDED TOWARD A
LITTLE MORE OF A THREAT OF SOME LIGHT RAIN OVER MUCH OF THE
COASTAL WATERS LATE TONIGHT THROUGH SUNDAY, AS WELL.

THIS WARM FRONT WILL YIELD A RAPID, SUBSTANTIAL, BUT BRIEF WARM-UP
ACROSS THE AREA ON MONDAY WITH HIGHS ABOUT 20 DEGREES HIGHER THAN
WAS OBSERVED TODAY.

&&

.CLIMATE...
BEGINNING WITH THE COLD FRONT EXPECTED ON TUESDAY, OPERATIONAL
NUMERICAL MODELS GENERALLY INDICATE TEMPERATURES AGAIN RETURNING
CLOSER TO NORMAL FOR THE REST OF NEXT WEEK INTO NEXT WEEKEND.
TRENDS IN CLIMATE ENSEMBLE MODELS HAVE ALSO BEEN INDICATING A
PERIOD OF COOLER THAN NORMAL CONDITIONS (THOUGH NOT SIGNIFICANTLY
SO) DURING ABOUT THE FIRST WEEK IN MAY. WHILE THIS IS GENERALLY
GOOD NEWS FOR SLOWING DRYING AND THE ONSET OF FIRE SEASON, IT
APPEARS THAT WE`LL RUN THE RISK OF SOME COLD NIGHTS DURING THIS
TIME PERIOD WHICH COULD BE OF CONCERN FOR THOSE TRYING TO GET AN
EARLY START ON SUMMER GARDENS. WE`LL ALSO NEED TO BE ON THE
LOOKOUT FOR DRY COLD FRONTS WITH BREEZY CONDITIONS DURING THIS
TIME PERIOD. BTL

&&

.AVIATION...FOR THE 26/06Z TAF CYCLE... VFR CONDITIONS ARE EXPECTED
TO PREVAIL TONIGHT AS TRANSIENT HIGH PRESSURE MOVES FROM THE COASTAL
WATERS INLAND. A WARM FRONT MOVING THROUGH ON SUNDAY WILL RESULT IN
MVFR CONDITIONS OVER THE COASTAL WATERS AS WELL AS ALONG PORTIONS OF
THE COAST, PRIMARILY NORTH OF CAPE BLANCO FROM MID AFTERNOON THROUGH
THE EVENING. EXPECT PARTIAL TERRAIN OBSCURATIONS FROM THE OREGON
CASCADES AND LOWER KLAMATH RIVER VALLEY WESTWARD DURING THE DAY ON
SUNDAY. BTL

&&

.MARINE...UPDATED 900 PM PDT SATURDAY, APR 25, 2015... LIGHT
NORTHWEST WINDS AND SEAS ARE EXPECTED TONIGHT AS HIGH PRESSURE
TRANSITIONS THROUGH THE COASTAL WATERS. A WEAK WARM FRONT WILL MOVE
THROUGH ON SUNDAY SWITCHING WINDS TO SOUTHERLY AND BRINGING THE
POSSIBILITY OF A LITTLE RAIN. GENERALLY LIGHT WINDS AND SEAS ARE
EXPECTED SUNDAY NIGHT THROUGH MONDAY AS A BRIEF AND WEAK THERMAL
TROUGH EXPANDS NORTHWARD FROM CALIFORNIA. SOUTH WINDS ARE LIKELY TO
DEVELOP AGAIN ON TUESDAY AHEAD OF THE NEXT FAIRLY WEAK COLD FRONT.
WEST-NORTHWEST SWELL WILL BUILD ON TUESDAY AND WILL APPROACH 10 FEET
TUESDAY AFTERNOON INTO THURSDAY. STRONGER NORTHERLIES ARE EXPECTED
BEHIND THIS FRONT. BTL

&&

.PREV DISCUSSION... /ISSUED 105 PM PDT SAT APR 25 2015/

DISCUSSION...25/12Z NAM/GFS IN.

AN UPPER LEVEL TROUGH REMAINS ALIGNED ALONG THE PACIFIC NORTHWEST
COAST...AND SHORT WAVES ROUNDING THE TROUGH ARE SUPPORTING LIGHT
SHOWER ACTIVITY. ONE WAVE IS COMING IN NOW...AND SHOWERS ARE
INCREASING IN COVERAGE AND INTENSITY. THERE MAY EVEN BE AN
ISOLATED THUNDERSTORM OR TWO EAST OF THE CASCADES THIS AFTERNOON
AND EVENING...BUT THAT APPEARS TO BE A MARGINAL FORECAST AT THIS
TIME.

ONCE THAT WAVE MOVES OUT THIS EVENING...A STRONG LONG WAVE RIDGE
WILL BUILD INTO THE WEST COAST. AFTER A WEAK WARM FRONT MOVES
NORTH SUNDAY...THERE WILL BE A STRETCH OF DRY AND WARMER WEATHER.

THE THERMAL TROUGH WILL SWING INLAND OVER THE WEST SIDE
MONDAY...AND THAT WILL BE THE HOTTEST DAY FOR THAT AREA WITH HIGH
TEMPERATURES 15 TO 20 DEGREES ABOVE NORMAL. THE TROUGH WILL MOVE
TO THE EAST SIDE TUESDAY AND THAT WILL BE THE HOTTEST DAY THERE
WITH HIGH TEMPERATURES 10 TO 15 DEGREES ABOVE NORMAL.

THE RIDGE WILL BREAK TO THE EAST OF THE AREA MONDAY EVENING. THE
NEXT UPSTREAM SHORT WAVE WILL BE WEAK AND WILL MOVE ONSHORE
TUESDAY MORNING. IT WILL PUSH A WEAK FRONT ONSHORE TUESDAY
MORNING...WHICH MAY BRING SOME LIGHT RAIN TO THE COAST AND
ISOLATED SHOWER ACTIVITY FARTHER INLAND. THE 25/12Z GFS SOLUTION
MOVED THE TIMING UP RATHER THAN DELAYING IT AS HAS BEEN THE TREND
FOR THE LAST SEVERAL RUNS. THOUGHT THIS TREND WOULD CONTINUE AND
IT MAY YET...BUT FOR NOW IT LINES UP WELL WITH THE EC SOLUTION.

&&

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

CA...NONE.

PACIFIC COASTAL WATERS...NONE.

$$

BTL/JRS/BPN



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