Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 290058
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
558 PM PDT TUE JUL 28 2015

.UPDATED FOR AVIATION...

.PREV DISCUSSION... /ISSUED 241 PM PDT TUE JUL 28 2015/

SHORT TERM...A WARMING AND DRYING TREND WILL CONTINUE WITH THE
THERMAL TROUGH ANCHORED ALONG THE COAST UP TO AROUND CAPE BLANCO.
EXPECT A WARM NIGHT FOR THE BROOKINGS AREA WITH WEDNESDAY`S HIGH
IN THE MID 90S AT BROOKINGS THROUGH WEDNESDAY. THE THERMAL TROUGH
IS EXPECTED TO MOVE INLAND WEDNESDAY AND THIS WILL USHER IN
SEVERAL DAYS OF VERY WARM TEMPERATURES INLAND WITH HIGHS IN THE
105-110 RANGE FOR VALLEYS WEST OF THE CASCADES. MID LEVEL MOISTURE
IN THE 700-500 MB LAYER WILL SPREAD NORTH INTO SOUTHERN OREGON AS
EARLY AS THURSDAY AND WE SAY MORE CUMULUS CLOUDS ON THURSDAY. WE
HAVE INTRODUCED A CHANCE OF SHOWERS AND THUNDERSTORMS ON FRIDAY AS
MORE MOISTURE SPREADS INTO OUR AREA BUT ANY STORM THAT FORMS ON
FRIDAY SHOULD BE CONFINED TO THE MOUNTAINS. /FB

LONG TERM...(SATURDAY THROUGH TUESDAY). DURING THIS PERIOD THE
UPPER LEVEL RIDGE WILL BE ENTRENCHED ALONG THE WEST COAST.
SOUTHERLY FLOW WILL BRING MORE MID LEVEL MOISTURE INTO THE AREA.
THIS WILL INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS. BOTH
THE GFS AND THE ECMWF ARE CONSISTENT WITH THIS TREND. HOW STRONG
THESE STORMS ARE DEPEND ON THE STRENGTH OF ANY SHORT WAVE
DISTURBANCE THAT WILL MOVE INTO OUR AREA AND THIS IS SOMETHING
THAT MODELS ARE NOT VERY GOOD AT PINPOINTING THIS FAR OUT. AS A
RESULT WE HAVE BROADBRUSHED THE UNSTABLE AREA FOR NOW. TEMPERATURES
WILL CONTINUE TO BE WARM BUT MAY BE MODERATED A BIT DUE TO
INCREASED CLOUD COVER. /FB

AVIATION...FOR THE 28/18Z TAF CYCLE...VFR CONDITIONS WILL PERSIST
ACROSS THE FORECAST AREA THROUGH TONIGHT. ONLY FORECAST CHALLENGE
WILL BE WINDS FOR THIS TAF CYCLE...  LOOK FOR WINDS TO WEAKEN
TONIGHT AND THEN STRENGTHEN NEAR THE COAST WITH GUSTS UP TO 30 KTS
DURING WEDNESDAY AFTERNOON. /SMITH

MARINE...UPDATED 230 PM PDT TUESDAY 28 JULY 2015...A STRONG THERMAL
TROUGH NEAR THE COAST WILL WEAKEN THROUGH FRIDAY...WHEN IT WILL MOVE
INLAND. STRONG NORTH WINDS AND HEAVY WIND-DRIVEN SEAS WILL PEAK THIS
AFTERNOON AND EVENING...THEN GRADUALLY SUBSIDE THROUGH LATE IN THE
WEEK.  REDUCED WINDS SLIGHTLY FOR THIS AFTERNOON AND EVENING AS BUOY
15 WAS REPORTING WEAKER WINDS.  STILL EXPECTING GALES AND HAZARDOUS
SEAS FOR THE OUTER WATERS SOUTH OF CAPE BLANCO UNTIL WEDNESDAY
MORNING. /SMITH

FIRE WEATHER...UPDATED 100 PM PDT TUESDAY 28 JULY 2015...A STRONG
SURFACE THERMAL TROUGH NEAR THE COAST WILL PERSIST THROUGH WEDNESDAY
MORNING. STRONG NORTH WINDS ARE SURFACING IN THE ILLINOIS VALLEY
THIS AFTERNOON...AND A RED FLAG WARNING CONTINUES FOR THAT AREA.
TONIGHT THROUGH WEDNESDAY THE RED FLAG WARNING AREA IS EXPANDING TO
COVER JACKSON COUNTY AND THE CASCADES AND SISKIYOUS. FORECAST TRENDS
GENERALLY SHOW 10 TO 20 PERCENT LOWER HUMIDITIES WEDNESDAY MORNING
IN THE RED FLAG WARNING AREAS COMPARED TO TUESDAY MORNING. HIGH
RESOLUTION MODELS SHOW VERY DRY AIR INTRUDING INTO THE UMPQUA
PORTION OF THE CASCADES AS WELL...ALTHOUGH EASTERLY WINDS THERE ARE
NOT AS STRONG AS WHAT IS EXPECTED ACROSS THE GAPS THROUGH THE
CASCADES. WE HAVE MAINTAINED THE RED FLAG WARNING FOR EXTREME
SOUTHWESTERN OREGON THROUGH 2PM WEDNESDAY DUE TO EXPECTED LINGERING
GUSTY WINDS AND VERY LOW HUMIDITIES IN THAT AREA...BEFORE WINDS
WEAKEN LATER IN THE AFTERNOON.

VERY HOT CONDITIONS WILL DEVELOP INLAND WEDNESDAY...AND THE HOT
TEMPERATURES WILL PERSIST INTO THE WEEKEND. ALSO EXPECT WARMER THAN
NORMAL TEMPERATURES ALONG THE COAST TUESDAY AND WEDNESDAY.

THUNDERSTORMS MAY DEVELOP OVER THE HIGHER TERRAIN AS EARLY AS FRIDAY
AFTERNOON. MODELS SHOW SOME TYPE OF IMPULSE MOVING SOUTH TO NORTH
OVER THE FORECAST AREA LATE FRIDAY...PROVIDING AN ENHANCE CHANCE FOR
THUNDERSTORMS. LONG RANGE GUIDANCE SHOWS INCREASING MOISTURE IN THE
700 TO 500 MB LAYER...AND THUNDERSTORMS CHANCES WILL CONTINUE INTO
THE WEEKEND. NOTE THAT ANY LIGHTNING THAT OCCURS LATE THIS WEEK OR
THIS WEEKEND WILL BE ACCOMPANYING OR FOLLOWING AN EXTREMELY HOT AND
DRY WEATHER PATTERN...AND THUS COULD CAUSE SIGNIFICANT IMPACTS.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 2 PM PDT WEDNESDAY FOR ORZ618>620.
     HEAT ADVISORY UNTIL 1 PM PDT THURSDAY FOR ORZ022.
     HEAT ADVISORY FROM 1 PM WEDNESDAY TO 11 PM PDT SATURDAY FOR
     ORZ023.
     RED FLAG WARNING FROM 11 PM THIS EVENING TO 11 AM PDT WEDNESDAY
     FOR ORZ617.
     RED FLAG WARNING FROM 11 PM THIS EVENING TO 11 AM PDT WEDNESDAY
     FOR ORZ621>623.
     HEAT ADVISORY FROM 1 PM WEDNESDAY TO 1 PM PDT SATURDAY FOR
     ORZ024-026.

CA...RED FLAG WARNING UNTIL 11 AM PDT WEDNESDAY FOR CAZ280.
     HEAT ADVISORY FROM 1 PM WEDNESDAY TO 1 PM PDT SATURDAY FOR
     CAZ080-081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT WEDNESDAY FOR
     PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT
     WEDNESDAY FOR PZZ350-356-370-376.
     GALE WARNING UNTIL 8 AM PDT WEDNESDAY FOR PZZ376.
     HAZARDOUS SEAS WARNING UNTIL 11 PM PDT WEDNESDAY FOR PZZ376.

$$

FJB/NSK/CZS



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