Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 281620
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
920 AM PDT TUE JUL 28 2015

.DISCUSSION...A WARMING AND DRYING TREND WILL CONTINUE WITH THE
THERMAL TROUGH ANCHORED ALONG THE COAST UP TO AROUND CAPE BLANCO.
HIGHS WILL BE IN THE LOWER TO MID 90S AT BROOKINGS THROUGH
WEDNESDAY WITH A VERY WARM NIGHT SANDWICHED IN BETWEEN. WESTERN
KLAMATH RIVER VALLEY AND THE ILLINOIS VALLEY ARE SOME OF THE AREAS
THAT COULD SEE HIGHS AROUND 100 TODAY.

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.

CURRENT FORECAST COVERS THIS TREND SO WE WILL NOT MAKE ANY CHANGES
THIS MORNING.

MEDIUM RANGE CONCERN SHIFTS TO THUNDERSTORM POTENTIAL AS MOISTURE
CREEPS NORTH INTO SISKIYOU COUNTY AROUND FRIDAY. A QUICK LOOK AT
THE MOISTURE FIELD SHOWS LATE NEXT WEEKEND THROUGH EARLY PART OF
NEXT WEEK AS BEING MORE FAVORABLE. WE WILL ADDRESS THIS CONCERN IN
THE AFTERNOON DISCUSSION. /FB

&&

.AVIATION...FOR THE 28/12Z TAF CYCLE...VFR CONDITIONS WILL PERSIST
ACROSS THE FORECAST AREA THROUGH TUESDAY NIGHT. GUSTY NORTHEAST TO
EAST WINDS OVER THE COASTAL MOUNTAIN RANGES WILL RESULT IN LOW LEVEL
TURBULENCE...GREATEST BETWEEN MIDNIGHT AND NOON PDT. GUSTY AFTERNOON
AND EVENING NORTH WINDS ALONG AND NEAR THE COAST TUESDAY AFTERNOON
AND EVENING.

&&

.MARINE...UPDATED 200 AM 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 INTO THE WEEKEND.

&&

.FIRE WEATHER...UPDATED 200 AM PDT TUESDAY 28 JULY 2015...A STRONG
SURFACE THERMAL TROUGH NEAR THE COAST WILL PERSIST THROUGH WEDNESDAY
MORNING. THIS PATTERN WILL BRING GUSTY EASTERLY WINDS TO THE UPPER
SLOPES AND RIDGES ALONG WITH POOR TO MODERATE RH RECOVERIES...
ESPECIALLY OVER THE RIDGES FROM THE CASCADES WESTWARD. THROUGH
TUESDAY MORNING...CONFIDENCE IS MODERATE TO HIGH THAT THIS PROBLEM
WILL AFFECT MAINLY CURRY COUNTY AND THE SOUTH COASTAL RANGE (ZONES
618/619/620) AND THE UPPER SLOPES OF WESTERN SISKIYOU COUNTY (ZONE
280) FROM THE MARBLE MOUNTAIN WESTWARD.

STRONG NORTH WINDS COULD SURFACE INTO THE ILLINOIS VALLEY DURING THE
DAY ON TUESDAY. THE RED FLAG WARNING WILL GO THROUGH THE DAY TO
ACCOUNT FOR THIS PHENOMENON.

OFFSHORE FLOW WILL RETURN TUESDAY NIGHT WITH THE DRY AIR MASS
EXPANDING FARTHER INLAND. FOR TUESDAY NIGHT THROUGH WEDNESDAY THE
RED FLAG WARNING AREA WILL EXPAND TO COVER JACKSON COUNTY AND THE
CASCADES AND SISKIYOUS. TUESDAY NIGHT COULD SEE GUSTY WINDS
AFFECTING THE FOOTHILLS OF THE CASCADES AND THE SISKIYOUS. 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.

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. THE ONSET HAS BEEN PUSHED BACK A DAY AS MOISTURE APPEARS
TOO HIGH BASED ON THURSDAY. LONG RANGE GUIDANCE SHOWS INCREASING
MOISTURE IN THE 700 TO 500 MB LAYER...AND THUNDERSTORMS CHANCES WILL
INCREASE INTO THE WEEKEND.

&&
.PREV DISCUSSION... /ISSUED 243 AM PDT TUE JUL 28 2015/

DISCUSSION...THE UPPER TROUGH THAT BROUGHT BELOW NORMAL, BUT
PLEASANT TEMPERATURES FOR THIS TIME OF THE YEAR IS NOW EXITING THE
REGION. A STRONG RIDGE WILL BUILD IN ITS PLACE TODAY WITH
TEMPERATURES BETWEEN 10-15 DEGREES HIGHER COMPARED TO YESTERDAY. AT
THE SURFACE, A THERMAL TROUGH HAS DEVELOPED AND THIS HAS RESULTED IN
INCREASING OFFSHORE FLOW ALONG THE COASTAL MOUNTAINS, WESTERN
SISKIYOU COUNTY AND COAST SOUTH OF CAPE BLANCO. THIS IS EVIDENT WITH
BROOKINGS REPORTING A TEMPERATURE OF 76 DEGREES WITH GUSTY NORTHWEST
WINDS AND ALSO GUSTY WINDS OVER THE RIDGES. THE CHETCO EFFECT WILL
CONTINUE TODAY AND BROOKINGS WILL EASILY GET INTO THE MID 90S AND
POSSIBLY THE UPPER 90S. SKIES WILL REMAIN CLEAR FOR THE ENTIRE
FORECAST AREA.

STRONG UPPER RIDGING BUILDS INTO THE AREA WEDNESDAY AND WILL PERSIST
INTO NEXT WEEKEND AND TEMPERATURES WILL EASILY GET INTO THE TRIPLE
DIGITS IN THE WESTSIDE VALLEYS WEDNESDAY INTO NEXT WEEKEND. THE
THERMAL TROUGH WILL SHIFT INLAND IN THE AFTERNOONS FROM WEDNESDAY
THROUGH FRIDAY AND THESE WILL BE THE DAYS WHERE WE EXPECT
TEMPERATURES TO PEAK OUT.

CONDITIONS WILL REMAIN DRY THROUGH THURSDAY, THEN THE MODELS SHOW
INCREASING MONSOONAL MOISTURE MOVING UP FROM THE SOUTH INTO THE
CENTRAL CAL THURSDAY AFTERNOON, THEN MOVING INTO OUR AREA FRIDAY.
BOTH THE GFS AND EC SHOW SHORTWAVES MOVING INTO THE AREA FRIDAY
AFTERNOON. THEREFORE THE COMBINATION OF INCREASING MOISTURE AND
TRIGGER SHOULD BE ENOUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF
THUNDERSTORMS. BASED ON CURRENT DATA, THE BEST CHANCE FOR
THUNDERSTORMS COULD END UP BEING ON FRIDAY. IT`S STILL A WAYS OUT
THERE AND THE DETAILS ON THIS COULD CHANGE, SO STAY TUNED FOR THE
LATEST UPDATES.

CONFIDENCE OF THUNDERSTORMS IS LOW FOR NEXT WEEKEND. MID LEVEL
MOISTURE IS PRESENT, BUT THE GFS OR EC DON`T SHOW MUCH IF ANY
TRIGGER AND THEY DIFFERENT SLIGHTLY WITH THE MID LEVEL FLOW. THE EC
SHOWS A MORE SOUTHWEST FLOW WHICH WOULD KEEP THE BEST CHANCE FOR
STORMS EAST OF THE CASCADES, IF THEY WERE TO DEVELOP AT ALL.
-PETRUCELLI

AVIATION...FOR THE 28/12Z TAF CYCLE...VFR CONDITIONS WILL PERSIST
ACROSS THE FORECAST AREA THROUGH TUESDAY NIGHT. GUSTY NORTHEAST TO
EAST WINDS OVER THE COASTAL MOUNTAIN RANGES WILL RESULT IN LOW LEVEL
TURBULENCE...GREATEST BETWEEN MIDNIGHT AND NOON PDT. GUSTY AFTERNOON
AND EVENING NORTH WINDS ALONG AND NEAR THE COAST TUESDAY AFTERNOON
AND EVENING.

MARINE...UPDATED 200 AM 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 INTO THE WEEKEND.

FIRE WEATHER...UPDATED 200 AM PDT TUESDAY 28 JULY 2015...A STRONG
SURFACE THERMAL TROUGH NEAR THE COAST WILL PERSIST THROUGH WEDNESDAY
MORNING. THIS PATTERN WILL BRING GUSTY EASTERLY WINDS TO THE UPPER
SLOPES AND RIDGES ALONG WITH POOR TO MODERATE RH RECOVERIES...
ESPECIALLY OVER THE RIDGES FROM THE CASCADES WESTWARD. THROUGH
TUESDAY MORNING...CONFIDENCE IS MODERATE TO HIGH THAT THIS PROBLEM
WILL AFFECT MAINLY CURRY COUNTY AND THE SOUTH COASTAL RANGE (ZONES
618/619/620) AND THE UPPER SLOPES OF WESTERN SISKIYOU COUNTY (ZONE
280) FROM THE MARBLE MOUNTAIN WESTWARD.

STRONG NORTH WINDS COULD SURFACE INTO THE ILLINOIS VALLEY DURING THE
DAY ON TUESDAY. THE RED FLAG WARNING WILL GO THROUGH THE DAY TO
ACCOUNT FOR THIS PHENOMENON.

OFFSHORE FLOW WILL RETURN TUESDAY NIGHT WITH THE DRY AIR MASS
EXPANDING FARTHER INLAND. FOR TUESDAY NIGHT THROUGH WEDNESDAY THE
RED FLAG WARNING AREA WILL EXPAND TO COVER JACKSON COUNTY AND THE
CASCADES AND SISKIYOUS. TUESDAY NIGHT COULD SEE GUSTY WINDS
AFFECTING THE FOOTHILLS OF THE CASCADES AND THE SISKIYOUS. 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.

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. THE ONSET HAS BEEN PUSHED BACK A DAY AS MOISTURE APPEARS
TOO HIGH BASED ON THURSDAY. LONG RANGE GUIDANCE SHOWS INCREASING
MOISTURE IN THE 700 TO 500 MB LAYER...AND THUNDERSTORMS CHANCES WILL
INCREASE INTO THE WEEKEND.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 AM 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 11 PM PDT SATURDAY FOR
     ORZ026.
     HEAT ADVISORY FROM 1 PM WEDNESDAY TO 11 PM PDT SATURDAY FOR
     ORZ024.

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

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT THURSDAY FOR
     PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THURSDAY
     FOR PZZ350-356-370-376.
     HAZARDOUS SEAS WARNING UNTIL 8 AM PDT WEDNESDAY FOR
     PZZ356-370-376.
     GALE WARNING UNTIL 8 AM PDT WEDNESDAY FOR PZZ376.

$$

FJB/FJB/NSK



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