Wildfire in Oregon, June 27 to 30, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
248 PM PDT SAT JUN 27 2015

.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...A STRONG UPPER LEVEL
RIDGE WILL REMAIN OVER THE REGION THROUGH THE REMAINDER OF THE
WEEKEND. THUS THE AIR MASS OVER THE REGION WILL REMAIN HOT THROUGH
SUNDAY NIGHT. OVERNIGHT LOWS WILL GENERALLY RUN FROM THE MID 60S TO
MID 70S AT LOWER ELEVATIONS, AND FROM THE UPPER 50S THROUGH THE 60S
AT HIGH ELEVATIONS. HIGH TEMPS SUNDAY AFTERNOON WILL AGAIN RUN
BETWEEN 95 AND 110 DEGREES, ESPECIALLY IN THE COLUMBIA BASIN, GRANDE
RONDE VALLEY AND THE VALLEYS OF WALLOWA COUNTY. THEREFORE WILL
CONTINUE THE CURRENT HEAT ADVISORIES.

SUB-TROPICAL MOISTURE WILL CONTINUE TO STREAM INTO THE REGION
TONIGHT AND SUNDAY. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL AFFECT MANY PORTIONS OF THE AREA THIS EVENING. A FEW OF THE
THUNDERSTORMS MAY PRODUCE STRONG WIND GUSTS. OVERNIGHT, A FEW
SHOWERS MAY LINGER OVER THE COLUMBIA BASIN, WHILE STRAY
THUNDERSTORMS MAY BE POSSIBLE ALONG THE CASCADE EAST SLOPES AND OVER
CENTRAL OREGON. A WEAK UPPER LOW OFF THE CALIFORNIA COAST WILL
APPROACH THE SOUTHWEST OREGON COAST LATE SUNDAY, THEN MOVE INTO THE
PACIFIC NORTHWEST LATE SUNDAY NIGHT AND MONDAY. THIS LOW WILL
INCREASE THE CHANCES OF THUNDERSTORMS AND SHOWERS OVER THE REGION
SUNDAY AFTERNOON AND SUNDAY NIGHT. SHOWERS AND STORMS WILL GRADUALLY
END FROM THE WEST THROUGH THE DAY ON MONDAY. INCREASED ONSHORE FLOW
MONDAY WILL LEAD TO 5 TO 10 DEGREES OF COOLING. 90

.LONG TERM...TUESDAY THROUGH SATURDAY NIGHT...ON TUESDAY AN UPPER
LEVEL DISTURBANCE WILL BE PASSING BY TO THE NORTH OF OUR CWA HELPING
TO INCREASE WEST TO NORTHWEST WINDS ACROSS THE AREA. WINDS WILL BE
SUSTAINED BETWEEN 10-20 MPH WITH HIGHER GUSTS POSSIBLE IN SOME
LOCATIONS TUESDAY AFTERNOON. OTHERWISE THERE MAY BE A FEW MORE
CLOUDS AROUND AND AN ISOLATED SHOWER UP ALONG THE CREST OF THE
WASHINGTON CASCADES. BY WEDNESDAY THIS WEAK DISTURBANCE WILL QUICKLY
RACE EAST OF THE REGION WITH AN UPPER LEVEL RIDGE BUILDING IN BEHIND
IT. OUR CWA WILL REMAIN ALONG THE NORTHEASTERN EDGE OF THIS
EXPANDING UPPER LEVEL RIDGE THROUGH THE END OF THE EXTENDED
PERIOD...WITH MAINLY DRY AND HOT WEATHER EXPECTED THROUGH AT LEAST
SATURDAY. TEMPERATURES "COOL" SLIGHTLY INTO THE MID-90S TO AROUND
100 IN THE LOWER ELEVATIONS FOR TUESDAY AND WEDNESDAY BEFORE AGAIN
RISING UP INTO THE UPPER 90S AND LOWER 100S FOR THURSDAY...FRIDAY
AND THE 4TH OF JULY. TEMPERATURES WILL MAINLY BE IN THE 80S FOR THE
MOUNTAINS THE ENTIRE PERIOD. THESE TEMPERATURES ARE ABOUT 10 TO
NEARLY 20 DEGREES ABOVE THE SEASONAL AVERAGE. 77

&&

.AVIATION...PREVIOUS DISCUSSION...18Z TAFS...VFR CONDITIONS ARE
EXPECTED OVER THE NEXT 24 HOURS. BIGGEST CONCERN FOR TODAY WILL BE
THE POSSIBILITY FOR THUNDERSTORMS NEAR KBDN AND KRDM MAINLY BETWEEN
27/20Z AND 28/02Z...FOR NOW WENT WITH VCTS BUT MAY NEED TO ADD A
TEMPO FOR TSRA IF CONFIDENCE INCREASES IN THIS CONVECTIVE ACTIVITY.
AS THIS ACTIVITY MOVES NORTH IT TENDS TO LOSE THE HIGHER INSTABILITY
AND SHOULD THEREFORE WEAKEN. LEFT VCSH IN THE FORECAST FOR KPDT AND
KDLS AS SOME -SHRA COULD PASS INVOF THESE TERMINALS LATE
AFTERNOON/EARLY EVENING...ALTHOUGH COULD VERY WELL BE ONLY VIRGA
WITH THE DEEP LOW LEVEL DRY AIR PRESENT. FOR ALL OTHER TAF SITES
EXPECT JUST PERIODIC MID TO HIGH LEVEL CLOUDS TO MOVE
THROUGH...MAINLY BETWEEN 12-25KFT AGL. WINDS WILL BE BREEZY THIS
AFTERNOON/EARLY EVENING AT KBDN AND KRDM...OUT OF THE NW AT 10-
20KTS. WINDS COULD SHIFT AND BECOME GUSTY WITH ANY SHOWERS OR
THUNDERSTORMS...ESPECIALLY AT KBDN AND KRDM. NORTHWEST WINDS WILL
ALSO BE BREEZY AT KDLS AFTER 27/21Z...BETWEEN 10-20KTS THROUGH THE
OVERNIGHT AND INTO SUNDAY MORNING. 77

&&

.FIRE WEATHER...RED FLAG WARNINGS ARE IN EFFECT THROUGH SUNDAY
EVENING FOR THE EAST SLOPES OF THE CENTRAL OREGON CASCADES...THE
CENTRAL OREGON MOUNTAINS...AND THE SOUTHERN BLUES.  THE FIRE WEATHER
WATCH FOR THE EAST SLOPES OF THE SOUTHERN WASHINGTON AND NORTHERN
OREGON CASCADES WILL BE UPGRADED TO A WARNING FOR THUNDERSTORMS ON
SUNDAY. IN THESE AREAS...SOME THUNDERSTORMS WILL BRING FREQUENT
LIGHTNING...AND A FEW MAY ALSO BRING GUSTY OUTFLOW WINDS.
UNFORTUNATELY...LIGHTNING CAUSED FIRES ARE LIKELY AND SOME MAY
SPREAD RAPIDLY IF OUTFLOW WINDS DEVELOP.

THE UPPER LEVEL WAVE ON SUNDAY NIGHT AND MONDAY WILL NOT ONLY BRING
THE THREAT OF THUNDERSTORMS BUT ALSO GUSTY POST FRONTAL WINDS IN THE
COLUMBIA BASIN.  CONFIDENCE IS HIGH THAT THE EASTERN COLUMBIA RIVER
GORGE WILL HAVE A MARINE SURGE OF COOLER AIR WITH WINDS AROUND 20-30
MPH LATE SUNDAY AFTERNOON AND EVENING...AND WILL HIGHLIGHT THIS IN
THE RED FLAG WARNING FOR THAT ZONE (FIRE ZONE 639).  A FIRE WEATHER
WATCH IS IN EFFECT FOR THE OREGON PORTION OF THE COLUMBIA BASIN AND
WILL KEEP THIS GOING FOR SUNDAY EVENING THROUGH MONDAY AFTERNOON.
ISOLATED THUNDERSTORMS ARE FORECAST FOR MOST OF THE ZONE WITH THE
BEST PROBABILITY SOUTH OF GRASS VALLEY AND LEXINGTON.  HOWEVER...IF
NEW FIRE STARTS OCCUR...THE GUSTY POST FRONTAL WINDS WILL CREATE A
PROBLEM FOR RAPID FIRE SPREAD. WISTER

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  72 107  71  97 /  20  10  20  20
ALW  76 108  76  98 /  20  10  20  20
PSC  69 111  75 102 /  20  10  20  20
YKM  72 105  75  97 /  10  10  20  10
HRI  71 108  74 100 /  20  10  20  20
ELN  68 106  74  95 /  20  20  20  10
RDM  68  97  60  94 /  30  30  30  10
LGD  64 103  73  92 /  20  20  20  20
GCD  70 105  69  97 /  20  30  30  20
DLS  76 100  74  97 /  20  20  20  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM 11 AM TO 9 PM PDT SUNDAY FOR ORZ639.

     HEAT ADVISORY UNTIL 10 PM PDT THIS EVENING FOR ORZ041-508-510-
     511.

     RED FLAG WARNING UNTIL 4 PM PDT MONDAY FOR ORZ642-644.

     HEAT ADVISORY UNTIL 10 PM PDT SUNDAY FOR ORZ044-049-050-505-507.

     RED FLAG WARNING UNTIL 9 PM PDT SUNDAY FOR ORZ610-611-640.

     FIRE WEATHER WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON
     FOR ORZ641.

WA...RED FLAG WARNING FROM 11 AM TO 9 PM PDT SUNDAY FOR WAZ639-681.

     HEAT ADVISORY UNTIL 10 PM PDT THIS EVENING FOR WAZ024.

     HEAT ADVISORY UNTIL 10 PM PDT SUNDAY FOR WAZ026>029.

&&

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

90/77/77