Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 311005
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
300 AM PDT FRI JUL 31 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...AN UPPER LEVEL RIDGE OF
HIGH PRESSURE WILL CONTINUE OVER THE REGION THROUGH THIS PERIOD.
THIS RIDGE WILL BEGIN TO SLOWLY WEAKEN SUNDAY NIGHT. HIGH
TEMPERATURES WILL BE HOT ACROSS THE REGION AGAIN TODAY WITH A NUMBER
OF AREAS REACHING TO NEAR RECORD VALUES. HIGH TEMPS SATURDAY WILL
AGAIN BE HOT THOUGH THEY SHOULD BE A DOWN A DEGREE OR TWO AT MOST
LOCATIONS. WILL CONTINUE THE CURRENT HEAT ADVISORIES ACROSS PORTIONS
OF THE COLUMBIA BASIN DESPITE THAT OVERNIGHT LOW TEMPS WILL OFFER
SOME RELIEF, ESPECIALLY TONIGHT (FRIDAY NIGHT). SUBTROPICAL MOISTURE
WILL CONTINUE TO TRY TO WORK INTO THE REGION DURING THIS PERIOD.
OVERALL, THE UPPER LEVEL FLOW SHOULD GENERALLY SUPPRESS THE DEEPER
MOISTURE SOUTH OUR AREA, ACROSS SOUTHWEST AND SOUTH-CENTRAL OREGON.
STILL COULD SEE A STRAY THUNDERSTORM DEVELOP OVER SOUTHWESTERN AND
WESTERN SECTIONS OF DESCHUTES COUNTY LATE AFTERNOON INTO THE EVENING
EACH DAY. 90

.LONG TERM...SUNDAY THROUGH THURSDAY...MID/UPPER LEVEL RIDGE OF HIGH
PRESSURE AMPLIFYING ON SUNDAY ALLOWING MID LEVEL MONSOON MOISTURE TO
ENTER CENTRAL OREGON AND EASTERN CENTRAL OREGON SUNDAY AFTERNOON.
THE MONSOON MOISTURE REACHES NORTHEAST OREGON BY SUNDAY EVENING. THIS
SETS THE STAGE FOR MARGINAL INSTABILITY AND A SLIGHT CHANCE OF
THUNDERSTORMS SUNDAY AFTERNOON/EVENING WITH A FEW STORMS POSSIBLY
DEVELOPING IN THE BLUE MOUNTAINS BEFORE SUN SET. SUNDAY NIGHT
THROUGH MONDAY NIGHT THE MONSOON MOISTURE CONTINUES THUS KEEPING A
SLIGHT CHANCE OF AFTERNOON/EVENING THUNDERSTORMS IN CENTRAL OREGON
AND NORTHEAST OREGON MOUNTAINS ON MONDAY. TUESDAY AND WEDNESDAY A
COUPLE OF DISTURBANCE PINWHEEL AROUND A LONG WAVE TROUGH SOUTH OF
VANCOUVER ISLAND AND MOVE ACROSS THE REGION WITH ASSOCIATED DYNAMIC
FORCING TRIGGERING THUNDERSTORMS IN EASTERN OREGON. THURSDAY THE
NEGATIVELY TILTED LONG WAVE TROUGH SWINGS INLAND AND ACROSS THE
INTERIOR PACIFIC NORTHWEST FOR A SLIGHT CHANCE OF THUNDERSTORMS. THE
DYNAMIC WILL TRIGGER SOME ISOLATED NOCTURNAL THUNDERSTORMS IN THE
BLUE MOUNTAINS WEDNESDAY NIGHT.  POLAN

&&

.AVIATION...12Z TAFS...VFR CONDITIONS WITH LIGHT WINDS ARE EXPECTED
THROUGH THE NEXT 24 HOURS.  POLAN

&&

.FIRE WEATHER...PREVIOUS DISCUSSION...HIGH PRESSURE OVER THE AREA
WILL CONTINUE TO MAKE CONDITIONS HOT AND DRY THROUGH THE WEEKEND.
MIN RH`S WILL LIKELY BE BELOW 20 PERCENT ACROSS ALL FIRE WEATHER
ZONES...WITH SEVERAL LOWER ELEVATIONS FALLING BELOW 10 PERCENT.
WINDS TOMORROW AFTERNOON ARE FORECAST TO BE JUST STRONG ENOUGH
ACROSS OR/WA639 TO CREATE CRITICAL FIRE WEATHER CONDITIONS.

IN ADDITION THE HAINES THREAT WILL BE MODERATE TO HIGH OVER THE NEXT
FEW DAYS. MODELS CURRENTLY SUPPORT A HIGH HAINES INDEX THROUGH
SATURDAY OVER OR640 AND OR642. DUE TO THE WEST FORK FIRE MOP UP THAT
CONTINUES HAVE DECIDED TO ISSUE A RED FLAG WARNING FROM TODAY
THROUGH SATURDAY EVENING FOR THESE ZONES.

MODELS ALSO HINT AT A HIGH HAINES FOR THE WA 640 AND 643 ZONE OVER
THE BLUE CREEK FIRE AS WELL FOR TOMORROW AND SATURDAY. CONFIDENCE IS
NOT HIGH ENOUGH YET FOR THESE AREAS...SO WILL STICK WITH A WATCH.

LOOKS LIKE THUNDERSTORM CHANCES AND COVERAGE WILL BE AT THEIR BEST
FROM SUNDAY ON INTO THE MIDDLE OF NEXT WEEK. THERE IS STILL A SLIGHT
POSSIBILITY SATURDAY OVER CENTRAL OREGON...BUT THE STORMS SHOULD BE
ISOLATED.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT 104  64 103  65 /   0   0   0   0
ALW 105  69 104  70 /   0   0   0   0
PSC 105  60 104  64 /   0   0   0   0
YKM 101  62 100  65 /   0   0   0   0
HRI 105  61 104  63 /   0   0   0   0
ELN 103  59 101  62 /   0   0   0   0
RDM 102  54 100  56 /  10  10  10  10
LGD  98  50  98  54 /   0   0  10  10
GCD 104  55 103  56 /  10  10  10  10
DLS 106  65 102  67 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM 10 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR ORZ639.

     HEAT ADVISORY UNTIL 9 PM PDT SATURDAY FOR ORZ041-044-507.

     RED FLAG WARNING UNTIL 10 PM PDT SATURDAY FOR ORZ640-642.

WA...FIRE WEATHER WATCH FROM 10 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR WAZ639.

     HEAT ADVISORY UNTIL 9 PM PDT SATURDAY FOR WAZ024-027>029.

     FIRE WEATHER WATCH FROM 1 PM PDT THIS AFTERNOON THROUGH SUNDAY
     EVENING FOR WAZ641-643.

&&

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

$$

90/99/99/89


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