Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 302156 AAA
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
255 PM PDT Thu Mar 30 2017

.SHORT TERM...Tonight through Saturday night...The upper level
trough axis is almost out of the area, as only Wallowa county is
still under a southerly flow. Some steadier light rain or snow
continues over portions of Wallowa county this afternoon. Elsewhere,
isolated to scattered rain or snow showers are occurring within the
northwest flow behind the trough axis. Winds are generally breezy to
locally windy this afternoon. Winds across the north side of the
Kittitas valley have been running in the 30 to 40 mph range, and
will continue the current advisory. Showers and winds will decrease
this evening as high pressure builds over the area. This high
pressure will be over the region Friday, then shift east Friday
night. Thus expect fair and dry conditions Friday and Friday
evening. A weak system will move across the region late Friday night
through Saturday night. This system looks to only limited amounts of
precip, mainly over the mountains. 90

.LONG TERM...SUNDAY THROUGH THURSDAY...THE EXTENDED PERIOD WILL
START OUT WITH THE FORECAST AREA UNDER A NORTHWEST FLOW PATTERN AS
AN UPPER RIDGE BUILDS OFFSHORE. A SHORTWAVE TROUGH IS PROGGED TO
MOVE THROUGH THE FORECAST AREA IN THE NORTHWEST FLOW SOMETIME LATE
SUNDAY INTO MONDAY. THEREFORE ADDED IN A SLIGHT CHANCE TO LOW END
CHANCE FOR MOUNTAIN RAIN AND SNOW SHOWERS DURING THIS
TIME...ESPECIALLY FOR FAVORED UPSLOPE LOCATIONS. THE LOWER VALLEYS,
BASINS, AND MUCH OF THE FOOTHILLS ZONES SHOULD REMAIN DRY DURING
THIS TIME. COLDER AIR ALOFT WILL MOVE INTO THE REGION SUNDAY NIGHT
AND MONDAY, WITH 850MB TEMPS FALLING TO BETWEEN -1 AND -4C....SNOW
LEVELS WILL BE QUITE LOW, GENERALLY AROUND 3000 FEET ON MONDAY.
OVERNIGHT LOW WILL BE QUITE COLD FOR MONDAY AND TUESDAY
MORNING...RANGING FROM THE LOWER TO MID 30S IN THE COLUMBIA BASIN
AND SURROUNDING VALLEYS, DOWN  INTO THE 20S FOR THE MOUNTAINS AND
HIGHER VALLEYS. THE AFOREMENTIONED OFFSHORE RIDGE WILL BE BUILDING
OVER THE FORECAST AREA FROM MONDAY NIGHT THROUGH EARLY WEDNESDAY.
EVEN THOUGH THE LATEST MODEL GUIDANCE IS INDICATING SOME MID-LEVEL
MOISTURE OVER THE REGION, BELIEVE THIS WILL BE NOTHING MORE THAN
JUST SOME CLOUDS/SPRINKLES AS THE 500MB RIDGE AXIS WILL BE DIRECTLY
OVERHEAD, WHICH IS TYPICALLY VERY DETRIMENTAL TO PRECIPITATION
DEVELOPMENT. THIS WILL MEAN PARTLY TO MOSTLY CLOUDY SKIES AND MAINLY
DRY CONDITIONS FOR THE REGION. DAYTIME HIGHS WILL BE NEAR AVERAGE,
WITH HIGHS IN THE MID 50S TO LOWER 60S, EXCEPT MID 40S TO LOWER 50S
IN THE MOUNTAINS TUESDAY AFTERNOON. LATER WEDNESDAY AND ESPECIALLY
WEDNESDAY NIGHT THE FLOW WILL TURN MORE SOUTHWESTERLY AND MOISTURE
WILL BEGIN TO INCREASE. A DEEP OFFSHORE TROUGH WILL BEGIN TO AFFECT
OUR AREA BY NEXT THURSDAY, AS MOISTURE CONTINUES TO INCREASE AND
TEMPERATURES RISE IN THE WARM SOUTH TO SOUTHWEST FLOW. AT THIS EARLY
JUNCTURE THE LATEST MODEL GUIDANCE IS EVEN INDICTING SOME MODERATE
ATMOSPHERIC INSTABILITY...AND THIS SEEMS REASONABLE BASED ON THE
OVERALL SET UP. DID NOT ADD ANY THUNDERSTORMS INTO THE FORECAST, BUT
THIS TREND WILL NEED TO BE MONITORED IN FUTURE FORECAST UPDATES.
TEMPERATURES ARE FORECAST TO RISE INTO THE MID TO UPPER 60S FOR THE
LOWER ELEVATIONS WITH 50S TO AROUND 60 IN THE MOUNTAINS BY THE
MIDDLE OF NEXT WEEK. 77

&&

.AVIATION...00Z TAFS...VFR CONDITIONS ARE FORECAST TO PREVAIL OVER
THE NEXT 24 HOURS AREAWIDE. ISOLATED SHOWERS ARE INVOF KPDT...KPSC
AND KALW THIS EVENING...EXPECT THESE TO QUICKLY DIMINISH AND END BY
SUNSET. OTHERWISE MOST TERMINALS ARE SEEING SCT TO BKN MID LEVEL
CLOUDS BETWEEN 3500-8000 FEET AGL. CLOUD COVER WILL TEND TO SLOWLY
DECREASE OVERNIGHT AND INTO FRIDAY MORNING. SKIES WILL REMAIN MOSTLY
CLEAR DURING THE DAY FRIDAY. WINDS ARE GUSTY THIS AFTERNOON/EVENING
MOSTLY BETWEEN 15-25KTS WITH GUSTS TO 30-35KT AT KYKM, KDLS, KBDN
AND KRDM. THESE WINDS ARE FORECAST TO SLOWLY DIMINISH BY MID TO LATE
EVENING. WINDS SHOULD DROP BELOW 12KTS FOR MOST LOCATIONS OVERNIGHT
AND REMAIN SO THROUGH THE DAY FRIDAY. 77

&&

.HYDROLOGY...Most area rivers and streams have are cresting or their
stages are beginning to fall. The exception is the Grande Ronde
river at Troy and the John Day river at Service Creek. These two
river points continue to see rises. At this time the Grande Ronde at
Troy is still expected to move above minor flood stage, and will
continue the current flood warning. 90

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  33  54  35  60 /  20   0   0  10
ALW  38  55  42  61 /  20   0   0  20
PSC  34  60  40  66 /  10   0   0  10
YKM  29  61  37  66 /   0   0  10  10
HRI  32  59  36  65 /  10   0   0  10
ELN  30  59  38  60 /   0   0  10  20
RDM  18  52  25  62 /  10   0   0  10
LGD  34  52  30  58 /  20  10   0  20
GCD  29  52  29  61 /  30  10   0  20
DLS  37  63  41  63 /  10   0  10  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...Wind Advisory until 8 PM PDT this evening for WAZ026.

&&

$$

90/77/77



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