Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 060433 AAA
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
925 PM PDT SUN JUL 5 2015

.UPDATE...A FEW SHOWERS DRIFTED ACROSS THE DESCHUTES COUNTY LINE
THIS EVENING. OTHERWISE THESE SHOWERS HAVE DISSIPATED WITH THE LOSS
OF DAYTIME HEATING AND THE BULK OF THE ACTIVITY REMAINED SOUTH OF
OUR AREA. SOME SMOKE WAS LINGERING OVER GRANT COUNTY AND THIS WILL
CONTINUE INTO MONDAY MORNING. OTHER THAN A FEW MINOR ADJUSTMENTS TO
OVERNIGHT TEMPS THE PRESENT SHORT TERM DRY FORECAST APPEARS ON TRACK
FOR NOW.

&&

.AVIATION...06Z TAFS. VFR CONDITIONS WILL PERSIST ACROSS ALL TAF
SITES FOR THE NEXT 24 HOURS.

&&

.PREV DISCUSSION... /ISSUED 233 PM PDT SUN JUL 5 2015/

SHORT TERM...TONIGHT THROUGH WEDNESDAY...A VERY WEAK BOUNDARY WHICH
IS EVIDENT IN VISIBLE SATELLITE IMAGERY IS DROPPING THROUGH NORTH-
CENTRAL PORTIONS OF OREGON THIS AFTERNOON...BEHIND THIS BOUNDARY
WINDS ARE SWITCHING TO A MORE NORTH OR NORTHWEST DIRECTION.
OTHERWISE SKIES ARE MAINLY CLEAR NORTH OF A MADRAS-SPRAY-LA GRANDE
LINE WITH MOSTLY CLOUDY SKIES SOUTH. WITH THE ACTIVE WILD FIRES IN
PARTS OF THE AREA EXPECT SOME PATCHY SMOKE TO PERSIST THROUGH THE
NIGHT AND INTO AT LEAST THE DAY ON MONDAY MAINLY IN SOUTHERN GRANT
COUNTY. SPC MESOANALYSIS IS INDICATING SOME MARGINAL INSTABILITY
OVER FAR SOUTHERN DESCHUTES COUNTY WHERE SBCAPE VALUES ARE BETWEEN
250-500 J/KG AND LIFTED INDICES ARE AROUND -2 PRESENTLY. THE LATEST
19Z HRRR MODEL IS INDICATING THE POSSIBILITY OF CONVECTIVE
DEVELOPMENT OVER FAR SOUTH-CENTRAL DESCHUTES COUNTY BETWEEN NOW AND
00Z THIS EVENING...ANY STORMS THAT DO DEVELOP SHOULD DRIFT SOUTH
AND OUT OF OUR CWA BETWEEN 04 TO 07Z THIS EVENING. THIS FITS WELL
WITH THE CURRENT FORECAST. CONDITIONS SHOULD THEN BE DRY AND RATHER
QUIET THROUGH THE OVERNIGHT HOURS AND INTO MONDAY MORNING...WITH
OVERNIGHT LOWS IN THE UPPER 50S TO MID-60S EXCEPT UPPER 40S TO MID-
50S MOUNTAINS. MONDAY MORNING WILL SEE MAINLY CLEAR SKIES NORTH WITH
PARTLY CLOUDY SKIES OVER CENTRAL OREGON AS THE BAND OF CLOUDS LINGERS
OVER THIS AREA. BY AFTERNOON THE LATEST GUIDANCE IS INDICATING AN
INCREASE IN MID-LEVEL MOISTURE AND INSTABILITY OVER MUCH OF CENTRAL
OREGON AND ESPECIALLY DESCHUTES COUNTY. EXPECT AN INCREASE IN CLOUD
COVER DURING THE AFTERNOON OVER CENTRAL OREGON WITH CUMULUS
DEVELOPMENT LIKELY. THE INSTABILITY AND MOISTURE WILL BE GREATEST
OVER DESCHUTES COUNTY WHERE THERE WILL BE A SLIGHT CHANCE TO CHANCE
OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON AND EVENING HOURS.
TUESDAY LOOKS LIKE A VERY SIMILAR SETUP WITH CHANCES FOR AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS MAINLY OVER DESCHUTES COUNTY
ONCE AGAIN. FOR THIS REASON A FIRE WEATHER WATCH HAS BEEN ISSUED FOR
FIRE WEATHER ZONE 611 FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
(SEE FIRE WEATHER SECTION BELOW FOR MORE INFORMATION). HEADING INTO
WEDNESDAY A WEAK DISTURBANCE PASSES BY TO THE NORTHEAST...SWITCHING
THE FLOW TO NORTH OR NORTHEASTERLY OVER MUCH OF THE AREA. THIS SHOULD
LEAD TO DRIER CONDITIONS...HOWEVER STILL CANNOT RULE OUT A SHOWER OR
THUNDERSTORM DURING THE AFTERNOON/EVENING OVER THE MOUNTAINS.
TEMPERATURES WILL REMAIN VERY WARM EACH DAY THROUGH
WEDNESDAY...EXPECT HIGHS MAINLY BETWEEN 98-103 DEGREES IN THE LOWER
ELEVATIONS AND 80S TO LOWER 90S IN THE MOUNTAINS...THIS IS ABOUT 10-
15 DEGREES ABOVE AVERAGE FOR THIS TIME OF YEAR. 77

LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.  UPPER LEVEL LOW
PRESSURE WILL MOVED INTO CENTRAL AND NORTHERN CALIFORNIA WEDNESDAY
NIGHT AND THURSDAY BEFORE MOVING NORTHEAST FRIDAY AND SATURDAY.
THERE WILL BE AN INCREASE IN MID LEVEL MOISTURE AND INSTABILITY OVER
SOUTHEAST OREGON WITH SOME AFTERNOON AND EVENING THUNDERSTORMS. BY
FRIDAY THUNDERSTORM COVERAGE WILL SPREAD TO NORTHEAST OREGON AS THE
LOW MOVES INLAND OVER CALIFORNIA AND NEVADA. SHOWERS AND
THUNDERSTORMS MAY PERSIST OVERNIGHT THURSDAY AND FRIDAY NIGHTS AS
THE LOW OPENS INTO A TROUGH OVER THE PACIFIC NORTHWEST. WINDS WILL
INCREASE FRIDAY AFTERNOON AND MAYBE BREEZY AT TIMES THROUGH
SATURDAY.  THIS SYSTEM IS EXPECTED TO MOVE EAST SATURDAY.
TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD...BUT MUCH
COOLER THAN THE PREVIOUS FEW DAYS. ML

FIRE WEATHER...FIRE WEATHER CONCERNS FOR THIS WEEK WILL BE THE
THREAT OF THUNDERSTORMS.  DETERMINING HOW FAR NORTH THUNDERSTORMS
WILL MIGRATE THIS AFTERNOON THROUGH WEDNESDAY HAS BEEN CHALLENGING.
ISOLATED THUNDERSTORMS ARE FORECAST IN FAR SE DESCHUTES COUNTY LATE
THIS AFTERNOON AND EVENING. CONFIDENCE IS ABOUT 60 PERCENT THAT
STORMS WILL BECOME SCATTERED WITH 10+ STRIKES IN THE DESCHUTES
NATIONAL FOREST ON MONDAY...AND ABOUT 50 PERCENT CONFIDENCE ON
TUESDAY. A FIRE WEATHER WATCH WAS ISSUED FOR THIS AREA (FIRE ZONE
611). THE CONFIDENCE IS NOT AS HIGH FOR THE SISTERS RANGER
DISTRICT...ALTHOUGH LAL 3 IS POSSIBLE THERE AS WELL.  ON
WEDNESDAY...THE THREAT OF ANY THUNDERSTORMS IS MINIMAL AS THE TRACK
OF THE LOW OVER CALIFORNIA TURNS SOUTH.  HOWEVER...THUNDERSTORMS ARE
EXPECTED TO INCREASE IN COVERAGE AND INTENSITY ACROSS CENTRAL AND
EASTERN OREGON LATE THURSDAY THROUGH NEXT WEEKEND WHEN THE LOW OPENS
AND DEVELOPS A BROAD TROUGH WEST OF THE ROCKIES.  THE GOOD NEWS IS
THAT STORMS MAY BRING HEAVY RAIN... ESPECIALLY LATE IN THE WEEK.
WISTER

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  64  97  65  97 /   0   0   0   0
ALW  68  97  71  98 /   0   0   0   0
PSC  65 101  67 102 /   0   0   0   0
YKM  66 100  66 101 /   0   0   0   0
HRI  64 101  67 102 /   0   0   0   0
ELN  60  99  65  99 /   0   0   0  10
RDM  57  94  58  95 /   0  10  10  10
LGD  55  91  57  92 /   0   0   0  10
GCD  56  95  58  98 /   0  10  10  10
DLS  68 101  68 100 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
     FOR ORZ611.

WA...NONE.
&&

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

$$

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