Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 041120 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
420 AM PDT SAT JUL 4 2015

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH MONDAY...AN UPPER RIDGE WILL CONTINUE
TODAY SOUTHEAST OF THE FORECAST AREA OVER THE GREAT BASIN AND THERE
WILL BE A NORTHWEST FLOW OVER THE CWA NORTH OF THE RIDGE. THIS WILL
KEEP HIGH HEIGHTS AND VERY WARM 850 MB TEMPERATURES OVER THE REGION
TODAY AND WILL RESULT IN ANOTHER HOT DAY FOR THE FORECAST AREA WITH
HIGHS AROUND 100 IN THE LOWER ELEVATIONS AND 80S TO LOWER 90S IN THE
MOUNTAINS. THESE TEMPERATURES HOWEVER DO NOT MEET HEAT ADVISORY
CRITERIA. SURFACE PRESSURE GRADIENTS WILL TIGHTEN UP ALONG THE
CASCADE EAST SLOPES THIS AFTERNOON. THIS WILL CAUSE INCREASING WINDS
ALONG THE CASCADE EAST SLOPES AND ADJACENT VALLEYS AND PLATEAUS.
THIS COMBINED WITH LOW RELATIVE HUMIDITY AND HOT TEMPERATURES WILL
CONTINUE TO WARRANT RED FLAG WARNINGS FOR CRITICAL FIRE WEATHER
CONDITIONS IN THE FIRE WEATHER ZONES JUST EAST OF THE CASCADES.
ELSEWHERE WINDS WILL BE MOSTLY LIGHT TODAY. ON SUNDAY WINDS WILL
REMAIN LIGHT IN ALL AREAS WHICH WILL REDUCE THE THREAT OF CRITICAL
FIRE WEATHER CONDITIONS. RED FLAG WARNINGS WILL REMAIN IN EFFECT
UNTIL 9 AM SUNDAY MORNING FOR PORTIONS OF THE WASHINGTON YAKIMA AND
KITTITAS VALLEYS AND A PORTION OF THE LOWER COLUMBIA BASIN ADJACENT
TO THESE VALLEYS. TEMPERATURES WILL BE ANOTHER COUPLE DEGREES COOLER
ON SUNDAY. THE UPPER RIDGE SOUTHEAST OF THE CWA WILL NUDGE BACK TO
THE NORTHWEST ON MONDAY RESULTING IN WARMING TEMPERATURES BY A
DEGREE OR TWO...BUT NOT ENOUGH FOR A HEAT ADVISORY ANYWHERE IN THE
CWA. TEMPERATURES WILL THEN REMAIN NEARLY STEADY GOING INTO THE
EXTENDED FORECAST PERIOD. 88

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT...UPPER LEVEL LOW OFF
THE CALIFORNIA COAST WILL SLOWLY PROGRESS EASTWARD THROUGH THE LONG
TERM PERIOD. AN UPPER LEVEL RIDGE WILL PERSIST TO THE SOUTHEAST. THE
LOW WILL BRING MID LEVEL MOISTURE AND INSTABILITY TO SOUTHEASTERN
OREGON. THIS MOISTURE AND INSTABILITY MAY BRING AFTERNOON AND
EVENING THUNDERSTORMS TO THE SOUTHERN BORDER OF THE CWA FROM CENTRAL
OREGON TO GRANT COUNTY. DRY WEST TO NORTHWEST FLOW WILL KEEP DRY
CONDITIONS WITH MOSTLY CLEAR SKIES IN OTHER AREAS. BY THURSDAY
COVERAGE WILL SPREAD TO NORTHEAST OREGON AS THE LOW MOVES INLAND AND
UPPER LEVEL FLOW CHANGES TO SOUTHERLY OVER THE REST OF EASTERN
OREGON AND WASHINGTON. AS THE LOW EXITS THE AREA FRIDAY
NIGHT...EXPECT DRY WESTERLY FLOW TO SET IN AND PERHAPS AN INCREASE
IN WINDS. GFS INDICATES MUCH COOLER AIR AND HIGHER SURFACE
HUMIDITIES POSSIBLE WITH THIS WESTERLY FLOW.  COONFIELD

&&

.AVIATION...12Z TAFS...VFR CONDITIONS WILL OCCUR OVER THE NEXT 24
HOURS WITH SCT CIRRUS OVER KBDN AND KRDM FROM THUNDERSTORM BLOWOFF
AND INCREASING UPPER LEVEL MOISTURE BROUGHT IN FROM THE SOUTH. WINDS
BTWN 5 TO 15 KTS WILL OCCUR OVERNIGHT TONIGHT BECOMING NORTHERLY 10
TO 20 KTS AFT 04/21Z DUE TO PASSING SHORTWAVE TROUGH. 76

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT 100  65  97  64 /   0   0   0   0
ALW 100  71  96  69 /   0   0   0   0
PSC 102  68  99  66 /   0   0   0   0
YKM  97  68  93  66 /   0   0   0   0
HRI 101  66  98  65 /   0   0   0   0
ELN 101  65  97  62 /   0   0   0   0
RDM  95  57  93  57 /   0   0   0   0
LGD  94  59  91  57 /   0   0   0   0
GCD  98  59  95  57 /   0   0   0   0
DLS  99  69  99  69 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ610-639>641.

WA...RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR WAZ639.

     RED FLAG WARNING UNTIL 9 AM PDT SUNDAY FOR WAZ675.

&&

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

$$

88/76/76



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