453 FXUS66 KPDT 271400 AAA AFDPDT AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PENDLETON OR 655 AM PDT SAT JUL 27 2013 UPDATED AVIATION DISCUSSION .SHORT TERM...TODAY THROUGH MONDAY...AN UPPER LOW IS MOVING INTO THE NORTHERN CANADIAN ROCKIES TODAY AND WILL EXTEND A TROUGH DOWN INTO THE PACIFIC NORTHWEST. THIS WILL BRING A DRY AND COOLER WESTERLY FLOW INTO THE PACIFIC NORTHWEST. CONDITIONS WILL BE MORE STABLE, SO DO NOT EXPECT ANY THUNDERSTORMS TO DEVELOP ANYWHERE IN THE FORECAST AREA TODAY. THE COOLER AIR WILL LOWER TEMPERATURES 8 TO 10 DEGREES FROM YESTERDAY. DESPITE THE COOLER AIR, RELATIVE HUMIDITIES WILL ONLY SHOW MODEST INCREASES FROM YESTERDAY. IN ADDITION, DUE TO STRONG PRESSURE GRADIENTS ALONG THE CASCADES, WINDS WILL REMAIN AT 10 TO 20 MPH TODAY WITH 15 TO 25 MPH WINDS IN THE KITTITAS VALLEY AND COLUMBIA GORGE, SO FIRE DANGER WILL REMAIN HIGH. THE WINDS WILL ALSO CONTINUE TO CARRY SMOKE FROM AREA WILDFIRES INTO MUCH OF THE AREA. HAVE KEPT PATCHY SMOKE FROM THE MILE MARKER 28 WILDFIRE IN THE COLUMBIA BASIN AND BLUE MOUNTAIN FOOTHILLS THIS MORNING AND AGAIN TONIGHT. PATCHY SMOKE WILL LINGER THROUGH THE DAY IN THE BICKLETON AREA. MODELS SHOW A WEAK WAVE MOVING THROUGH THE TROUGH SUNDAY AFTERNOON BUT DO NOT SEE ENOUGH MOISTURE, SO HAVE KEPT A DRY FORECAST BUT DID INCREASE POPS SLIGHTLY IN THE WASHINGTON CASCADES WHERE THE CHANCES OF A STRAY THUNDERSTORM ARE GREATEST. TEMPERATURES WILL DROP ANOTHER 2 OR 3 DEGREES SUNDAY TO THE MID 80S TO LOWER 90S WITH 70S AND LOWER 80S IN THE MOUNTAINS. WINDS WILL BE LIGHTER WITH THE AREA AT 5 TO 15 MPH WITH 10 TO 20 MPH IN THE COLUMBIA GORGE AND KITTITAS VALLEY. THE TROUGH WILL EXPAND ON MONDAY WITH THE BULK OF THE LOW MOVING INTO SASKATCHEWAN WHILE A LOBE OF THE LOW WILL RETROGRADE WESTWARD TO AROUND VANCOUVER ISLAND. THIS WILL INDUCE SOME MODEST RIDGING AND SHIFT THE FLOW MORE SOUTHWESTERLY BUT STILL EXPECT DRY CONDITIONS. TEMPERATURES WILL BE A DEGREE OR SO HIGHER THAN SUNDAY WITH GENERALLY LIGHT WINDS. PERRY .LONG TERM...MONDAY NIGHT THROUGH SATURDAY...MONDAY NIGHT AND TUESDAY A MID/UPPER LEVEL TROUGH IN NE PACIFIC NEAR 130W MAINTAINS SOUTHWEST FLOW ALOFT ACROSS FORECAST AREA. SOME MID LEVEL MOISTURE MOVES INTO EASTERN OREGON MONDAY NIGHT BUT CLOUD BASES ARE TOO HIGH TO SUPPORT PRECIPITATION. ON TUESDAY, MODELS HINT AT A MID LEVEL SHORT WAVE BRINGING BETTER MID LEVEL MOISTURE AHEAD OF A WEAK MARINE PUSH INTO FORECAST AREA FOR A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY IN THE BLUE/WALLOWA MOUNTAINS. BY WEDNESDAY, THE UPPER LEVEL LOW WILL COME ASHORE WITH A NEGATIVELY TILTED SHORT WAVE TROUGH PASSING THROUGH THE INTERIOR PACIFIC NORTHWEST AND MID LEVEL FLOW BACKING TO THE SOUTH-SOUTHWEST. SHOWERS AND HIGH BASED THUNDERSTORMS WILL BE POSSIBLE WEDNESDAY AFTERNOON AND EVENING DUE TO DESTABILIZATION CAUSED BY SURFACE HEATING, ELEVATED INSTABILITY AND DYNAMIC LIFT. THURSDAY CONSENSUS IN THE MODELS IS FOR THE MID/UPPER LEVEL TROUGH TO REMAIN OVER THE REGION FOR A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON/EVENING IN THE BLUE MOUNTAINS EASTWARD ACROSS UNION AND WALLOWA COUNTIES. FRIDAY AND SATURDAY MODELS SUGGEST A TROUGH WITH VARYING AMPLITUDE CONTINUES OVER THE PACIFIC NORTHWEST FOR A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ALONG THE EAST SLOPES OF THE CENTRAL WASHINGTON CASCADES AND THE BLUE MOUNTAINS, THE ELKHORN MOUNTAINS AND THE WALLOWA MOUNTAINS. POLAN && .AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL DURING THE NEXT 24 HOURS. THERE WILL BE A SMOKE LAYER AT AROUND 8-10K FEET OVER KPSC AND POSSIBLY OVER KYKM, KPDT AND KALW. EXPECT MOSTLY CLEAR SKIES THROUGHOUT THE NEXT 24 HOURS. WINDS OF 5 TO 15 KTS WITH GUSTS TO 25 KTS CAN BE EXPECTED FROM THE CASCADE EAST SLOPES EASTWARD ACROSS THE LOWER COLUMBIA BASIN INTO THE BLUE MOUNTAIN FOOTHILLS THROUGH TONIGHT. GUSTS THIS AFTERNOON AT KDLS WILL BE 25-30 KTS. POLAN && FIRE WEATHER...WEST WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON AND EVENING ALONG THE EAST SLOPES OF THE CASCADES AND THEN SPILL OUT INTO THE COLUMBIA BASIN. THIS WILL COMBINE WITH VERY LOW RELATIVE HUMIDITIES TO CREATE A CRITICAL FIRE WEATHER DAY IN FIRE WEATHER ZONES 609 610 630 631 AND 675 WHERE RED FLAG WARNINGS ARE IN EFFECT UNTIL 8 PM SATURDAY. WINDS WILL DECREASE OVERNIGHT THEN INCREASE AGAIN SATURDAY AFTERNOON AND EVENING CREATING ANOTHER CRITICAL FIRE WEATHER DAY. && .PRELIMINARY POINT TEMPS/POPS... PDT 91 56 88 55 / 0 0 0 0 ALW 91 61 88 60 / 0 0 0 0 PSC 93 59 91 59 / 0 0 0 0 YKM 90 59 87 60 / 0 0 0 0 HRI 92 58 89 58 / 0 0 0 0 ELN 87 58 86 60 / 0 0 0 0 RDM 88 44 83 43 / 0 0 0 0 LGD 86 53 82 52 / 0 0 0 0 GCD 87 53 82 52 / 0 0 0 0 DLS 86 57 83 57 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING ORZ042-505-506-509. RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING ORZ041-044-503-507-508. WA...RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING WAZ024-028-029-521. RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING WAZ026-027. && THREAT INDEX TODAY : YELLOW SUNDAY : GREEN MONDAY : GREEN GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES. YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT. RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT. FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 83/99/99