124
FXUS66 KPDT 071541
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
841 AM PDT TUE JUL 7 2020
UPDATE
MINOR EDITS THIS MORNING. TROUGH/COLD FRONT CONTINUE TO
PUSH EAST OF THE REGION THIS MORNING, BRINGING AN END TO LINGERING
SHOWERS/STORMS ACROSS WALLOWA COUNTY. IN ITS WAKE, DRY CONDITIONS,
OUTSIDE OF SHOWERS ALONG CASCADE CREST, THEN EXPECTED AS THE FLOW
BECOMES WESTERLY. BREEZY TO WINDY CONDITIONS AND COOLER TEMPS
EXPECTED BEHIND THE FRONT WITH HIGHS UPPER 60S TO LOW 80S. WINDS
WILL LIKELY REACH ADVISORY CRITERIA IN THE KITTITAS VALLEY AND
THE GORGE EAST OF THE DALLES. WEAK TRANSIENT RIDGE PUSHES ACROSS
THE REGION TONIGHT INTO WEDNESDAY. THIS WILL BRING AN END TO
CASCADE SHOWERS AND ALSO BRING SLIGHTLY WARMER TEMPS, LIGHTER
WINDS AND MOSTLY SUNNY SKIES FOR WEDNESDAY. THE DRY AND CALM
CONDITIONS CONTINUE WEDNESDAY NIGHT INTO MOST OF THURSDAY. WARMER
TEMPS EXPECTED THURSDAY (UPPER 70S TO UPPER 80S) AS THE FLOW TURNS
SOUTHWEST AS ANOTHER SHORTWAVE TROUGH/FRONT APPROACHES THE
REGION. MODELS IN BETTER AGREEMENT ON TIMING AND HAVE IT PUSHING
ACROSS THURSDAY NIGHT. NOT A LOT OF MOISTURE WITH THIS SYSTEM AS
THE FLOW REMAINS WEST TO SOUTHWEST, BUT MAY BE ENOUGH MOISTURE AND
INSTABILITY FOR BE A CHANCE OR SHOWERS/STORMS OVER THE EASTERN
MOUNTAINS WITH SHOWERS ALONG THE CASCADE CREST. MANY AREAS OF THE
LOWER COLUMBIA BASIN AND SURROUNDING VALLEYS WILL EXPERIENCE
BREEZY TO WINDY CONDITIONS ONCE AGAIN WITH GUSTS MAINLY AROUND
25-35 MPH...LOCALLY HIGHER.
AVIATION...18Z TAFS
VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD. OUTSIDE OF SOME THIN CIRRUS AND PERHAPS A FEW AFTERNOON
CUMULUS CLOUDS SKIES WILL BE CLEAR. WINDS INCREASE TO
14-22G22-30KTS. COULD BE GUSTS UP TO 35KTS AT DLS AND PDT. WINDS
WILL DECREASE TONIGHT TO AROUND 10KTS OR LESS AND REMAIN LOWER
THROUGH TOMORROW, EXCEPT AT DLS WHICH WILL INCREASE TO 12-18KTS.
PREV DISCUSSION
/ISSUED 310 AM PDT TUE JUL 7 2020/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT. A SHORTWAVE TROUGH AND
SURFACE COLD FRONT MAKING ITS WAY ACROSS THE FORECAST AREA HAVE
BOTH SURFACE AND ELEVATED INSTABILITY FOR SCATTERED THUNDERSTORMS
ACROSS A LARGE PORTION OF THE FORECAST AREA, EVEN FARTHER WEST
THAN PREVIOUSLY ANTICIPATED. PRECIPITATION AMOUNTS HAVE BEEN LESS
THAN 0.10 INCH ALONG WITH REPORTS OF NEW FIRE STARTS. THE TROUGH
IS NOW ALONG THE IDAHO BORDER WITH THUNDERSTORMS TAPERING OFF
BEHIND IT. BY MID-MORNING, ANY SHOWERS WILL BE ALONG THE CASCADES
WHERE A FAIRLY MOIST NORTHWEST FLOW ALOFT IS PRESENT AS WELL AS
THE WALLOWA MOUNTAINS. THE SURFACE COLD FRONT HAS LEFT BREEZY
WINDS IN ITS WAKE, AND THESE WINDS WILL CONTINUE THROUGH THE DAY.
ANOTHER SHORTWAVE TROUGH TRAVELING ALONG THE WA/BC BORDER WILL
ENHANCE THE WINDS IN THE KITTITAS VALLEY WHERE SUSTAINED WINDS
30-40 MPH ARE LIKELY THIS AFTERNOON AND EVENING. THE EASTERN
COLUMBIA RIVER GORGE--MAINLY EAST OF THE DALLES--WILL EXPERIENCE
SIMILAR WINDS. A WIND ADVISORY WILL BE ISSUED FOR THESE TWO ZONES
FOR THIS MORNING'S FORECAST PACKAGE. TEMPERATURES TODAY WILL BE
ABOUT 5-10 DEGREES COOLER THAN YESTERDAY, AND AFTERNOON RHS WILL
BE IN THE 20S TO MID-30S. RED FLAG CONDITIONS ARE NOT EXPECTED,
BUT THERE COULD BE PROBLEMS CONTROLLING SOME FIRES EXPOSED TO
GUSTY WINDS.
TONIGHT THROUGH WEDNESDAY NIGHT CAN BE SUMMARIZED AS A DRY
WESTERLY FLOW ALOFT. SHOWERS ALONG THE CASCADES WILL END
OVERNIGHT. WINDS WILL DECREASE OVERNIGHT, AND WEDNESDAY'S WINDS
WILL NOT BE AS STRONG BUT REMAIN WINDY IN THE TYPICAL AREAS
THROUGH THE CASCADE GAPS.
THE NEXT SHORTWAVE TROUGH ARRIVES THURSDAY EVENING, BUT IT'S BEST
DESCRIBED AS A MOSTLY DRY COLD FRONT. LIMITED MOISTURE AND
INSTABILITY COULD BRING ISOLATED SHOWERS AND THUNDERSTORMS TO THE
NORTHEAST MOUNTAINS, AND THE CASCADES WILL HAVE SCATTERED SHOWERS.
MANY AREAS OF THE LOWER COLUMBIA BASIN AND SURROUNDING VALLEYS
WILL EXPERIENCE BREEZY TO WINDY CONDITIONS ONCE AGAIN WITH GUSTS
MAINLY AROUND 25-35 MPH...LOCALLY HIGHER. WISTER
LONG TERM...FRIDAY THROUGH TUESDAY...MODELS IN GOOD AGREEMENT IN
CONTINUING THE TROUGHY WEATHER PATTERN OVER THE PACIFIC NORTHWEST
THROUGH THE PERIOD. GENERAL SOUTHWEST UPPER LEVEL FLOW WILL CONTINUE
THROUGH SATURDAY AS A PERSISTENT TROUGH REMAINS OFF THE COAST
OF BC. THE FLOW IS EXPECTED TO BECOME MORE ZONAL SUNDAY AND MONDAY
AS THE AFOREMENTIONED TROUGH SLOWLY MOVES EAST. BY TUESDAY, THE
UPPER LEVEL FLOW IS EXPECTED TO BECOME MORE NORTHWESTERLY AS A RIDGE
TRIES TO BUILD OVER THE EASTERN PACIFIC. THERE IS ONE PROMINENT
DIFFERENCE IN THIS SCENARIO TO KEEP AN EYE ON AS THE GFS SHOWS A
WEAK LOW OFF THE COAST OF CALIFORNIA MOVING INLAND AND WEAKENING AS
IT MOVES INTO SOUTHERN OREGON SATURDAY AFTERNOON. THIS COULD FIRE
OFF SOME CONVECTION OVER OUR SOUTHERN CWA SATURDAY AFTERNOON AND
EVENING IF IT PANS OUT; HOWEVER, THE ECMWF DOES NOT SHOW SUCH A
FEATURE. AT THIS TIME WITH LIMITED MOISTURE, WILL KEEP THE WEATHER
DRY OVER MUCH OF THE AREA, EXCEPT A FEW AFTERNOON AND EVENING
SHOWERS OVER THE CASCADES, MAINLY THE WASHINGTON SIDE. DAYTIME
HIGHS WILL REMAIN NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.
EARLE
PRELIMINARY POINT TEMPS/POPS
PDT 76 52 81 54 / 0 0 0 0
ALW 78 55 82 56 / 10 0 0 0
PSC 81 56 85 57 / 0 0 0 0
YKM 76 52 81 55 / 0 0 0 0
HRI 79 55 84 56 / 0 0 0 0
ELN 69 51 77 55 / 0 10 0 0
RDM 72 44 80 47 / 0 0 0 0
LGD 70 49 76 51 / 10 0 0 0
GCD 72 48 79 51 / 10 0 0 0
DLS 72 56 80 59 / 10 10 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING
FOR ORZ041.
WA...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING
FOR WAZ024-026.
84/85/81/84
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page