951
FXUS66 KPDT 260941
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
241 AM PDT SAT APR 26 2025
SHORT TERM...TODAY THROUGH MONDAY
MAIN FEATURE OVER THE WEEKEND
CONTINUES TO BE A CUTOFF LOW SITUATED WELL TO OUR SOUTH OVER CENTRAL
CALIFORNIA. THIS SYSTEM WAS ORIGINALLY THOUGHT TO BRING AT LEAST
SOME LIGHT PRECIP TO THE EASTERN MOUNTAINS AND CENTRAL OREGON, BUT
THUS FAR, NOT MUCH HAS MATERIALIZED. A BAND OF SHOWERS IS STARTING
TO INCH INTO GRANT COUNTY FROM THE SOUTHEAST, AS THIS CUTOFF LOW
STARTS TO INTRODUCE SOME WRAPAROUND MOISTURE INTO THE REGION, BUT
JUST FROM LOOKING AT CAMS, FORECAST MODELS DO NOT SEEM TO HAVE
INITIALIZED THIS SYSTEM WELL. AS A RESULT, HAVE SCALED BACK POPS
FROM WHAT THE NBM WANTS TO DEPICT, WITH THE CAVEAT THAT A NARROW
AREA FROM WALLOWA COUNTY TO EXTREME SOUTHEASTERN DESCHUTES COUNTY
WILL REMAIN UNDER AT LEAST A SLIGHT CHANCE OF POPS. THE SYNOPTIC SET-
UP STILL FAVORS AN ISOLATED STORM OR TWO SATURDAY AFTERNOON, BUT
CONFIDENCE IS LOW (10-20%) GIVEN, AGAIN, THE POOR GRIP MODELS
CURRENTLY HAVE ON THIS SYSTEM.
GUSTY WINDS, HOWEVER, ARE AT A MUCH HIGHER LEVEL OF CONFIDENCE OF
OCCURRING. ALREADY SEEING SOME BREEZY GAP WINDS THROUGH THE COLUMBIA
RIVER GORGE AND KITTITAS VALLEY, WHICH IS EXPECTED TO CONTINUE
THROUGH SUNDAY AS THIS CUTOFF LOW LEADS TO A DECENT CROSS-CASCADE
PRESSURE GRADIENT. GUIDANCE IS SUGGESTING WINDS JUST BELOW ADVISORY
LEVEL, BUT SUNDAY IN PARTICULAR COULD COME CLOSE TO >45 MPH WIND
GUSTS IN THE KITTITAS VALLEY. ELSEWHERE, GENERALLY EXPECT GUSTS IN
THE 15-25 MPH RANGE, WITH SUNDAY ONCE AGAIN BEING THE WINDIEST DAY
OF THE PERIOD.
POPS FALL OFF BY SUNDAY AFTERNOON, WITH QUIET WEATHER EXPECTED
HEADING INTO MONDAY AS DRY NW FLOW PREVAILS OVERHEAD. EXPECT
SEASONAL TEMPERATURES BEFORE ANOTHER CHANCE OF LIGHT PRECIP ARRIVES
OVERNIGHT MONDAY INTO TUESDAY, AS MODELS INTRODUCE A WEAK SHORTWAVE
INTO THE PACNW.
LONG TERM...TUESDAY THROUGH SATURDAY
ACTIVE WEATHER WILL
BOOKEND A PERIOD DRY AND QUIET CONDITIONS ACROSS THE FORECAST AREA
NEXT WEEK. BREEZY CONDITIONS WITH MAINLY MOUNTAIN AND ADJACENT
FOOTHILL LOCATIONS SEEING SHOWERS DEVELOP WITH PASSING UPPER LEVEL
SYSTEMS TUESDAY AND FRIDAY THROUGH SATURDAY.
ENSEMBLE MEMBERS ARE IN GREAT AGREEMENT IN AN UPPER SHORTWAVE
TROUGH SLIDING ACROSS THE PACNW TUESDAY WITH MAINLY MOUNTAIN
SHOWERS (CONFIDENCE 70-80%). ADJACENT FOOTHILL LOCATIONS,
INCLUDING THE FOOTHILLS OF THE BLUES WILL ALSO SEE AT LEAST A
CHANCE(30-50%) OF SHOWERS AS THEY DEVELOP INTO THE BLUE MOUNTAINS
THROUGH TUESDAY. SURFACE PRESSURE GRADIENTS WILL REMAIN TIGHTENED
ACROSS THE AREA TUESDAY, RESULTING IN BREEZY CONDITIONS(30-40MPH)
THAT WILL DEVELOP IN THE CASCADE GAP AREAS AND WEAKEN (20-30MPH)
AS THEY SPILL INTO PORTIONS OF THE COLUMBIA BASIN AND ADJACENT
VALLEYS (CONFIDENCE 60-80%).
BY TUESDAY NIGHT, ENSEMBLE CLUSTER GUIDANCE SHOWS THE UPPER
SHORTWAVE TROUGH EXITING TO THE EAST, ALLOWING UPPER LEVEL RIDGING
TO BUILD BACK INTO THE PACNW THROUGH THURSDAY. CONDITIONS WILL
REMAIN QUITE DRY AT THE SURFACE, WHILE A WARMING TREND WILL PUSH
THE AFTERNOON TEMPERATURES WELL INTO THE MID 70S TO LOWER 80S
ACROSS THE LOWER ELEVATIONS (CONFIDENCE 60-80%). WINDS WILL ALSO
REMAIN LIGHT TO LOCALLY BREEZY THROUGH THURSDAY.
THURSDAY NIGHT INTO FRIDAY, THERE IS GREAT AGREEMENT AMONGST
ENSEMBLE CLUSTER MEMBERS THAT THE UPPER LEVEL RIDGE OVER THE AREA
WILL BE PUSHED EAST INTO THE ROCKIES BY AN UPPER TROUGH
APPROACHING FROM THE NORTHEAST PACIFIC. AGREEMENT REMAINS GOOD
THAT THE UPPER TROUGH WILL TRAVERSE EAST INTO WESTERN CONUS FRIDAY
INTO SATURDAY, PROVIDING RAIN SHOWER CHANCES ACROSS THE
PACNW(CONFIDENCE 40-60%) AND A COOLING TREND INTO NEXT
WEEKEND(CONFIDENCE 45-60%). THAT SAID, THERE IS DISAGREEMENT
AMONGST EACH OF THE FOUR ENSEMBLE CLUSTER SOLUTIONS IN THE
STRENGTH/TIMING OF THE UPPER TROUGH PASSAGE ACROSS THE AREA,
RESULTING IN LOW CONFIDENCE (20-30%) IN FORECAST DETAILS
(PRECIPITATION AMOUNTS, TEMPERATURES, ETC.) AT THIS TIME.
LAWHORN/82
AVIATION...12Z TAFS
VFR CONDITIONS TO PREVAIL THROUGH THE
PERIOD. A SYSTEM SKIRTING THE AREA TO THE SOUTH WILL CONTINUE TO
PRODUCE SCT-BKN CIGS GENERALLY ABOVE 10KFT AGL, THOUGH SITES
RDM/BDN MAY SEE CIGS DROP TO BETWEEN 6KFT AND 10KFT AGL THROUGH
THIS MORNING. WINDS WILL REMAIN BREEZY, 12-20KTS WITH GUSTS UP TO
30KTS, AT SITE DLS THROUGH THE PERIOD. WINDS AT SITES RDM/BDN WILL
INCREASE TO 10-15KTS AND GUSTS 20-25KTS THIS AFTERNOON, BUT
BECOME LIGHT OVERNIGHT. OTHERWISE, WINDS WILL BE LIGHT, LESS THAN
12KTS, AT ALL OTHER SITES THROUGH THE PERIOD.
PRELIMINARY POINT TEMPS/POPS
PDT 74 45 69 43 / 0 0 0 0
ALW 73 48 69 46 / 0 0 0 0
PSC 80 46 76 44 / 0 0 0 0
YKM 80 46 75 45 / 0 0 0 0
HRI 79 46 73 45 / 0 0 0 0
ELN 75 46 68 45 / 0 0 0 0
RDM 69 35 64 32 / 10 0 0 0
LGD 69 44 65 39 / 30 10 0 0
GCD 66 42 65 37 / 40 10 0 0
DLS 72 44 65 45 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...74
LONG TERM....82
AVIATION...82
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